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Sample records for average interplanetary magnetic

  1. Interplanetary magnetic field data book

    NASA Technical Reports Server (NTRS)

    King, J. H.

    1975-01-01

    An interplanetary magnetic field (IMF) data set is presented that is uniform with respect to inclusion of cislunar IMF data only, and which has as complete time coverage as presently possible over a full solar cycle. Macroscale phenomena in the interplanetary medium (sector structure, heliolatitude variations, solar cycle variations, etc.) and other phenomena (e.g., ground level cosmic-ray events) for which knowledge of the IMF with hourly resolution is necessary, are discussed. Listings and plots of cislunar hourly averaged IMP parameters over the period November 27, 1963, to May 17, 1974, are presented along with discussion of the mutual consistency of the IMF data used herein. The magnetic tape from which the plots and listings were generated, which is available from the National Space Science Data Center (NSSDC), is also discussed.

  2. Average high latitude magnetic field: Variations with interplanetary sector and with season. 2: Comparison of disturbance levels and discussion of ionospheric currents

    NASA Technical Reports Server (NTRS)

    Langel, R. A.; Brown, N.

    1973-01-01

    Average high latitude magnetic field data from northern observatories are examined for three ranges of magnetic disturbance level, Kp = 1 minus to 1+,2 minus to 3+, and or = 4 minus. Except for 0-8h MLT, 55-78 deg invariant latitude, during away interplanetary magnetic field sectors, the variations between season and sector have the the same characteristics at all Kp ranges. Because the amplitude of sector differences is much larger at sunlit local times than in the midnight sector, it is concluded that the current system of Svalgaard (1973) is not adequate to describe the sector variations in magnetic disturbance, other current systems are discussed briefly. The disturbance morphology and seasonal variation at all Kp levels confirms the results of previous studies which indicate that latitudinally broad current systems and non-ionospheric sources are present in addition to latitudinally narrow electrojet currents. Comparison of data between Kp levels indicates that the Harang discontinuity shifts toward earlier MLT with increasing Kp level.

  3. Magnetic Storms and Associated Interplanetary Phenomena

    NASA Technical Reports Server (NTRS)

    Tsurutani, B. T.; Gonzalez, W. D.

    1996-01-01

    The physical mechanism for energy transfer from the solar wind to the magnetosphere is magnetic reconnection between the interplanetary field and the Earth's field. From Intro: It is the purpose of this paper to review the sources of such interplanetary magnetic fields distinguishing between the solar maximum and the declining phases of the solar cycle.

  4. Magnetic sails and interplanetary travel

    SciTech Connect

    Zubrin, R.M.; Andrews, D.G.

    1989-01-01

    A new concept, the magnetic sail, or 'magsail' is proposed which propels spacecraft by using the magnetic field generated by a loop of superconducting cable to deflect interplanetary or interstellar plasma winds. The performance of such a device is evaluated using both a plasma particle model and a fluid model, and the results of a series of investigations are presented. It is found that a magsail sailing on the solar wind at a radius of one astronautical unit can attain accelerations on the order of 0.01 m/sec squared, much greater than that available from a conventional solar lightsail, and also greater than the acceleration due to the sun's gravitational attraction. A net tangential force, or 'lift' can also be generated. Lift to drag ratios of about 0.3 appear attainable. Equations are derived whereby orbital transfers using magsail propulsion can be calculated analytically.

  5. Interplanetary magnetic field and geomagnetic Dst variations.

    NASA Technical Reports Server (NTRS)

    Patel, V. L.; Desai, U. D.

    1973-01-01

    The interplanetary magnetic field has been shown to influence the ring current field represented by Dst. Explorer 28 hourly magnetic field observations have been used with the hourly Dst values. The moderate geomagnetic storms of 60 gammas and quiet-time fluctuations of 10 to 30 gammas are correlated with the north to south change of the interplanetary field component perpendicular to the ecliptic. This change in the interplanetary field occurs one to three hours earlier than the corresponding change in the Dst field.

  6. Interplanetary stream magnetism - Kinematic effects

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Barouch, E.

    1976-01-01

    The particle density and the magnetic-field intensity and direction are calculated for volume elements of the solar wind as a function of the initial magnetic-field direction and the initial speed gradient. It is assumed that the velocity is constant and radial. These assumptions are approximately valid between about 0.1 and 1.0 AU for many streams. Time profiles of the particle density, field intensity, and velocity are calculated for corotating streams, neglecting effects of pressure gradients. The compression and rarefaction of the magnetic field depend sensitively on the initial field direction. By averaging over a typical stream, it is found that the average radial field intensity is inversely proportional to the square of the heliocentric distance, whereas the average intensity in the direction of the planets' motion does not vary in a simple way, consistent with deep space observations. Changes of field direction may be very large, depending on the initial angle; but when the initial angle at 0.1 AU is such that the base of the field line corotates with the sun, the spiral angle is the preferred direction at 1 AU. The theory is also applicable to nonstationary flows.

  7. Interplanetary Magnetic Field Guiding Relativistic Particles

    NASA Technical Reports Server (NTRS)

    Masson, S.; Demoulin, P.; Dasso, S.; Klein, K. L.

    2011-01-01

    The origin and the propagation of relativistic solar particles (0.5 to few Ge V) in the interplanetary medium remains a debated topic. These relativistic particles, detected at the Earth by neutron monitors have been previously accelerated close to the Sun and are guided by the interplanetary magnetic field (IMF) lines, connecting the acceleration site and the Earth. Usually, the nominal Parker spiral is considered for ensuring the magnetic connection to the Earth. However, in most GLEs the IMF is highly disturbed, and the active regions associated to the GLEs are not always located close to the solar footprint of the nominal Parker spiral. A possible explanation is that relativistic particles are propagating in transient magnetic structures, such as Interplanetary Coronal Mass Ejections (ICMEs). In order to check this interpretation, we studied in detail the interplanetary medium where the particles propagate for 10 GLEs of the last solar cycle. Using the magnetic field and the plasma parameter measurements (ACE/MAG and ACE/SWEPAM), we found widely different IMF configurations. In an independent approach we develop and apply an improved method of the velocity dispersion analysis to energetic protons measured by SoHO/ERNE. We determined the effective path length and the solar release time of protons from these data and also combined them with the neutron monitor data. We found that in most of the GLEs, protons propagate in transient magnetic structures. Moreover, the comparison between the interplanetary magnetic structure and the interplanetary length suggest that the timing of particle arrival at Earth is dominantly determined by the type of IMF in which high energetic particles are propagating. Finally we find that these energetic protons are not significantly scattered during their transport to Earth.

  8. Coronal and interplanetary magnetic field models

    NASA Astrophysics Data System (ADS)

    Schatten, Kenneth H.

    1999-06-01

    We provide an historical perspective of coronal and interplanetary field models. The structure of the interplanetary medium is controlled by the coronal magnetic field from which the solar wind emanates. This field has been described with ``Source Surface'' (SS) and ``Heliospheric Current Sheet'' (HCS) models. The ``Source Surface'' model was the first to open the solar field into interplanetary space using volumetric coronal currents, which were a ``source'' for the IMF. The Heliospheric Current Sheet (HCS) model provided a more physically realistic solution. The field structure was primarily a dipole, however, without regard to sign, the shape appeared to be a monopole pattern (uniform field stress). Ulysses has observed this behavior. Recently, Sheeley and Wang have utilized the HCS field model to calculate solar wind structures fairly accurately. Fisk, Schwadron, and Zurbuchen have investigated small differences from the SS model. These differences allow field line motions reminiscent of a ``timeline'' or moving ``streakline'' in a flow field, similar to the smoke pattern generated by a skywriting plane. Differences exist in the magnetic field geometry, from the Parker ``garden hose'' model affecting both the ``winding angle'' as well as the amount of latitudinal ``wandering.''

  9. Fractal structure of the interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Klein, L. W.

    1985-01-01

    Under some conditions, time series of the interplanetary magnetic field strength and components have the properties of fractal curves. Magnetic field measurements made near 8.5 AU by Voyager 2 from June 5 to August 24, 1981 were self-similar over time scales from approximately 20 sec to approximately 3 x 100,000 sec, and the fractal dimension of the time series of the strength and components of the magnetic field was D = 5/3, corresponding to a power spectrum P(f) approximately f sup -5/3. Since the Kolmogorov spectrum for homogeneous, isotropic, stationary turbulence is also f sup -5/3, the Voyager 2 measurements are consistent with the observation of an inertial range of turbulence extending over approximately four decades in frequency. Interaction regions probably contributed most of the power in this interval. As an example, one interaction region is discussed in which the magnetic field had a fractal dimension D = 5/3.

  10. An interplanetary magnetic field ensemble at 1 AU

    NASA Technical Reports Server (NTRS)

    Matthaeus, W. H.; Goldstein, M. L.; King, J. H.

    1985-01-01

    A method for calculation ensemble averages from magnetic field data is described. A data set comprising approximately 16 months of nearly continuous ISEE-3 magnetic field data is used in this study. Individual subintervals of this data, ranging from 15 hours to 15.6 days comprise the ensemble. The sole condition for including each subinterval in the averages is the degree to which it represents a weakly time-stationary process. Averages obtained by this method are appropriate for a turbulence description of the interplanetary medium. The ensemble average correlation length obtained from all subintervals is found to be 4.9 x 10 to the 11th cm. The average value of the variances of the magnetic field components are in the approximate ratio 8:9:10, where the third component is the local mean field direction. The correlation lengths and variances are found to have a systematic variation with subinterval duration, reflecting the important role of low-frequency fluctuations in the interplanetary medium.

  11. Interplanetary magnetic clouds at 1 AU

    NASA Technical Reports Server (NTRS)

    Klein, L. W.; Burlaga, L. F.

    1981-01-01

    Magnetic clouds are defined as regions with a radial dimension approximately 0.25 AU (at 1 AU) in which the magnetic field strength is high and the magnetic field direction changes appreciably by means of rotation of one component of B nearly parallel to a plane. The magnetic field geometry in such a magnetic cloud is consistent with that of a magnetic loop, but it cannot be determined uniquely. Forty-five clouds were identified in interplanetary data obtained near Earth between 1967 and 1978; at least one cloud passed the Earth every three months. Three classes of clouds were identified, corresponding to the association of a cloud with a shock, a stream interface, or a CME. There are approximately equal numbers of clouds in each class, and the three types of clouds might be different manifestations of a coronal transient. The magnetic pressure inside the clouds is higher than the ion pressure and the sum is higher than the pressure of the material outside of the cloud.

  12. Large-scale properties of the interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Schatten, K. H.

    1972-01-01

    Early theoretical work of Parker is presented along with the observational evidence supporting his Archimedes spiral model. Variations present in the interplanetary magnetic field from the spiral angle are related to structures in the solar wind. The causes of these structures are found to be either nonuniform radial solar wind flow or the time evolution of the photospheric field. Coronal magnetic models are related to the connection between the solar magnetic field and the interplanetary magnetic field. Direct extension of the solar field-magnetic nozzle controversy is discussed along with the coronal magnetic models. Effects of active regions on the interplanetary magnetic field is discussed with particular reference to the evolution of interplanetary sectors. Interplanetary magnetic field magnitude variations are shown throughout the solar cycle. The percentage of time the field magnitude is greater than 10 gamma is shown to closely parallel sunspot number. The sun's polar field influence on the interplanetary field and alternative views of the magnetic field structure out of the ecliptic plane are presented. In addition, a variety of significantly different interplanetary field structures are discussed.

  13. Magnetic holes in the solar wind. [(interplanetary magnetic fields)

    NASA Technical Reports Server (NTRS)

    Turner, J. M.; Burlaga, L. F.; Ness, N. F.; Lemaire, J. F.

    1976-01-01

    An analysis is presented of high resolution interplanetary magnetic field measurements from the magnetometer on Explorer 43 which showed that low magnetic field intensities in the solar wind at 1 AU occur as distinct depressions or 'holes'. These magnetic holes are new kinetic-scale phenomena, having a characteristic dimension on the order of 20,000 km. They occurred at a rate of 1.5/day in the 18-day time span (March 18 to April 6, 1971) that was analyzed. Most of the magnetic holes are characterized by both a depression in the absolute value of the magnetic field, and a change in the magnetic field direction; some of these are possibly the result of magnetic merging. However, in other cases the magnetic field direction does not change; such holes are not due to magnetic merging, but might be a diamagnetic effect due to localized plasma inhomogeneities.

  14. Heliocentric distance dependence of the interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Behannon, K. W.

    1977-01-01

    Recent and ongoing planetary missions have provided extensive observations of the variations of the Interplanetary Magnetic Field (IMF) both in time and with heliocentric distance from the sun. Large time variations in both the IMF and its fluctuations were observed. These are produced predominantly by dynamical processes in the interplanetary medium associated with stream interactions. Magnetic field variations near the sun are propagated to greater heliocentric distances, also contributing to the observed variablity of the IMF. Temporal variations on a time-scale comparable to or less than the corotation period complicate attempts to deduce radial gradients of the field and its fluctuations from the various observations. However, recent measurements inward to 0.46 AU and outward to 5 AU suggest that the radial component of the field on average decreases approximately as r to the minus second power, while the azimuthal component decreases more rapidly than the r to the minum first power dependence predicted by simple theory. This, and other observations, are discussed.

  15. Solar sources of the interplanetary magnetic field and solar wind

    NASA Technical Reports Server (NTRS)

    Levine, R. H.; Altschuler, M. D.; Harvey, J. W.

    1977-01-01

    Open magnetic field lines, those which extend from the solar photosphere to interplanetary space, are traced in the current-free (potential field) approximation using measured photospheric fields as a boundary condition. It is found that (1) only a relatively small fraction of the photospheric area connects via open field lines to the interplanetary magnetic field; (2) those photospheric areas which do contribute open field lines lie beneath coronal holes and within the boundaries of the holes as projected onto the photosphere or else between loop systems of an active region; (3) the interplanetary magnetic field in the plane of the sun's equator, essentially the field in the ecliptic plane, may connect to photospheric regions of high latitude; and (4) the fastest solar wind streams are correlated with those magnetic flux tubes which expand least in cross-sectional area over the distance between the photosphere and the coronal height where the solar wind begins.

  16. Cusp proton signatures and the interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Reiff, P. H.; Spiro, R. W.; Burch, J. L.

    1980-01-01

    The variation of proton average energy with latitude in the cusp has been suggested as an indicator of the means of particle entry. If magnetic merging is the principal means of particle entry, the proton average energy should fall with increasing latitude; if diffusion is the principal means, the average energy should first fall and then briefly rise as a function of latitude, showing a 'V' signature. In the present work, 60 selected cusp passes of the AE-D satellite for which IMP-J interplanetary or magnetosheath magnetic-field data were available were examined. About one-third of these passes showed clear or likely merging-type energy dispersions; a third showed clear or likely V-type energy dispersions, and a third showed unclear or no energy dispersions. The results are strongly correlated with the IMF - the merging signatures are associated with southward IMF and the V signatures with northward IMF. Unclear cases are associated with unsteady or weakly northward IMF.

  17. The regular interplanetary magnetic field during the 1980s

    NASA Technical Reports Server (NTRS)

    Kalinin, M. S.; Krainev, M. B.

    1995-01-01

    The regular magnetic field in the interplanetary space for 1980-1990 is calculated using the results of the Hoeksema-Zhao model for the radial magnetic field on the source surface. The unsteady radial component gives birth to the latitudinal and longitudinal components which could be of importance for, e.g., the galactic cosmic ray modulation.

  18. How are Forbush decreases related to interplanetary magnetic field enhancements?

    NASA Astrophysics Data System (ADS)

    Arunbabu, K. P.; Antia, H. M.; Dugad, S. R.; Gupta, S. K.; Hayashi, Y.; Kawakami, S.; Mohanty, P. K.; Oshima, A.; Subramanian, P.

    2015-08-01

    Aims: A Forbush decrease (FD) is a transient decrease followed by a gradual recovery in the observed galactic cosmic ray intensity. We seek to understand the relationship between the FDs and near-Earth interplanetary magnetic field (IMF) enhancements associated with solar coronal mass ejections (CMEs). Methods: We used muon data at cutoff rigidities ranging from 14 to 24 GV from the GRAPES-3 tracking muon telescope to identify FD events. We selected those FD events that have a reasonably clean profile, and magnitude >0.25%. We used IMF data from ACE/WIND spacecrafts. We looked for correlations between the FD profile and that of the one-hour averaged IMF. We wanted to find out whether if the diffusion of high-energy protons into the large scale magnetic field is the cause of the lag observed between the FD and the IMF. Results: The enhancement of the IMF associated with FDs occurs mainly in the shock-sheath region, and the turbulence level in the magnetic field is also enhanced in this region. The observed FD profiles look remarkably similar to the IMF enhancement profiles. The FDs typically lag behind the IMF enhancement by a few hours. The lag corresponds to the time taken by high-energy protons to diffuse into the magnetic field enhancement via cross-field diffusion. Conclusions: Our findings show that high-rigidity FDs associated with CMEs are caused primarily by the cumulative diffusion of protons across the magnetic field enhancement in the turbulent sheath region between the shock and the CME. Appendices are available in electronic form at http://www.aanda.org

  19. INTERPLANETARY MAGNETIC FLUX DEPLETION DURING PROTRACTED SOLAR MINIMA

    SciTech Connect

    Connick, David E.; Smith, Charles W.; Schwadron, Nathan A. E-mail: Charles.Smith@unh.edu

    2011-01-20

    We examine near-Earth solar wind observations as assembled within the Omni data set over the past 15 years that constitute the latest solar cycle. We show that the interplanetary magnetic field continues to be depleted at low latitudes throughout the protracted solar minimum reaching levels below previously predicted minima. We obtain a rate of flux removal resulting in magnetic field reduction by 0.5 nT yr{sup -1} at 1 AU when averaged over the years 2005-2009 that reduces to 0.3 nT yr{sup -1} for 2007-2009. We show that the flux removal operates on field lines that follow the nominal Parker spiral orientation predicted for open field lines and are largely unassociated with recent ejecta. We argue that the field line reduction can only be accomplished by ongoing reconnection of nominally open field lines or very old closed field lines and we contend that these two interpretations are observationally equivalent and indistinguishable.

  20. SIGNATURES OF MAGNETIC RECONNECTION AT BOUNDARIES OF INTERPLANETARY SMALL-SCALE MAGNETIC FLUX ROPES

    SciTech Connect

    Tian Hui; Yao Shuo; Zong Qiugang; Qi Yu; He Jiansen

    2010-09-01

    The interaction between interplanetary small-scale magnetic flux ropes and the magnetic field in the ambient solar wind is an important topic in the understanding of the evolution of magnetic structures in the heliosphere. Through a survey of 125 previously reported small flux ropes from 1995 to 2005, we find that 44 of them reveal clear signatures of Alfvenic fluctuations and thus classify them as Alfven wave trains rather than flux ropes. Signatures of magnetic reconnection, generally including a plasma jet of {approx}30 km s{sup -1} within a magnetic field rotational region, are clearly present at boundaries of about 42% of the flux ropes and 14% of the wave trains. The reconnection exhausts are often observed to show a local increase in the proton temperature, density, and plasma beta. About 66% of the reconnection events at flux rope boundaries are associated with a magnetic field shear angle larger than 90{sup 0} and 73% of them reveal a decrease of 20% or more in the magnetic field magnitude, suggesting a dominance of anti-parallel reconnection at flux rope boundaries. The occurrence rate of magnetic reconnection at flux rope boundaries through the years 1995-2005 is also investigated and we find that it is relatively low around the solar maximum and much higher when approaching solar minima. The average magnetic field depression and shear angle for reconnection events at flux rope boundaries also reveal a similar trend from 1995 to 2005. Our results demonstrate for the first time that boundaries of a substantial fraction of small-scale flux ropes have properties similar to those of magnetic clouds, in the sense that both of them exhibit signatures of magnetic reconnection. The observed reconnection signatures could be related either to the formation of small flux ropes or to the interaction between flux ropes and the interplanetary magnetic fields.

  1. Further study of the theta component of the interplanetary magnetic field.

    NASA Technical Reports Server (NTRS)

    Rosenberg, R. L.; Coleman, P. J., Jr.; Ness, N. F.

    1973-01-01

    Measurements of the interplanetary magnetic field taken with Imp 3, Pioneer 6, and Explorer 34 constitute a large portion of the data available at low and moderate solar activity and provide nearly continuous coverage from mid-1965 through 1966 without radial effects. Study of these observations provides further evidence for the following B sub theta effect initially discovered with Mariners 2, 4, and 5. At low or moderate solar activity, the mean value of B sub theta is negative (approximately northward in the observations) above the solar equatorial plane and positive below it for an interplanetary field directed outward from the sun, and vice versa for an inward field. Thus, for an outward field, the r-theta component of a line of magnetic force above or below the equatorial plane was skewed relative to the average value of r in the direction away from the equatorial plane. Comparisons between different spacecraft are discussed.

  2. Interplanetary Magnetic Field Power Spectrum Variations: A VHO Enabled Study

    NASA Technical Reports Server (NTRS)

    Szabo, A.; Koval, A.; Merka, J.; Narock, T.

    2011-01-01

    The newly reprocessed high time resolution (11/22 vectors/sec) Wind mission interplanetary magnetic field data and the solar wind key parameter search capability of the Virtual Heliospheric Observatory (VHO) affords an opportunity to study magnetic field power spectral density variations as a function of solar wind conditions. In the reprocessed Wind Magnetic Field Investigation (MFI) data, the spin tone and its harmonics are greatly reduced that allows the meaningful fitting of power spectra to the 2 Hz limit above which digitization noise becomes apparent. The power spectral density is computed and the spectral index is fitted for the MHD and ion inertial regime separately along with the break point between the two for various solar wind conditions. The time periods of fixed solar wind conditions are obtained from VHO searches that greatly simplify the process. The functional dependence of the ion inertial spectral index and break point on solar wind plasma and magnetic field conditions will be discussed

  3. Interplanetary Magnetic Field Power Spectrum Variations: A VHO Enabled Study

    NASA Technical Reports Server (NTRS)

    Szabo, A.; Koval, A.; Merka, J.; Narock, T.

    2010-01-01

    The newly reprocessed high time resolution (11/22 vectors/sec) Wind mission interplanetary magnetic field data and the solar wind key parameter search capability of the Virtual Heliospheric Observatory (VHO) affords an opportunity to study magnetic field power spectral density variations as a function of solar wind conditions. In the reprocessed Wind Magnetic Field Investigation (MFI) data, the spin tone and its harmonics are greatly reduced that allows the meaningful fitting of power spectra to the approx.2 Hz limit above which digitization noise becomes apparent. The power spectral density is computed and the spectral index is fitted for the MHD and ion inertial regime separately along with the break point between the two for various solar wind conditions . The time periods of fixed solar wind conditions are obtained from VHO searches that greatly simplify the process. The functional dependence of the ion inertial spectral index and break point on solar wind plasma and magnetic field conditions will be discussed

  4. Strong geomagnetic activity forecast by neural networks under dominant southern orientation of the interplanetary magnetic field

    NASA Astrophysics Data System (ADS)

    Valach, Fridrich; Bochn?ek, Josef; Hejda, Pavel; Revallo, Milo

    2014-02-01

    The paper deals with the relation of the southern orientation of the north-south component Bz of the interplanetary magnetic field to geomagnetic activity (GA) and subsequently a method is suggested of using the found facts to forecast potentially dangerous high GA. We have found that on a day with very high GA hourly averages of Bz with a negative sign occur at least 16 times in typical cases. Since it is very difficult to estimate the orientation of Bz in the immediate vicinity of the Earth one day or even a few days in advance, we have suggested using a neural-network model, which assumes the worse of the possibilities to forecast the danger of high GA - the dominant southern orientation of the interplanetary magnetic field. The input quantities of the proposed model were information about X-ray flares, type II and IV radio bursts as well as information about coronal mass ejections (CME). In comparing the GA forecasts with observations, we obtain values of the Hanssen-Kuiper skill score ranging from 0.463 to 0.727, which are usual values for similar forecasts of space weather. The proposed model provides forecasts of potentially dangerous high geomagnetic activity should the interplanetary CME (ICME), the originator of geomagnetic storms, hit the Earth under the most unfavorable configuration of cosmic magnetic fields. We cannot know in advance whether the unfavorable configuration is going to occur or not; we just know that it will occur with the probability of 31%.

  5. Large-scale interplanetary magnetic fields: Voyager 1 and 2 observations between 1 AU and 9.5 AU

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Klein, L. W.; Lepping, R. P.; Behannon, K. W.

    1984-01-01

    The large-scale radial and temporal variations of the interplanetary magnetic field strength B observed by Voyagers 1 and 2 are discussed. Two components of the magnetic field strength were considered: (1) an average component, B sub zero, based on solar rotation averages, and (2) a fluctuation component, delta B, expressed by 10- or 24-hour averages of B normalized by the best-fit average field for the corresponding time and distance. Observations of the sector structure, interfaces, and shocks are presented to further describe magnetic field strength.

  6. Counterstreaming electrons in small interplanetary magnetic flux ropes

    NASA Astrophysics Data System (ADS)

    Feng, H. Q.; Zhao, G. Q.; Wang, J. M.

    2015-12-01

    Small interplanetary magnetic flux ropes (SIMFRs) are commonly observed by spacecraft at 1 AU, and their origin still remains disputed. We investigated the counterstreaming suprathermal electron (CSE) signatures of 106 SIMFRs measured by Wind during 1995-2005. We found that 79 (75%) of the 106 flux ropes contain CSEs, and the percentages of counterstreaming vary from 8% to 98%, with a mean value of 51%. CSEs are often observed in magnetic clouds (MCs), and this indicates these MCs are still attached to the Sun at both ends. CSEs are also related to heliospheric current sheets (HCSs) and the Earth's bow shock. We divided the SIMFRs into two categories: The first category is far from HCSs, and the second category is in the vicinity of HCSs. The first category has 57 SIMFRs, and only 7 of 57 ropes have no CSEs. This ratio is similar to that of MCs. The second category has 49 SIMFRs; however, 20 of the 49 events have no CSEs. This ratio is larger than that of MCs. These two categories have different origins. One category originates from the solar corona, and most ropes are still connected to the Sun at both ends. The other category is formed near HCSs in the interplanetary space.

  7. Interplanetary magnetic field orientation for transient events in the outer magnetosphere

    NASA Technical Reports Server (NTRS)

    Sibeck, D. G.; Newell, P. T.

    1995-01-01

    It is generally believed that flux transfer events (FTEs) in the outer dayside magneosphere, usually identified by transient (approximately 1 min) bipolar magneitc field perturbations in the direction normal to the nominal magnetopause, occur when the magnetosheath magetic field has a southward component. We compare the results of three methods for determining the magnetosheath magnetic field orientationat the times of previously identified UKS/IRM events: (1) the average magnetosheath magnetic field orientation in the 30-min period adjacent to the nearest magnetopause crossing, (2) the magnetosheath magnetic field orientation observed just outside the magnetopause, and (3) the lagged interplanetary magnetic field (IMF) orientation at the time of the transient events. Whereas the results of method 2 indicate that the events tend to occur for a southward magnetosheath magnetic field, the results of methods 1 and 3 show no such tnedency. The fact that the three methods yield significantly diffeent results emphasizes the need for caution in future studies.

  8. Three-dimensional interplanetary stream magnetism and energetic particle motion

    NASA Technical Reports Server (NTRS)

    Barouch, E.; Burlaga, L. F.

    1976-01-01

    Cosmic rays interact with mesoscale configurations of the interplanetary magnetic field. A technique is presented for calculating such configurations in the inner solar system, which are due to streams and source conditions near the sun, and maps of magnetic field are constructed for some plausible stream and source conditions. One effect of these mesoscale configurations on galactic cosmic rays is shown to be an out-of-the-ecliptic gradient drift sufficient to explain Forbush decreases. The effects on solar energetic particles include small polar drifts due to the field gradients and a possibly large modification of the time-intensity profiles and anisotropy characteristics due to the formation of mirror configurations in space. If a diffusion model is applicable to solar particles, the true diffusion coefficient will be masked by the effects of streams. A conceptual model which incorporates these ideas and those of several other models is presented.

  9. Transport of solar electrons in the turbulent interplanetary magnetic field

    NASA Astrophysics Data System (ADS)

    Ablaßmayer, J.; Tautz, R. C.; Dresing, N.

    2016-01-01

    The turbulent transport of solar energetic electrons in the interplanetary magnetic field is investigated by means of a test-particle Monte-Carlo simulation. The magnetic fields are modeled as a combination of the Parker field and a turbulent component. In combination with the direct calculation of diffusion coefficients via the mean-square displacements, this approach allows one to analyze the effect of the initial ballistic transport phase. In that sense, the model complements the main other approach in which a transport equation is solved. The major advancement is that, by recording the flux of particles arriving at virtual detectors, intensity and anisotropy-time profiles can be obtained. Observational indications for a longitudinal asymmetry can thus be explained by tracing the diffusive spread of the particle distribution. The approach may be of future help for the systematic interpretation of observations for instance by the solar terrestrial relations observatory (STEREO) and advanced composition explorer (ACE) spacecrafts.

  10. Pioneer Solar Plasma and Magnetic Field Measurements in Interplanetary Space During August 2-17, 1972

    NASA Technical Reports Server (NTRS)

    Mihalov, J. D.; Colburn, D. S.; Collard, H. R.; Smith, B. F.; Sonett, C. P.; Wolfe, J. H.

    1974-01-01

    Solar wind plasma and magnetic field measurements from Pioneers 9 and 10 during August 2-17, 1972, reveal complex and large-amplitude variations on a one-hour time scale and numerous discontinuities. During this time period an approximate radial alignment of the two spacecraft as seen from the Sun occurred with heliocentric distances of 0.8 AU for Pioneer 9 and 2.2 AU for Pioneer 10, both at 45 deg east of the Earth's solar longitude. The peak hourly average solar wind proton bulk velocity measured at Pioneer 9 was 990 km sec (exp -1) during hour 0 UT of August 5. The peak hourly average proton number density was 62 cm (exp -3) during hour 11 UT of August 3. The peak solar wind speeds are generally much reduced at Pioneer 10 compared with those observes at Pioneer 9. The peak 30 minute average magnetic field magnitude was 85 gamma during 1245 - 1315 UT of August 3. The Pioneer 9 data indicate passage of four fast forward interplanetary shocks, and one slow forward interplanetary shock.

  11. Magnetic shielding of interplanetary spacecraft against solar flare radiation

    NASA Technical Reports Server (NTRS)

    Cocks, Franklin H.; Watkins, Seth

    1993-01-01

    The ultimate objective of this work is to design, build, and fly a dual-purpose, piggyback payload whose function is to produce a large volume, low intensity magnetic field and to test the concept of using such a magnetic field (1) to protect spacecraft against solar flare protons, (2) to produce a thrust of sufficient magnitude to stabilize low satellite orbits against orbital decay from atmospheric drag, and (3) to test the magsail concept. These all appear to be capable of being tested using the same deployed high temperature superconducting coil. In certain orbits, high temperature superconducting wire, which has now been developed to the point where silver-sheathed high T sub c wires one mm in diameter are commercially available, can be used to produce the magnetic moments required for shielding without requiring any mechanical cooling system. The potential benefits of this concept apply directly to both earth-orbital and interplanetary missions. The usefulness of a protective shield for manned missions needs scarcely to be emphasized. Similarly, the usefulness of increasing orbit perigee without expenditure of propellant is obvious. This payload would be a first step in assessing the true potential of large volume magnetic fields in the US space program. The objective of this design research is to develop an innovative, prototype deployed high temperature superconducting coil (DHTSC) system.

  12. Interplanetary magnetic field dependence of the suprathermal energetic neutral atoms originated in subsolar magnetopause

    NASA Astrophysics Data System (ADS)

    Ogasawara, K.; Dayeh, M. A.; Funsten, H. O.; Fuselier, S. A.; Livadiotis, G.; McComas, D. J.

    2015-02-01

    Using energetic neutral atom (ENA) emission observations of the subsolar magnetopause measured by the Interstellar Boundary Explorer (IBEX), we study the correlation between the upstream interplanetary magnetic field (IMF) conditions and the spectral index of the source ion population. Our ENA data set includes hour-averaged ENA measurements at energies between 0.5 and 6 keV obtained by the IBEX High Energy ENA imager from January 2009 to May 2011. Under the condition of quiet geomagnetic activity (SYM-H index >-20 nT), we find that the shallower spectra in the suprathermal tail of the ion population of the subsolar magnetopause is weakly correlated (correlation coefficient of -0.30) with the shock angle of the Earth's bow shock, but not correlated with parameters related to magnetic reconnection (i.e., elevation and clock angle of the interplanetary magnetic field orientation). The observed correlation suggests suprathermal ion energization from diffusive shock acceleration and thus that the suprathermal ions in the subsolar magnetopause are of shocked solar wind origin. We also argue that the roles of magnetospheric ion leakage or ion acceleration by magnetic reconnection are reduced in the magnetopause emissions compared to shock acceleration processes.

  13. High latitude electric fields an the modulations related to interplanetary magnetic field parameters

    NASA Technical Reports Server (NTRS)

    Heppner, J. P.

    1973-01-01

    The meaning and characteristics of basic and average convection (i.e., electric field) patterns are described. The continuous existence of the basic convection pattern argues against treating magnetic field merging mechanisms as the fundamental cause of magnetospheric convection. However, whether related to merging or some other mechanism, interplanetary (IP) magnetic field conditions significantly modulate the distribution, magnitudes, and boundaries of the convection pattern. A previous correlation between azimuthal angles of the IP magnetic field and asymmetries in polar cap electric field distributions as seen by OGO-6 was reviewed. A new approach was taken to reveal correlations with the north-south angle and magnitude of the IP field as well as additional features which correlate with the azimuthal angle. Both significant correlations and conditions which show a lack of correlation were found. Several aspects of the correlations appear to be particularly important.

  14. Advanced Propulsion for Interplanetary Flights using Magnetized Target Fusion

    NASA Astrophysics Data System (ADS)

    Thio, Y. C. F.; Freeze, B.; Gerrish, H.; Kirkpatrick, R. C.; Landrum, D. B.; Schmidt, G. R.

    1998-11-01

    Magnetized target fusion is an approach in which a magnetized target plasma is compressed inertially by an imploding material wall. The use of a high energy plasma liner to provide the required implosion was recently proposed by Thio, et al. The plasma liner is formed by the merging of a number (nominally 60) of high momentum plasma jets converging towards the center of a sphere where two compact toroids have been introduced. Preliminary 3-D hydrodynamics modeling results using the SPHINX code of LANL have been very encouraging and confirm earlier theoretical expectations. The concept appears ready for experimental exploration, and plans for doing so are being pursued. In this talk, we explore conceptually how this innovative fusion approach could be packaged for space propulsion for interplanetary travel. We discuss the critical componenets of a baseline propulsion concept including the fusion engine, high velocity plasma accelerators, generators of compact toroids using conical theta pinches, magnetic nozzle, neutron absorption blanket, tritium reprocessing system, shock absorber, MHD generator, capacitor pulsed power system, thermal management system, and micrometeorite shields.

  15. Tongues, bottles, and disconnected loops: The opening and closing of the interplanetary magnetic field

    SciTech Connect

    McComas, D.J.

    1994-06-01

    For years the field of Space Physics has had a problem, a really big problem for it occurs on the largest spatial scales in Space physics -- across the entire region under the Sun`s influence, the heliosphere. The problem is that the Sun appears to keep opening new magnetic flux into interplanetary space with no obvious way for this flux to close back off again. This state of affairs, without some previously unknown method for closing the open interplanetary magnetic field (IMF), leads to an ever growing amount of magnetic flux in interplanetary space: the magnetic flux catastrophe. Recently, considerable progress has been made in understanding why this catastrophic state is not the observed state of the heliosphere. This brief article paints the newly emerging picture of the opening and closing of the IMF and how these processes may account for the observed variation in the amount of magnetic flux in interplanetary space over the solar cycle.

  16. Polar cap electric field distributions related to the interplanetary magnetic field direction

    NASA Technical Reports Server (NTRS)

    Heppner, J. P.

    1972-01-01

    The correlations between the azimuthal direction of the interplanetary magnetic field and the most simple polar cap signatures are discussed. Only the spatial distribution of the dawn-dusk polar cap field is considered. For each OGO 6 traverse across the northern or southern polar cap, the simultaneous values of the interplanetary magnetic field in solar-equatorial coordinates were recorded by the Explorer 33 magnetometer. Histograms of these values are presented and are discussed. The high degree of correlation with the longitudinal angle indicates that the relative geometry of the interplanetary magnetic field and magnetospheric magnetic fields must be fundamental to explaining the distribution of polar cap electric fields. The sign of the solar-equatorial component perpendicular to the sun-earth line appears to be a more critical parameter than the sign of the component toward the sun. The Svalgaard-Mansurov correlation and the correspondence between fast convection and parallel magnetospheric and interplanetary magnetic fields are described.

  17. The Interplanetary Magnetic Field and Magnetospheric Current Systems

    NASA Technical Reports Server (NTRS)

    El-Alaoui, Mostafa

    2003-01-01

    We have performed systematic global magnetohydrodynamic (MHD) simulation studies driven by an idealized time series of solar wind parameters to establish basic cause and effect relationships between the solar wind variations and the ionosphere parameters. We studied six cases in which the interplanetary magnetic field (IMF) rotated from southward to northward in one minute. In three cases (cases A, B, and C) we ran five hours of southward IMF with Beta(sub Zeta) = 5 nT, followed by five hours of northward IMF with Beta(sub Zeta) = 5 nT. In the other three cases (cases D, E, and F) the magnetic field magnitude was increased to 10 nT. The solar wind parameters were: For cases A and D a density of 5 cm(exp -3), a thermal pressure of 3.3 nPa, and a solar wind speed 375 km/s, for cases B and E a density of 10 cm(exp -3), a thermal pressure of 9.9 nPa, and a solar wind speed 420 km/s, while for cases C and F a density of 15 cm(exp -3), a thermal pressure of 14.9 nPa, and a solar wind speed of 600 km/s.

  18. Interplanetary stream magnetism: Kinematic effects. [solar magnetic fields and wind

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Barouch, E.

    1974-01-01

    The particle density, and the magnetic field intensity and direction are calculated in corotating streams of the solar wind, assuming that the solar wind velocity is constant and radial and that its azimuthal variations are not two rapid. The effects of the radial velocity profile in corotating streams on the magnetic fields were examined using kinematic approximation and a variety of field configurations on the inner boundary. Kinematic and dynamic effects are discussed.

  19. The Bastille day Magnetic Clouds and Upstream Shocks: Near-Earth Interplanetary Observations

    NASA Astrophysics Data System (ADS)

    Lepping, R. P.; Berdichevsky, D. B.; Burlaga, L. F.; Lazarus, A. J.; Kasper, J.; Desch, M. D.; Wu, C.-C.; Reames, D. V.; Singer, H. J.; Smith, C. W.; Ackerson, K. L.

    2001-12-01

    The energetic charged particle, interplanetary magnetic field, and plasma characteristics of the `Bastille Day' shock and ejecta/magnetic cloud events at 1 AU occurring over the days 14 16 July 2000 are described. Profiles of MeV (WIND/LEMT) energetic ions help to organize the overall sequence of events from the solar source to 1 AU. Stressed are analyses of an outstanding magnetic cloud (MC2) starting late on 15 July and its upstream shock about 4 hours earlier in WIND magnetic field and plasma data. Also analyzed is a less certain, but likely, magnetic cloud (MC1) occurring early on 15 July; this was separated from MC2 by its upstream shock and many heliospheric current sheet (HCS) crossings. Other HCS crossings occurred throughout the 3-day period. Overall this dramatic series of interplanetary events caused a large multi-phase magnetic storm with min Dst lower than -300 nT. The very fast solar wind speed (? 1100 km s-1) in and around the front of MC2 (for near average densities) was responsible for a very high solar wind ram pressure driving in the front of the magnetosphere to geocentric distances estimated to be as low as ? 5 R E, much lower than the geosynchronous orbit radius. This was consistent with magnetic field observations from two GOES satellites which indicated they were in the magnetosheath for extended times. A static force-free field model is used to fit the two magnetic cloud profiles providing estimates of the clouds' physical and geometrical properties. MC2 was much larger than MC1, but their axes were nearly antiparallel, and their magnetic fields had the same left-handed helicity. MC2's axis and its upstream shock normal were very close to being perpendicular to each other, as might be expected if the cloud were driving the shock at the time of observation. The estimated axial magnetic flux carried by MC2 was 521020 Mx, which is about 5 times the typical magnetic flux estimated for other magnetic clouds in the WIND data over its first 4 years and is 17 times the flux of MC1. This large flux is due to both the strong axially-directed field of MC2 (46.8 nT on the axis) and the large radius ( R 0=0.189 AU) of the flux tube. MC2's average speed is consistent with the expected transit time from a halo-CME to which it is apparently related.

  20. The Bastille Day Magnetic Clouds and Upstream Shocks: Near Earth Interplanetary Observations

    NASA Technical Reports Server (NTRS)

    Lepping, R. P.; Berdichevsky, D. B.; Burlaga, L. F.; Lazarus, A. J.; Kasper, J.; Desch, M. D.; Wu, C.-C.; Reames, D. V.; Singer, H. J.; Singer, H. J.; Vondrak, Richard R. (Technical Monitor)

    2001-01-01

    The energetic charged particle, interplanetary magnetic field, and plasma characteristics of the 'Bastille Day' shock and ejecta/magnetic cloud events at 1 AU occurring over the days 14-16 July 2000 are described. Profiles of MeV (WIND/LEMT) energetic ions help to organize the overall sequence of events from the solar source to 1 AU. Stressed are analyses of an outstanding magnetic cloud (MC2) starting late on 15 July and its upstream shock about 4 hours earlier in WIND magnetic field and plasma data. Also analyzed is a less certain, but likely, magnetic cloud (MC1) occurring early on 15 July; this was separated from MC2 by its upstream shock and many heliospheric current sheet (HCS) crossings. Other HCS crossings occurred throughout the 3-day period. Overall this dramatic series of interplanetary events caused a large multi-phase magnetic storm with min Dst lower than -300 nT. The very fast solar wind speed (greater than or equal to 1100 km/s) in and around the front of MC2 (for near average densities) was responsible for a very high solar wind ram pressure driving in the front of the magnetosphere to geocentric distances estimated to be as low as approx. 5 R(sub E), much lower than the geosynchronous orbit radius. This was consistent with magnetic field observations from two GOES satellites which indicated they were in the magnetosheath for extended times. A static force free field model is used to fit the two magnetic cloud profiles providing estimates of the clouds' physical and geometrical properties. MC2 was much larger than MCI, but their axes were nearly antiparallel, and their magnetic fields had the same left-handed helicity. MC2's axis and its upstream shock normal were very close to being perpendicular to each other, as might be expected if the cloud were driving the shock at the time of observation. The estimated axial magnetic flux carried by MC2 was 52 x 10(exp 20) Mx, which is about 5 times the typical magnetic flux estimated for other magnetic clouds in the WIND data over its first 4 years and is 17 times the flux of MC1. This large flux is due to both the strong axially-directed field of MC2 (46.8 nT on the axis) and the large radius (R(sub 0) = 0.189 AU) of the flux tube. MC2's average speed is consistent with the expected transit time from a halo-CME to which it is apparently related.

  1. Three Dimensional Probability Distributions of the Interplanetary Magnetic Field

    NASA Astrophysics Data System (ADS)

    Podesta, J. J.

    2014-12-01

    Empirical probability density functions (PDFs) of the interplanetary magnetic field (IMF) have been derived from spacecraft data since the early years of the space age. A survey of the literature shows that past studies have investigated the separate Cartesian components of the magnetic field, the vector magnitude, and the direction of the IMF by means of one-dimensional or two-dimensional PDFs. But, to my knowledge, there exist no studies which investigate the three dimensional nature of the IMF by means of three dimensional PDFs, either in (Bx,By,Bz)(B_x,B_y,B_z)-coordinates or (BR,BT,BN)(B_R,B_T,B_N)-coordinates or some other appropriate system of coordinates. Likewise, there exist no studies which investigate three dimensional PDFs of magnetic field fluctuations, that is, vector differences bmB(t+?)-bmB(t)bm{B}(t+tau)-bm{B}(t). In this talk, I shall present examples of three dimensional PDFs obtained from spacecraft data that demonstrate the solar wind magnetic field possesses a very interesting spatial structure that, to my knowledge, has not previously been identified. Perhaps because of the well known model of Barnes (1981) in which the magnitude of the IMF remains constant, it may be commonly believed that there is nothing new to learn from a full three dimensional PDF. To the contrary, there is much to learn from the investigation of three dimensional PDFs of the solar wind plasma velocity and the magnetic field, as well as three dimensional PDFs of their fluctuations. Knowledge of these PDFs will not only improve understanding of solar wind physics, it is an essential prerequisite for the construction of realistic models of the stochastic time series measured by a single spacecraft, one of the longstanding goals of space physics research. In addition, three dimensional PDFs contain valuable information about the anisotropy of solar wind fluctuations in three dimensional physical space, information that may help identify the reason why the three dimensional wave vector spectrum of magnetic field fluctuations in the solar wind is not axisymmetric about the direction of the mean magnetic field as recent observations in the ecliptic plane at 1 AU have shown.

  2. PUZZLES OF THE INTERPLANETARY MAGNETIC FIELD IN THE INNER HELIOSPHERE

    SciTech Connect

    Khabarova, Olga; Obridko, Vladimir

    2012-12-20

    Deviations of the interplanetary magnetic field (IMF) from Parker's model are frequently observed in the heliosphere at different distances r from the Sun. Usually, it is supposed that the IMF behavior corresponds to Parker's model overall, but there is some turbulent component that impacts and disrupts the full picture of the IMF spatial and temporal distribution. However, the analysis of multi-spacecraft in-ecliptic IMF measurements from 0.29 AU to 5 AU shows that the IMF radial evolution is rather far from expected. The radial IMF component decreases with the adiabatic power index (|B{sub r} | {proportional_to} r {sup -5/3}), the tangential component |B{sub r}| {proportional_to} r {sup -1}, and the IMF strength B {proportional_to} r {sup -1.4}. This means that the IMF is not completely frozen in the solar wind. It is possible that turbulent processes in the inner heliosphere significantly influence the IMF expansion. This is confirmed by the analysis of the B{sub r} distribution's radial evolution. B{sub r} has a well-known bimodal histogram only at 0.7-2.0 AU. The bimodality effect gradually disappears from 1 AU to 4 AU, and B{sub r} becomes quasi-normally distributed at 3-4 AU (which is a sign of rapid vanishing of the stable sector structure with heliocentric distance). We consider a quasi-continuous magnetic reconnection, occurring both at the heliospheric current sheet and at local current sheets inside the IMF sectors, to be a key process responsible for the solar wind turbulization with heliocentric distance as well as for the breakdown of the ''frozen-in IMF'' law.

  3. Variation with interplanetary sector of the total magnetic field measured at the OGO 2, 4, and 6 satellites

    NASA Technical Reports Server (NTRS)

    Langel, R. A.

    1973-01-01

    Variations in the scalar magnetic field (delta B) from the polar orbiting OGO 2, 4, and 6 spacecraft are examined as a function of altitude for times when the interplanetary magnetic field is toward the sun and for times when the interplanetary magnetic field away from the sun. This morphology is basically the same as that found when all data, irrespective of interplanetary magnetic sector, are averaged together. Differences in delta B occur, both between sectors and between seasons, which are similar in nature to variations in the surface delta Z found by Langel (1973c). The altitude variation of delta B at sunlit local times, together with delta Z at the earth's surface, demonstrates that the delta Z and delta B which varies with sector has an ionospheric source. Langel (1973b) showed that the positive delta B region in the dark portion of the hemisphere is due to at least two sources, the westward electrojet and an unidentified non-ionospheric source(s). Comparison of magnetic variations between season/sector at the surface and at the satellite, in the dark portion of the hemisphere, indicates that these variations are caused by variations in the latitudinally narrow electrojet currents and not by variations in the non-ionospheric source of delta B.

  4. Criteria of interplanetary parameters causing intense magnetic storms (Dst less than -100nT)

    NASA Technical Reports Server (NTRS)

    Gonzalez, Walter D.; Tsurutani, Bruce T.

    1987-01-01

    Ten intense storms occurred during the 500 days of August 16, 1978 to December 28, 1979. From the analysis of ISEE-3 field and plasma data, it is found that the interplanetary cause of these storms are long-duration, large and negative IMF B sub Z events, associated with interplanetary duskward-electric fields greater than 5 mV/m. Because a one-to-one relationship was found between these interplanetary events and intense storms, it is suggested that these criteria can, in the future, be used as predictors of intense storms by an interplanetary monitor such as ISEE-3. These B sub Z events are found to occur in association with large amplitudes of the IMF magnitude within two days after the onset of either high-speed solar wind streams or of solar wind density enhancement events, giving important clues to their interplanetary origin. Some obvious possibilities will be discussed. The close proximity of B sub Z events and magnetic storms to the onset of high speed streams or density enhancement events is in sharp contrast to interplanetary Alfven waves and HILDCAA events previously reported, and thus the two interplanetary features corresponding geomagnetic responses can be thought of as being complementary in nature. An examination of opposite polarity B sub Z events with the same criteria show that their occurrence is similar both in number as well as in their relationship to interplanetary disturbances, and that they lead to low levels of geomagnetic activity.

  5. A Scheme for finding the Front Boundary of an Interplanetary Magnetic Cloud

    NASA Technical Reports Server (NTRS)

    Lepping, Ronald P.; Narock, Thomas W.; Wu, Chin-Chun

    2006-01-01

    We developed a scheme for finding the front boundary of an interplanetary magnetic cloud (MC) based on criteria that depend on the possible existence of any one or all of six specific solar wind features. The features that the program looks for, within +/- 2 hours of a preliminarily determined time for the front boundary, estimated either by visual inspection or by an automatic MC identification scheme, are: (1) a sufficiently large directional discontinuity in the interplanetary magnetic field (IMF), (2) existence of a magnetic hole, (3) a significant proton plasma beta drop, (4) a significant proton temperature drop, (5) a marked increase in the IMF's intensity, and (6) a significant decrease in a normalized root-mean-square deviation (RMS)of the magnetic field - where the scheme was tested using 5, 10, 15, and 20 minute averages of the relevant physical quantities, in order to find the optimum average (and RMS) to use. Other criteria, besides these six, were examined and dismissed as not reliable, e.g., plasma speed. The scheme was developed specifically for aiding in forecasting the strength and timing of a geomagnetic storm due to the passage of an interplanetary MC in real-time, but can be used in post ground-data collection for imposition of consistency in choosing a MC's front boundary. The scheme has been extensively tested, first using 80 bona fide MCs over about 9 years of WIND data, and also for 121 MC-like structures as defined by a program that automatically identifies such structures over the same period. Optimum limits for various parameters in the scheme were found by statistical studies of the WIND MCs. The resulting limits can be user-adjusted for other data sets, if desired. Final testing of the 80 MCs showed that for 50 percent of the events the boundary estimates occurred within +/-10 minutes of visually determined times, 80 percent occurred within +/-30 minutes, and 91 percent occur within +/-60 minutes, and three or more individual boundary tests were passed for 88 percent of the total MCs. The scheme and its testing will be described.

  6. Relation between the coronal magnetic helicity to the helicity in interplanetary magnetic clouds

    NASA Astrophysics Data System (ADS)

    Luoni, M. L.; Mandrini, C. H.; Dmoulin, P.; van Driel-Gesztelyi, L.; Lpez Fuentes, M. C.

    On October 18, 1995, the Solar Wind Experiment and the Magnetic Field Instrument on board the WIND spacecraft registered a magnetic cloud at 1 AU, which was followed by a strong geomagnetic storm. The solar source of this phenomenon was located in active region (AR) NOAA 7912. On October 14, 1995, a C1.6 long duration event (LDE) started at approximately 5:00 UT and lasted for around 15 hours. In this work, we compute the variation of the coronal magnetic helicity using a linear force-free model of the field. We use magnetograms obtained at Kitt Peak National Solar Observatory as boundary conditions to extrapolate the photospheric magnetic field to the corona. The magnetic helicity is calculated at three different times, changing the parameters of the magnetic field model to fit the loops observed in soft X-rays by the Soft X-ray Telescope on board of Yohkoh (SXT/Yohkoh). The computations are done before the LDE, during its maximun and its decay phase. The variation of the coronal magnetic helicity is compared to the helicity of the interplanetary magnetic cloud observed by WIND. These values turn out to be quite similar, considering the errors involved. Our results confirm quantitatively the link between solar and interplanetary phenomena.

  7. Relationships Among Geomagnetic Storms, Interplanetary Shocks, Magnetic Clouds, and Sunspot Number During 1995 - 2012

    NASA Astrophysics Data System (ADS)

    Wu, Chin-Chun; Lepping, Ronald P.

    2015-11-01

    During 1995 - 2012, the Wind spacecraft has recorded 168 magnetic clouds (MCs), 197 magnetic cloud-like structures (MCLs), and 358 interplanetary (IP) shocks. Ninety-four MCs and 56 MCLs had upstream shock waves. The following features are found: i) The averages of the solar wind speed, interplanetary magnetic field (IMF), duration ( < ? t rangle), the minimum of B_{min}, and intensity of the associated geomagnetic storm/activity ( Dst_{min}) for MCs with upstream shock waves ( MC_{shock}) are higher (or stronger) than those averages for the MCs without upstream shock waves ( MC_{no-shock}). ii) The average < ? t rangle of MC_{shock} events ( {?} 19.8 h) is 9 % longer than that for MC_{no-hock} events ( {?} 17.6 h). iii) For the MC_{shock} events, the average duration of the sheath ( average. iv) The occurrence frequency of IP shocks is well associated with sunspot number (SSN). The average intensity of geomagnetic storms measured by < Dst_{min}rangle for MC_{shock} and MC_{no-shock} events is -102 and -31 nT, respectively. The average values < Dst_{min} rangle are -78, -70, and -35 nT for the 358 IP shocks, 168 MCs, and 197 MCLs, respectively. These results imply that IP shocks, when they occur with MCs/MCLs, must play an important role in the strength of geomagnetic storms. We speculate about the reason for this. Yearly occurrence frequencies of MC_{shock} and IP shocks are well correlated with solar activity (e.g., SSN). Choosing the correct Dst_{min} estimating formula for predicting the intensity of MC-associated geomagnetic storms is crucial for space weather predictions.

  8. Relationships Among Geomagnetic Storms, Interplanetary Shocks, Magnetic Clouds, and Sunspot Number During 1995 - 2012

    NASA Astrophysics Data System (ADS)

    Wu, Chin-Chun; Lepping, Ronald P.

    2016-01-01

    During 1995 - 2012, the Wind spacecraft has recorded 168 magnetic clouds (MCs), 197 magnetic cloud-like structures (MCLs), and 358 interplanetary (IP) shocks. Ninety-four MCs and 56 MCLs had upstream shock waves. The following features are found: i) The averages of the solar wind speed, interplanetary magnetic field (IMF), duration (< Δ t >), the minimum of B_{min}, and intensity of the associated geomagnetic storm/activity (Dst_{min}) for MCs with upstream shock waves (MC_{shock}) are higher (or stronger) than those averages for the MCs without upstream shock waves (MC_{no-shock}). ii) The average < Δ t > of MC_{shock} events ({≈} 19.8 h) is 9 % longer than that for MC_{no-shock} events ({≈} 17.6 h). iii) For the MC_{shock} events, the average duration of the sheath (<Δ t_{sheath}>) is 12.1 h. These findings could be very useful for space weather predictions, i.e. IP shocks driven by MCs are expected to arrive at Wind (or at 1 AU) about 12 h ahead of the front of the MCs on average. iv) The occurrence frequency of IP shocks is well associated with sunspot number (SSN). The average intensity of geomagnetic storms measured by < Dst_{min}> for MC_{shock} and MC_{no-shock} events is -102 and -31 nT, respectively. The average values < {Dst}_{min} > are -78, -70, and -35 nT for the 358 IP shocks, 168 MCs, and 197 MCLs, respectively. These results imply that IP shocks, when they occur with MCs/MCLs, must play an important role in the strength of geomagnetic storms. We speculate about the reason for this. Yearly occurrence frequencies of MC_{shock} and IP shocks are well correlated with solar activity ( e.g., SSN). Choosing the correct Dst_{min} estimating formula for predicting the intensity of MC-associated geomagnetic storms is crucial for space weather predictions.

  9. Influence of interplanetary magnetic field and solar wind on auroral brightness in different regions

    NASA Astrophysics Data System (ADS)

    Yang, Y. F.; Lu, J. Y.; Wang, J.-S.; Peng, Z.; Zhou, L.

    2013-01-01

    Abstract<p label="1">By integrating and <span class="hlt">averaging</span> the auroral brightness from Polar Ultraviolet Imager auroral images, which have the whole auroral ovals, and combining the observation data of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) and solar wind from NASA Operating Missions as a Node on the Internet (OMNI), we investigate the influence of IMF and solar wind on auroral activities, and analyze the separate roles of the solar wind dynamic pressure, density, and velocity on aurora, respectively. We statistically analyze the relations between the <span class="hlt">interplanetary</span> conditions and the auroral brightness in dawnside, dayside, duskside, and nightside. It is found that the three components of the IMF have different effects on the auroral brightness in the different regions. Different from the nightside auroral brightness, the dawnside, dayside, and duskside auroral brightness are affected by the IMF Bx, and By components more significantly. The IMF Bx and By components have different effects on these three regional auroral brightness under the opposite polarities of the IMF Bz. As expected, the nightside aurora is mainly affected by the IMF Bz, and under southward IMF, the larger the |Bz|, the brighter the nightside aurora. The IMF Bx and By components have no visible effects. On the other hand, it is also found that the aurora is not intensified singly with the increase of the solar wind dynamic pressure: when only the dynamic pressure is high, but the solar wind velocity is not very fast, the aurora will not necessarily be intensified significantly. These results can be used to qualitatively predict the auroral activities in different regions for various <span class="hlt">interplanetary</span> conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19800009705&hterms=magnetic+anisotropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmagnetic%2Banisotropy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19800009705&hterms=magnetic+anisotropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmagnetic%2Banisotropy"><span id="translatedtitle">Coronal holes, solar diurnal anisotropy of cosmic rays and off-ecliptic <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ahluwalia, H. S.</p> <p>1980-01-01</p> <p>The information regarding the electromagnetic states of the <span class="hlt">interplanetary</span> medium, derived from the analyses of the cosmic ray intensity variations observed with a global network of cosmic ray detectors such as neutron monitors and muon telescopes, is reviewed. The relation of the temporal characteristics of the cosmic ray solar diurnal anisotropy to the large scale characteristics of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field, far away from the ecliptic plane, is addressed. A model for the phenomenon is described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770027147','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770027147"><span id="translatedtitle">Sources of <span class="hlt">magnetic</span> fields in recurrent <span class="hlt">interplanetary</span> streams</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burlaga, L. F.; Behannon, K. W.; Hansen, S. F.; Pneuman, G. W.; Feldman, W. C.</p> <p>1977-01-01</p> <p>The sources of <span class="hlt">magnetic</span> fields in recurrent streams were examined. Most fields and plasmas at 1 AU were related to coronal holes, and the <span class="hlt">magnetic</span> field lines were open in those holes. Some of the <span class="hlt">magnetic</span> fields and plasmas were related to open field line regions on the sun which were not associated with known coronal holes, indicating that open field lines are more basic than coronal holes as sources of the solar wind. <span class="hlt">Magnetic</span> field intensities in five equatorial coronal holes ranged from 2G to 18G. <span class="hlt">Average</span> measured photospheric <span class="hlt">magnetic</span> fields along the footprints of the corresponding unipolar fields on circular equatorial arcs at 2.5 solar radii had a similar range and <span class="hlt">average</span>, but in two cases the intensities were approximately three times higher than the projected intensities. The coronal footprints of the sector boundaries on the source surface at 2.5 solar radii, meandered between -45 deg and +45 deg latitude, and their inclination ranged from near zero to near ninety degrees.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JSASS..60...31M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JSASS..60...31M"><span id="translatedtitle">Two-Dimensional Hybrid-PIC Simulation of <span class="hlt">Magnetic</span> Sail Including <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matsumoto, Masaharu; Kajimura, Yoshihiro; Usui, Hideyuki; Funaki, Ikkoh; Shinohara, Iku</p> <p></p> <p>Solar wind plasma behavior and thrust of a <span class="hlt">magnetic</span> sail under the condition with <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) are examined by time-dependent, two-dimensional, X-Y Cartesian, hybrid particle-in-cell (PIC) simulations. <span class="hlt">Magnetic</span> sail is a propellant less propulsion system proposed for an <span class="hlt">interplanetary</span> space flight. The thrust force is produced by the interaction between <span class="hlt">magnetic</span> dipole field artificially generated by superconducting coils in a spacecraft and a solar wind. In the present simulations, the ratio of ion Larmor radius at the magnetopause to characteristic length of the magnetosphere is set to 0.1, and IMF strength is set to 0 and 10nT. As simulation results, <span class="hlt">magnetic</span> reconnection occurs due to superposition of IMF and dipole field in the solar wind flow field. The reconnection points depend on the direction of IMF and those have an important role in the formation of shock wave. When IMF is perpendicular to the solar wind flow direction, the thrust acting on the spacecraft increases compared to the case without IMF. When IMF is parallel to the solar wind flow direction, lift force is generated on the spacecraft. These phenomena are attributed to the difference in location of <span class="hlt">magnetic</span> reconnection point depending on the direction of IMF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770027122','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770027122"><span id="translatedtitle"><span class="hlt">Interplanetary</span> medium data book, appendix</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>King, J. H.</p> <p>1977-01-01</p> <p>Computer generated listings of hourly <span class="hlt">average</span> <span class="hlt">interplanetary</span> plasma and <span class="hlt">magnetic</span> field parameters are given. Parameters include proton temperature, proton density, bulk speed, an identifier of the source of the plasma data for the hour, <span class="hlt">average</span> <span class="hlt">magnetic</span> field magnitude and cartesian components of the <span class="hlt">magnetic</span> field. Also included are longitude and latitude angles of the vector made up of the <span class="hlt">average</span> field components, a vector standard deviation, and an identifier of the source of <span class="hlt">magnetic</span> field data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5182344','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5182344"><span id="translatedtitle">Multifractal structure of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field: Voyager 2 observations near 25 AU, 1987 - 1988</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Burlaga, L.F. )</p> <p>1991-01-01</p> <p>This paper analyzes the large-scale fluctuations of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field strength observed by Voyager 2 from 23.3 AU to 27.8 AU during the period from day 190, 1987 to day 345, 1988. The q-th moments of B{sub {tau}} show scaling behavior in the range of scales from 16 hours to 21 days for {minus}10 {le} q {le} 10, i.e., <B{sub {tau}}{sup q}> {approximately} {tau}{sup s(q)} in this range. s(q) is approximately a quadratic function of q for {minus}4 {le} q {le} 4, as one expects for a distribution that is approximately lognormal, but the higher moments diverge from those of a lognormal distribution. The function D{sub q}(q) = 1 + s(q)/(q {minus} 1) has the form that is characteristic of multifractals. For a multifractal <span class="hlt">magnetic</span> field, the moments of the field should scale as {tau}{sup {alpha}} on a set with fractal dimension f({alpha}), where {alpha} has a continuum of values over some limited range. For the large-scale <span class="hlt">magnetic</span> field fluctuations, the function f({alpha}) computed from D{sub q}(q) is approximately a fourth order polynomial for {minus}10 {le} q {le} 10, and positive values of f({alpha}) occur for 0.8 {le} {alpha} {le} 1.2. The multifractional character of the <span class="hlt">magnetic</span> field strength fluctuations generalizes the concept that the <span class="hlt">magnetic</span> field is organized into interaction regions (regions in which the <span class="hlt">magnetic</span> field strength and pressure are higher than <span class="hlt">average</span> for several hours) and rarefaction regions (regions in which the <span class="hlt">magnetic</span> field strength and pressure are lower than <span class="hlt">average</span>). Near solar maximum the interaction regions in the distant heliosphere might be viewed as cluster of strong disturbed fields with considerable fine structure on various scales.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Icar..263...10H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Icar..263...10H"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field structure at Saturn inferred from nanodust measurements during the 2013 aurora campaign</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hsu, H.-W.; Kempf, S.; Badman, S. V.; Kurth, W. S.; Postberg, F.; Srama, R.</p> <p>2016-01-01</p> <p>Interactions between the solar wind and planetary magnetospheres provide important diagnostic information about the magnetospheric dynamics. The lack of monitoring of upstream solar wind conditions at the outer planets, however, restrains the overall scientific output. Here we apply a new method, using Cassini nanodust stream measurements, to derive the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field structure during the 2013 Saturn aurora campaign. Due to the complex dynamical interactions with the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field, a fraction of fast nanodust particles emerging from the Saturnian system is sent back into the magnetosphere and can be detected by a spacecraft located within. The time-dependent directionality caused by the variable <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field enable these particles to probe the solar wind structure remotely. Information about the arrival time of solar wind compression regions (coupled with the heliospheric current sheet crossings) as well as the field direction associated with the solar wind sector structure can be inferred. Here we present a tentative identification of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field sector structure based on Cassini nanodust and radio emission measurements during the 2013 Saturn aurora campaign. Our results show that, the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field near Saturn during 2013-080 to 176 was consistent with a two-sector structure. The intensifications of aurora and the radio emission on 2013-095, 112 and 140 coincide with the IMF sector boundaries, indicating that the encounter of the compressed solar wind is the main cause of the observed activities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AnGeo..23.1405B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AnGeo..23.1405B"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field control of Saturn's polar cusp aurora</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bunce, E. J.; Cowley, S. W. H.; Milan, S. E.</p> <p>2005-06-01</p> <p>Dayside UV emissions in Saturn's polar ionosphere have been suggested to be the first observational evidence of the kronian "cusp" (Gérard et al., 2004). The emission has two distinct states. The first is a bright arc-like feature located in the pre-noon sector, and the second is a more diffuse "spot" of aurora which lies poleward of the general location of the main auroral oval, which may be related to different upstream <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) orientations. Here we take up the suggestion that these emissions correspond to the cusp. However, direct precipitation of electrons in the cusp regions is not capable of producing significant UV aurora. We have therefore investigated the possibility that the observed UV emissions are associated with reconnection occurring at the dayside magnetopause, possibly pulsed, akin to flux transfer events seen at the Earth. We devise a conceptual model of pulsed reconnection at the low-latitude dayside magnetopause for the case of northwards IMF which will give rise to pulsed twin-vortical flows in the magnetosphere and ionosphere in the vicinity of the open-closed field-line boundary, and hence to bi-polar field-aligned currents centred in the vortical flows. During intervals of high-latitude lobe reconnection for southward IMF, we also expect to have pulsed twin-vortical flows and corresponding bi-polar field-aligned currents. The vortical flows in this case, however, are displaced poleward of the open-closed field line boundary, and are reversed in sense, such that the field-aligned currents are also reversed. For both cases of northward and southward IMF we have also for the first time included the effects associated with the IMF By effect. We also include the modulation introduced by the structured nature of the solar wind and IMF at Saturn's orbit by developing "slow" and "fast" flow models corresponding to intermediate and high strength IMF respectively. We then consider the conditions under which the plasma populations appropriate to either sub-solar reconnection or high-latitude lobe reconnection can carry the currents indicated. We have estimated the field-aligned voltages required, the resulting precipitating particle energy fluxes, and the consequent auroral output. Overall our model of pulsed reconnection under conditions of northwards and southwards IMF, and for varying orientations of IMF By, is found to produce a range of UV emission intensities and geometries which is in good agreement with the data presented by Gérard et al. (2004). The recent HST-Cassini solar wind campaign provides a unique opportunity to test the theoretical ideas presented here.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6371196','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6371196"><span id="translatedtitle">A study of an expanding interplantary <span class="hlt">magnetic</span> cloud and its interaction with the Earth's magnetosphere: The <span class="hlt">interplanetary</span> aspect</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Farrugia, C.J.; Burlaga, L.F.; Lepping, R.P. ); Osherovich, V.A. ); Richardson, I.G. Univ. of Maryland, College Park ); Freeman, M.P. ); Lazarus, A.J. )</p> <p>1993-05-01</p> <p>This is the first of three papers studying an expanding <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> cloud, and its interaction with the earth's magnetosphere. A <span class="hlt">magnetic</span> cloud is a very large scale <span class="hlt">interplanetary</span> phenomena which when viewed by an observer tied to the sun has certain characteristics: the <span class="hlt">magnetic</span> field direction rotates slowly over a period of a day through a large angle; the <span class="hlt">magnetic</span> field strength is larger than <span class="hlt">average</span>; and the proton pressure is much less than the <span class="hlt">magnetic</span> pressure. Here the authors interpret and discuss high time resolution measurements made by the IMP 8 spacecraft over roughly two days, at 1 AU, of interplantary <span class="hlt">magnetic</span> fields and plasma properties, on Jan 14-15, 1988. The observations are consistent with the model of <span class="hlt">magnetic</span> clouds as flux ropes of local cylindrical geometry. These clouds are large scale MHD configurations. As it evolves antisunward it expands. The authors modeled this behaviour. They also studied the question of the attachment of field lines in the cloud with the sun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910060875&hterms=mars+cross+section&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmars%2Bcross%2Bsection','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910060875&hterms=mars+cross+section&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmars%2Bcross%2Bsection"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field control of the Mars bow shock - Evidence for Venuslike interaction</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zhang, T. L.; Schwingenschuh, K.; Lichtenegger, H.; Riedler, W.; Russell, C. T.</p> <p>1991-01-01</p> <p>The Mars bow shock location and shape have been determined by examining the Phobos spacecraft magnetometer data. Observations show that the position of the terminator bow shock varies with <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field orientation in the same way as at Venus. The shock is farthest from Mars in the direction of the <span class="hlt">interplanetary</span> electric field, consistent with the idea that mass loading plays an important role in the solar wind interaction with Mars. The shock cross section at the terminator plane is asymmetric and is controlled by the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. The shock is farther from Mars during solar maximum. Thus the solar wind interaction with Mars appears to be Venuslike, with a <span class="hlt">magnetic</span> moment too small to affect significantly the solar wind interaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5224461','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5224461"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field control of the Mars bow shock: Evidence for Venuslike interaction</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhang, T.L.; Schwingenschuh, K.; Lichtenegger, H.; Riedler, W. ); Russell, C.T.; Luhmann, J.G. )</p> <p>1991-07-01</p> <p>The Mars bow shock location and shape have been determined by examining the PHOBOS spacecraft magnetometer data. Observations show that the position of the terminator bow shock varies with <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field orientation in the same way as at Venus. The shock is farthest from Mars in the direction of the <span class="hlt">interplanetary</span> electric field, consistent with the idea that mass loading plays an important role in the solar wind interaction with Mars. The authors also find that the shock cross section at the terminator plane is asymmetric and is controlled by the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field as expected from the asymmetric propagation velocity of the fast magnetosonic wave. Comparing with earlier mission data, they show that the Mars shock location varies with solar activity. The shock is farther from Mars during solar maximum. Thus the solar wind interaction with Mars appears to be Venuslike, with a <span class="hlt">magnetic</span> moment too small to affect significantly the solar wind interaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22270946','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22270946"><span id="translatedtitle">DECLINE AND RECOVERY OF THE <span class="hlt">INTERPLANETARY</span> <span class="hlt">MAGNETIC</span> FIELD DURING THE PROTRACTED SOLAR MINIMUM</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Smith, Charles W.; Schwadron, Nathan A.; DeForest, Craig E. E-mail: N.Schwadron@unh.edu</p> <p>2013-09-20</p> <p>The <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) is determined by the amount of solar <span class="hlt">magnetic</span> flux that passes through the top of the solar corona into the heliosphere, and by the dynamical evolution of that flux. Recently, it has been argued that the total flux of the IMF evolves over the solar cycle due to a combination of flux that extends well outside of 1 AU and is associated with the solar wind, and additionally, transient flux associated with coronal mass ejections (CMEs). In addition to the CME eruption rate, there are three fundamental processes involving conversion of <span class="hlt">magnetic</span> flux (from transient to wind-associated), disconnection, and interchange reconnection that control the levels of each form of <span class="hlt">magnetic</span> flux in the <span class="hlt">interplanetary</span> medium. This is distinct from some earlier models in which the wind-associated component remains steady across the solar cycle. We apply the model of Schwadron et al. that quantifies the sources, interchange, and losses of <span class="hlt">magnetic</span> flux to 50 yr of <span class="hlt">interplanetary</span> data as represented by the Omni2 data set using the sunspot number as a proxy for the CME eruption rate. We do justify the use of that proxy substitution. We find very good agreement between the predicted and observed <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> flux. In the absence of sufficient CME eruptions, the IMF falls on the timescale of ?6 yr. A key result is that rising toroidal flux resulting from CME eruption predates the increase in wind-associated IMF.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_1");'>1</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li class="active"><span>3</span></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_3 --> <div id="page_4" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="61"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950063970&hterms=real+gas+models&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dreal%2Bgas%2Bmodels','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950063970&hterms=real+gas+models&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dreal%2Bgas%2Bmodels"><span id="translatedtitle"><span class="hlt">Magnetic</span> flux rope versus the spheromak as models for <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farrugia, C. J.; Osherovich, V. A.; Burlaga, L. F.</p> <p>1995-01-01</p> <p><span class="hlt">Magnetic</span> clouds form a subset of <span class="hlt">interplanetary</span> ejecta with well-defined <span class="hlt">magnetic</span> and thermodynamic properties. Observationally, it is well established that <span class="hlt">magnetic</span> clouds expand as they propagate antisunward. The aim of this paper is to compare and contrast two models which have been proposed for the global <span class="hlt">magnetic</span> field line topology of <span class="hlt">magnetic</span> clouds: a <span class="hlt">magnetic</span> flux tube geometry, on the one hand, and a spheromak geometry (including possible higher multiples), on the other. Traditionally, the <span class="hlt">magnetic</span> structure of <span class="hlt">magnetic</span> clouds has been modeled by force-free configurations. In a first step, we therefore analyze the ability of static force-free models to account for the asymmetries observed in the <span class="hlt">magnetic</span> field profiles of <span class="hlt">magnetic</span> clouds. For a cylindrical flux tube the <span class="hlt">magnetic</span> field remains symmetric about closest approach to the <span class="hlt">magnetic</span> axis on all spacecraft orbits intersecting it, whereas in a spheromak geometry one can have asymmetries in the <span class="hlt">magnetic</span> field signatures along some spacecraft trajectories. The duration of typical <span class="hlt">magnetic</span> cloud encounters at 1 AU (1 to 2 days) is comparable to their travel time from the Sun to 1 AU and thus <span class="hlt">magnetic</span> clouds should be treated as strongly nonstationary objects. In a second step, therefore, we abandon the static approach and model <span class="hlt">magnetic</span> clouds as self-similarly evolving MHD configurations. In our theory, the interaction of the expanding <span class="hlt">magnetic</span> cloud with the ambient plasma is taken into account by a drag force proportional to the density and the velocity of expansion. Solving rigorously the full set of MHD equations, we demonstrate that the asymmetry in the <span class="hlt">magnetic</span> signature may arise solely as a result of expansion. Using asymptotic solutions of the MHD equations, we least squares fit both theoretical models to <span class="hlt">interplanetary</span> data. We find that while the central part of the <span class="hlt">magnetic</span> cloud is adequately described by both models, the 'edges' of the cloud data are modeled better by the <span class="hlt">magnetic</span> flux tube. Further comparisons of the two models necessarily involve thermodynamic properties, since real <span class="hlt">magnetic</span> configurations are never exactly force-free and gas pressure plays an essential role. We consider a polytropic gas. Our theoretical analysis shows that the self-similar expansion of a <span class="hlt">magnetic</span> flux tube requires the polytropic index gamma to be less than unity. For the spheromak, however, self-similar, radially expanding solutions are known only for gamma equal to 4/3. This difference, therefore, yields a good way of distinguishing between the two geometries. It has been shown recently that the polytropic relationship is applicable to <span class="hlt">magnetic</span> clouds and that the corresponding polytropic index is approximately 0.5. This observational result is consistent with the self-similar model of the <span class="hlt">magnetic</span> flux rope but is in conflict with the self-similar spheromak model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSH41A2168K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSH41A2168K"><span id="translatedtitle">The Role Played by the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Topology in the Observed intensities of Solar Energetic Particle Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Karelitz, A. M.; Lario, D.</p> <p>2013-12-01</p> <p>The presence of large-scale solar wind structures in the <span class="hlt">interplanetary</span> medium may affect the transport of solar energetic particles (SEPs) in the heliosphere. In particular, the <span class="hlt">interplanetary</span> counterparts of coronal mass ejections (ICMEs) are able to modify the surrounding <span class="hlt">interplanetary</span> medium by introducing changes in the direction and strength of the <span class="hlt">magnetic</span> field as well as increasing the level of <span class="hlt">magnetic</span> field turbulence. Understanding the transport of SEPs in the heliosphere can lead to the increased capability in forecasting and predicting of the intensity of future SEP events. In this study, we classify paring SEP and ICME events from the 23rd solar cycle into six different categories based on when the peak of the SEP event occurred. For example, two different categories are: (1) the SEP peak occurred when an ICME was between the Sun and the Earth and (2) the SEP peak occurred after the ICME was beyond Earth. We perform a statistical analysis of the SEP peak intensities for each class of event and according to the characteristics of the solar x-ray flare or the CME associated with the origin of the SEP event For similar properties of the associated solar flare or CME we find that, on <span class="hlt">average</span>, events observed after the passage of an ICME have larger peak intensities than those events observed with an ICME between the Sun and Earth. Strict analysis and understanding of the influence that the dynamic <span class="hlt">interplanetary</span> solar wind has on the peak intensity of SEPs can enable space weather operational forecasters to better predict solar energetic particle intensities based on the occurrence of previous solar activity. By forecasting solar energetic particle events spacecraft, satellites, and humans in space, can be better protected from the impact of space weather.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19750027844&hterms=Observation+solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DObservation%2Bsolar','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19750027844&hterms=Observation+solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DObservation%2Bsolar"><span id="translatedtitle">Observation of sectored structure in the outer solar corona - Correlation with <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Howard, R. A.; Koomen, M. J.</p> <p>1974-01-01</p> <p>Review of the daily images of the white light corona between 3 and 10 solar radii recorded by a coronagraph aboard the OSO-7 unmanned satellite since October 3, 1971. The observed sectored structure in the outer solar corona is discussed and correlated with the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. The correlations support the observation of Hansen et al. (1973).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720015727','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720015727"><span id="translatedtitle">Effects of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field azimuth on auroral zone and polar cap <span class="hlt">magnetic</span> activity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burch, J. L.</p> <p>1972-01-01</p> <p>During relatively quiet times in the period 1964-1968, AE is found to be greater when the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (b sub IMF) is directed toward the sun in Jan., Feb., and Apr., and when B sub IMF is directed away from the sun in Oct. to Dec. Using Murmansk hourly H values and the AE components, AU and AL, it is shown that this sector dependence is present only in the negative H deviations. This observation supports the idea that negative bay magnitudes are determined chiefly by particle-produced ionization, while positive bay magnitudes are rather insensitive to increases in particle precipitation. The ratio of DP2-type <span class="hlt">magnetic</span> activity in the southern polar cap to that in the northern polar cap is found to be greater by a factor of about 1.75 for B sub IMF toward the sun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770027121','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770027121"><span id="translatedtitle"><span class="hlt">Interplanetary</span> medium data book</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>King, J. H.</p> <p>1977-01-01</p> <p>Unresolved questions on the physics of solar wind and its effects on magnetospheric processes and cosmic ray propagation were addressed with hourly <span class="hlt">averaged</span> <span class="hlt">interplanetary</span> plasma and <span class="hlt">magnetic</span> field data. This composite data set is described with its content and extent, sources, limits of validity, and the mutual consistency studies and normalizations to which the input data were subjected. Hourly <span class="hlt">averaged</span> parameters were presented in the form of digital listings and 27-day plots. The listings are contained in a separately bound appendix.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110008573','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110008573"><span id="translatedtitle"><span class="hlt">Magnetic</span> Flux Circulation During Dawn-Dusk Oriented <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mitchell, E. J.; Lopez, R. E.; Fok, M.-C.; Deng, Y.; Wiltberger, M.; Lyon, J.</p> <p>2010-01-01</p> <p><span class="hlt">Magnetic</span> flux circulation is a primary mode of energy transfer from the solar wind into the ionosphere and inner magnetosphere. For southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF), <span class="hlt">magnetic</span> flux circulation is described by the Dungey cycle (dayside merging, night side reconnection, and magnetospheric convection), and both the ionosphere and inner magnetosphere receive energy. For dawn-dusk oriented IMF, <span class="hlt">magnetic</span> flux circulation is not well understood, and the inner magnetosphere does not receive energy. Several models have been suggested for possible reconnection patterns; the general pattern is: dayside merging; reconnection on the dayside or along the dawn/dusk regions; and, return flow on dayside only. These models are consistent with the lack of energy in the inner magnetosphere. We will present evidence that the Dungey cycle does not explain the energy transfer during dawn-dusk oriented IMF. We will also present evidence of how <span class="hlt">magnetic</span> flux does circulate during dawn-dusk oriented IMF, specifically how the <span class="hlt">magnetic</span> flux reconnects and circulates back.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.3979W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.3979W"><span id="translatedtitle">Strong ionospheric field-aligned currents for radial <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Hui; Lhr, Hermann; Shue, Jih-Hong; Frey, Harald. U.; Kervalishvili, Guram; Huang, Tao; Cao, Xue; Pi, Gilbert; Ridley, Aaron J.</p> <p>2014-05-01</p> <p>The present work has investigated the configuration of field-aligned currents (FACs) during a long period of radial <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) on 19 May 2002 by using high-resolution and precise vector <span class="hlt">magnetic</span> field measurements of CHAMP satellite. During the interest period IMF By and Bz are weakly positive and Bx keeps pointing to the Earth for almost 10 h. The geomagnetic indices Dst is about -40 nT and AE about 100 nT on <span class="hlt">average</span>. The cross polar cap potential calculated from Assimilative Mapping of Ionospheric Electrodynamics and derived from DMSP observations have <span class="hlt">average</span> values of 10-20 kV. Obvious hemispheric differences are shown in the configurations of FACs on the dayside and nightside. At the south pole FACs diminish in intensity to magnitudes of about 0.1 ?A/m2, the plasma convection maintains two-cell flow pattern, and the thermospheric density is quite low. However, there are obvious activities in the northern cusp region. One pair of FACs with a downward leg toward the pole and upward leg on the equatorward side emerge in the northern cusp region, exhibiting opposite polarity to FACs typical for duskward IMF orientation. An obvious sunward plasma flow channel persists during the whole period. These ionospheric features might be manifestations of an efficient <span class="hlt">magnetic</span> reconnection process occurring in the northern magnetospheric flanks at high latitude. The enhanced ionospheric current systems might deposit large amount of Joule heating into the thermosphere. The air densities in the cusp region get enhanced and subsequently propagate equatorward on the dayside. Although geomagnetic indices during the radial IMF indicate low-level activity, the present study demonstrates that there are prevailing energy inputs from the magnetosphere to both the ionosphere and thermosphere in the northern polar cusp region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730008106','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730008106"><span id="translatedtitle">Mie scattering of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field by the whole moon</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sonett, C. P.; Colburn, D. S.</p> <p>1973-01-01</p> <p>It is known from the Apollo magnetometer experiments that significant electromagnetic induction takes place in the lunar interior. This induction is excited by fluctuations of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and is detected by the induced fields on the surface of the moon. These results are reviewed briefly and the formal properties of the theory are discussed. It is shown that the mathematical treatment parallels that for classical electromagnetic scattering. Further the wavelength spectrum of the fluctuations of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field include scales consistent with the radius of the moon. The consequence is that the moon is excited in several modes. Quadrupole and possibly octupole <span class="hlt">magnetic</span> multipoles are found in the data. The electric type radiation corresponding to transverse <span class="hlt">magnetic</span> excitation appears suppressed and far below the detection threshold of the magnetometers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014Ge%26Ae..54..920V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014Ge%26Ae..54..920V"><span id="translatedtitle"><span class="hlt">Magnetic</span> fields of photosphere and <span class="hlt">interplanetary</span> space: Imbalance between positive and negative polarities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vernova, E. S.; Tyasto, M. I.; Baranov, D. G.</p> <p>2014-12-01</p> <p>Photospheric <span class="hlt">magnetic</span> fields are studied in this work on the basis of synoptic maps from the Kitt Peak Observatory (1976-2003) and WSO (1976-2012). The imbalance between positive and negative fluxes is considered for strong <span class="hlt">magnetic</span> fields in the sunspot zone. The imbalance sign coincides with the polar field sign in the Northern hemisphere; it depends on both the phase of the 11-year cycle and the solar cycle parity. These features of variation in the <span class="hlt">magnetic</span> field can be explained by a strong quadrupole moment of the photospheric <span class="hlt">magnetic</span> field, which is also seen in a change of the polarity of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19760040203&hterms=Equator&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DEquator','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760040203&hterms=Equator&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DEquator"><span id="translatedtitle">Effect of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field on ionosphere over the <span class="hlt">magnetic</span> equator</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rastogi, R. G.; Patel, V. L.</p> <p>1975-01-01</p> <p>Large and quick changes of the latitude of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field from its southward to northward direction are shown to be associated with the disappearance of the Es-q layer (Knecht, 1959) at the equatorial ionosphere during the daytime or with the reversal of E region horizontal and F region vertical electron drifts during both night and day. This phenomenon is suggested as the imposition of an electric field in the ionosphere in a direction opposite to that of the Sq electric field. The resultant electrostatic field on the equatorial ionosphere would be decreased or even reversed from its normal direction, resulting in the reduction of electron drift velocity. When the normal Sq field is over-compensated by the magnetospheric electric field, the electron drifts are reversed and the irregularities in the E region due to the cross-field instabilities are inhibited, resulting in the sudden disappearance of the Es-q layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850026500','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850026500"><span id="translatedtitle">Low energy proton bidirectional anisotropies and their relation to transient <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> structures: ISEE-3 observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Marsden, R. G.; Sanderson, T. R.; Wenzel, K. P.; Smith, E. J.</p> <p>1985-01-01</p> <p>It is known that the <span class="hlt">interplanetary</span> medium in the period approaching solar maximum is characterized by an enhancement in the occurrence of transient solar wind streams and shocks and that such systems are often associated with looplike <span class="hlt">magnetic</span> structures or clouds. There is observational evidence that bidirectional, field aligned flows of low energy particles could be a signature of such looplike structures, although detailed models for the <span class="hlt">magnetic</span> field configuration and injection mechanisms do not exist at the current time. Preliminary results of a survey of low energy proton bidirectional anisotropies measured on ISEE-3 in the <span class="hlt">interplanetary</span> medium between August 1978 and May 1982, together with <span class="hlt">magnetic</span> field data from the same spacecraft are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/166713','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/166713"><span id="translatedtitle">Digisonde measurements of polar cap convection for northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cannon, P.S.; Crowley, G.; Reinisch, B.W.; Buchau, J.</p> <p>1992-11-01</p> <p>Controversy still exists regarding even the <span class="hlt">average</span> convection pattern when the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) has a northward component. Using two years of convection data from a Digisonde located at Qaanaaq only 3{degrees} from the corrected geomagnetic pole the authors have examined the diurnal convection flow direction variation in the central polar cap when the IMF is particularly stable. They find that when B{sub z} is positive, and when B{sub y} positive and B{sub y} negative data are treated independently, each exhibits a clear diurnal pattern. The patterns are most nearly consistent with a multicell convection model, e.g., Potemra et al.; there are, however, two anomalies. These synthesized polar cap convection patterns exhibit a polar cap cell centered on 10 corrected geomagnetic local time (CGLT) when B{sub y}>1 nT and 13 CGLT when B{sub y}<{minus}1 nT in contrast to 06 and 18 CGLT predicted by the multicell models. Furthermore, in contrast to the simple multicell models the convection flow patterns for opposite B{sub y} polarities are not simple mirror images of each other. When B{sub y}<{minus}1 nT the convection is directed across the central polar cap toward 02 CGLT for much of the day but when B{sub y}> 1 nT the flow is tangential to the Qaanaaq geomagnetic latitude for much of the day. 18 refs., 11 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810004452','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810004452"><span id="translatedtitle"><span class="hlt">Magnetic</span> field directional discontinuities. 2: Characteristics between 0.46 and 1.0 AU. [<span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lepping, R. P.; Benhannon, K. W.</p> <p>1980-01-01</p> <p>The characteristics of directional discontinuities (DD's) in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field are studied using data from the Mariner 10 primary mission between 1.0 and 0.46 AU. Statistical and visual survey methods for DD identification resulted in a total of 644 events. Two methods were used to estimate the ratio of the number of tangential discontinuities (TD's) to the number of rotational discontinuities (RD's). Both methods show that the ratio of TD's to RD's varied with time and decreased with decreasing radial distance. A decrease in <span class="hlt">average</span> discontinuity thickness of approx. 40 percent was found between 1.0 and 0.72 AU and approx. 54 percent between 1.0 and 0.46 AU, independent of type (TD or RD). This decrease in thickness for decreasing r is in qualitative agreement with Pioneer 10 observations between 1 and 5 AU. When the individual DD thickness are normalized with respect to the estimated local proton gyroradius (RA sub L), the <span class="hlt">average</span> thickness at the three locations is nearly constant, 43 + or - 6 R sub L. This also holds true for both RD's and TD's separately. Statistical distributions of other properties, such as normal components and discontinuity plane angles, are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770031631&hterms=pioneers+solar+power&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpioneers%2Bsolar%2Bpower','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770031631&hterms=pioneers+solar+power&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpioneers%2Bsolar%2Bpower"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field power spectra - Mean field radial or perpendicular to radial</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sari, J. W.; Valley, G. C.</p> <p>1976-01-01</p> <p>A detailed frequency analysis of Pioneer-6 <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field data is carried out for 5 to 15 hour periods during which the mean <span class="hlt">interplanetary</span> field is approximately radial or perpendicular to radial. The reason why these data sets were chosen is that by making the usual assumption that the phase speed of any wave present is much less than the mean solar wind speed, the measured frequency spectra can be interpreted in terms of the wave number parallel or perpendicular to the mean field, without such additional assumptions as isotropy or the dominance of a particular mode and without measurements of velocity and density. The details of the calculation of the <span class="hlt">magnetic</span> field power spectra, coherencies, and correlation functions are discussed, along with results obtained directly from the data (such as spectra, slopes, anisotropies, and coherencies). The results are interpreted in terms of MHD theory, and are related to work in other areas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19800031782&hterms=15926&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D15926','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19800031782&hterms=15926&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D15926"><span id="translatedtitle">Empirical relationships between <span class="hlt">interplanetary</span> conditions, magnetospheric flux transfer, and the AL index. [auroral zone <span class="hlt">magnetic</span> index</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Slavin, J. A.; Holzer, R. E.</p> <p>1979-01-01</p> <p>Holzer and Slavin (1978) have found that the transfer of <span class="hlt">magnetic</span> flux to and from the dayside magnetosphere as inferred from observed displacements of the magnetopause surface is correlated with both the magnitude of the auroral zone <span class="hlt">magnetic</span> index AL and the incident flux of southward IMF. Empirical expressions specifying the rate at which <span class="hlt">magnetic</span> flux is eroded in terms of <span class="hlt">interplanetary</span> parameters and the rate of <span class="hlt">magnetic</span> flux return as a function of AL have been developed. These relations are then used to predict magnetotail <span class="hlt">magnetic</span> field enhancements from <span class="hlt">interplanetary</span> and ground based data during an interval of substorm activity. The total <span class="hlt">magnetic</span> flux in the tail is increased during intervals when the amount of flux transferred into its volume by dayside erosion exceeds the flux lost to the dayside by magnetospheric convection. Using Ogo-5 tail observations it is found for the sample events considered that these <span class="hlt">magnetic</span> field enhancements can be described by empirical expressions for the <span class="hlt">magnetic</span> flux transfer rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770024113','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770024113"><span id="translatedtitle">On the existence of finite amplitude, transverse Alfven waves in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sari, J. W.</p> <p>1977-01-01</p> <p><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field data from the Mariner 10 spacecraft were examined for evidence of small and finite amplitude transverse Alfven waves, general finite amplitude Alfven waves, and magnetosonic waves. No evidence for transverse Alfven waves was found. Instead, the field fluctuations were found to be dominated by the general finite amplitude Alfven wave. Such wave modes correspond to non-plane-wave solutions of the nonlinear magnetohydrodynamic equations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013LRSP...10....4L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013LRSP...10....4L"><span id="translatedtitle">Reconstruction and Prediction of Variations in the Open Solar <span class="hlt">Magnetic</span> Flux and <span class="hlt">Interplanetary</span> Conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lockwood, Mike</p> <p>2013-09-01</p> <p>Historic geomagnetic activity observations have been used to reveal centennial variations in the open solar flux and the near-Earth heliospheric conditions (the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and the solar wind speed). The various methods are in very good agreement for the past 135 years when there were sufficient reliable <span class="hlt">magnetic</span> observatories in operation to eliminate problems due to site-specific errors and calibration drifts. This review underlines the physical principles that allow these reconstructions to be made, as well as the details of the various algorithms employed and the results obtained. Discussion is included of: the importance of the <span class="hlt">averaging</span> timescale; the key differences between ``range'' and ``interdiurnal variability'' geomagnetic data; the need to distinguish source field sector structure from heliospherically-imposed field structure; the importance of ensuring that regressions used are statistically robust; and uncertainty analysis. The reconstru! ctions are exceedingly useful as they provide calibration between the in-situ spacecraft measurements from the past five decades and the millennial records of heliospheric behaviour deduced from measured abundances of cosmogenic radionuclides found in terrestrial reservoirs. Continuity of open solar flux, using sunspot number to quantify the emergence rate, is the basis of a number of models that have been very successful in reproducing the variation derived from geomagnetic activity. These models allow us to extend the reconstructions back to before the development of the magnetometer and to cover the Maunder minimum. Allied to the radionuclide data, the models are revealing much about how the Sun and heliosphere behaved outside of grand solar maxima and are providing a means of predicting how solar activity is likely to evolve now that the recent grand maximum (that had prevailed throughout the space age) has come to an end.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSMSH41A..04B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSMSH41A..04B"><span id="translatedtitle">SEPs Dropout Events Associated with Advected <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Structures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bruno, R.; Trenchi, L.; Telloni, D.; D'Amicis, R.; Marcucci, F.; Zurbuchen, T.; Weberg, M. J.</p> <p>2013-05-01</p> <p>The intensity profile of energetic particles from impulsive solar flares (SEP) often shows abrupt dropouts affecting all energies simultaneously, without time-dispersion. Part of the community thinks that these modulations are directly related to the presence of <span class="hlt">magnetic</span> structures with a different <span class="hlt">magnetic</span> topology advected by the wind, a sort of <span class="hlt">magnetic</span> flux tubes. During the expansion, following the dynamical interaction between plasma regions travelling at different speed, these structures would be partially tangled up in a sort of spaghetti-like bundle. These flux tubes would be alternatively connected or not connected with the flare site and, consequently, they would be filled or devoid of SEPs. When the observer passes through them, he would observe clear particles dropout signatures. We will report about results from a detailed analysis of SEP events which showed several signatures in the local <span class="hlt">magnetic</span> field and/or plasma parameters associated with SEP modulations. These findings corroborate the idea of a possible link between these particles events observed at the Earth's orbit and <span class="hlt">magnetic</span> connection or disconnection of the ambient <span class="hlt">magnetic</span> field with the flare region at the Sun. We will also discuss the advantages represented by future Solar Orbiter in-situ observations. As a matter of fact, Solar Orbiter, from its orbital vantage point during the quasi corotation phase, will be a priviledged observer of this kind of phenomenon since it will observe the advected structure of the solar wind not yet reprocessed by dynamical interaction due to wind expansion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930005148','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930005148"><span id="translatedtitle">Venus internal <span class="hlt">magnetic</span> field and its interaction with the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Knudsen, W. C.</p> <p>1992-01-01</p> <p>In a previous study, Knudsen et al. suggested that Venus has a weak internal <span class="hlt">magnetic</span> dipole field of the order of 7 x 10 + 20 G cm(exp -3) that is manifested in the form of <span class="hlt">magnetic</span> flux tubes threading the ionospheric holes in the Venus nightside ionosphere. They pointed out that any internal field of Venus, dipole or multipole, would be weakened in the subsolar region and concentrated in the antisolar region of the planet by the supersonic transterminator convection of the dayside ionosphere into the nightside hemisphere. The inferred magnitude of the dipole field does not violate the upper limit for an internal <span class="hlt">magnetic</span> field established by the Pioneer Venus magnetometer experiment. The most compelling objection to the model suggested by Knudsen et al. has been the fact that it does not explain the observed <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) control of the polarity of the ionospheric hole flux tubes. In this presentation I suggest that a <span class="hlt">magnetic</span> reconnection process analogous to that occurring at earth is occurring at Venus between the IMF and a weak internal dipole field. At Venus in the subsolar region, the reconnection occurs within the ionosphere. At Earth it occurs at the magnetopause. Reconnection will occur only when the IMF has an appropriate orientation relative to that of the weak internal field. Thus, reconnection provides a process for the IMF to control the flux tube polarity. The reconnection in the subsolar region takes place in the ionosphere as the barrier <span class="hlt">magnetic</span> field is transported downward into the lower ionosphere by downward convection of ionospheric plasma and approaches the oppositely directed internal <span class="hlt">magnetic</span> field that is diffusing upward. The reconnected flux tubes are then transported anti-Sunward by the anti-Sunward convecting ionospheric plasma as well as by the anti-Sunward-flowing solar wind. Reconnection will also occur in the Venus <span class="hlt">magnetic</span> tail region, somewhat analogously to the reconnection that occurs in the magnetotail of the Earth. The possibility that reconnection is occurring between the IMF and an internal dipole field may be tested by measuring the orientation of the IMF projected into a plane perpendicular to the solar wind velocity during time intervals for which ionospheric holes are observed. The orientations of the IMV components should fall within a 180 deg angle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750025912','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750025912"><span id="translatedtitle">The large-scale <span class="hlt">magnetic</span> field in the solar wind. [<span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields/solar activity effects</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burlaga, L. F.; Ness, N. F.</p> <p>1975-01-01</p> <p>A large-scale, three dimensional <span class="hlt">magnetic</span> field in the <span class="hlt">interplanetary</span> medium with an expected classical spiral pattern to zeroth order is discussed. Systematic and random deviations which are expected are treated. The sector structure which should be evident at high latitudes is examined. <span class="hlt">Interplanetary</span> streams are discussed as determining the patterns of <span class="hlt">magnetic</span> field intensity. It was proposed that the large-scale spiral field can induce a meridional flow which might alter the field geometry somewhat. The nonuniformities caused by streams will probably significantly influence the motion of solar and galactic particles. It was concluded that knowledge of the 3-dimensional field and its dynamical effects can be obtained by in situ measurements by a probe which goes over the sun's poles. Diagrams of the <span class="hlt">magnetic</span> fields are given.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_2");'>2</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li class="active"><span>4</span></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_4 --> <div id="page_5" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="81"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21367387','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21367387"><span id="translatedtitle">DRIFT ORBITS OF ENERGETIC PARTICLES IN AN <span class="hlt">INTERPLANETARY</span> <span class="hlt">MAGNETIC</span> FLUX ROPE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Krittinatham, W.; Ruffolo, D. E-mail: scdjr@mahidol.ac.t</p> <p>2009-10-10</p> <p><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> flux ropes have significant effects on the distribution of energetic particles in space. Flux ropes can confine solar energetic particles (SEPs) for hours, and have relatively low densities of Galactic cosmic rays (GCRs), as seen during second-stage Forbush decreases. As particle diffusion is apparently inhibited across the flux rope boundary, we suggest that guiding center drifts could play a significant role in particle motion into and out of the flux ropes. We develop an analytic model of the <span class="hlt">magnetic</span> field in an <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> flux rope attached to the Sun at both ends, in quasi-toroidal coordinates, with the realistic features of a flux rope cross section that is small near the Sun, expanding with distance from the Sun, and field lines that are wound less tightly close to the Sun due to stretching by the solar wind. We calculate the particle drift velocity field due to the <span class="hlt">magnetic</span> field curvature and gradient as a function of position and pitch-angle cosine, and trace particle guiding center orbits numerically, assuming conservation of the first adiabatic invariant. We find that SEPs in the interior of a flux rope can have drift orbits that are trapped for long times, as in a tokamak configuration, with resonant escape features as a function of the winding number. For Forbush decreases of GCRs, the drifts should contribute to a unidirectional anisotropy and net flow from one leg of the loop to the other, in a direction determined by the poloidal field direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910055756&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910055756&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlazarus"><span id="translatedtitle">The interaction of a very large <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> cloud with the magnetosphere and with cosmic rays</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lepping, R. P.; Burlaga, L. F.; Ogilvie, K. W.; Tsurutani, B. T.; Lazarus, A. J.</p> <p>1991-01-01</p> <p>The observation of one of the largest <span class="hlt">magnetic</span> clouds ever observed at a distance of 1 AU, with a diameter of greater than about 0.4 AU, is reported. The cloud is shown to be almost unchanged structurally by interaction with the earth bow shock. The first observations are reported of an auroral activity response to the passage of a <span class="hlt">magnetic</span> cloud, with a nearly immediate increase in auroral activity when the IMF theta(B) angle reversed polarity to negative near the cloud center. The results provide strong evidence that turbulent <span class="hlt">magnetic</span> fields behind <span class="hlt">interplanetary</span> shocks are a possible cause of Forbush decreases, but contest the idea that relatively smooth, strong fields in clouds are a cause of such decreases. The cloud field modeling supports the existence of <span class="hlt">magnetic</span> force-free fields in describing cloud structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUFMSH13B..06M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUFMSH13B..06M"><span id="translatedtitle">New Insights into The Structure of the Turbulent <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Matthaeus, W. H.; Giacalone, J.; Jokipii, J. R.</p> <p>2005-12-01</p> <p>We present new insights into the structure of the turbulent <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. Various authors [1,2] have studied field line random walk associated with <span class="hlt">interplanetary</span> fields consisting of smooth mean fields and fluctuations. One possible way to generate fluctuations [3,4] is at a source surface near the solar surface, by random transverse plasma motions (such as supergranulation at the solar photosphere or perhaps reconnection), together with a uniform radial outflow at a specified solar wind speed. In this approach, the structure of the <span class="hlt">magnetic</span> field fluctuations is controlled by the temporal and spatial dependence of the footpoint velocity field. These combine to regulate the spatial structure observed in the <span class="hlt">interplanetary</span> field. Further dynamical processing is ignored in this view, which is therefore most appropriate for large scale fluctuations. Comparison of this picture with observations from the magnetometer on the Ulysses spacecraft has shown good agreement. A quite different approach to modeling the spatial structure of <span class="hlt">interplanetary</span> fluctuations is embodied in the so-called two component model, This was introduced [5,6,7] as a useful simplified parameterization of <span class="hlt">interplanetary</span> fluctuations, and, since it is associated with no specific generation mechanism, this approach is consistent with either solar-surface or in situ generation of turbulence. This also shows good agreement with observations. Here, we show that these two apparently different ways of modeling turbulent fields can be closely related. In particular, we show that by properly choosing the temporal and spatial dependence of the transverse velocity field at the solar source surface, we can generate the two component model (as well as many other possible models). The consequences of this insight for our understanding of turbulence and energetic-particle transport are discussed. [1] Jokipii and Parker, Phys. Rev. Lett, 21, 44, 1968 [2] Matthaeus et al, Phys. Rev Lett. 75, 2136, 1995 [3] Jokipii and Kota Geophys. Res. Lett., 16, 1, 1989 [4] Giacalone and Jokipii, Astrophys. J. 616, 573, 2004 [5] Matthaeus, Goldstein and Roberts, JGR, 95, 20673, 1990 [6] Tu and Marsch, 98, 1257, 1993 [7] Bieber etal, Atrophys. J., 420, 294, 1994</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850029359&hterms=bifurcation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dbifurcation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850029359&hterms=bifurcation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dbifurcation"><span id="translatedtitle">A magnetohydrodynamic simulation of the bifurcation of tail lobes during intervals with a northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ogino, T.; Walker, R. J.</p> <p>1984-01-01</p> <p>The interaction of the solar wind with the earth's magnetosphere during a northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field was studied by using a three-dimensional magneto-hydrodynamic model. For a northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field on 5 nT, the plasma sheet thickens near the noon-midnight meridian plane. When projected onto the polar cap this appears as a narrow channel extending from midnight towards noon. This plasma pattern is associated with three pairs of convection cells. The high latitude sunward convection and northern B(z) Birkeland current are caused by <span class="hlt">magnetic</span> merging in the polar region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021432&hterms=helios&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dhelios','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021432&hterms=helios&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dhelios"><span id="translatedtitle">The effects of 8 Helios observed solar proton events of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field fluctuations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>ValdezGalicia, J. F.; Alexander, P.; Otaola, J. A.</p> <p>1995-01-01</p> <p>There have been recent suggestions that large fluxes during solar energetic particle events may produce their own turbulence. To verify this argument it becomes essential to find out whether these flows cause an enhancement of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field fluctuations. In the present work, power and helicity spectra of the IMF before, during and after 8 Helios-observed solar proton events in the range 0.3 - 1 AU are analyzed. In order to detect proton self generated waves, the time evolution of spectra are followed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19790012789','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19790012789"><span id="translatedtitle">Contributions to the Fourth Solar Wind Conference. [<span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields and medium</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Acuna, M. H.; Behannon, K. W.; Burlaga, L. F.; Lepping, R.; Ness, N.; Ogilvie, K.; Pizzo, J.</p> <p>1979-01-01</p> <p>Recent results in <span class="hlt">interplanetary</span> physics are examined. These include observations of shock waves and post-shock <span class="hlt">magnetic</span> fields made by Voyager 1, 2; observations of the electron temperature as a function of distance between 1.36 AU and 2.25 AU; and observations of the structure of sector boundaries observed by Helios 1. A theory of electron energy transport in the collisionless solar wind is presented, and compared with observations. Alfven waves and Alvenic fluctuations in the solar wind are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740023205','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740023205"><span id="translatedtitle">Possible acceleration of charged particles through the reconnection of <span class="hlt">magnetic</span> field lines in <span class="hlt">interplanetary</span> space</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Levy, E. H.; Ipavich, F. M.; Gloeckler, G.</p> <p>1974-01-01</p> <p>Prominent intensity spikes in the flux of protons and alphas with less than 0.5 MeV per charge were observed in the region several hours behind an <span class="hlt">interplanetary</span> shock front. The small spatial scale of these events and the high anisotropy of the particle flux suggest local acceleration. The spectra of the particles, which are cut off at equal energy per charge, suggest acceleration through an electric field. The possibility is examined that these events have their origin in active <span class="hlt">magnetic</span> neutral sheets in the shocked solar wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17815417','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17815417"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field enhancements and their association with the asteroid 2201 oljato.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Russell, C T; Aroian, R; Arghavani, M; Nock, K</p> <p>1984-10-01</p> <p>Comparison of the times of occurrence of a newly discovered type of disturbance in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field at 0.72 astronomical unit with the passage of the small Venus-crossing asteroid, 2201 Oljato, reveals a possible association, but the source of these disturbances appears to be associated with outgassing material in the Oljato orbit some distance behind the asteroid and not with the asteroid itself. This suggested association can account for one quarter of the total number of events seen in eight Venus years. PMID:17815417</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22364987','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22364987"><span id="translatedtitle">Structures of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> flux ropes and comparison with their solar sources</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hu, Qiang; Dasgupta, B.; Khare, A.; Webb, G. M. E-mail: qiu@physics.montana.edu</p> <p>2014-09-20</p> <p>Whether a <span class="hlt">magnetic</span> flux rope is pre-existing or formed in situ in the Sun's atmosphere, there is little doubt that <span class="hlt">magnetic</span> reconnection is essential to release the flux rope during its ejection. During this process, the question remains: how does <span class="hlt">magnetic</span> reconnection change the flux-rope structure? In this work, we continue with the original study of Qiu et al. by using a larger sample of flare-coronal mass ejection (CME)-<span class="hlt">interplanetary</span> CME (ICME) events to compare properties of ICME/<span class="hlt">magnetic</span> cloud (MC) flux ropes measured at 1 AU and properties of associated solar progenitors including flares, filaments, and CMEs. In particular, the <span class="hlt">magnetic</span> field-line twist distribution within <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> flux ropes is systematically derived and examined. Our analysis shows that, similar to what was found before, for most of these events, the amount of twisted flux per AU in MCs is comparable with the total reconnection flux on the Sun, and the sign of the MC helicity is consistent with the sign of the helicity of the solar source region judged from the geometry of post-flare loops. Remarkably, we find that about half of the 18 <span class="hlt">magnetic</span> flux ropes, most of them associated with erupting filaments, have a nearly uniform and relatively low twist distribution from the axis to the edge, and the majority of the other flux ropes exhibit very high twist near the axis, up to ≳ 5 turns per AU, which decreases toward the edge. The flux ropes are therefore not linearly force-free. We also conduct detailed case studies showing the contrast of two events with distinct twist distribution in MCs as well as different flare and dimming characteristics in solar source regions, and discuss how reconnection geometry reflected in flare morphology may be related to the structure of the flux rope formed on the Sun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20030014815','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20030014815"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Control of the Entry of Solar Energetic Particles into the Magnetosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richard, R. L.; El-Alaoui, M.; Ashour-Abdalla, M.; Walker, R. J.</p> <p>2002-01-01</p> <p>We have investigated the entry of energetic ions of solar origin into the magnetosphere as a function of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field orientation. We have modeled this entry by following high energy particles (protons and 3 He ions) ranging from 0.1 to 50 MeV in electric and <span class="hlt">magnetic</span> fields from a global magnetohydrodynamic (MHD) model of the magnetosphere and its interaction with the solar wind. For the most part these particles entered the magnetosphere on or near open field lines except for some above 10 MeV that could enter directly by crossing field lines due to their large gyroradii. The MHD simulation was driven by a series of idealized solar wind and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) conditions. It was found that the flux of particles in the magnetosphere and transport into the inner magnetosphere varied widely according to the IMF orientation for a constant upstream particle source, with the most efficient entry occurring under southward IMF conditions. The flux inside the magnetosphere could approach that in the solar wind implying that SEPs can contribute significantly to the magnetospheric energetic particle population during typical SEP events depending on the state of the magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.1478B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.1478B"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field and solar cycle dependence of Northern Hemisphere F region joule heating</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bjoland, L. M.; Chen, X.; Jin, Y.; Reimer, A. S.; Skjveland, .; Wessel, M. R.; Burchill, J. K.; Clausen, L. B. N.; Haaland, S. E.; McWilliams, K. A.</p> <p>2015-02-01</p> <p>Joule heating in the ionosphere takes place through collisions between ions and neutrals. Statistical maps of F region Joule heating in the Northern Hemisphere polar ionosphere are derived from satellite measurements of thermospheric wind and radar measurements of ionospheric ion convection. Persistent mesoscale heating is observed near postnoon and postmidnight <span class="hlt">magnetic</span> local time and centered around 70 <span class="hlt">magnetic</span> latitude in regions of strong relative ion and neutral drift. The magnitude of the Joule heating is found to be largest during solar maximum and for a southeast oriented <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. These conditions are consistent with stronger ion convection producing a larger relative flow between ions and neutrals. The global-scale Joule heating maps quantify persistent (in location) regions of heating that may be used to provide a broader context compared to small-scale studies of the coupling between the thermosphere and ionosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.3039D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.3039D"><span id="translatedtitle">Onset time of solar energetic particles under the influence of scattering by <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> turbulence</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Diaz, Ismael; Zhang, Ming; Rassoul, Hamid</p> <p></p> <p>When a solar flare or CME occurs, solar energetic particles (SEP) are produced and can quickly travel along the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field lines, some of which connect the sun to the earth. Because these particles are extremely hazardous to astronauts or sensitive microelectronics on spacecraft, it is an important to predict their arrival and provide a window of time when the danger will subsist. Analysis of onset time of SEP arrival has been carried out by many researchers in the community (e.g., Reames, 2009). Assuming that first arrival particles have traveled nearly scatter-free, one can determine the length of the connecting <span class="hlt">magnetic</span> field line since the onset time will be linearly proportional to 1/v. The proportionality constant of the linear relation is the length of the field line. At Earth the nominal Parker field line length is 1.12 AU, but many onset time analyses yield larger estimates, sometimes, up to twice that length. In this paper we present a calculation of SEP onset times from a model that solves the focused transport equation that allows for particle scattering during the <span class="hlt">interplanetary</span> transport (Zhang et. al., 2009). With typical mean free paths found in SEP observations (Bieber et al., 1994) we found that the onset time of SEP flux is delayed compared to scatter-free transport. The time delay depends on the particle rigidity. Under most reasonable ranges of mean free path and its rigidity dependence, the onset time appears to be linearly proportional to 1/v. Such a property may easily mislead researchers to think the transport is scatter-free and derive larger field line lengths than the expected Parker field line. The smaller the mean free path the longer the field line length will be derived. The model results show how <span class="hlt">interplanetary</span> scattering can severely affect the onset times of SEP's.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790045591&hterms=humanistic&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dhumanistic','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790045591&hterms=humanistic&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dhumanistic"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field polarity and the size of low-pressure troughs near 180 deg W longitude</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilcox, J. M.; Duffy, P. B.; Schatten, K. H.; Svalgaard, L.; Scherrer, P. H.; Roberts, W. O.; Olson, R. H.</p> <p>1979-01-01</p> <p>The relationship between <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field polarity and the area of low pressure (300 mbar) troughs near 180 deg W longitude is examined. For most of the winters from 1951 to 1973, the trough size, as indicated by the vorticity area index, is found to be significantly greater when the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is directed away from the sun than when the field is directed towards the sun. This relationship is shown to hold for various combinations of winters and for most months within a winter, and be most pronounced at the time when polarity was determined. It is suggested that the phenomenon is caused by merging of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field lines, when polarity is directed away from the sun, with geomagnetic field lines in the Northern Hemisphere (where these measurements were made), allowing energetic particle fluxes to have access to the north polar region</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6048190','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6048190"><span id="translatedtitle">The control of auroral zone dynamics and thermodynamics by the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field dawn-dusk (Y) component</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sica, R.J. ); Hernandez, G. ); Emery, B.A.; Roble, R.G. ); Smith, R.W.; Rees, M.H. )</p> <p>1989-09-01</p> <p>Previous theoretical and experimental studies have shown that the dawn-dusk component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF B{sub y}) expands the classical symmetric two-cell convection pattern toward dusk (B{sub y} negative) or toward dawn (B{sub y} positive) in the northern hemisphere, altering the ion drag forcing on the neutral atmosphere. Measurements of the neutral dynamics associated with these convection patterns have been presented primarily at <span class="hlt">magnetic</span> latitudes greater than 70{degree} in the polar cap. In this study, nights with coincident IMF measurements have been selected from the extensive four-year auroral zone thermospheric wind and temperature data set derived from Fabry-Perot spectrometer measurements of the Doppler shifts and widths of the O({sup 1}D) 15,867 cm{sup {minus}1} (630.0 nm) emission from College, Alaska. <span class="hlt">Averages</span> from 112 nights of measurements from College were also computed using a selection criterion that depended on the previous 2 hours of IMF measurements (case 2). This procedure yielded <span class="hlt">averages</span> that differed at times from case 1. The wind and temperature <span class="hlt">averages</span> for both cases show large variations with B{sub y} in the auroral zone. The wind <span class="hlt">averages</span> for B{sub y} negative and positive are compared with National Center for Atmospheric Research thermospheric general circulation model predictions that use a B{sub y}-dependent model of ionospheric convection. The results for B{sub y} negative and positive are compared with National Center for Atmospheric Research thermospheric general circulation model predictions that use a B{sub y}-dependent model of ionospheric convection. The results for B{sub y} negative compare favorably with the <span class="hlt">averages</span>, but there are significant differences between model calculations and <span class="hlt">averages</span> for the B{sub y} positive case.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003EAEJA.....7961P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003EAEJA.....7961P"><span id="translatedtitle">The dependence of solar wind ion entry on the direction of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Peroomian, V.</p> <p>2003-04-01</p> <p>We have investigated the entry characteristics of solar wind ions into the magnetosphere by tracing particle orbits in time-dependent electric and <span class="hlt">magnetic</span> fields obtained from a three-dimensional global magnetohydrodynamic (MHD) simulation of the magnetosphere. The MHD simulation used in the study began with a 2-hour period of northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). The IMF then rotated by 45^o every two hours. The final four hours of the simulation had southward IMF. Millions of ions were launched in the solar wind, upstream of the bowshock, at x = 17 R_E, at time intervals corresponding to the midpoint of each IMF interval and collected after crossing the magnetopause current layer. We found that the region of the upstream solar wind that mapped to the magnetopause entry regions was parallel to the y z orientation of the IMF. Moreover, ions entry into the magnetosphere was in general agreement with the regions identified by Luhmann et al. [1984]. However, there were significant asymmetries in the entry locations due to the direction of the <span class="hlt">interplanetary</span> electric field and the acceleration experienced by ions in crossing the magnetopause current layer. In all cases the ions entering the magnetosphere did so in sufficient numbers to account for the plasma observed within that region and successfully populated the plasma sheet and ring current regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6720643','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6720643"><span id="translatedtitle">Sudden impulses at low-latitude stations: Steady state response for northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Russell, C.T.; Ginskey, M.; Petrinec, S.M. )</p> <p>1994-01-01</p> <p>An examination of the response of the low-latitude H component of the Earth's <span class="hlt">magnetic</span> field during the passage of <span class="hlt">interplanetary</span> shocks when the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is northward reveals that this response can be understood quantitatively in terms of the compression of a simple vacuum magnetospheric model. The compression at the surface of the Earth at 20[degrees] latitude at noon in the absence of equatorial electrojet effects is found to be 18.4 nT/(nPa)[sup 1/2]. Stations below 15[degrees] latitude and above 40[degrees] appear to have additional but variable sources of current which magnify this effect. The diurnal variation of the compression is larger than expected from the simple vacuum magnetosphere, [+-]20% about the mean instead of [+-]10%. The authors interpret this difference to indicate that tail currents, not in the vacuum model, are as important as the magnetopause currents in determining the diurnal variation of the field at the surface of the Earth. 21 refs., 10 figs., 3 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013EGUGA..15.6315K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013EGUGA..15.6315K"><span id="translatedtitle">Analysis of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field observations at different heliocentric distances</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khabarova, Olga</p> <p>2013-04-01</p> <p>Multi-spacecraft measurements of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) from 0.29 AU to 5 AU along the ecliptic plane have demonstrated systematic deviations of the observed IMF strength from the values predicted on the basis of the Parker-like radial extension models (Khabarova, Obridko, 2012). In particular, it was found that the radial IMF component |Br| decreases with a heliocentric distance r with a slope of -5/3 (instead of r-2 expansion law). The current investigation of multi-point observations continues the analysis of the IMF (and, especially, Br) large-scale behaviour, including its latitudinal distribution. Additionally, examples of the mismatches between the expected IMF characteristics and observations at smaller scales are discussed. It is shown that the observed effects may be explained by not complete IMF freezing-in to the solar wind plasma. This research was supported by the Russian Fund of Basic Researches' grants Nos.11-02-00259-a, and 12-02-10008-K. Khabarova Olga, and Obridko Vladimir, Puzzles of the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field in the Inner Heliosphere, 2012, Astrophysical Journal, 761, 2, 82, doi:10.1088/0004-637X/761/2/82, http://arxiv.org/pdf/1204.6672v2.pdf</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930053282&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930053282&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dlazarus"><span id="translatedtitle">A study of an expanding interplanatary <span class="hlt">magnetic</span> cloud and its interaction with the earth's magnetosphere - The <span class="hlt">interplanetary</span> aspect</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farrugia, C. J.; Burlaga, L. F.; Osherovich, V. A.; Richardson, I. G.; Freeman, M. P.; Lepping, R. P.; Lazarus, A. J.</p> <p>1993-01-01</p> <p>High time resolution <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and plasma measurements of an <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> cloud and its interaction with the earth's magnetosphere on January 14/15, 1988 are interpreted and discussed. It is argued that the data are consistent with the theoretical model of <span class="hlt">magnetic</span> clouds as flux ropes of local straight cylindrical geometry. The data also suggest that this cloud is aligned with its axis in the ecliptic plane and pointing in the east-west direction. Evidence consisting of the intensity and directional distribution of energetic particle in the <span class="hlt">magnetic</span> cloud argues in favor of the connectedness of the <span class="hlt">magnetic</span> field lines to the sun's surface. The intensities of about 0.5 MeV ions is rapidly enhanced and the particles stream in a collimated beam along the <span class="hlt">magnetic</span> field preferentially from the west of the sun. The particles travel form a flare site along the cloud <span class="hlt">magnetic</span> field lines, which are thus presumably still attached to the sun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22270882','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22270882"><span id="translatedtitle">AN ANALYSIS OF MAGNETOHYDRODYNAMIC INVARIANTS OF <span class="hlt">MAGNETIC</span> FLUCTUATIONS WITHIN <span class="hlt">INTERPLANETARY</span> FLUX ROPES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Telloni, D.; Perri, S.; Carbone, V.; Bruno, R.; D Amicis, R.</p> <p>2013-10-10</p> <p>A statistical analysis of <span class="hlt">magnetic</span> flux ropes, identified by large-amplitude, smooth rotations of the <span class="hlt">magnetic</span> field vector and a low level of both proton density and temperature, has been performed by computing the invariants of the ideal magnetohydrodynamic (MHD) equations, namely the <span class="hlt">magnetic</span> helicity, the cross-helicity, and the total energy, via <span class="hlt">magnetic</span> field and plasma fluctuations in the <span class="hlt">interplanetary</span> medium. A technique based on the wavelet spectrograms of the MHD invariants allows the localization and characterization of those structures in both scales and time: it has been observed that flux ropes show, as expected, high <span class="hlt">magnetic</span> helicity states (|?{sub m}| in [0.6: 1]), but extremely variable cross-helicity states (|?{sub c}| in [0: 0.8]), which, however, are not independent of the <span class="hlt">magnetic</span> helicity content of the flux rope itself. The two normalized MHD invariants observed within the flux ropes tend indeed to distribute, neither trivially nor automatically, along the ?(?{sub m}{sup 2}+?{sub c}{sup 2})=1 curve, thus suggesting that some constraint should exist between the <span class="hlt">magnetic</span> and cross-helicity content of the structures. The analysis carried out has further showed that the flux rope properties are totally independent of their time duration and that they are detected either as a sort of interface between different portions of solar wind or as isolated structures embedded in the same stream.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/227129','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/227129"><span id="translatedtitle">Anomalous magnetosheath properties during Earth passage of an <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> cloud</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Farrugia, C.J.; Erkaev, N.V.; Burlaga, L.F.</p> <p>1995-10-01</p> <p>In this work the authors present a model for the behavior of the magnetosheath during the passage of the earth thru an <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> cloud. They study the variation of plasma flow and field values as a result of this encounter. The unique feature of such encounters is that they present substantial changes in the solar wind conditions along the bow shock and magnetopause for periods of 1 to 2 days. The mach number upstream of the bow shock can be as low as 3, compared to normal value of 8 to 10. The mach number and <span class="hlt">magnetic</span> shear across the magnetopause have a major impact on the magnetosheath properties. The authors use the encounter of January 14-15, 1988, as a basis for their model, and apply ideal MHD equations, by means of a boundary layer technique, to study changes in field and plasma flow patterns.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_3");'>3</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li class="active"><span>5</span></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_5 --> <div id="page_6" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="101"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19810029040&hterms=lorentz&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dlorentz','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810029040&hterms=lorentz&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dlorentz"><span id="translatedtitle">Influence of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field on cometary and primordial dust orbits - Applications of Lorentz Scattering</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Consolmagno, G. J.</p> <p>1980-01-01</p> <p>The equations describing the change in orbital elements of <span class="hlt">interplanetary</span> dust due to Lorentz-force accelerations are presented in a simplified form. Such accelerations depend on the charge state of the dust; results of theoretical calculations for five possible dust materials are presented. Under present-day conditions, it is possible that semiconducting material such as graphite might carry a net voltage near zero, compared with a roughly 10-V charge expected for other grains. The scattering of dust by a randomly changing <span class="hlt">magnetic</span> field can be viewed analogously to the dust diffusing in space; the equations presented thus can be used to interpret observations of the present distribution of dust in terms of its possible sources and sinks. The stronger <span class="hlt">magnetic</span> fields of the early solar system would have led to more vigorous scattering of the dust; particles as large as 1 mm could have been significantly transported by Lorentz scattering during this time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22304094','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22304094"><span id="translatedtitle">Simulation of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field B{sub y} penetration into the magnetotail</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Guo, Jiuling; Shen, Chao; Liu, Zhenxing</p> <p>2014-07-15</p> <p>Based on our global 3D magnetospheric MHD simulation model, we investigate the phenomena and physical mechanism of the B{sub y} component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) penetrating into the magnetotail. We find that the dayside reconnected <span class="hlt">magnetic</span> field lines move to the magnetotail, get added to the lobe fields, and are dragged in the IMF direction. However, the B{sub y} component in the plasma sheet mainly originates from the tilt and relative slippage of the south and north lobes caused by plasma convection, which results in the original B{sub z} component in the plasma sheet rotating into a B{sub y} component. Our research also shows that the penetration effect of plasma sheet B{sub y} from the IMF B{sub y} during periods of northward IMF is larger than that during periods of southward IMF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19730051463&hterms=plasma+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dplasma%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19730051463&hterms=plasma+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dplasma%2Bfield"><span id="translatedtitle">Observation and analysis of abrupt changes in the <span class="hlt">interplanetary</span> plasma velocity and <span class="hlt">magnetic</span> field.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Martin, R. N.; Belcher, J. W.; Lazarus, A. J.</p> <p>1973-01-01</p> <p>This paper presents a limited study of the physical nature of abrupt changes in the <span class="hlt">interplanetary</span> plasma velocity and <span class="hlt">magnetic</span> field based on 19 day's data from the Pioneer 6 spacecraft. The period was chosen to include a high-velocity solar wind stream and low-velocity wind. Abrupt events were accepted for study if the sum of the energy density in the <span class="hlt">magnetic</span> field and velocity changes was above a specified minimum. A statistical analysis of the events in the high-velocity solar wind stream shows that Alfvenic changes predominate. This conclusion is independent of whether steady state requirements are imposed on conditions before and after the event. Alfvenic changes do not dominate in the lower-speed wind. This study extends the plasma field evidence for outwardly propagating Alfvenic changes to time scales as small as 1 min (scale lengths on the order of 20,000 km).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020088125','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020088125"><span id="translatedtitle">Long-term Trends in <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Strength and Solar Wind Structure during the 20th Century</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richardson, I. G.; Cliver, E. W.; Cane, H. V.; White, Nicholas E. (Technical Monitor)</p> <p>2002-01-01</p> <p>Lockwood et al have recently reported an approximately 40% increase in the radial component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) at Earth between 1964 and 1996. We argue that this increase does not constitute a secular trend but is largely the consequence of lower than <span class="hlt">average</span> fields during solar cycle 20 (1964-1976) in comparison with surrounding cycles. For times after 1976 the <span class="hlt">average</span> IMF strength has actually decreased slightly. Examination of the cosmic ray intensity, an indirect measure of the IMF strength, over the last five solar cycles (19-23) also indicates that cycle <span class="hlt">averages</span> of the IMF strength have been relatively constant since approximately 1954. We also consider the origin of the well-documented increase in the geomagnetic alphaalpha index that occurred primarily during the first half of the twentieth century. We surmise that the coronal mass ejection (CME) rate for recent solar cycles was approximately twice as high as that for solar cycles 100 years ago. However, this change in the CME rate and the accompanying increase in 27-day recurrent storm activity reported by others are unable to account completely for the increase in alphaalpha. Rather, the CMEs and recurrent high-speed streams at the beginning of the twentieth century must have been embedded in a background of slow solar wind that was less geoeffective (having, for example, lower IMF strength and/or flow speed) than its modern counterpart.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015P%26SS..119..264V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015P%26SS..119..264V"><span id="translatedtitle">The effect of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field orientation on the solar wind flux impacting Mercury's surface</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Varela, J.; Pantellini, F.; Moncuquet, M.</p> <p>2015-12-01</p> <p>The aim of this paper is to study the plasma flows on the Mercury surface for different <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field orientations on the day side of the planet. We use a single fluid MHD model in spherical coordinates to simulate the interaction of the solar wind with the Hermean magnetosphere for six solar wind realistic configurations with different <span class="hlt">magnetic</span> field orientations: Mercury-Sun, Sun-Mercury, aligned with the <span class="hlt">magnetic</span> axis of Mercury (Northward and Southward) and with the orbital plane perpendicular to the previous cases. In the Mercury-Sun (Sun-Mercury) simulation the Hermean <span class="hlt">magnetic</span> field is weakened in the South-East (North-East) of the magnetosphere leading to an enhancement of the flows on the South (North) hemisphere. For a Northward (Southward) orientation there is an enhancement (weakening) of the Hermean <span class="hlt">magnetic</span> field in the nose of the bow shock so the fluxes are reduced and drifted to the poles (enhanced and drifted to the equator). If the solar wind <span class="hlt">magnetic</span> field is in the orbital plane the magnetosphere is tilted to the West (East) and weakened at the nose of the shock, so the flows are enhanced and drifted to the East (West) in the Northern hemisphere and to the West (East) in the Southern hemisphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JASTP..67.1734L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JASTP..67.1734L"><span id="translatedtitle">Tracing <span class="hlt">magnetic</span> helicity from the solar corona to the <span class="hlt">interplanetary</span> space</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luoni, M. L.; Mandrini, C. H.; Dasso, Sergio; van Driel-Gesztelyi, L.; Dmoulin, P.</p> <p>2005-12-01</p> <p>On October 14, 1995, a C1.6 long duration event (LDE) started in active region (AR) NOAA 7912 at approximately 5:00 UT and lasted for about 15 h. On October 18, 1995, the Solar Wind Experiment and the <span class="hlt">Magnetic</span> Field Instrument (MFI) on board the Wind spacecraft registered a <span class="hlt">magnetic</span> cloud (MC) at 1 AU, which was followed by a strong geomagnetic storm. We identify the solar source of this phenomenon as AR 7912. We use magnetograms obtained by the Imaging Vector Magnetograph at Mees Solar Observatory, as boundary conditions to the linear force-free model of the coronal field, and, we determine the model in which the field lines best fit the loops observed by the Soft X-ray Telescope on board Yohkoh. The computations are done before and after the ejection accompanying the LDE. We deduce the loss of <span class="hlt">magnetic</span> helicity from AR 7912. We also estimate the <span class="hlt">magnetic</span> helicity of the MC from in situ observations and force-free models. We find the same sign of <span class="hlt">magnetic</span> helicity in the MC and in its solar source. Furthermore, the helicity values turn out to be quite similar considering the large errors that could be present. Our results are a first step towards a quantitative confirmation of the link between solar and <span class="hlt">interplanetary</span> phenomena through the study of <span class="hlt">magnetic</span> helicity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22039339','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22039339"><span id="translatedtitle"><span class="hlt">MAGNETIC</span> VARIANCES AND PITCH-ANGLE SCATTERING TIMES UPSTREAM OF <span class="hlt">INTERPLANETARY</span> SHOCKS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Perri, Silvia; Zimbardo, Gaetano E-mail: gaetano.zimbardo@fis.unical.it</p> <p>2012-07-20</p> <p>Recent observations of power-law time profiles of energetic particles accelerated at <span class="hlt">interplanetary</span> shocks have shown the possibility of anomalous, superdiffusive transport for energetic particles throughout the heliosphere. Those findings call for an accurate investigation of the <span class="hlt">magnetic</span> field fluctuation properties at the resonance frequencies upstream of the shock's fronts. Normalized <span class="hlt">magnetic</span> field variances, indeed, play a crucial role in the determination of the pitch-angle scattering times and then of the transport regime. The present analysis investigates the time behavior of the normalized variances of the <span class="hlt">magnetic</span> field fluctuations, measured by the Ulysses spacecraft upstream of corotating interaction region (CIR) shocks, for those events which exhibit superdiffusion for energetic electrons. We find a quasi-constant value for the normalized <span class="hlt">magnetic</span> field variances from about 10 hr to 100 hr from the shock front. This rules out the presence of a varying diffusion coefficient and confirms the possibility of superdiffusion for energetic electrons. A statistical analysis of the scattering times obtained from the <span class="hlt">magnetic</span> fluctuations upstream of the CIR events has also been performed; the resulting power-law distributions of scattering times imply long range correlations and weak pitch-angle scattering, and the power-law slopes are in qualitative agreement with superdiffusive processes described by a Levy random walk.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110023374','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110023374"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Power Spectrum Variations in the Inner Heliosphere: A Wind and MESSENGER Study</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Szabo, Adam; Koval, A.</p> <p>2011-01-01</p> <p>The newly reprocessed high time resolution (11/22 vectors/sec) Wind mission <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field data and the similar observations made by the MESSENGER spacecraft in the inner heliosphere affords an opportunity to compare <span class="hlt">magnetic</span> field power spectral density variations as a function of radial distance from the Sun under different solar wind conditions. In the reprocessed Wind <span class="hlt">Magnetic</span> Field Investigation (MFI) data, the spin tone and its harmonics are greatly reduced that allows the meaningful fitting of power spectra to the approx.2 Hz limit above which digitization noise becomes apparent. The powe'r spectral density is computed and the spectral index is fitted for the MHD and ion inertial regime separately along with the break point between the two for various solar wind conditions. Wind and MESSENGER <span class="hlt">magnetic</span> fluctuations are compared for times when the two spacecraft are close to radial and Parker field alignment. The functional dependence of the ion inertial spectral index and break point on solar wind plasma and <span class="hlt">magnetic</span> field conditions will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AdSpR..55..401K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AdSpR..55..401K"><span id="translatedtitle">Variations of solar, <span class="hlt">interplanetary</span>, and geomagnetic parameters with solar <span class="hlt">magnetic</span> multipole fields during Solar Cycles 21-24</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Bogyeong; Lee, Jeongwoo; Yi, Yu; Oh, Suyeon</p> <p>2015-01-01</p> <p>In this study we compare the temporal variations of the solar, <span class="hlt">interplanetary</span>, and geomagnetic (SIG) parameters with that of open solar <span class="hlt">magnetic</span> flux from 1976 to 2012 (from Solar Cycle 21 to the early phase of Cycle 24) for a purpose of identifying their possible relationships. By the open flux, we mean the <span class="hlt">average</span> <span class="hlt">magnetic</span> field over the source surface (2.5 solar radii) times the source area as defined by the potential field source surface (PFSS) model of the Wilcox Solar Observatory (WSO). In our result, most SIG parameters except the solar wind dynamic pressure show rather poor correlations with the open solar <span class="hlt">magnetic</span> field. Good correlations are recovered when the contributions from individual multipole components are counted separately. As expected, solar activity indices such as sunspot number, total solar irradiance, 10.7 cm radio flux, and solar flare occurrence are highly correlated with the flux of <span class="hlt">magnetic</span> quadrupole component. The dynamic pressure of solar wind is strongly correlated with the dipole flux, which is in anti-phase with Solar Cycle (SC). The geomagnetic activity represented by the Ap index is correlated with higher order multipole components, which show relatively a slow time variation with SC. We also found that the unusually low geomagnetic activity during SC 23 is accompanied by the weak open solar fields compared with those in other SCs. It is argued that such dependences of the SIG parameters on the individual multipole components of the open solar <span class="hlt">magnetic</span> flux may clarify why some SIG parameters vary in phase with SC and others show seemingly delayed responses to SC variation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21562438','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21562438"><span id="translatedtitle">ON THE INTERNAL STRUCTURE OF THE <span class="hlt">MAGNETIC</span> FIELD IN <span class="hlt">MAGNETIC</span> CLOUDS AND <span class="hlt">INTERPLANETARY</span> CORONAL MASS EJECTIONS: WRITHE VERSUS TWIST</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Al-Haddad, N.; Roussev, I. I.; Lugaz, N.; Moestl, C.; Jacobs, C.; Poedts, S.; Farrugia, C. J. E-mail: nlugaz@ifa.hawaii.edu</p> <p>2011-09-10</p> <p>In this study, we test the flux rope paradigm by performing a 'blind' reconstruction of the <span class="hlt">magnetic</span> field structure of a simulated <span class="hlt">interplanetary</span> coronal mass ejection (ICME). The ICME is the result of a magnetohydrodynamic numerical simulation and does not exhibit much <span class="hlt">magnetic</span> twist, but appears to have some characteristics of a <span class="hlt">magnetic</span> cloud, due to a writhe in the <span class="hlt">magnetic</span> field lines. We use the Grad-Shafranov technique with simulated spacecraft measurements at two different distances and compare the reconstructed <span class="hlt">magnetic</span> field with that of the ICME in the simulation. While the reconstructed <span class="hlt">magnetic</span> field is similar to the simulated one as seen in two dimensions, it yields a helically twisted <span class="hlt">magnetic</span> field in three dimensions. To further verify the results, we perform the reconstruction at three different position angles at every distance point, and all results are found to be in agreement. This work demonstrates that the current paradigm of associating <span class="hlt">magnetic</span> clouds with flux ropes may have to be revised.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/254431','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/254431"><span id="translatedtitle">Statistical properties of particle precipitation in the polar cap during intervals of northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Shinohara, Iku; Kokubun, Susumu</p> <p>1996-01-01</p> <p>The authors present a study of the properties of electron and ion precipitation in the polar cap during periods of northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). They look at a years worth of data from DMSP F8 for their study. They find localized periods of electron precipitation, referred to as polar showers, over a soft background polar rain. They find the shower events can be classified into two groups, Type A and B, dependent upon whether ion precipitation is/or is not observed in conjunction with the electron precipitation. The type A events do not seem to depend upon the IMF x or y components, and have more energetic electrons than typical of the solar wind, which leads the authors to conclude these events are on closed field lines. The type B events show statistical variations consistent with solar wind properties, and therefore the authors conclude they are indicative of open field line events, even with B{sub z}>0.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006IAUS..233..407K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006IAUS..233..407K"><span id="translatedtitle">Contribution of geometry of interaction between <span class="hlt">interplanetary</span> and terrestrial <span class="hlt">magnetic</span> fields into geomagnetic activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuznetsova, T. V.; Laptukhov, A. I.; Kuznetsov, V. D.</p> <p></p> <p>We present results of our study of dependence of planetary geomagnetic activity from geometric factors in geoeffective parameters taking into account orientation of the geomagnetic moment M relative to the vectors of the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field (IMF) and electric field of the solar wind E during annual and daily motions of the Earth. We take as our data base space measurements of the IMF and solar wind velocity at the Earth's orbit for 1964-1998 and Kp, Dst indices. Variations of the geometric factors determined by mutual orientation of the vectors E and M can explain 50% of observed variations of Kp and 75% of Dst. We show that geomagnetic activity can reach very high levels of geomagnetic activity Kp = 8 for invariable values of the solar wind electric field by changing only geometric factors.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009GeoRL..3618112S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009GeoRL..3618112S"><span id="translatedtitle">Anomalous magnetosheath flows and distorted subsolar magnetopause for radial <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shue, J.-H.; Chao, J.-K.; Song, P.; McFadden, J. P.; Suvorova, A.; Angelopoulos, V.; Glassmeier, K. H.; Plaschke, F.</p> <p>2009-09-01</p> <p>On 12 August 2007 from 1436 to 1441 UT, when the five THEMIS probes (THA, THB, THC, THD, and THE) were located near the subsolar magnetopause, a sunward flow was observed in the magnetosheath. A fast anti-sunward flow (-280 km/s) was observed in the magnetosheath before the sunward flow. Although THA observed this fast anti-sunward flow, THC and THD, which were also in the magnetosheath, instead observed a slow flow, indicating that the fast flow was small in scale. With the observed flow vectors and the magnetopause normal directions estimated from tangential discontinuity analysis, we conclude that this fast flow creates an indentation on the magnetopause, 1 R E deep and 2 R E wide. The magnetopause subsequently rebounds, rotating the flow direction sunward along the surface of the magnetopause. The fast flow is likely related to the radial <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSM31B1525S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSM31B1525S"><span id="translatedtitle">Anomalous Magnetosheath Flows and Distorted Subsolar Magnetopause for Radial <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shue, J.; Chao, J. K.; Song, P.; McFadden, J. P.; Suvorova, A.; Angelopoulos, V.; Glassmeier, K.; Plaschke, F.</p> <p>2009-12-01</p> <p>On 12 August 2007 from 1436 to 1441 UT, when the five THEMIS probes (THA, THB, THC, THD, and THE) were located near the subsolar magnetopause, a sunward flow was observed in the magnetosheath. A fast anti-sunward flow (-280 km/s) was observed in the magnetosheath before the sunward flow. Although THA observed this fast anti-sunward flow, THC and THD, which were also in the magnetosheath, instead observed a slow flow, indicating that the fast flow was small in scale. With the observed flow vectors and the magnetopause normal directions estimated from tangential discontinuity analysis, we conclude that this fast flow creates an indentation on the magnetopause, 1 Re deep and 2 Re wide. The magnetopause subsequently rebounds, rotating the flow direction sunward along the surface of the magnetopause. The fast flow is likely related to the radial <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH41D..01S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH41D..01S"><span id="translatedtitle">Origin of the Radial <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field and Its Effects on the Magnetospheric System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shue, J. H.</p> <p>2014-12-01</p> <p>The orientation of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) is usually aligned with a spiral form. Sometimes this orientation becomes radial, i.e., the solar wind plasma flowing in align with the IMF. Under this circumstance, the magnetospheric system, including the bow shock, magnetosheath, magnetopause, and magnetosphere, responds to the radial IMF in a way that is different from the other orientations. For example, the magnetopause moves outward and the bow shock moves inward, resulting a thin magnetosheath. Although the magnetospheric state for radial IMF is generally quiet, active local field-aligned currents can be observed in the high-latitude ionosphere. In this presentation, the current understandings and future perspectives on the origin of the radial IMF and its effects on the magnetospheric system will be reviewed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983JGR....88.4005N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983JGR....88.4005N"><span id="translatedtitle">Response of nightside auroral-oval boundaries to the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakai, H.; Kamide, Y.</p> <p>1983-05-01</p> <p>The size of the auroral oval varies dynamically in association with geomagnetic activity and with the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). The present investigation can be regarded as an extension of studies conducted by Kamide and Winningham (1977), Gussenhoven et al. (1981), and Hardy et al. (1981). These investigators have reported on the relationship of the location of the auroral oval, as recorded by satellite borne electron spectrometers, with the intensity of the solar wind and magnetospheric electric fields. In the current investigation it is attempted to determine the most probable time scale of the auroral oval response to the IMF variations. Aurora imagery data for the nightside auroral oval recorded by three Defense Meteorological Satellite Program (DMSP) satellites are utilized. IMF data with high-time resolution are utilized to explain a detailed role of the solar wind parameters regarding changes in the auroral oval location at midnight.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040171460&hterms=magnetic+signature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bsignature','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040171460&hterms=magnetic+signature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bsignature"><span id="translatedtitle">In-Situ Solar Wind and <span class="hlt">Magnetic</span> Field Signatures of <span class="hlt">Interplanetary</span> Coronal Mass Ejections</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zurbuchen, Thomas H.; Richardson, Ian G.</p> <p>2004-01-01</p> <p>The heliospheric counterparts of coronal mass ejections (CMEs) at the Sun, <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs), can be identified in-situ based on a number of <span class="hlt">magnetic</span> field, plasma, compositional and energetic particle signatures, as well as combinations thereof. Although many of these signatures have been recognized since the early space era, recent observations from improved instrumentation on spacecraft such as Ulysses, Wind, and ACE, in conjunction with solar observations from SOHO, have advanced our understanding of the characteristics of ICMEs and their solar counterparts. We summarize these signatures and their implications for understanding the nature of these structures and the physical properties of coronal mass ejections. We conclude that our understanding of ICMEs is far from complete, and formulate several challenges that, if addressed, would substantially improve our knowledge of the relationship between CMEs at the Sun and in the heliosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850026690','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850026690"><span id="translatedtitle">The effect of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field on sidereal variations observed at medium depth underground detectors</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Humble, J. E.; Fenton, A. G.</p> <p>1985-01-01</p> <p>It has been known for some years that the intensity variations in sidereal time observed by muon detectors at moderate underground depths are sensitive to the polarity of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (ipmf) near the Earth. There are differences in the response to these anisotropies as observed in the Norhtern and southern hemispheres. When fully understood, the nature of the anisotropy seems likely to provide information on the 3-dimensional structure of the heliomagnetosphere, its time variations, and its linking with the local interstellar field. The summation harmonic dials for the sidereal diurnal variation during 1958 to 1982 show that there is a strong dependence on whether the ipmf near the Earth is directed outwards from the Sun or inwards it.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Ge%26Ae..55..938V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Ge%26Ae..55..938V"><span id="translatedtitle">Radiocarbon version of 11-year variations in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field since 1250</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Volobuev, D. M.; Makarenko, N. G.</p> <p>2015-12-01</p> <p>It is known that the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF), which is controlled by solar activity, modulates the flux of galactic cosmic rays (GCRs). Because GCRs are the only source of the 14C isotope in the atmosphere before the era of atmospheric nuclear tests, the formation rate of this isotope in the atmosphere is one of the few reliable sources of information on solar activity before the initiation of regular telescopic observations. In this study, we solve the inverse problem for the equation of radiocarbon diffusion from the atmosphere into the ocean by calibrating the radiocarbon content in tree rings from 1510 to 1950. We obtain an approximation of 11-year IMF cycles represented by the IDV index from 1872 to 1950. The model extrapolation to the calibration curve for the Korean Peninsula over the time period from 1250 to 1650 makes it possible to calculate the sequence of minima of quasi-11-year cycles since 1250.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JGRA..11211103X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JGRA..11211103X"><span id="translatedtitle">Magnetohydrodynamic simulation of the interaction between two <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds and its consequent geoeffectiveness</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiong, Ming; Zheng, Huinan; Wu, S. T.; Wang, Yuming; Wang, Shui</p> <p>2007-11-01</p> <p>Numerical studies of the <span class="hlt">interplanetary</span> "multiple <span class="hlt">magnetic</span> clouds (Multi-MC)" are performed by a 2.5-dimensional ideal magnetohydrodynamic (MHD) model in the heliospheric meridional plane. Both slow MC1 and fast MC2 are initially emerged along the heliospheric equator, one after another with different time intervals. The coupling of two MCs could be considered as the comprehensive interaction between two systems, each comprising of an MC body and its driven shock. The MC2-driven shock and MC2 body are successively involved into interaction with MC1 body. The momentum is transferred from MC2 to MC1. After the passage of MC2-driven shock front, <span class="hlt">magnetic</span> field lines in MC1 medium previously compressed by MC2-driven shock are prevented from being restored by the MC2 body pushing. MC1 body undergoes the most violent compression from the ambient solar wind ahead, continuous penetration of MC2-driven shock through MC1 body, and persistent pushing of MC2 body at MC1 tail boundary. As the evolution proceeds, the MC1 body suffers from larger and larger compression, and its original vulnerable <span class="hlt">magnetic</span> elasticity becomes stiffer and stiffer. So there exists a maximum compressibility of Multi-MC when the accumulated elasticity can balance the external compression. This cutoff limit of compressibility mainly decides the maximally available geoeffectiveness of Multi-MC because the geoeffectiveness enhancement of MCs interacting is ascribed to the compression. Particularly, the greatest geoeffectiveness is excited among all combinations of each MC helicity, if <span class="hlt">magnetic</span> field lines in the interacting region of Multi-MC are all southward. Multi-MC completes its final evolutionary stage when the MC2-driven shock is merged with MC1-driven shock into a stronger compound shock. With respect to Multi-MC geoeffectiveness, the evolution stage is a dominant factor, whereas the collision intensity is a subordinate one. The <span class="hlt">magnetic</span> elasticity, <span class="hlt">magnetic</span> helicity of each MC, and compression between each other are the key physical factors for the formation, propagation, evolution, and resulting geoeffectiveness of <span class="hlt">interplanetary</span> Multi-MC.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_4");'>4</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li class="active"><span>6</span></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_6 --> <div id="page_7" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="121"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140016484','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140016484"><span id="translatedtitle">The B-dot Earth <span class="hlt">Average</span> <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Capo-Lugo, Pedro A.; Rakoczy, John; Sanders, Devon</p> <p>2013-01-01</p> <p>The <span class="hlt">average</span> Earth's <span class="hlt">magnetic</span> field is solved with complex mathematical models based on mean square integral. Depending on the selection of the Earth <span class="hlt">magnetic</span> model, the <span class="hlt">average</span> Earth's <span class="hlt">magnetic</span> field can have different solutions. This paper presents a simple technique that takes advantage of the damping effects of the b-dot controller and is not dependent of the Earth <span class="hlt">magnetic</span> model; but it is dependent on the <span class="hlt">magnetic</span> torquers of the satellite which is not taken into consideration in the known mathematical models. Also the solution of this new technique can be implemented so easily that the flight software can be updated during flight, and the control system can have current gains for the <span class="hlt">magnetic</span> torquers. Finally, this technique is verified and validated using flight data from a satellite that it has been in orbit for three years.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...812..152Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...812..152Z"><span id="translatedtitle">Strong Solar Wind Dynamic Pressure Pulses: <span class="hlt">Interplanetary</span> Sources and Their Impacts on Geosynchronous <span class="hlt">Magnetic</span> Fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zuo, Pingbing; Feng, Xueshang; Xie, Yanqiong; Wang, Yi; Xu, Xiaojun</p> <p>2015-10-01</p> <p>In this investigation, we first present a statistical result of the <span class="hlt">interplanetary</span> sources of very strong solar wind dynamic pressure pulses (DPPs) detected by WIND during solar cycle 23. It is found that the vast majority of strong DPPs reside within solar wind disturbances. Although the variabilities of geosynchronous <span class="hlt">magnetic</span> fields (GMFs) due to the impact of positive DPPs have been well established, there appears to be no systematic investigations on the response of GMFs to negative DPPs. Here, we study both the decompression effects of very strong negative DPPs and the compression from strong positive DPPs on GMFs at different <span class="hlt">magnetic</span> local time sectors. In response to the decompression of strong negative DPPs, GMFs on the dayside near dawn and near dusk on the nightside, are generally depressed. But near the midnight region, the responses of GMF are very diverse, being either positive or negative. For part of the events when GOES is located at the midnight sector, the GMF is found to abnormally increase as the result of magnetospheric decompression caused by negative DPPs. It is known that under certain conditions <span class="hlt">magnetic</span> depression of nightside GMFs can be caused by the impact of positive DPPs. Here, we find that a stronger pressure enhancement may have a higher probability of producing the exceptional depression of GMF at the midnight region. Statistically, both the decompression effect of strong negative DPPs and the compression effect of strong positive DPPs depend on the <span class="hlt">magnetic</span> local time, which are stronger at the noon sector.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.3328J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.3328J"><span id="translatedtitle">Comparing generic models for <span class="hlt">interplanetary</span> shocks and <span class="hlt">magnetic</span> clouds axis configurations at 1 AU</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Janvier, M.; Dasso, S.; Dmoulin, P.; Masas-Meza, J. J.; Lugaz, N.</p> <p>2015-05-01</p> <p><span class="hlt">Interplanetary</span> coronal mass ejections (ICMEs) are the manifestation of solar transient eruptions, which can significantly modify the plasma and <span class="hlt">magnetic</span> conditions in the heliosphere. They are often preceded by a shock, and a <span class="hlt">magnetic</span> flux rope is detected in situ in a third to half of them. The main aim of this study is to obtain the best quantitative shape for the flux rope axis and for the shock surface from in situ data obtained during spacecraft crossings of these structures. We first compare the orientation of the flux rope axes and shock normals obtained from independent data analyses of the same events, observed in situ at 1 AU from the Sun. Then we carry out an original statistical analysis of axes/shock normals by deriving the statistical distributions of their orientations. We fit the observed distributions using the distributions derived from several synthetic models describing these shapes. We show that the distributions of axis/shock orientations are very sensitive to their respective shape. One classical model, used to analyze <span class="hlt">interplanetary</span> imager data, is incompatible with the in situ data. Two other models are introduced, for which the results for axis and shock normals lead to very similar shapes; the fact that the data for MCs and shocks are independent strengthens this result. The model which best fits all the data sets has an ellipsoidal shape with similar aspect ratio values for all the data sets. These derived shapes for the flux rope axis and shock surface have several potential applications. First, these shapes can be used to construct a consistent ICME model. Second, these generic shapes can be used to develop a quantitative model to analyze imager data, as well as constraining the output of numerical simulations of ICMEs. Finally, they will have implications for space weather forecasting, in particular, for forecasting the time arrival of ICMEs at the Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35.3567F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35.3567F"><span id="translatedtitle">A real-time solar wind and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field model for space radiation analysis and prediction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fry, C. D.; Detman, T. R.; Dryer, M.; Smith, Z.; Sun, W.; Deehr, C. S.; Akasofu, S.-I.; Wu, C.-C.</p> <p></p> <p>We describe an observation-driven model for assessing and predicting the solar wind and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) environment. High energy particles generated during solar/<span class="hlt">interplanetary</span> disturbances will pose a serious hazard to crew members traveling beyond low-Earth orbit. In order to provide warnings of dangerous radiation conditions, mission operators will need accurate forecasts of solar energetic particle (SEP) fluxes and fluences in <span class="hlt">interplanetary</span> space. However, physics-based models for accelerating and propagating SEPs require specifications and predictions of the solar wind conditions and IMF configuration near the evolving <span class="hlt">interplanetary</span> shock region, and along the IMF lines connecting the shock to the observation point. We are presently using the Hakamada-Akasofu-Fry kinematic solar wind model to predict, in real time, solar wind conditions in the heliosphere, including at the location of Mars, and beyond. This model is being extended via a hybrid approach to include a 3D MHD model, the <span class="hlt">Interplanetary</span> Global Model, Vectorized (IGMV). We present our modeling results and conclude that uncertainties in determining, from real-time solar observations, the physical parameters used for model inputs are the biggest factors limiting the accuracy of solar wind models used for space radiation analysis and prediction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21562644','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21562644"><span id="translatedtitle">DETECTION OF CURRENT SHEETS AND <span class="hlt">MAGNETIC</span> RECONNECTIONS AT THE TURBULENT LEADING EDGE OF AN <span class="hlt">INTERPLANETARY</span> CORONAL MASS EJECTION</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chian, Abraham C.-L.; Munoz, Pablo R. E-mail: pablocus@gmail.com</p> <p>2011-06-01</p> <p>The relation between current sheets, turbulence, and <span class="hlt">magnetic</span> reconnections at the leading edge of an <span class="hlt">interplanetary</span> coronal mass ejection detected by four Cluster spacecraft on 2005 January 21 is studied. We report the observational evidence of two <span class="hlt">magnetically</span> reconnected current sheets in the vicinity of a front <span class="hlt">magnetic</span> cloud boundary layer with the following characteristics: (1) a Kolmogorov power spectrum in the inertial subrange of the <span class="hlt">magnetic</span> turbulence, (2) the scaling exponent of structure functions of <span class="hlt">magnetic</span> fluctuations exhibiting multi-fractal scaling predicted by the She-Leveque magnetohydrodynamic model, and (3) bifurcated current sheets with the current density computed by both single-spacecraft and multi-spacecraft techniques.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009JGRA..11411101X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JGRA..11411101X"><span id="translatedtitle">Magnetohydrodynamic simulation of the interaction between two <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds and its consequent geoeffectiveness: 2. Oblique collision</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiong, Ming; Zheng, Huinan; Wang, Shui</p> <p>2009-11-01</p> <p>The numerical studies of the <span class="hlt">interplanetary</span> coupling between multiple <span class="hlt">magnetic</span> clouds (MCs) are continued by a 2.5-dimensional ideal magnetohydrodynamic (MHD) model in the heliospheric meridional plane. The <span class="hlt">interplanetary</span> direct collision (DC)/oblique collision (OC) between both MCs results from their same/different initial propagation orientations. Here the OC is explored in contrast to the results of the DC. Both the slow MC1 and fast MC2 are consequently injected from the different heliospheric latitudes to form a compound stream during the <span class="hlt">interplanetary</span> propagation. The MC1 and MC2 undergo contrary deflections during the process of oblique collision. Their deflection angles of ??$\\theta$1? and ??$\\theta$2? continuously increase until both MC-driven shock fronts are merged into a stronger compound one. The ??$\\theta$1?, ??$\\theta$2?, and total deflection angle ?$\\theta$ (?$\\theta$ = ??$\\theta$1? + ??$\\theta$2?) reach their corresponding maxima when the initial eruptions of both MCs are at an appropriate angular difference. Moreover, with the increase of MC2's initial speed, the OC becomes more intense, and the enhancement of ?$\\theta$1 is much more sensitive to ?$\\theta$2. The ??$\\theta$1? is generally far less than the ??$\\theta$2?, and the unusual case of ??$\\theta$1? $\\simeq$ ??$\\theta$2? only occurs for an extremely violent OC. But because of the elasticity of the MC body to buffer the collision, this deflection would gradually approach an asymptotic degree. As a result, the opposite deflection between the two MCs, together with the inherent <span class="hlt">magnetic</span> elasticity of each MC, could efficiently relieve the external compression for the OC in the <span class="hlt">interplanetary</span> space. Such a deflection effect for the OC case is essentially absent for the DC case. Therefore, besides the <span class="hlt">magnetic</span> elasticity, <span class="hlt">magnetic</span> helicity, and reciprocal compression, the deflection due to the OC should be considered for the evolution and ensuing geoeffectiveness of <span class="hlt">interplanetary</span> interaction among successive coronal mass ejections.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21576547','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21576547"><span id="translatedtitle">CORONAL JETS, <span class="hlt">MAGNETIC</span> TOPOLOGIES, AND THE PRODUCTION OF <span class="hlt">INTERPLANETARY</span> ELECTRON STREAMS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Li, C.; Matthews, S. A.; Van Driel-Gesztelyi, L.; Sun, J.; Owen, C. J.</p> <p>2011-07-01</p> <p>We investigate the acceleration source of the impulsive solar energetic particle (SEP) events on 2007 January 24. Combining the in situ electron measurements and remote-sensing solar observations, as well as the calculated <span class="hlt">magnetic</span> fields obtained from a potential-field source-surface model, we demonstrate that the jets associated with the hard X-ray flares and type-III radio bursts, rather than the slow and partial coronal mass ejections, are closely related to the production of <span class="hlt">interplanetary</span> electron streams. The jets, originated from the well-connected active region (AR 10939) whose <span class="hlt">magnetic</span> polarity structure favors the eruption, are observed to be forming in a coronal site, extending to a few solar radii, and having a good temporal correlation with the electron solar release. The open-field lines near the jet site are rooted in a negative polarity, along which energetic particles escape from the flaring AR to the near-Earth space, consistent with the in situ electron pitch angle distribution. The analysis enables us to propose a coronal <span class="hlt">magnetic</span> topology relating the impulsive SEP events to their solar source.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013PhDT.......161W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013PhDT.......161W"><span id="translatedtitle">Numerical analysis and theory of oblique alfvenic solitons observed in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wheeler, Harry Raphael, IV</p> <p></p> <p>Recently, there have been reports of small <span class="hlt">magnetic</span> pulses or bumps in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field observed by various spacecraft. Most of these reports claim that these localized pulses or bumps are solitons. Solitons are weakly nonlinear localized waves that tend to retain their form as they propagate and can be observed in various media which exhibit nonlinear steepening and dispersive eects. This thesis expands the claim that these pulses or bumps are nonlinear oblique Alfven waves with soliton components, through the application of analytical techniques used in the inverse scattering transform in a numerical context and numerical integration of nonlinear partial dierential equations. One event, which was observed by the Ulysses spacecraft on February 21st, 2001, is extensively scrutinized through comparison with soliton solutions that emerge from the Derivative Nonlinear Schrodinger (DNLS) equation. The direct scattering transform of a wave prole that has corresponding morphology to the selected <span class="hlt">magnetic</span> bump leads to the implication of a soliton component. Numerical integration of the scaled prole matching the event in the context of the DNLS leads to generation of dispersive waves and a one parameter dark soliton.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5103583','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5103583"><span id="translatedtitle">Polar region Birkeland current, convection, and aurora for northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zanetti, L.J.; Potemra, T.A.; Erlandson, R.E.; Bythrow, P.F.; Anderson, B.J. ); Murphree, J.S. ); Marklund, G.T. )</p> <p>1990-05-01</p> <p>Viking <span class="hlt">magnetic</span> field, electric field, and image data have been used to assess polar region phenomena for steady state northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) conditions. Regions of polar Birkeland current and convection and their extent from the vicinity of the <span class="hlt">magnetic</span> pole are determined. Also discussed are mechanisms that could produce polar aurora in general; two suggestions are (1) converging electric fields from convection patterns alone and (2) the bifurcation of the magnetotail with its associated plasma transport from convection patterns. Macroscopic (> 1{degree} latitude) systems of Birkeland currents and convection in the polar regions have been established for a case on April 9, 1986, from Viking spacecraft data. The current systems were confined to the highest latitudes of the polar regions and occurred during strongly northward IMF with a significantly negative B{sub x}. An arc extends across the polar region within the dawn cell of Birkeland current. The arc is located at a sunward to antisunward convection reversal that corresponds to a converging electric field. A converging electric field ({gradient} {center dot} E < 0) alone is suggested as the cause of this polar arc. The signature of both transverse disturbance vectors indicates that the polar region dawn NBZ Birkeland current does not connect to the dayside auroral region. It is inferred that the dawn polar region convection cell associated with this Birkeland current is also limited in the sunward direction and does not connect to the dayside auroral region convection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SoPh..290..553L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SoPh..290..553L"><span id="translatedtitle">Yearly Comparison of <span class="hlt">Magnetic</span> Cloud Parameters, Sunspot Number, and <span class="hlt">Interplanetary</span> Quantities for the First 18 Years of the Wind Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lepping, R. P.; Wu, C.-C.; Berdichevsky, D. B.</p> <p>2015-02-01</p> <p>In the scalar part of this study, we determine various statistical relationships between estimated <span class="hlt">magnetic</span> cloud (MC) model fit-parameters and sunspot number (SSN) for the interval defined by the Wind mission, i.e., early 1995 until the end of 2012, all in terms of yearly <span class="hlt">averages</span>. The MC-fitting model used is that of Lepping, Jones, and Burlaga ( J. Geophys. Res. 95, 11957 - 11965, <CitationRef CitationID="CR19">1990). We also statistically compare the MC fit-parameters and other derived MC quantities [ e.g., axial <span class="hlt">magnetic</span> flux (?O) and total axial current density ( J O)] with some associated ambient <span class="hlt">interplanetary</span> quantities (including the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field ( B IMF), proton number density ( N P), and others). Some of the main findings are that the minimum SSN is nearly simultaneous with the minimum in the number of MCs per year ( N MC), which occurs in 2008. There are various fluctuations in N MC and the MC model-fit quality ( Q') throughout the mission, but the last four years (2009 - 2012) are markedly different from the others; Q' is low and N MC is large over these four years. N MC is especially large for 2012. The linear correlation coefficient (c.c.?0.75) between the SSN and each of the three quantities J O, MC diameter (2 R O), and B IMF, is moderately high, but none of the MC parameters track the SSN well in the sense defined in this article. However, there is good statistical tracking among the following: MC axial field, B IMF, 2 R O, <span class="hlt">average</span> MC speed ( V MC), and yearly <span class="hlt">average</span> solar wind speed ( V SW) with relatively high c.c.s among most of these. From the start of the mission until late 2005, J O gradually increases, with a slight violation in 2003, but then a dramatic decrease (by more than a factor of five) occurs to an almost steady and low value of ? 3 ?A km-2 until the end of the interval of interest, i.e., lasting for at least seven years. This tends to split the overall 18-year interval into two phases with a separator at the end of 2005. There is good tracking between 2 R O and the total axial current density, as expected. The MC duration is also correlated well with these two quantities. ?O shows marked variations throughout the mission, but has no obvious trend. N P, B IMF, V MC, Q', and V SW are all quite steady over the full 18 years and have markedly low relative variation. Concerning vector quantities, we examine the distribution of MC type for the 18 years, where type refers to the field directional change through a given MC starting at first encounter ( i.e., North-to-South, or South-to-North, All South, All North, etc.). Combining all 18 years of MC types shows that the occurrence rate varies strongly across the various MC types, with N-to-S being most prevalent, with a 27 % occurrence rate (of all MCs), and S-to-N being second, with a 23 % occurrence. Then All N and All S come next at 16 % and 10 % occurrence rate, respectively. All others are at 7 % or lower. For the variation of MC types with time, the southern types ( i.e., those that start with a southern <span class="hlt">magnetic</span> field, a negative B Z in geocentric-solar-ecliptic coordinates) decrease, as the northern types ( i.e., those that start with a northern field) increase, apparently consistent with the specific timing of the polarity change of the solar <span class="hlt">magnetic</span> field, as predicted by Bothmer and Rust (in Crooker, N., Joselyn, J., Feynman J. (eds), Geophys. Monogr., 139 - 146, <CitationRef CitationID="CR3">1997).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990056482&hterms=Ulysses&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DUlysses','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990056482&hterms=Ulysses&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DUlysses"><span id="translatedtitle">Self-similar evolution of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds and Ulysses measurements of the polytropic index inside the cloud</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Osherovich, Vladimir A.; Fainberg, J.; Stone, R. G.; MacDowall, R. J.; Berdichevsky, D.</p> <p>1997-01-01</p> <p>A self similar model for the expanding flux rope is developed for a magnetohydrodynamic model of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds. It is suggested that the dependence of the maximum <span class="hlt">magnetic</span> field on the distance from the sun and the polytropic index gamma has the form B = r exp (-1/gamma), and that the ratio of the electron temperature to the proton temperature increases with distance from the sun. It is deduced that ion acoustic waves should be observed in the cloud. Both predictions were confirmed by Ulysses observations of a 1993 <span class="hlt">magnetic</span> cloud. Measurements of gamma inside the cloud demonstrate sensitivity to the internal topology of the <span class="hlt">magnetic</span> field in the cloud.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985AZh....62..780L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985AZh....62..780L"><span id="translatedtitle">Reflection of the structure of the chromosphere and corona in the solar wind and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lyubimov, G. P.; Pereslegina, N. V.</p> <p>1985-08-01</p> <p>New features in the structure of the low-velocity solar wind are found and additional indications of the sources of the solar wind are obtained by the method of concrete comparison of data on the solar wind and the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field with solar data. These regularities were discovered in data for April 1968 and were confirmed for other intervals. It is shown that: (1) the low-velocity solar wind corresponds to sections of the quiet solar chromosphere between groups of active regions; (2) the low-velocity solar wind carries off the weak large-scale solar <span class="hlt">magnetic</span> field, the sign of which corresponds to the sign of the weak <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field; (3) doublet pulses of density, which correspond to the minimum value of the <span class="hlt">magnetic</span> field strength, are observed at the line of reversal of the sign of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. The hypothesis is advanced that coronal-loop plasma structures transported by the solar wind to 1 AU are observed. A phenomenological model of the phenomenon is proposed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820005721','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820005721"><span id="translatedtitle">Large-scale variations of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field: Voyager 1 and 2 observations between 1-5 AU</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burlaga, L. F.; Lepping, R. P.; Behannon, K. W.; Klein, L. W.; Neubauer, F. M.</p> <p>1981-01-01</p> <p>Observations by the Voyager 1 and 2 spacecraft of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field between 1 and 5 AU were used to investigate the large scale structure of the IMF in a period of increasing solar activity. The Voyager spacecraft found notable deviations from the Parker axial model. These deviations are attributed both to temporal variations associated with increasing solar activity, and to the effects of fluctuations of the field in the radial direction. The amplitude of the latter fluctuations were found to be large relative to the magnitude of the radial field component itself beyond approximately 3 AU. Both Voyager 1 and Voyager 2 observed decreases with increasing heliocentric distance in the amplitude of transverse fluctuations in the <span class="hlt">averaged</span> field strength (B) which are consistent with the presence of predominantly undamped Alfven waves in the solar wind, although and necessarily implying the presence of them. Fluctuations in the strength of B (relative to mean field strength) were found to be small in amplitude, with a RMS which is approximately one third of that for the transverse fluctuations and they are essentially independent of distance from the Sun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUSMSH31A..06R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUSMSH31A..06R"><span id="translatedtitle">Sharp Trapping Boundaries in the Random Walk of <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Lines</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ruffolo, D.; Chuychai, P.; Meechai, J.; Pongkitiwanichkul, P.; Kimpraphan, N.; Matthaeus, W. H.; Rowlands, G.</p> <p>2004-05-01</p> <p>Although <span class="hlt">magnetic</span> field lines in space are believed to undergo a diffusive random walk in the long-distance limit, observed dropouts of solar energetic particles, as well as computer simulations, indicate sharply defined filaments in which <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field lines have been temporarily trapped. We identify mechanisms that can explain such sharp boundaries in the framework of 2D+slab turbulence, a model that provides a good explanation of solar wind turbulence spectra and the parallel transport of solar energetic particles. Local trapping boundaries (LTBs) are empirically defined as trajectories of 2D turbulence where the mean 2D field is a local maximum. In computer simulations, the filaments (or ``islands'' in the two dimensions perpendicular to the mean field) that are most resistant to slab diffusion correspond closely to the mathematically defined LTBs, that is, there is a mathematical prescription for defining the trapping regions. Furthermore, we provide computational evidence and a theoretical explanation that strong 2D turbulence can inhibit diffusion due to the slab component. Therefore, while these filaments are basically defined by the small-scale topology of 2D turbulence, there can be sharp trapping boundaries where the 2D field is strongest. This work was supported by the Thailand Research Fund, the Rachadapisek Sompoj Fund of Chulalongkorn University, and NASA Grant NAG5-11603. G.R. thanks Mahidol University for its hospitality and the Thailand Commission for Higher Education for travel support.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970026617','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970026617"><span id="translatedtitle">Penetration of the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field B(sub y) into Earth's Plasma Sheet</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hau, L.-N.; Erickson, G. M.</p> <p>1995-01-01</p> <p>There has been considerable recent interest in the relationship between the cross-tail <span class="hlt">magnetic</span> field component B(sub y) and tail dynamics. The purpose of this paper is to give an overall description of the penetration of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) B(sub y) into the near-Earth plasma sheet. We show that plasma sheet B(sub y) may be generated by the differential shear motion of field lines and enhanced by flux tube compression. The latter mechanism leads to a B(sub y) analogue of the pressure-balance inconsistency as flux tubes move from the far tail toward the Earth. The growth of B(sub y), however, may be limited by the dawn-dusk asymmetry in the shear velocity as a result of plasma sheet tilting. B(sub y) penetration into the plasma sheet implies field-aligned currents flowing between hemispheres. These currents together with the IMF B(sub y) related mantle field-aligned currents effectively shield the lobe from the IMF B(sub y).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.8327Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.8327Z"><span id="translatedtitle">Excitation of dayside chorus waves due to <span class="hlt">magnetic</span> field line compression in response to <span class="hlt">interplanetary</span> shocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Chen; Li, Wen; Thorne, Richard M.; Bortnik, Jacob; Ma, Qianli; An, Xin; Zhang, Xiao-jia; Angelopoulos, Vassilis; Ni, Binbin; Gu, Xudong; Fu, Song; Zhao, Zhengyu</p> <p>2015-10-01</p> <p>The excitation of magnetospheric whistler-mode chorus in response to <span class="hlt">interplanetary</span> (IP) shocks is investigated using wave data from the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft. As an example, we show a typical chorus wave excitation following an IP shock event that was observed by THEMIS in the postnoon sector near the magnetopause on 3 August 2010. We then analyze characteristic changes during this event and perform a survey of similar events during the period 2008-2014 using the THEMIS and OMNI data set. Our statistical analysis demonstrates that the chorus wave excitation/intensification in response to IP shocks occurs only at high L shells (L > 8) on the dayside. We analyzed the variations of <span class="hlt">magnetic</span> curvature following the arrival of the IP shock and found that IP shocks lead to more homogeneous background <span class="hlt">magnetic</span> field configurations in the near-equatorial dayside magnetosphere; and therefore, the threshold of nonlinear chorus wave growth is likely to be reduced, favoring chorus wave generation. Our results provide the observational evidence to support the concept that the geomagnetic field line configuration plays a key role in the excitation of dayside chorus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.8709Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.8709Y"><span id="translatedtitle">Dependence of efficiency of <span class="hlt">magnetic</span> storm generation on the types of <span class="hlt">interplanetary</span> drivers.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yermolaev, Yuri; Nikolaeva, Nadezhda; Lodkina, Irina</p> <p>2015-04-01</p> <p>To compare the coupling coefficients between the solar-wind electric field Ey and Dst (and corrected Dst*) index during the <span class="hlt">magnetic</span> storms generated by different types of <span class="hlt">interplanetary</span> drivers, we use the Kyoto Dst-index data, the OMNI data of solar wind plasma and <span class="hlt">magnetic</span> field measurements, and our "Catalog of large scale phenomena during 1976-2000" (published in [1] and presented on websites: ftp://ftp.iki.rssi.ru/pub/omni/). Both indexes at the main phase of <span class="hlt">magnetic</span> storms are approximated by the linear dependence on the following solar wind parameters: integrated electric field of solar wind (sumEy), solar wind dynamic pressure (Pd), and the level of <span class="hlt">magnetic</span> field fluctuations (sB), and the fitting coefficients are determined by the technique of least squares. We present the results of the main phase modelling for <span class="hlt">magnetic</span> storms with Dst<-50 nT induced by 4 types of the solar wind streams: MC (10 events), CIR (41), Sheath (26), Ejecta (45). Our analysis [2, 3] shows that the coefficients of coupling between Dst and Dst* indexes and integral electric field are significantly higher for Sheath (for Dst*and Dst they are -3.4 and -3.3 nT/V m-1 h, respectively) and CIR (-3.0 and -2.8) than for MC (-2.0 and -2.5) and Ejecta (-2.1 and -2.3). Thus we obtained additional confirmation of experimental fact that Sheath and CIR have higher efficiency in generation of <span class="hlt">magnetic</span> storms than MC and Ejecta. This work was supported by the RFBR, project 13-02-00158a, and by the Program 9 of Presidium of Russian Academy of Sciences. References 1. Yu. I. Yermolaev, N. S. Nikolaeva, I. G. Lodkina, and M. Yu. Yermolaev, Catalog of Large-Scale Solar Wind Phenomena during 1976-2000, Cosmic Research, 2009, Vol. 47, No. 2, pp. 81-94. 2. N.S. Nikolaeva, Yu.I. Yermolaev, I.G. Lodkina, Modeling of Dst-index temporal profile on the main phase of the <span class="hlt">magnetic</span> storms generated by different types of solar wind, Cosmic Research, 2013, Vol. 51, No. 6, pp. 401-412 3. Nikolaeva N.S., Yermolaev Yu.I., Lodkina I.G., Modeling of corrected Dst-index temporal profile on the main phase of the <span class="hlt">magnetic</span> storms generated by different types of solar wind, Cosmic Research, 2015, Vol.53, No. 2, 81, DOI: 10.7868/S0023420615020077</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015TESS....140503K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015TESS....140503K"><span id="translatedtitle">The <span class="hlt">magnetic</span> flux excess effect as a consequence of non-Parker radial evolution of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Khabarova, Olga</p> <p>2015-04-01</p> <p>The <span class="hlt">magnetic</span> flux excess effect is exceeding of <span class="hlt">magnetic</span> flux Fs=4?|Br|r2 measured by distant spacecraft over the values obtained through measurements at the Earths orbit (Owens et al., JGR, 2008). Theoretically, its conservation should take place at any heliocentric distance r further than 10 solar radii, which means that the difference between the flux measured at 1 AU and Fs observed in another point in the heliosphere should be zero. However, the difference is negative closer to the Sun and increasingly positive at larger heliocentric distances. Possible explanations of this effect are continuously discussed, but the consensus is yet not reached.It is shown that a possible source of this effect is the solar wind expansion not accordingly with the Parker solution at least at low heliolatitudes. The difference between the experimentally found (r-5/3) and commonly used (r-2) radial dependence of the radial component of the IMF Br may lead to mistakes in the IMF point-to-point recalculations (Khabarova & Obridko, ApJ, 2012; Khabarova, Astronomy Reports, 2013). Using the observed Br (r) dependence, it is easy to find the variation of difference between the <span class="hlt">magnetic</span> flux Fs(r) at certain heliocentric distance r and Fs_1AU at 1 AU, which can be calculated as Fs(r)-Fs_1AU =4?(B1AU /[1AU]-5/3) (r2-5/3 -[1AU]2-5/3) (Khabarova, Astronomy Reports, 2013).The possible influence of presence of the heliospheric current sheet near the ecliptic plane on the picture of <span class="hlt">magnetic</span> field lines and consequent deviation from the Parker's model is discussed.- Khabarova Olga, and Obridko Vladimir, Puzzles of the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field in the Inner Heliosphere, 2012, Astrophysical Journal, 761, 2, 82, doi:10.1088/0004-637X/761/2/82, http://arxiv.org/pdf/1204.6672v2.pdf- Olga V. Khabarova, The <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field: radial and latitudinal dependences. Astronomy Reports, 2013, Vol. 57, No. 11, pp. 844-859, http://arxiv.org/ftp/arxiv/papers/1305/1305.1204.pdf</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM23A2222R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM23A2222R"><span id="translatedtitle">Auroral intensity asymmetries associated with the x-component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field in the two polar hemispheres</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reistad, J. P.; Ostgaard, N.; Laundal, K.; Haaland, S.; Oksavik, K.</p> <p>2013-12-01</p> <p>We present a statistical study of the <span class="hlt">average</span> response of the two auroral ovals to an x-component in the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field (IMF) during non-substorm and negative IMF Bz conditions. Event studies using simultaneous global imaging of the entire auroral ovals have suggested that non-conjugate features of the aurora, meaning a significant difference of auroral intensity in conjugate regions, could be related to hemispheric differences in energy transfer from the Solar Wind (SW). The energy transfer mechanism is referred to as the SW dynamo. In the presence of an x-component in the IMF, open field lines will experience different <span class="hlt">magnetic</span> tension forces in the two hemispheres. In order to investigate the importance of this asymmetry only identified in events studies earlier, we derive <span class="hlt">average</span> patterns of the auroral oval brightness for two extreme (+/- IMF Bx) situations where other effects have been excluded as good as possible in the selection of data. This is achieved using global imaging. In the Northern Hemisphere we use the IMAGE FUV-WIC camera and in the Southern Hemisphere the Polar VIS Earth camera. The most evident difference is found in the Northern Hemisphere between the positive and negative IMF Bx situations. Here the data coverage is excellent during the first years of the IMAGE mission (2000-2003). We find that there seems to be a significant difference in <span class="hlt">average</span> intensity in the dusk/pre-midnight sector between the two situations (+/- IMF Bx) in which the negative IMF Bx situation is the brighter one. This is consistent with the arguments on IMF Bx dependence on <span class="hlt">magnetic</span> tension on open field-lines in the two hemispheres. However, how this mechanism could possibly affect closed field-lines is still unclear. The same analysis is performed for the Southern Hemisphere oval. Although an opposite asymmetry is expected for the proposed mechanism, our results are somehow ambiguous due to the poor coverage compared to the Northern Hemisphere. Our analysis will hopefully address whether this is an hemispheric asymmetry or an effect just evident in the Northern Hemisphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850026542','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850026542"><span id="translatedtitle">The effect of the neutral sheet structure of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field on cosmic ray distribution in space</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Alania, M. V.; Aslamazashvili, R. G.; Bochorishvili, T.; Djapiashvili, T. V.; Tkemaladze, V. S.</p> <p>1985-01-01</p> <p>Results of the numerical solution of the anistoropic diffusion equation are presented. The modulation depth of galactic cosmic rays is defined by the degree of curvature of the neutral current sheet in the heliosphere. The effect of the regular <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) on cosmic ray anisotropy in the period of solar activity minimum (in 1976) is analyzed by the data of the neutron super-monitors of the world network, and the heliolatitudinal gradient and cosmic ray diffusion coefficient are defined.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_5");'>5</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li class="active"><span>7</span></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_7 --> <div id="page_8" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="141"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/207220','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/207220"><span id="translatedtitle">Dynamic response of the cusp morphology to the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field changes: An example observed by Viking</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yamauchi, M.; Lundin, R.; Potemra, T.A.</p> <p>1995-05-01</p> <p>In this article the authors discuss a unique obsevation made in the cusp region by the IMP 8 satellite of ion signatures during a step change in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field from southward to northward, and back southward. The solar wind was relatively steady in density and velocity during this stepwise change. The ion population is observed to have two independent populations, well separated in energy, along the same field lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.2067J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.2067J"><span id="translatedtitle">Magnetohydrodynamic Simulation of the Earth's Magnetotail Response to the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Variations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jauer, Paulo Ricardo; Echer, Ezequiel; Alves, Maria Virginia</p> <p></p> <p>In the present work, a study of the dynamical response of the macroscopic parameters, den-sity, pressure, and velocity, of the Earth's magnetotail, was carried out. The goal of this work was to study the variation of such parameters as a response to the different topologies of the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field (IMF) present in some of the geoeffective solar wind <span class="hlt">magnetic</span> structures. We used Magnetohydrodynamic simulation in order to approach this problem. The bi-dimensional Magnetohydrodynamic code was originally developed by Ogino et al. (1986), being restricted to the formation of the terrestrial magnetosphere with a stationary IMF. After we performed the necessary modifications in the original code, the magnetospheric dynamics was observed. Based on that, we investigated the response of the different regions of the magne-tosphere (specially the magnetotail) to different IMF conditions. Four different configurations of the IMF were analyzed when interacting with the Earth's magnetosphere. Among these different topologies, one could find a representative for a positive shock, i.e, a shock with a pos-itive Bz , another for a negative shock, i.e, a shock with a negative Bz , an idealized HILDCAA event with a Bz squared fluctuation similar to an Alfvnic one, and, finally, a structure similar to a <span class="hlt">Magnetic</span> Cloud. The considered changes in the IMF configuration favored the observation of different physical processes. Among these processes, it was possible to observe the forma-tion of the Near-Earth Neutral Line for the IMF configuration representative of a negative Bz (negative shock). Furthermore, a plasmoid release was observed, which is associated with one of the most dynamics phenomena in the terrestrial magnetosphere: the substorm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011epsc.conf...93L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011epsc.conf...93L"><span id="translatedtitle">Collisions in Space: Observations of Disturbances in the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Caused by Destructive Collisions of Small Bodies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lai, H. R.; Russell, C. T.; Delzanno, G. L.; Jia, Y. D.</p> <p>2011-10-01</p> <p>Collisions between small <span class="hlt">interplanetary</span> bodies can produce clouds of dust particles, which rapidly become charged in the solar wind plasma. A wide range of particle sizes will be produced and the smallest nanoscale particles can be accelerated to solar wind speed in minutes. Our multi-fluid MHD simulation with charged dust as one fluid shows a three-dimensional disturbance in the <span class="hlt">magnetic</span> field with compression and draping in the flow direction and bending in the direction perpendicular to both the flow and unperturbed <span class="hlt">magnetic</span> field, producing a current sheet orthogonal to the flow. The Lorentz force of this current balances the transverse momentum of the gyrating dust particles and the solar gravity force balances the <span class="hlt">magnetic</span> pressure gradient force. Thus the <span class="hlt">magnetic</span> gradient force is proportional to the mass of the picked up dust and allows us to weigh the dust cloud. The <span class="hlt">magnetic</span> field behavior in the simulation results qualitatively resembles the phenomenon called an <span class="hlt">interplanetary</span> field enhancement (IFE), which is featured by a cuspshaped <span class="hlt">magnetic</span> field enhancement lasting from several minutes to hours, with a sharp discontinuity in at least one component of the <span class="hlt">magnetic</span> field. The association between IFE appearance and dust production was first inferred from PVO data in the 1980s, but the IFE formation process has been unclear until now. In this paper, we will gather the statistics of IFEs and use the <span class="hlt">magnetic</span> compression to weigh the mass of the dust cloud. We will also estimate the volume over which individual events may be sensed. Using this volume together with the IFE occurrence rate we can calculate the inferred collision rate. We find for the IFE with mass about 107 kg, this rate approximately agrees with the estimated rate of collision of <span class="hlt">interplanetary</span> bodies which can produce dust within the same mass range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4497471','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4497471"><span id="translatedtitle">Saturn's dayside ultraviolet auroras: Evidence for morphological dependence on the direction of the upstream <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Meredith, C J; Alexeev, I I; Badman, S V; Belenkaya, E S; Cowley, S W H; Dougherty, M K; Kalegaev, V V; Lewis, G R; Nichols, J D</p> <p>2014-01-01</p> <p>We examine a unique data set from seven Hubble Space Telescope (HST) “visits” that imaged Saturn's northern dayside ultraviolet emissions exhibiting usual circumpolar “auroral oval” morphologies, during which Cassini measured the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) upstream of Saturn's bow shock over intervals of several hours. The auroras generally consist of a dawn arc extending toward noon centered near ∼15° colatitude, together with intermittent patchy forms at ∼10° colatitude and poleward thereof, located between noon and dusk. The dawn arc is a persistent feature, but exhibits variations in position, width, and intensity, which have no clear relationship with the concurrent IMF. However, the patchy postnoon auroras are found to relate to the (suitably lagged and <span class="hlt">averaged</span>) IMF Bz, being present during all four visits with positive Bz and absent during all three visits with negative Bz. The most continuous such forms occur in the case of strongest positive Bz. These results suggest that the postnoon forms are associated with reconnection and open flux production at Saturn's magnetopause, related to the similarly interpreted bifurcated auroral arc structures previously observed in this local time sector in Cassini Ultraviolet Imaging Spectrograph data, whose details remain unresolved in these HST images. One of the intervals with negative IMF Bz however exhibits a prenoon patch of very high latitude emission extending poleward of the dawn arc to the <span class="hlt">magnetic</span>/spin pole, suggestive of the occurrence of lobe reconnection. Overall, these data provide evidence of significant IMF dependence in the morphology of Saturn's dayside auroras. Key Points We examine seven cases of joint HST Saturn auroral images and Cassini IMF data The persistent but variable dawn arc shows no obvious IMF dependence Patchy postnoon auroras are present for northward IMF but not for southward IMF PMID:26167441</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720018182','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720018182"><span id="translatedtitle">Precipitation of low energy electrons at high latitudes: Effects of substorms, <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and dipole tilt angle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burch, J. L.</p> <p>1972-01-01</p> <p>Data from the auroral particles experiment on OGO-4 were used to study effects of substorm activity, <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field latitutde, and dipole tilt angle on high-latitude precipitation of 700 eV electrons. It was found that: (1) The high-latitude zone of 700 eV electron precipitation in late evening and early morning hours moves equatorward by 5 to 10 deg during substorms. (2) The low-latitude boundary of polar cusp electron precipitation at 9 to 15 hours MLT also moves equatorward by several degrees during substorms and, in the absence of significant substorm activity, after a period of southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. (3) With times containing substorm activity or a southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field eliminated, the low-latitude boundary of polar cusp electron precipitation is found to move by approximately 4 deg over the total yearly range of tilt angles. At maximum winter and summer conditions the invariant latitude of the boundary is shown to shift by approximately -3 deg and +1 deg respectively from its equinox location.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSM41A1999D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSM41A1999D"><span id="translatedtitle">Solar Wind Energy Input during Prolonged, Intense Northward <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Fields: A New Coupling Function</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Du, A.; Tsurutani, B.; Sun, W.</p> <p>2011-12-01</p> <p>Substorm activity during intense (B > 10 nT), long duration (T > 3 hr) northward (Bz > 0 nT = N) IMF <span class="hlt">magnetic</span> clouds (MCs) during solar cycle 23 (SC23) have been examined in detail. The MCs with northward-then-southward (NS) IMFs were analyzed separately from MCs with southward-then-northward (SN) configurations. It is found that there is a lack of substorms during the N field intervals of NS clouds. In sharp contrast, substorms do occur during the N field portions of SN MCs. From the above two results it is reasonable to conclude that the latter substorms represent residual energy remaining from the preceding S portions of the SN MCs. We use this scenario to derive a new solar wind-magnetosphere coupling function during northward IMFs: E_(NIMF) = ? N^(-1/12) V^(7/3) B^(1/2)+? V |Dst_(min)|. The first term on the right-hand side of the equation represents the energy input via "viscous interaction", and the second term indicates the residual energy stored in the magnetotail. It was empirically found that the magnetosphere/magnetotail can store energy for ~ 4 hrs before it dissipates away. The concept of magnetosphere/magnetotail short term energy storage should prove to be useful to predict when <span class="hlt">interplanetary</span> shocks will and will not trigger substorms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870055304&hterms=different+association&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Ddifferent%2Bassociation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870055304&hterms=different+association&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Ddifferent%2Bassociation"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field enhancements - Further evidence for an association with asteroid 2201 Oljato</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Russell, C. T.</p> <p>1987-01-01</p> <p>In 1980 and 1983 the asteroid 2201 Oljato passed inside the orbit of Venus, respectively 65 and 21 days prior to the passage of Venus, apparently causing disturbances in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field, possibly through the interaction of its debris trail with the solar wind. In July 1986 the asteroid passed through the inner solar system 25 days after Venus and it is expected to find similar disturbances if the debris trail extended in front of the asteroid. The expected disturbances were observed. All data from the longitude range of the disturbances have been examined for all Venus years as well as from a control period over the same solar longitudes but at different ecliptic longitudes. No enhancements in the rate of occurrence of events were seen in the control periods during 1980, 1983 and 1986, and the rate was uniformly low at all other times. The new data reaffirm the association of solar wind disturbances with the asteroidal passage and imply a debris trail that extends perhaps 1 AU both in front of and behind the asteroid.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860056287&hterms=magnetic+signature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmagnetic%2Bsignature','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860056287&hterms=magnetic+signature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmagnetic%2Bsignature"><span id="translatedtitle">Ionospheric convection signatures observed by DE 2 during northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Heelis, R. A.; Hanson, W. B.; Reiff, P. H.; Winningham, J. D.</p> <p>1986-01-01</p> <p>Observations of the ionospheric convection signature at high latitudes are examined during periods of prolonged northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). The data from Dynamics Explorer 2 show that a four-cell convection pattern can frequently be observed in a region that is displaced to the sunward side of the dawn-dusk meridian regardless of season. In the eclipsed ionosphere, extremely structured or turbulent flow exists with no identifiable connection to a more coherent pattern that may simultaneously exist in the dayside region. The two highest-latitude convection cells that form part of the coherent dayside pattern show a dependence on the y component of the IMF. This dependence is such that a clockwise circulating cell displaced toward dawn dominates the high-latitude region when B(Y) is positive. Anti-clockwise circulation displaced toward dusk dominates the highest latitudes when B(Y) is negative. Examination of the simultaneously observed energetic particle environment suggests that both open and closed field lines may be associated with the high-latitude convection cells. On occasions these entire cells can exist on open field lines. The existence of closed field lines in regions of sunward flow is also apparent in the data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5361639','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5361639"><span id="translatedtitle">Magnetosheath plasma precipitation in the polar cusp and its control by the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Woch, J.; Lundin, R. )</p> <p>1992-02-01</p> <p>Magnetosheath particle precipitation in the polar cusp region is studied based on Viking hot plasma data obtained on meridional cusp crossings. Two distinctively different regions are commonly encountered on a typical pass. One region is characterized by high-density particle precipitation, with an ion population characterized by a convecting Maxwellian distribution. Typical magnetosheath parameters are inferred for the spectrum of the source population. The spectral shape of the ion population encountered in the second region suggests that here the magnetosheath ions have been energized by about 1 keV, corresponding to an ion velocity gain of about twice the magnetosheath Alfven velocity. The location of the region containing the accelerated plasma is dependent on the IMF B{sub z} component. For southward IMF the acceleration region is bounded by the ring current population on the equatorward side and by the unaccelerated magnetosheath plasma precipitation on the poleward side. For northward IMF the region is located at the poleward edge of the region with unaccelerated precipitation. The accelerated ion population is obviously transported duskward (dawnward) for a dawnward (duskward) directed IMF. These observations are interpreted as evidence for plasma acceleration due to magnetopause current sheet disruptions/merging of magnetospheric and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> flux tubes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021421&hterms=spaghetti&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dspaghetti','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021421&hterms=spaghetti&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dspaghetti"><span id="translatedtitle">Field lines and <span class="hlt">magnetic</span> surfaces in a two-component slab/2D model of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fluctuations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Matthaeus, W. H.; Pontius, D. H., Jr.; Gray, P. C.; Bieber, J. W.</p> <p>1995-01-01</p> <p>A two-component model for the spectrum of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fluctuations was proposed on the basis of ISEE observations, and has found an intriguing level of application in other solar wind studies. The model fluctuations consist of a fraction of 'slab' fluctuations, varying only in the direction parallel to the locally uniform mean <span class="hlt">magnetic</span> field B(0) and a complement of 2D (two-dimensional) fluctuations that vary in the directions transverse to B(0). We have developed an spectral method computational algorithm for computing the <span class="hlt">magnetic</span> flux surfaces (flux tubes) associated with the composite model, based upon a precise analogy with equations for ideal transport of a passive scalar in planar two dimensional geometry. Visualization of various composite models will be presented, including the 80 percent 2D/ 20 percent slab model with delta B/B(0) approximately equals 1 and a minus 5/3 spectral law, that is thought to approximately represent a snapshot of solar wind turbulence. Characteristically, the visualizations show that flux tubes, even when defined as regular on some plane, shred and disperse rapidly as they are viewed along the parallel direction. This diffusive process, which generalizes the standard picture of field line random walk, will be discussed in detail. Evidently, the traditional picture that flux tubes randomize like strands of spaghetti with a uniform tangle along the axial direction is in need of modification.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950046221&hterms=F6&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DF6','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950046221&hterms=F6&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DF6"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field control of mantle precipitation and associated field-aligned currents</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Xu, Dingan; Kivelson, Margaret G.; Walker, Ray J.; Newell, Patrick T.; Meng, C.-I.</p> <p>1995-01-01</p> <p>Dayside reconnection, which is particularly effective for a southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF), allows magnetosheath particles to enter the magnetosphere where they form the plasma mantle. The motions of the reconnected flux tube produce convective flows in the ionosphere. It is known that the convection patterns in the polar cap are skewed to the dawnside for a positive IMF B(sub y) (or duskside for a negative IMF B(sub y)) in the northern polar cap. Correspondingly, one would expect to find asymmetric distributions of mantle particle precipitation, but previous results have been unclear. In this paper the correlation between B(sub y) and the distribution of mantle particle precipitation is studied for steady IMF conditions with southward IMF. Ion and electron data from the Defense Meteorological Satellite Program (DMSP) F6 and F7 satellites are used to identify the mantle region and IMP 8 is used as a solar wind monitor to characterize the IMF. We study the local time extension of mantle precipitation in the prenoon and postnoon regions. We find that, in accordance with theoretical expectations for a positive (negative) IMF B(sub y), mantle particle precipitation mainly appears in the prenoon region of the northern (southern) hemisphere. The mantle particle precipitation can extend to as early as 0600 <span class="hlt">magnetic</span> local time (MLT) in the prenoon region but extends over a smaller local time region in the postnoon sector (we did not find mantle plasma beyond 1600 MLT in our data set although coverage is scant in this area). Magnetometer data from F7 are used to determine whether part of the region 1 current flows on open field lines. We find that at times part of the region 1 sense current extends into the region of mantle particle precipitation, and is therefore on open field lines. In other cases, region 1 currents are absent on open field lines. Most of the observed features can be readily interpreted in terms of the open magnetosphere model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730018611','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730018611"><span id="translatedtitle">The relation between the azimuthal component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and the geomagnetic field in the polar caps</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Svalgaard, L.</p> <p>1973-01-01</p> <p>The recently discovered relation between the azimuthal component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and <span class="hlt">magnetic</span> variations in the earth's polar caps is reviewed. When the IMF azimuthal component is positive (typical of an <span class="hlt">interplanetary</span> sector with <span class="hlt">magnetic</span> field directed away from the sun) geomagnetic perturbations directed away from the earth are observed within 8 deg from the corrected geomagnetic pole. When the IMF azimuthal component is negative (typically within toward sectors) the geomagnetic perturbations are directed towards the earth at both poles. These perturbations can also be described by an equivalent current flowing at a constant <span class="hlt">magnetic</span> latitude of 80 - 82 deg clockwise around the <span class="hlt">magnetic</span> poles during toward sectors and counterclockwise during away sectors. This current fluctuates in magnitude and direction with the azimuthal component of the IMF, with a delay time of the order of 20 minutes. The importance of this effect for understanding of both solar <span class="hlt">magnetism</span> and magnetospheric physics is stressed in view of the possibility for investigating the solar sector structure during the last five sunspot cycles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21578263','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21578263"><span id="translatedtitle"><span class="hlt">MAGNETIC</span> FIELD-LINE LENGTHS IN <span class="hlt">INTERPLANETARY</span> CORONAL MASS EJECTIONS INFERRED FROM ENERGETIC ELECTRON EVENTS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kahler, S. W.; Haggerty, D. K.; Richardson, I. G.</p> <p>2011-08-01</p> <p>About one quarter of the observed <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs) are characterized by enhanced <span class="hlt">magnetic</span> fields that smoothly rotate in direction over timescales of about 10-50 hr. These ICMEs have the appearance of <span class="hlt">magnetic</span> flux ropes and are known as '<span class="hlt">magnetic</span> clouds' (MCs). The total lengths of MC field lines can be determined using solar energetic particles of known speeds when the solar release times and the 1 AU onset times of the particles are known. A recent examination of about 30 near-relativistic (NR) electron events in and near 8 MCs showed no obvious indication that the field-line lengths were longest near the MC boundaries and shortest at the MC axes or outside the MCs, contrary to the expectations for a flux rope. Here we use the impulsive beamed NR electron events observed with the Electron Proton and Alpha Monitor instrument on the Advanced Composition Explorer spacecraft and type III radio bursts observed on the Wind spacecraft to determine the field-line lengths inside ICMEs included in the catalog of Richardson and Cane. In particular, we extend this technique to ICMEs that are not MCs and compare the field-line lengths inside MCs and non-MC ICMEs with those in the ambient solar wind outside the ICMEs. No significant differences of field-line lengths are found among MCs, ICMEs, and the ambient solar wind. The estimated number of ICME field-line turns is generally smaller than those deduced for flux-rope model fits to MCs. We also find cases in which the electron injections occur in solar active regions (ARs) distant from the source ARs of the ICMEs, supporting CME models that require extensive coronal <span class="hlt">magnetic</span> reconnection with surrounding fields. The field-line lengths are found to be statistically longer for the NR electron events classified as ramps and interpreted as shock injections somewhat delayed from the type III bursts. The path lengths of the remaining spike and pulse electron events are compared with model calculations of solar wind field-line lengths resulting from turbulence and found to be in good agreement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ApJ...736..106K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ApJ...736..106K"><span id="translatedtitle"><span class="hlt">Magnetic</span> Field-line Lengths in <span class="hlt">Interplanetary</span> Coronal Mass Ejections Inferred from Energetic Electron Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kahler, S. W.; Haggerty, D. K.; Richardson, I. G.</p> <p>2011-08-01</p> <p>About one quarter of the observed <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs) are characterized by enhanced <span class="hlt">magnetic</span> fields that smoothly rotate in direction over timescales of about 10-50 hr. These ICMEs have the appearance of <span class="hlt">magnetic</span> flux ropes and are known as "<span class="hlt">magnetic</span> clouds" (MCs). The total lengths of MC field lines can be determined using solar energetic particles of known speeds when the solar release times and the 1 AU onset times of the particles are known. A recent examination of about 30 near-relativistic (NR) electron events in and near 8 MCs showed no obvious indication that the field-line lengths were longest near the MC boundaries and shortest at the MC axes or outside the MCs, contrary to the expectations for a flux rope. Here we use the impulsive beamed NR electron events observed with the Electron Proton and Alpha Monitor instrument on the Advanced Composition Explorer spacecraft and type III radio bursts observed on the Wind spacecraft to determine the field-line lengths inside ICMEs included in the catalog of Richardson & Cane. In particular, we extend this technique to ICMEs that are not MCs and compare the field-line lengths inside MCs and non-MC ICMEs with those in the ambient solar wind outside the ICMEs. No significant differences of field-line lengths are found among MCs, ICMEs, and the ambient solar wind. The estimated number of ICME field-line turns is generally smaller than those deduced for flux-rope model fits to MCs. We also find cases in which the electron injections occur in solar active regions (ARs) distant from the source ARs of the ICMEs, supporting CME models that require extensive coronal <span class="hlt">magnetic</span> reconnection with surrounding fields. The field-line lengths are found to be statistically longer for the NR electron events classified as ramps and interpreted as shock injections somewhat delayed from the type III bursts. The path lengths of the remaining spike and pulse electron events are compared with model calculations of solar wind field-line lengths resulting from turbulence and found to be in good agreement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20110023536&hterms=mcs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmcs','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110023536&hterms=mcs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmcs"><span id="translatedtitle"><span class="hlt">Magnetic</span> Field-Line Lengths in <span class="hlt">Interplanetary</span> Coronal Mass Ejections Inferred from Energetic Electron Events</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kahler, S. W.; Haggerty, D. K.; Richardson, I. G.</p> <p>2011-01-01</p> <p>About one quarter of the observed <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs) are characterized by enhanced <span class="hlt">magnetic</span> fields that smoothly rotate in direction over timescales of about 10-50 hr. These ICMEs have the appearance of <span class="hlt">magnetic</span> flux ropes and are known as "<span class="hlt">magnetic</span> clouds" (MCs). The total lengths of MC field lines can be determined using solar energetic particles of known speeds when the solar release times and the I AU onset times of the particles are known. A recent examination of about 30 near-relativistic (NR) electron events in and near 8 MCs showed no obvious indication that the field-line lengths were longest near the MC boundaries and shortest at the MC axes or outside the MCs, contrary to the expectations for a flux rope. Here we use the impulsive beamed NR electron events observed with the Electron Proton and Alpha Monitor instrument on the Advanced Composition Explorer spacecraft and type III radio bursts observed on the Wind spacecraft to determine the field-line lengths inside ICMEs included in the catalog of Richardson & Cane. In particular, we extend this technique to ICMEs that are not MCs and compare the field-line lengths inside MCs and non-MC ICMEs with those in the ambient solar wind outside the ICMEs. No significant differences of field-line lengths are found among MCs, ICMEs, and the ambient solar wind. The estimated number of ICME field-line turns is generally smaller than those deduced for flux-rope model fits to MCs. We also find cases in which the electron injections occur in solar active regions CARs) distant from the source ARs of the ICMEs, supporting CME models that require extensive coronal <span class="hlt">magnetic</span> reconnection with surrounding fields. The field-line lengths are found to be statistically longer for the NR electron events classified as ramps and interpreted as shock injections somewhat delayed from the type III bursts. The path lengths of the remaining spike and pulse electron events are compared with model calculations of solar wind field-line lengths resulting from turbulence and found to be in good agreement.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6850377','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6850377"><span id="translatedtitle">Control of auroral-zone dynamics and thermodynamics by the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field dawn-dusk (Y) component</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sica, R.J.; Hernandez, G.; Emery, B.A.; Roble, R.G.; Smith, R.W.</p> <p>1989-09-01</p> <p>It is well known that ion drag momentum forcing is one of the primary drivers of the thermospheric wind at high latitudes. Previous theoretical and experimental studies have shown that the dawn-dusk component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF By) expands the classical symmetric two-cell convection pattern toward dusk (By negative) or toward dawn (By positive) in the northern hemisphere, altering the ion drag forcing on the neutral atmosphere. Measurements of the neutral dynamics associated with these convection patterns have been presented primarily at <span class="hlt">magnetic</span> latitudes greater than 70 deg. in the polar cap.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016P%26SS..120...78V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016P%26SS..120...78V"><span id="translatedtitle">Parametric study of the solar wind interaction with the Hermean magnetosphere for a weak <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Varela, J.; Pantellini, F.; Moncuquet, M.</p> <p>2016-01-01</p> <p>The aim of this study is to simulate the interaction of the solar wind with the Hermean magnetosphere when the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is weak, performing a parametric study for all the range of hydrodynamic values of the solar wind predicted on Mercury for the ENLIL + GONG WSA + Cone SWRC model: density from 12 to 180 cm-3, velocity from 200 to 500 km/s and temperatures from 2 ·104 to 18 ·104 K, and compare the results with a real MESSENGER orbit as reference case. We use the code PLUTO in spherical coordinates and an asymmetric multipolar expansion for the Hermean <span class="hlt">magnetic</span> field. The study shows for all simulations a stand off distance larger than the Mercury radius and the presence of close <span class="hlt">magnetic</span> field lines on the day side of the planet, so the dynamic pressure of the solar wind is not high enough to push the magnetopause on the planet surface if the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is weak. The simulations with large dynamic pressure lead to a large compression of the Hermean <span class="hlt">magnetic</span> field modifying its topology in the inner magnetosphere as well as the plasma flows from the magnetosheath towards the planet surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AdSpR..52.2112A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AdSpR..52.2112A"><span id="translatedtitle">Sunspot numbers, <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field, and cosmic ray intensity at earth: Nexus for the twentieth century</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ahluwalia, H. S.</p> <p>2013-12-01</p> <p>The pivotal role played by the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (B) in modulating galactic cosmic ray (GCR) intensity in the heliosphere is described. We show that the inverse correlation observed by Forbush (1958) between GCRs and sunspot numbers (SSNs) is reflected in high correlation between SSNs and B (cc = 0.94). The SSN data are available since 1700 and the derived B data since 1835. The paleo-cosmic ray data are available for several millennia in the form of 10Be radionuclide sequestered in polar ice. The data of the ion chambers (ICs) at the Cheltenham-Fredericksburg-Yakutsk (CFY) sites are combined to create a data string for 1937-1988. In turn, these data are used to extend the measurements of the low energy GCR ions (>0.1 GeV) at balloon altitudes at high latitudes in Russia to 1937. These data are then correlated to B and the fit parameters are used to extend the low energy ion data to 1900, creating the instrumental era GCR time series for the twentieth century. The derived GCR time series is compared to 10Be measured at two sites in Greenland, namely Dye 3 and NGRIP for 1900-2000 to check the internal consistency of datasets for the long-term trend. We find that the annual mean rate (%) for 1965 at NGRIP is an outlier. We replace it with the mean of 1964 and 1965 rates and construct a new re-normalized time series at NGIP, improving the agreement with the derived instrumental era GCR time series for the twentieth century as well. This should encourage its use by heliophysics community for varied applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20110007245&hterms=butterfly&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbutterfly','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110007245&hterms=butterfly&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dbutterfly"><span id="translatedtitle">Solar Sources and Geospace Consequences of <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Clouds Observed During Solar Cycle 23</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gopalswamy, N.; Akiyama, S.; Yashiro, S.; Michalek, G.; Lepping, R. P.</p> <p>2007-01-01</p> <p>We present results of a statistical investigation of 99 <span class="hlt">magnetic</span> clouds (MCs) observed during 1995-2005. The MC-associated coronal mass ejections (CMEs) are faster and wider on the <span class="hlt">average</span> and originate within +/-30deg from the solar disk center. The solar sources of MCs also followed the butterfly diagram. The correlation between the <span class="hlt">magnetic</span> field strength and speed of MCs was found to be valid over a much wider range of speeds. The number of south-north (SN) MCs was dominant and decreased with solar cycle, while the number of north-south (NS) MCs increased confirming the odd-cycle behavior. Two-thirds of MCs were geoeffective; the Dst index was highly correlated with speed and <span class="hlt">magnetic</span> field in MCs as well as their product. Many (55%) fully northward (FN) MCs were geoeffective solely due to their sheaths. The non-geoeffective MCs were slower (<span class="hlt">average</span> speed approx. 382 km/s), had a weaker southward <span class="hlt">magnetic</span> field (<span class="hlt">average</span> approx. -5.2nT), and occurred mostly during the rise phase of the solar activity cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080015820&hterms=magnetic+flux&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bflux','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080015820&hterms=magnetic+flux&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bflux"><span id="translatedtitle">An Alternative Interpretation of the Relationship between the Inferred Open Solar Flux and the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Riley, Pete</p> <p>2007-01-01</p> <p>Photospheric observations at the Wilcox Solar Observatory (WSO) represent an uninterrupted data set of 32 years and are therefore unique for modeling variations in the <span class="hlt">magnetic</span> structure of the corona and inner heliosphere over three solar cycles. For many years, modelers have applied a latitudinal correction factor to these data, believing that it provided a better estimate of the line-of-sight <span class="hlt">magnetic</span> field. Its application was defended by arguing that the computed open flux matched observations of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) significantly better than the original WSO correction factor. However, no physically based argument could be made for its use. In this Letter we explore the implications of using the constant correction factor on the value and variation of the computed open solar flux and its relationship to the measured IMF. We find that it does not match the measured IMF at 1 AU except at and surrounding solar minimum. However, we argue that <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs) may provide sufficient additional <span class="hlt">magnetic</span> flux to the extent that a remarkably good match is found between the sum of the computed open flux and inferred ICME flux and the measured flux at 1 AU. If further substantiated, the implications of this interpretation may be significant, including a better understanding of the structure and strength of the coronal field and I N providing constraints for theories of field line transport in the corona, the modulation of galactic cosmic rays, and even possibly terrestrial climate effects.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_6");'>6</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li class="active"><span>8</span></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_8 --> <div id="page_9" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="161"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001JGR...10629419S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001JGR...10629419S"><span id="translatedtitle">Simulations of the magnetosphere for zero <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field: The ground state</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sonnerup, Bengt U. .; Siebert, Keith D.; White, Willard W.; Weimer, Daniel R.; Maynard, Nelson C.; Schoendorf, Jacqueline A.; Wilson, Gordon R.; Siscoe, George L.; Erickson, Gary M.</p> <p>2001-12-01</p> <p>A global MHD simulation code, the Integrated Space Weather Prediction Model, is used to examine the steady state properties of the magnetosphere for zero <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. In this ``ground state'' of the system, reconnection at the magnetopause is absent. Topics reported here include (1) qualitative description of global <span class="hlt">magnetic</span> field, plasma flow, and current systems (Chapman-Ferraro, geotail, Region 1 and Region 2 currents); (2) quantitative parametric studies of shock jump conditions, magnetopause and shock standoff distance, polar cap voltage, and total Region 1 current for different solar wind speeds and ionospheric Pedersen conductances; and (3) quantitative analysis of the low-latitude boundary layer (LLBL) and its coupling to the ionosphere. The central part of the geomagnetic tail is found to be very long, extending beyond the downstream end of the simulation box at X=-300 RE. Along each flank a ``wing-like'' region containing closed, albeit strongly stretched, field lines is present. Each such region contains a narrow convection cell, consisting of the tailward flowing LLBL and an adjoining narrow channel of sunward return flow. These cells are the result of viscous-like interaction along the magnetospheric flanks, with an effective kinematic viscosity, entirely of numerical origin, estimated to be ?=1.8108m2s-1. Except in certain regions near the magnetopause, the magnetosheath flow is steady and laminar while the internal motion in the tail displays turbulent vortical motion in the plasma sheet. Plasma transport in the tail occurs as a result of this turbulence, and substantial turbulent plasma entry across the equatorial magnetopause is seen in the region -10RE<X<0 RE behind the torus of dipolar field lines. The polar cap potential ??PC is 29.9+/-1.4kV for VSW=400kms-1 and ?P=6mho, which is in reasonable agreement with results inferred from satellite observations. About half of ??PC can be attributed to the LLBLs with the remainder coming from a dawn-to-dusk potential drop along the dayside magnetopause, caused by nonlinearly switched resistivity, added explicitly to the MHD equations, and/or by numerical diffusion. The magnetospheric voltage-current relation at VSW=400kms-1 has a constant negative slope with an open circuit voltage of ??PC=38.5kV. The total Region 1 current (into the northern dawn hemisphere) is 0.66 MA (at VSW=400kms-1 and ?P=6mho). It maximizes at about 2.83 MA during short-circuit conditions (?P=? ??PC=0).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/121258','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/121258"><span id="translatedtitle">Polar cap field-aligned currents for southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Xu, D.; Kivelson, M.G.</p> <p>1994-04-01</p> <p>It has been common to suppose that polar region field-aligned currents for southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields (IMF) consist of two parts: region 1 and region 2 currents. It is often suggested that both of these current systems flow on closed field lines. In this pilot study the limited data available from the ISIS 2 satellite are used to examine region 1 currents with the objective of establishing whether or not they can exist partially on open field lines (i.e., inside the polar caps) for southward IMF. <span class="hlt">Magnetic</span> field perturbations were used to identify the field-aligned currents (FACs). The absence of {ge}keV electrons but the presence of {le}200 eV electrons in the polar cap or background polar rain is considered as the signature of open field lines. On some passes, region 1 sense FACs appear to be composed of two parts. The poleward part of the current signature is accompanied by electron fluxes at energies {le}200 eV or occasionally by fluxes at background levels while the equatorward part of the interval is accompanied by electron fluxes at energies both {le}200 eV and {ge}keV. On other passes, region 1 sense currents are accompanied by both {le}200 eV and {ge}keV electron fluxes during the entire pass. The authors propose that region 1 sense FACs flow on both closed and open field lines for the first situation and on closed field lines for the second situation. In seeking to understand why region 1 currents sometimes flow only on closed field lines and sometimes flow on open as well as closed field lines, the authors suggest a control by the IMF B{sub y}. The IMF B{sub y} may also shift the region 1 currents on open field lines to one side (dawn or dusk) of the polar cap like the convection cells. Such a shift provides a consistent model of the data taken on the dayside and the authors discuss why night side observations may be different. 47 refs., 6 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760009906','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760009906"><span id="translatedtitle">Observations of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field between 0.46 and 1 A.U. by the Mariner 10 spacecraft. Ph.D. Thesis - Catholic Univ. of Am.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Behannon, K. W.</p> <p>1976-01-01</p> <p>Almost continuous measurement of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) at a sampling rate of 25 vectors/sec was performed by the <span class="hlt">magnetic</span> field experiment onboard the Mariner 10 spacecraft during the period November 3, 1973 to April 14, 1974, comprising approximately 5-2/3 solar rotations and extending in radial distance from the sun from 1 to 0.46 AU. A clearly discernible two-sector pattern of field polarity was observed during the last 3-1/2 months of the period, with the dominant polarity toward the sun below the solar equatorial plane. Two compound high-speed solar wind streams were also present during this period, one in each <span class="hlt">magnetic</span> field sector. Relative fluctuations of the field in magnitude and direction were found to have large time variations, but on <span class="hlt">average</span> the relative magnitude fluctuations were approximately constant over the range of heliocentric distance covered while the relative directional fluctuations showed a slight decrease on <span class="hlt">average</span> with increasing distance. The occurrence rate of directional discontinuities was also found to decrease with increasing radial distance from the sun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/207213','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/207213"><span id="translatedtitle">Observations of solar-wind-driven progression of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field B{sub Y}-related dayside ionospheric disturbances</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Stauning, P.; Friis-Christensen, E.; Clauer, C.R.</p> <p>1995-05-01</p> <p>Observations from August 2, and 3, 1991, of poleward progressing, dayside convection disturbances accompanied by geomagnetic perturbations and ionospheric radio wave absorption have been analyzed and compared to variations in the solar wind parameters as observed from the IMP 8 satellite. The convection disturbances appear to start at dayside cusp latitudes from where they progress antisunward to high latitudes. The reported observations have enabled calculations of the progression directions and velocities and precise estimates of the delays between solar wind variations as measured by the IMP 8 satellite and ionospheric convection changes as observed from an array of polar <span class="hlt">magnetic</span> observatories. The progressing ionospheric disturbance events occur during intervals of southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields (negative <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) B{sub Z} component); they are found to be closely related to variations of the east-west component B{sub Y} of the IMF. The close coupling between the solar wind and the polar ionosphere(s) is explained in an open magnetospheric model in which the geomagnetic field extending from a localized region of the dayside polar cap merges with the southward <span class="hlt">interplanetary</span> field. Variations in the IMF B{sub Y} component are reproduced in corresponding modulations of the east-west component of the plasma flow at the ionospheric foot points of the connecting `open` field lines. The perturbations of the plasma flow persist while the open field lines are convected with the ionospheric plasma across part of the dayside polar cap. The observed geomagnetic perturbations result from the combined effects of field-aligned currents and horizontal ionospheric currents, notably the convection-related Hall currents. The associated radio wave absorption events are explained as the result of E region electron heating by the horizontal electric fields associated with the convection enhancements. 48 refs., 16 figs., 3 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800011715','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800011715"><span id="translatedtitle"><span class="hlt">Interplanetary</span> medium data book, supplement, 1975 - 1978</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>King, J. H.</p> <p>1979-01-01</p> <p>Since the issurance of the <span class="hlt">Interplanetary</span> Medium Data Book (NSSDC/WDC-A-R&S 77-04, 1977) which contains plots and listings of hourly <span class="hlt">average</span> <span class="hlt">interplanetary</span> field and plasma parameters covering the period November 27, 1963 through December 30, 1975, additional data are available which fill some 1975 data gaps and which extend the data coverage well into 1978. This supplement contains all the presently available data for the years 1975-1978, <span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field (IMF) data are from the IMP 8 triaxial fluxgate magnetometer experiment. Derived plasma parameters are form the IMP 7 and IMP 8 instruments. Some of the early 1975 IMF data are from a HEOS 1 experiment.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/166283','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/166283"><span id="translatedtitle">Effect of sudden impulses on currents in the auroral ionosphere under northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field conditions: A case study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Russell, C.T.; Ginskey, M.; Angelopoulos, V.</p> <p>1994-09-01</p> <p>The authors examine the response of auroral <span class="hlt">magnetic</span> records to the passage of an <span class="hlt">interplanetary</span> shock at a time when the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field was northward. They restrict their attention solely to the sector within 3 hours of local <span class="hlt">magnetic</span> midnight for a single case selected when a bursty bulk flow event was recorded in the near tail by ISEE 2. Over most of the nightside at high latitudes only a weak disturbance if any is seen. At lower latitudes a plateau is seen in the H component, coincident with the bursty bulk flow event. At 65{degrees} latitude from about midnight to 3:00 LT a weak pair of negative bays is observed, also coincident with the bursty bulk flow event. The authors conclude that the tail and the auroral ionosphere were closely coupled during this sudden impulse, but the auroral zone disturbance appears to be mainly the brief activation of a section of the auroral electrojet rather than a classic substorm. No expansion or motion of the electrojet was observed, and the activation was no longer than that of the bursty bulk flow in the tail. 10 refs., 9 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AnGeo..29...31B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AnGeo..29...31B"><span id="translatedtitle">Impact of solar wind depression on the dayside magnetosphere under northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Baraka, S.; Ben-Jaffel, L.</p> <p>2011-01-01</p> <p>We present a follow up study of the sensitivity of the Earth's magnetosphere to solar wind activity using a particles-in-cell model (Baraka and Ben Jaffel, 2007), but here during northward <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field (IMF). The formation of the magnetospheric cavity and its elongation around the planet is obtained with the classical structure of a magnetosphere with parallel lobes. An impulsive disturbance is then applied to the system by changing the bulk velocity of the solar wind to simulate a decrease in the solar wind dynamic pressure followed by its recovery. In response to the imposed drop in the solar wind velocity, a gap (abrupt depression) in the incoming solar wind plasma appears moving toward the Earth. The gap's size is a ~15 RE and is comparable to the sizes previously obtained for both Bz<0 and Bz=0. During the initial phase of the disturbance along the x-axis, the dayside magnetopause (MP) expands slower than the previous cases of IMF orientations as a result of the abrupt depression. The size of the MP expands nonlinearly due to strengthening of its outer boundary by the northward IMF. Also, during the initial 100 ?t, the MP shrank down from 13.3 RE to ~9.2 RE before it started expanding, a phenomenon that was also observed for southern IMF conditions but not during the no IMF case. As soon as they felt the solar wind depression, cusps widened at high altitude while dragged in an upright position. For the field's topology, the reconnection between magnetospheric and magnetosheath fields is clearly observed in both the northward and southward cusps areas. Also, the tail region in the northward IMF condition is more confined, in contrast to the fishtail-shape obtained in the southward IMF case. An X-point is formed in the tail at ~110 RE compared to ~103 RE and ~80 RE for Bz=0 and Bz<0, respectively. Our findings are consistent with existing reports from many space observatories (Cluster, Geotail, Themis, etc.) for which predictions are proposed to test furthermore our simulation technique.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM33A2155A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM33A2155A"><span id="translatedtitle">Using ACE Observations of <span class="hlt">Interplanetary</span> Particles and <span class="hlt">Magnetic</span> Fields as Possible Contributors to Variations Observed at Van Allen Probes during Major events in 2013</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Armstrong, T. P.; Manweiler, J. W.; Gerrard, A. J.; Gkioulidou, M.; Lanzerotti, L. J.; Patterson, J. D.</p> <p>2013-12-01</p> <p>Observations from ACE EPAM including energy spectra of protons, helium, and oxygen will be prepared for coordinated use in estimating the direct and indirect access of energetic particles to inner and outer geomagnetic trapping zones. Complete temporal coverage from ACE at 12 seconds, 5 minutes, 17 minutes, hourly and daily cadences will be used to catalog <span class="hlt">interplanetary</span> events arriving at Earth including <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field sector boundaries, <span class="hlt">interplanetary</span> shocks, and <span class="hlt">interplanetary</span> coronal mass ejections, ICMEs. The first 6 months of 2013 have included both highly disturbed times, March 17 and May 22, and extended quiet periods of little or no variations. Among the specific questions that ACE and Van Allen Probes coordinated observations may aid in resolving are: 1. How much, if any, direct capture of <span class="hlt">interplanetary</span> energetic particles occurs and what conditions account for it? 2. How much influence do <span class="hlt">interplanetary</span> field and particle variations have on energization and/or loss of geomagnetically trapped populations? The poster will also present important links and describe methods and important details of access to numerically expressed ACE EPAM and Van Allen Probes RBSPICE observations that can be flexibly and easily accessed via the internet for student and senior researcher use.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/183248','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/183248"><span id="translatedtitle">Magnetopause shape as a bivariate function of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field B{sub z} and solar wind dynamic pressure</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Roelof, E.C.; Sibeck, D.G.</p> <p>1993-12-01</p> <p>The authors present a new method for determining the shape of the magnetopause as a bivariate function of the hourly <span class="hlt">averaged</span> solar wind dynamic pressure (p) and the north-south component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) B{sub z}. They represent the magnetopause (for X{sub GSE}>{minus}40R{sub E}) as an ellipsoid of revolution in solar-wind-aberrated coordinates and express the (p, B{sub z}) dependence of each of the three ellipsoid parameters as a second-order (6-term) bivariate expansion in lnp and B{sub z}. The authors define 12 overlapping bins in a normalized dimensionless (p,B{sub z}) {open_quotes}control space{close_quotes} and fit an ellipsoid to those magnetopause crossings having (p,B{sub z}) values within each bin. They also calculate the bivariate (lnp, B{sub z}) moments to second order over each bin in control space. They can then calculate the six control-space expansion coefficients for each of the three ellipsoid parameters in configuration space. From these coefficients they can derive useful diagnostics of the magnetopause shape as joint functions of p and B{sub z}: the aspect ratio of the ellipsoid`s minor-to-major axes the flank distance radius of curvature, and flaring angle (at X{sub GSE}=0); and the subsolar distance and radius of curvature. The authors confirm and quantify previous results that during periods of southward B{sub z} the subsolar magnetopause moves inward, while at X{sub GSE}=0 the flank magnetopause moves outward and the flaring angle increases. These changes are most pronounced during periods of low pressure, wherein all have a dependence on B{sub z} that is stronger and functionally different for B{sub z} southward as compared to B{sub z} northward. In contrast, all these changes are much less sensitive to IMF B{sub z} at the highest pressures. 44 refs., 22 figs., 6 tabs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040171393','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040171393"><span id="translatedtitle">The Fraction of <span class="hlt">Interplanetary</span> Coronal Mass Ejections That Are <span class="hlt">Magnetic</span> Clouds: Evidence for a Solar Cycle Variation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richardson, I. G.; Cane, H. V.</p> <p>2004-01-01</p> <p>"<span class="hlt">Magnetic</span> clouds" (MCs) are a subset of <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs) characterized by enhanced <span class="hlt">magnetic</span> fields with an organized rotation in direction, and low plasma beta. Though intensely studied, MCs only constitute a fraction of all the ICMEs that are detected in the solar wind. A comprehensive survey of ICMEs in the near- Earth solar wind during the ascending, maximum and early declining phases of solar cycle 23 in 1996 - 2003 shows that the MC fraction varies with the phase of the solar cycle, from approximately 100% (though with low statistics) at solar minimum to approximately 15% at solar maximum. A similar trend is evident in near-Earth observations during solar cycles 20 - 21, while Helios 1/2 spacecraft observations at 0.3 - 1.0 AU show a weaker trend and larger MC fraction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19830030751&hterms=1061&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231061','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830030751&hterms=1061&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2526%25231061"><span id="translatedtitle">Dawn-dusk asymmetry of the tail region of the magnetosphere of Saturn and the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Akasofu, S.-I.; Roederer, M.; Krimigis, S. M.</p> <p>1982-01-01</p> <p>In connection with the findings of the Voyager 1 mission, it appears that the tail lobe of Saturn is very different from that of earth and Jupiter, in that the latter are devoid of energetic particles, and <span class="hlt">magnetic</span> field lines in this region are thought to be open and interconnecting with the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field at large distances in the antisolar direction. The present investigation is concerned with a possible explanation of these observations, taking into account a model of Saturn's magnetosphere. It is shown that the Voyager 1 spacecraft remained in the closed region of the magnetotail during its entire tail traversal and did not have an opportunity to penetrate into the high latitude lobe. It is concluded that Saturn probably has a tail lobe just like earth and Jupiter. However, this tail lobe was not traversed by Voyager.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950048767&hterms=1575&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231575','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950048767&hterms=1575&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231575"><span id="translatedtitle">The determination of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field polarities around sector boundaries using E greater than 2 keV electrons</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kahler, S.; Lin, R. P.</p> <p>1994-01-01</p> <p>The determination of the polarities of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields (whether the field direction is outward from or inward toward the sun) has been based on a comparison of observed field directions with the nominal Parker spiral angle. These polarities can be mapped back to the solar source field polarities. This technique fails when field directions deviate substantially from the Parker angle or when fields are substantially kinked. We introduce a simple new technique to determine the polarities of <span class="hlt">interplanetary</span> fields using E greater than 2 keV <span class="hlt">interplanetary</span> electrons which stream along field lines away from the sun. Those electrons usually show distinct unidirectional pitch-angle anisotropies either parallel or anti-parallel to the field. Since the electron flow direction is known to be outward from the sun, the anisotropies parallel to the field indicate outward-pointing, positive-polarity fields, and those anti-parallel indicate inward-pointing, negative-polarity fields. We use data from the UC Berkeley electron experiment on the International Sun Earth Explorer 3 (ISSE-3) spacecraft to compare the field polarities deduced from the electron data, Pe (outward or inward), with the polarities inferred from field directions, Pd, around two sector boundaries in 1979. We show examples of large (greater than 100 deg) changes in azimuthal field direction Phi over short (less than 1 hr) time scales, some with and some without reversals in Pe. The latter cases indicate that such large directional changes can occur in unipolar structures. On the other hand, we found an example of a change in Pe during which the rotation in Phi was less than 30 deg, indicating polarity changes in nearly unidirectional structures. The field directions are poor guides to the polarities in these cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006JGRA..11111102X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006JGRA..11111102X"><span id="translatedtitle">Magnetohydrodynamic simulation of the interaction between <span class="hlt">interplanetary</span> strong shock and <span class="hlt">magnetic</span> cloud and its consequent geoeffectiveness: 2. Oblique collision</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiong, Ming; Zheng, Huinan; Wang, Yuming; Wang, Shui</p> <p>2006-11-01</p> <p>Numerical studies of the <span class="hlt">interplanetary</span> "shock overtaking <span class="hlt">magnetic</span> cloud (MC)" event are continued by a 2.5-dimensional magnetohydrodynamic (MHD) model in heliospheric meridional plane. <span class="hlt">Interplanetary</span> direct collision (DC)/oblique collision (OC) between an MC and a shock results from their same/different initial propagation orientations. For radially erupted MC and shock in solar corona, the orientations are only determined respectively by their heliographic locations. OC is investigated in contrast with the results in DC (Xiong, 2006). The shock front behaves as a smooth arc. The cannibalized part of MC is highly compressed by the shock front along its normal. As the shock propagates gradually into the preceding MC body, the most violent interaction is transferred sideways with an accompanying significant narrowing of the MC's angular width. The opposite deflections of MC body and shock aphelion in OC occur simultaneously through the process of the shock penetrating the MC. After the shock's passage, the MC is restored to its oblate morphology. With the decrease of MC-shock commencement interval, the shock front at 1 AU traverses MC body and is responsible for the same change trend of the latitude of the greatest geoeffectiveness of MC-shock compound. Regardless of shock orientation, shock penetration location regarding the maximum geoeffectiveness is right at MC core on the condition of very strong shock intensity. An appropriate angular difference between the initial eruption of an MC and an overtaking shock leads to the maximum deflection of the MC body. The larger the shock intensity is, the greater is the deflection angle. The interaction of MCs with other disturbances could be a cause of deflected propagation of <span class="hlt">interplanetary</span> coronal mass ejection (ICME).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21576620','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21576620"><span id="translatedtitle">PROPAGATION OF SOLAR ENERGETIC PARTICLES IN THREE-DIMENSIONAL <span class="hlt">INTERPLANETARY</span> <span class="hlt">MAGNETIC</span> FIELDS: IN VIEW OF CHARACTERISTICS OF SOURCES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>He, H.-Q.; Qin, G.; Zhang, M. E-mail: gqin@spaceweather.ac.cn</p> <p>2011-06-20</p> <p>In this paper, a model of solar energetic particle (SEP) propagation in the three-dimensional Parker <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is calculated numerically. We study the effects of the different aspects of particle sources on the solar surface, which include the source location, coverage of latitude and longitude, and spatial distribution of source particle intensity, on propagation of SEPs with both parallel and perpendicular diffusion. We compute the particle flux and anisotropy profiles at different observation locations in the heliosphere. From our calculations, we find that the observation location relative to the latitudinal and longitudinal coverage of particle source has the strongest effects on particle flux and anisotropy profiles observed by a spacecraft. When a spacecraft is directly connected to the solar sources by the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field lines, the observed particle fluxes are larger than when the spacecraft is not directly connected. This paper focuses on the situations when a spacecraft is not connected to the particle sources on the solar surface. We find that when the <span class="hlt">magnetic</span> footpoint of the spacecraft is farther away from the source, the observed particle flux is smaller and its onset and maximum intensity occur later. When the particle source covers a larger range of latitude and longitude, the observed particle flux is larger and appears earlier. There is east-west azimuthal asymmetry in SEP profiles even when the source distribution is east-west symmetric. However, the detail of particle spatial distribution inside the source does not affect the profile of the SEP flux very much. When the <span class="hlt">magnetic</span> footpoint of the spacecraft is significantly far away from the particle source, the anisotropy of particles in the early stage of an SEP event points toward the Sun, which indicates that the first arriving particles come from outside of the observer through perpendicular diffusion at large radial distances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4750503L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4750503L"><span id="translatedtitle">Impacts of an <span class="hlt">Interplanetary</span> Coronal Mass Ejection and the Crustal <span class="hlt">Magnetic</span> Fields to the Martian hot O corona</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, Yuni; Combi, Michael; Tenishev, Valeriy; Bougher, Stephen</p> <p>2015-11-01</p> <p>An <span class="hlt">interplanetary</span> coronal mass ejection (ICME) is a large amount of mass entrained in the heliospheric <span class="hlt">magnetic</span> field and propagating outward from the Sun into the <span class="hlt">interplanetary</span> medium. Upon arrival at Mars, ICMEs interact with its upper atmosphere and ionosphere, causing important impacts in the planetary environment. In March 2015, a strong solar event was observed and associated with a major ICME. The major ICME events aroused a chain of events on Mars, which were detected by the instruments onboard Mars Atmosphere and Volatile EvolutioN (MAVEN). The consequences in the upper atmosphere are directly related to the important processes that lead to the atmospheric escape. We report here our examinations of the impacts of the March 8th ICME event on the Martian hot O corona by using our 3D framework, which couples the Mars application of the Adaptive Mesh Particle Simulator (M-AMPS), the Mars Global Ionosphere-Thermosphere Model (M-GITM), and the Mars multi-fluid MHD (MF-MHD) model. Also, we present the effects of the crustal <span class="hlt">magnetic</span> fields on the structure of the hot O corona to study the interesting signatures of the crustal <span class="hlt">magnetic</span> fields. Due to the minimal impacts of the ICME deep in the thermosphere and ionosphere, where the maximum production of hot O occurs, our model results showed a stable hot O corona during and after the peak ICME event. However, the structure of the corona was affected by the existence of the crustal <span class="hlt">magnetic</span> fields with a decrease in escape rate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950029575&hterms=aurora+polar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Daurora%2Bpolar','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950029575&hterms=aurora+polar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Daurora%2Bpolar"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field dependency of stable Sun-aligned polar cap arcs</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Valladares, C. E.; Carlson, H. C., Jr.; Fukui, K.</p> <p>1994-01-01</p> <p>This is the first analysis, using a statistically significant data set, of the morphological dependence of the presence, orientation, and motion of stable sun-aligned polar cap arcs upon the vector <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). For the one winter season analyzed we had 1392 all-sky 630.0-nm images of 2-min resolution containing a total of 150 polar cap arcs, all with corresponding values of the IMF as measured by International Monitoring Platform (IMP) 8 or International Sun Earth Explorer (ISEE) 2. After demonstrating an unbiased data set with smooth normal distributions of events versus the dimensions of time, space, and IMF component, we examine IMF dependencies of the properties of the optical arcs. A well-defined dependence for B(sub z) is found for the presence/absence of stable Sun-aligned polar cap arcs. Consistent with previous statistical studies, the probability of observing polar cap aurora steadily increases for larger positive values of B(sub z), and linearly decreases when B(sub z) becomes more negative. The probability of observing Sun-aligned arcs within the polar cap is determined to vary sharply as a function of the arc location; arcs were observed 40% of the time on the dawnside and only 10% on the duskside. This implies an overall probability of at least 40% for the whole polar cap. 20% of the arcs were observed during 'southward IMF conditions,' but in fact under closer inspection were found to have been formed under northward IMF conditions; these 'residual' positive B(sub z) arcs ha d a delayed residence time in the polar cap of about what would be expected after a north to south transition of B(sub z). A firm dependence on B(sub y) is also found for both the orientation and the dawn-dusk direction of motion of the arcs. All the arcs are Sun-aligned to a first approximation, but present deviations from this orientation, depending primarily upon the location of the arc in corrected geomagnetic (CG) coordinates. The arcs populating the 06-12 and the 12-18 quadrants of the CG coordinate system point toward the cusp. The B(sub y) dependency of the arc alignment is consistent with a cusp displacement in local time according to the sign of B(sub y). We found that the arc direction of motion depended both on B(sub y) and the arc location within the polar cap. For a given value of B(sub y) two well-defined regions (or cells) exist. Within each cell the arcs move in the same direction toward the boundary between the cells. The arcs located in the duskside move dawnward; those in the dawnside move duskward. The relative size of these dusk and dawn regions (or cells) are controlled by the magnitude of B(sub y). This persistent dusk-dawn motion fo the polar cap arcs is interpreted in terms of newly open flux tubes entering the polar cap and exerting a displacement of the convective cells and the polar cap arcs that are embedded within them.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5190170','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5190170"><span id="translatedtitle">High-latitude dayside electric fields and currents during strong northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field: Observations and model simulation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Clauer, C.R.; Friis-Christensen, E.</p> <p>1988-04-01</p> <p>On July 23, 1983, the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field turned strongly northward, becoming about 22 nT for several hours. Using a combined data set of ionospheric convection measurements made by the Sondre Stromfjord incoherent scatter radar and convection inferred from Greenland magnetometer measurements, we observe the onset of the reconfiguration of the high-latitude ionospheric currents to occur about 3 min following the northward IMF encountering the magnetopause. The large-scale reconfiguration of currents, however, appears to evolve over a period of about 22 min. Using a computer model in which the distribution of field-aligned current in the polar cleft is directly determined by the strength and orientation of the <span class="hlt">interplanetary</span> electric field, we are able to simulate the time-varying pattern of ionospheric convection, including the onset of high-latitude ''reversed convection'' cells observed to form during the interval of strong northward IMF. These observations and the simulation results indicate that the dayside polar cap electric field observed during strong northward IMF is produced by a direct electrical current coupling with the solar wind. copyright American Geophysical Union 1988</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740020146','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740020146"><span id="translatedtitle"><span class="hlt">Interplanetary</span> shock waves associated with solar flares</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chao, J. K.; Sakurai, K.</p> <p>1974-01-01</p> <p>The interaction of the earth's <span class="hlt">magnetic</span> field with the solar wind is discussed with emphasis on the influence of solar flares. The geomagnetic storms are considerered to be the result of the arrival of shock wave generated by solar flares in <span class="hlt">interplanetary</span> space. Basic processes in the solar atmosphere and <span class="hlt">interplanetary</span> space, and hydromagnetic disturbances associated with the solar flares are discussed along with observational and theoretical problems of <span class="hlt">interplanetary</span> shock waves. The origin of <span class="hlt">interplanetary</span> shock waves is also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.632a2083W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.632a2083W"><span id="translatedtitle">The connection of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field turbulence and rigidity spectrum of Forbush decrease of the galactic cosmic ray intensity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wawrzynczak, A.; Alania, M. V.</p> <p>2015-08-01</p> <p>We analyze the temporal changes in the rigidity spectrum of Forbush decrease (Fd) of the galactic cosmic ray (GCR) intensity observed in November 2004. We compute the rigidity spectrum in two energy ranges based on the daily data from the worldwide network of neutron monitors and Nagoya ground muon telescope. We demonstrate that the changes in the rigidity spectrum of Fd are linked to the evolution/decay of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) turbulence during various phases of the Fd. We analyze the time-evolution of the state of the turbulence of the IMF in various frequency ranges during the Fd. Performed analysis show that the decrease of the exponent ? of the Power Spectral Density (PSD ? f-?, where f is frequency) of the IMF turbulence with decreasing frequency lead to the soft rigidity spectrum of Fd for GCR particles with relatively higher energies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20110023418&hterms=cosmic+rays&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2528cosmic%2Brays%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110023418&hterms=cosmic+rays&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2528cosmic%2Brays%2529"><span id="translatedtitle">Galactic Cosmic Ray Intensity Response to <span class="hlt">Interplanetary</span> Coronal Mass Ejections/<span class="hlt">Magnetic</span> Clouds in 1995-2009</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richardson, I. G.; Cane, H. V.</p> <p>2011-01-01</p> <p>We summarize the response of the galactic cosmic ray (CGR) intensity to the passage of the more than 300 <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs) and their associated shocks that passed the Earth during 1995-2009, a period that encompasses the whole of Solar Cycle 23. In approx.80% of cases, the GCR intensity decreased during the passage of these structures, i.e., a "Forbush decrease" occurred, while in approx.10% there was no significant change. In the remaining cases, the GCR intensity increased. Where there was an intensity decrease, minimum intensity was observed inside the ICME in approx.90% of these events. The observations confirm the role of both post-shock regions and ICMEs in the generation of these decreases, consistent with many previous studies, but contrary to the conclusion of Reames, Kahler, and Tylka (Astrophys. 1. Lett. 700, L199, 2009) who, from examining a subset of ICMEs with flux-rope-like <span class="hlt">magnetic</span> fields (<span class="hlt">magnetic</span> clouds) argued that these are "open structures" that allow free access of particles including GCRs to their interior. In fact, we find that <span class="hlt">magnetic</span> clouds are more likely to participate in the deepest GCR decreases than ICMEs that are not <span class="hlt">magnetic</span> clouds.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_7");'>7</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li class="active"><span>9</span></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_9 --> <div id="page_10" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="181"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003GeoRL..30.1798F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003GeoRL..30.1798F"><span id="translatedtitle">Weighted <span class="hlt">averages</span> of <span class="hlt">magnetization</span> from <span class="hlt">magnetic</span> field measurements: A fast interpretation tool</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fedi, Maurizio</p> <p>2003-08-01</p> <p><span class="hlt">Magnetic</span> anomalies may be interpreted in terms of weighted <span class="hlt">averages</span> of <span class="hlt">magnetization</span> (WAM) by a simple transformation. The WAM transformation consists of dividing at each measurement point the experimental <span class="hlt">magnetic</span> field by a normalizing field, computed from a source volume with a homogeneous unit-<span class="hlt">magnetization</span>. The transformation yields a straightforward link among source and field position vectors. A main WAM outcome is that sources at different depths appear well discriminated. Due to the symmetry of the problem, the higher the considered field altitude, the deeper the sources outlined by the transformation. This is shown for single and multi-source synthetic cases as well as for real data. We analyze the real case of Mt. Vulture volcano (Southern Italy), where the related anomaly strongly interferes with that from deep intrusive sources. The volcanic edifice is well identified. The deep source is estimated at about 9 km depth, in agreement with other results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015IAUGA..2256637B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015IAUGA..2256637B"><span id="translatedtitle">Solar and <span class="hlt">interplanetary</span> signatures of declining of solar <span class="hlt">magnetic</span> fields: Implications to the next solar cycle 25</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bisoi, Susanta Kumar; Janardhan, P.; Ananthakrishnan, S.; Tokumaru, M.; Fujiki, K.</p> <p>2015-08-01</p> <p>Our detailed study of solar surface <span class="hlt">magnetic</span> fields at high-latitudes, using <span class="hlt">magnetic</span> synoptic magnetograms of NSO/Kitt Peak observatory from 1975-2014, has shown a steady decline of the field strength since mid-1990's until mid-2014, i.e. the solar maximum of cycle 24. We also found that <span class="hlt">magnetic</span> field strength at high-latitudes declines after each solar cycle maximum, and since cycle 24 is already past its peak implies that solar surface <span class="hlt">magnetic</span> fields will be continuing to decline until solar minimum of cycle 24. In addition, <span class="hlt">interplanetary</span> scintillation (IPS) measurements of solar wind micro-turbulence levels, from Solar and Terrestrial Environment Laboratory (STEL), Japan, have also shown a steady decline in sync with the declining surface fields. Even the heliospheric <span class="hlt">magnetic</span> fields (HMF) at 1 AU have been declined much below the previously proposed floor level of HMF of ~4.6 nT. From study of a correlation between the high-latitude surface fields and the HMF at the last four solar minima we found a floor value of HMF of ~3.2 nT. Using the above correlation and the fact that the high-latitude surface fields is expected to decline until the minimum of cycle 24, we estimate the value of the HMF at the minimum of cycle 24 will be 3.8 ± 0.2 nT and the peak sunspot number for solar cycle 25 will be 56±12 suggesting a weak sunspot activity to be continued in cycle 25 too.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/doepatents/biblio/869326','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/doepatents/biblio/869326"><span id="translatedtitle">High <span class="hlt">average</span> power <span class="hlt">magnetic</span> modulator for metal vapor lasers</span></a></p> <p><a target="_blank" href="http://www.osti.gov/doepatents">DOEpatents</a></p> <p>Ball, Don G. (Livermore, CA); Birx, Daniel L. (Oakley, CA); Cook, Edward G. (Livermore, CA); Miller, John L. (Livermore, CA)</p> <p>1994-01-01</p> <p>A three-stage <span class="hlt">magnetic</span> modulator utilizing <span class="hlt">magnetic</span> pulse compression designed to provide a 60 kV pulse to a copper vapor laser at a 4.5 kHz repetition rate is disclosed. This modulator operates at 34 kW input power. The circuit includes a step up auto transformer and utilizes a rod and plate stack construction technique to achieve a high packing factor.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810016474','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810016474"><span id="translatedtitle"><span class="hlt">Magnetic</span> loop behind an <span class="hlt">interplanetary</span> shock: Voyager, Helios and IMP-8 observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burlaga, L.; Sittler, E.; Mariani, F.; Schwenn, R.</p> <p>1981-01-01</p> <p>The shock was followed by a turbulent sheath in which there were large fluctuations in both the strength and direction of the <span class="hlt">magnetic</span> field. This in turn was followed by a region (<span class="hlt">magnetic</span> cloud) in which the <span class="hlt">magnetic</span> field vectors were observed to change by rotating nearly parallel to a plane, consistent with the passage of a <span class="hlt">magnetic</span> loop. This loop extended at least 30 deg in longitude between 1-2 AU, and its radial dimension was approximately 0.5 AU. In the cloud the field strength was high and the density and temperature were relatively low. Thus, the dominant pressure in the cloud was that of the <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830011396','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830011396"><span id="translatedtitle">Dynamical evolution of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields and flows between 0.3 AU and 8.5 AU: Entrainment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burlaga, L. F.; Schwenn, R.; Rosenbauer, H.</p> <p>1983-01-01</p> <p>The radial evolution of <span class="hlt">interplanetary</span> flows and associated <span class="hlt">magnetic</span> fields between 0.3 AU and 8.5 was analyzed using data from Helios 1 and Voyager 1, respectively. During a 70 day interval Voyager 1 observed two streams which appeared to be recurrent and which had little fine structure. The corresponding flows observed by Helios 1 were much more complex, showing numerous small streams, transient flows and shocks as well as a few large corotating streams. It is suggested that in moving to 8 AU the largest corotating streams swept up the slower flows (transient and/or corotating streams) and shocks into a relatively thin region in which they coalesced to form a single large amplitude compression wave. This combined process of sweeping and coalescence is referred to as entrainment. The resulting large amplitude compression wave is different from that formed by the steepening of a corotating stream from a coronal hole, because different flows from distinct sources, with possibly different composition and <span class="hlt">magnetic</span> polarity, are brought together to form a single new structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910042730&hterms=superconducting+materials+space&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsuperconducting%2Bmaterials%2Bspace','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910042730&hterms=superconducting+materials+space&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsuperconducting%2Bmaterials%2Bspace"><span id="translatedtitle">A deployable high temperature superconducting coil (DHTSC) - A novel concept for producing <span class="hlt">magnetic</span> shields against both solar flare and Galactic radiation during manned <span class="hlt">interplanetary</span> missions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cocks, F. Hadley</p> <p>1991-01-01</p> <p>The discovery of materials which are superconducting above 100 K makes possible the use of superconducting coils deployed beyong the hull of an <span class="hlt">interplanetary</span> spacecraft to produce a <span class="hlt">magnetic</span> shield capable of giving protection not only against solar flare radiation, but also even against Galactic radiation. Such deployed coils can be of very large size and can thus achieve the great <span class="hlt">magnetic</span> moments required using only relatively low currents. Deployable high-temperature-superconducting coil <span class="hlt">magnetic</span> shields appear to offer very substantial reductions in mass and energy compared to other concepts and could readily provide the radiation protection needed for a Mars mission or space colonies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1998JGR...103.4023R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1998JGR...103.4023R"><span id="translatedtitle">A statistical study of the ionospheric convection response to changing <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field conditions using the assimilative mapping of ionospheric electrodynamics technique</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ridley, A. J.; Lu, Gang; Clauer, C. R.; Papitashvili, V. O.</p> <p>1998-03-01</p> <p>We examine 65 ionospheric convection changes associated with changes in the Y and Z components of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). We measure the IMF reorientations (for all but six of the events) at the Wind satellite. For 22 of the events the IMF reorientation is clearly observed by both Wind and IMP 8. Various methods are used to estimate the propagation time of the IMF between the two satellites. We find that using the <span class="hlt">magnetic</span> field before the IMF orientation change gives the smallest error in the expected propagation time. The IMF is then propagated to the magnetopause. The communication time between when the IMF encounters the magnetopause and the start of the convection change is estimated to be 8.4(+/-8.2)min. The resulting change in the ionospheric potential is examined by subtracting a base potential pattern from the changing potential patterns. From these residual patterns, a number of conclusions are made: (1) the location of the change in convection is stationary, implying that the change in convection is broadcast from the cusp region to the rest of the ionosphere in a matter of seconds and that the electric field mapped down the cusp controls the entire dayside ionospheric convection pattern; (2) the shape of the change in the ionospheric convection is dependent on the IMF component that changes, which is indicative of the change in the merging rate on the dayside magnetopause; (3) 62% of the events change linearly form one state to another, while 11% of the events change asymptotically; (4) the change in the ionospheric potential is linearly related to the magnitude of the IMF orientation, with Bz changes having a larger proportionality constant than By changes; (5) the ionospheric convection takes, on <span class="hlt">average</span>, 13 min to completely reconfigure; and (6) some of the ionospheric convection changes occur on a timescale shorter than that of the corresponding IMF reorientation, possibly as a result of thresholding in the dayside merging region.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5257942','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5257942"><span id="translatedtitle">Response of the polar cap F region convection direction to changes in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field: Digisonde measurements in northern Greenland</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Cannon, P.S.; Reinisch, B.W.; Bullett, T.W. ); Buchau, J. )</p> <p>1991-02-01</p> <p>Results of ionospheric drift measurements with a Digisonde 256 digital ionospheric sounder located at Qaanaaq, Greenland (87{degree}N, corrected geomagnetic latitude), are presented. Digisonde drift data have been related to the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) measured by the IMP 8 satellite for 32 days during 1986, 1987, and 1988. Extremely good statistical agreement between these measurements and convection directions derived from satellite instrumentation is demonstrated when the IMF {sub z} component is negative. The excellent agreement between the Digisonde measurements and models derived from satellite measurements demonstrates the utility of the Digisonde for making ground-based measurements of the convection direction in the polar cap F region when B{sub z} is south. The convection directions under conditions of positive B{sub z} have also been examined, and the authors have measured three types of temporal variation in azimuth, namely, an ordered and slowly (OS) varying change in direction, an ordered and quickly (OQ) varying change in direction, and disordered (D) variations in direction. The latter are believed to result from a breakdown of the analysis technique due to velocity shears in the vicinity of polar caps arcs, and the authors estimate that they account for {approximately}25% of the measurements when B{sub z} > 0. When B{sub z} is positive and B{sub y} is negative, their small subset of OS measurements supports the distorted two-cell model of Heppner and Maynard (1987). The remainder of the measurements show no well-defined daily <span class="hlt">average</span> convection direction or diurnal variation. Likewise for B{sub z} positive and B{sub y} positive, no well-defined convection direction can be discerned, nor can any diurnal variation. The existence of OQ variations when B{sub z}> 0 suggests that meaningful <span class="hlt">average</span> statistical convection patterns may be much harder to synthesize than similar patterns when B{sub z}< 0.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.4519Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.4519Z"><span id="translatedtitle">Direct observations of the full Dungey convection cycle in the polar ionosphere for southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, Q.-H.; Lockwood, M.; Foster, J. C.; Zhang, S.-R.; Zhang, B.-C.; McCrea, I. W.; Moen, J.; Lester, M.; Ruohoniemi, J. M.</p> <p>2015-06-01</p> <p>Tracking the formation and full evolution of polar cap ionization patches in the polar ionosphere, we directly observe the full Dungey convection cycle for southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) conditions. This enables us to study how the Dungey cycle influences the patches' evolution. The patches were initially segmented from the dayside storm enhanced density plume at the equatorward edge of the cusp, by the expansion and contraction of the polar cap boundary due to pulsed dayside magnetopause reconnection, as indicated by in situ Time History of Events and Macroscale Interactions during Substorms (THEMIS) observations. Convection led to the patches entering the polar cap and being transported antisunward, while being continuously monitored by the globally distributed arrays of GPS receivers and Super Dual Auroral Radar Network radars. Changes in convection over time resulted in the patches following a range of trajectories, each of which differed somewhat from the classical twin-cell convection streamlines. Pulsed nightside reconnection, occurring as part of the magnetospheric substorm cycle, modulated the exit of the patches from the polar cap, as confirmed by coordinated observations of the magnetometer at Tromsø and European Incoherent Scatter Tromsø UHF radar. After exiting the polar cap, the patches broke up into a number of plasma blobs and returned sunward in the auroral return flow of the dawn and/or dusk convection cell. The full circulation time was about 3 h.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SoPh..tmp...24K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SoPh..tmp...24K"><span id="translatedtitle">Study of Cosmic Ray Intensity in Relation to the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field and Geomagnetic Storms for Solar Cycle 23</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kharayat, Hema; Prasad, Lalan; Mathpal, Rajesh; Garia, Suman; Bhatt, Beena</p> <p>2016-02-01</p> <p>We investigate the association of the cosmic-ray intensity (CRI) with the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF, B) and geomagnetic storms (GS) for the period 1997 - 2006 (Solar Cycle 23). To do this, we conducted a Chree analysis by the superposed-epoch method. A transient decrease in CRI is found on the occurrence days of GS, and this decrease shows a similar pattern to that of the disturbance storm-time index (Dst). In addition, we show that the CRI decreases with the increase in IMF. The time lag between the decrease in CRI and increase in IMF is about one day or less. Furthermore, an increase in IMF B is found with the decrease in Dst index. IMF and Dst index are highly anti-correlated to each other, while the sunspot number is not found to be correlated with IMF, Dst index, or CRI for the period studied. The IMF is found to be an effective parameter combination for producing GS and Forbush decrease. We also found two types of decrease in CRI for Solar Cycle 23: i) symmetric and ii) asymmetric decreases. The study of CRI decreases may be useful for studying space-weather effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19830051481&hterms=evolution+sun&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Devolution%2Bsun','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830051481&hterms=evolution+sun&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Devolution%2Bsun"><span id="translatedtitle">Dynamical evolution of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields and flows between 0.3 AU and 8.5 AU - Entrainment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burlaga, L. F.; Schwenn, R.; Rosenbauer, H.</p> <p>1983-01-01</p> <p>An analysis is presented of the radial evolution of <span class="hlt">interplanetary</span> flows and associated <span class="hlt">magnetic</span> fields between 0.3 AU and 8.5 AU using data from Helios 1 and B Voyager 1, respectively. The results indicate that in moving to 8 AU the largest corotating streams swept up the slower flows and shocks into a relatively thin region in which they coalesced to form a single large-amplitude compression. As a result of this process, referred to as entrainment, memory of the sources and flow configurations near the sun is lost, while small-scale features are erased as the flows move outward and energy is transferred from small scales to large scales.It is concluded that in the outer solar system the structure of the solar wind may be dominated by large scale pressure waves separated by several AU, while beyond several AU most of the compression waves are no longer driven by streams, and the compression waves expand freely. At large distances (greater than 25 AU) these compression waves will have interacted extensively with one another producing another state of the solar wind, with fewer large-scale nonuniformities and more small-scale nonuniformities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015P%26SS..117...15L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015P%26SS..117...15L"><span id="translatedtitle">Solar wind interaction effects on the <span class="hlt">magnetic</span> fields around Mars: Consequences for <span class="hlt">interplanetary</span> and crustal field measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luhmann, J. G.; Ma, Y.-J.; Brain, D. A.; Ulusen, D.; Lillis, R. J.; Halekas, J. S.; Espley, J. R.</p> <p>2015-11-01</p> <p>The first unambiguous detections of the crustal remanent <span class="hlt">magnetic</span> fields of Mars were obtained by Mars Global Surveyor (MGS) during its initial orbits around Mars, which probed altitudes to within ?110 km of the surface. However, the majority of its measurements were carried out around 400 km altitude, fixed 2 a.m. to 2 p.m. local time, mapping orbit. While the general character and planetary origins of the localized crustal fields were clearly revealed by the mapping survey data, their effects on the solar wind interaction could not be investigated in much detail because of the limited mapping orbit sampling. Previous analyses (Brain et al., 2006) of the field measurements on the dayside nevertheless provided an idea of the extent to which the interaction of the solar wind and planetary fields leads to non-ideal field draping at the mapping altitude. In this study we use numerical simulations of the global solar wind interaction with Mars as an aid to interpreting that observed non-ideal behavior. In addition, motivated by models for different <span class="hlt">interplanetary</span> field orientations, we investigate the effects of induced and reconnected (planetary and external) fields on the Martian field's properties derived at the MGS mapping orbit altitude. The results suggest that inference of the planetary low order moments is compromised by their influence. In particular, the intrinsic dipole contribution may differ from that in the current models because the induced component is so dominant.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860056271&hterms=Dimension&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D50%26Ntt%3DDimension','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860056271&hterms=Dimension&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D50%26Ntt%3DDimension"><span id="translatedtitle"><span class="hlt">Average</span> dimension and <span class="hlt">magnetic</span> structure of the distant Venus magnetotail</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Saunders, M. A.; Russell, C. T.</p> <p>1986-01-01</p> <p>The first major statistical investigation of the far wake of an unmagnetized object embedded in the solar wind is reported. The investigation is based on Pioneer Venus Orbiter magnetometer data from 70 crossings of the Venus wake at altitudes between 5 and 11 Venus radii during reasonably steady IMF conditions. It is found that Venus has a well-developed-tail, flaring with altitude and possibly broader in the direction parallel to the IMF cross-flow component. Tail lobe field polarities and the direction of the cross-tail field are consistent with tail accretion from the solar wind. <span class="hlt">Average</span> values for the cross-tail field (2 nT) and the distant tail flux (3 MWb) indicate that most distant tail field lines close across the center of the tail and are not rooted in the Venus ionosphere. The findings are illustrated in a three-dimensional schematic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890056315&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dluhmann','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890056315&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dluhmann"><span id="translatedtitle">Electron heat flux dropouts in the solar wind - Evidence for <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field reconnection?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mccomas, D. J.; Gosling, J. T.; Phillips, J. L.; Bame, S. J.; Luhmann, J. G.; Smith, E. J.</p> <p>1989-01-01</p> <p>An examination of ISEE-3 data from 1978 reveal 25 electron heat flux dropout events ranging in duration from 20 min to over 11 hours. The heat flux dropouts are found to occur in association with high plasma densities, low plasma velocities, low ion and electron temperatures, and low <span class="hlt">magnetic</span> field magnitudes. It is suggested that the heat flux dropout intervals may indicate that the spacecraft is sampling plasma regimes which are <span class="hlt">magnetically</span> disconnected from the sun and instead are connected to the outer heliosphere at both ends.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140009617','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140009617"><span id="translatedtitle">Turbulence in a Global Magnetohydrodynamic Simulation of the Earth's Magnetosphere during Northward and Southward <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>El-Alaoui, M.; Richard, R. L.; Ashour-Abdalla, M.; Walker, R. J.; Goldstein, M. L.</p> <p>2012-01-01</p> <p>We report the results of MHD simulations of Earth's magnetosphere for idealized steady solar wind plasma and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) conditions. The simulations feature purely northward and southward <span class="hlt">magnetic</span> fields and were designed to study turbulence in the magnetotail plasma sheet. We found that the power spectral densities (PSDs) for both northward and southward IMF had the characteristics of turbulent flow. In both cases, the PSDs showed the three scale ranges expected from theory: the energy-containing scale, the inertial range, and the dissipative range. The results were generally consistent with in-situ observations and theoretical predictions. While the two cases studied, northward and southward IMF, had some similar characteristics, there were significant differences as well. For southward IMF, localized reconnection was the main energy source for the turbulence. For northward IMF, remnant reconnection contributed to driving the turbulence. Boundary waves may also have contributed. In both cases, the PSD slopes had spatial distributions in the dissipative range that reflected the pattern of resistive dissipation. For southward IMF there was a trend toward steeper slopes in the dissipative range with distance down the tail. For northward IMF there was a marked dusk-dawn asymmetry with steeper slopes on the dusk side of the tail. The inertial scale PSDs had a dusk-dawn symmetry during the northward IMF interval with steeper slopes on the dawn side. This asymmetry was not found in the distribution of inertial range slopes for southward IMF. The inertial range PSD slopes were clustered around values close to the theoretical expectation for both northward and southward IMF. In the dissipative range, however, the slopes were broadly distributed and the median values were significantly different, consistent with a different distribution of resistivity.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM13B2158H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM13B2158H"><span id="translatedtitle">Reconnection and Energy Conversion at the Magnetopause as Influenced by Earth's Dipole Tilt Angle and <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hoilijoki, S.; Palmroth, M.</p> <p>2013-12-01</p> <p>We study the effect of Earth's dipole tilt angle and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) Bx and By components on the location of reconnection and the energy conversion at the magnetopause. We simulate southward IMF satisfying both inward- and outward-type Parker spiral conditions during three different dipole tilt angles using a global magnetohydrodynamic model GUMICS-4. Different combinations of dipole tilt angle and IMF Bx and By components change the magnetopause reconnection morphology and magnitude. This can be studied by comparing the location of the reconnection line and the location and strength of the energy conversion for different parameter combinations. We find that the IMF Bx and the dipole tilt angle modify the reconnection line location and both magnitude and location of the energy conversion. We discuss the relative role of the non-zero Bx and the dipole tilt angle in dayside reconnection first separately and then by letting the parameters change simultaneously. We find that positive (negative) Bx moves the reconnection line northward (southward) and positive (negative) tilt angle moves the line southward (northward). When both tilt angle and Bx are positive or negative they reverse each others effect so that the reconnection line location is almost the same as it is when both Bx and tilt angle are zero. When these two parameters have opposite signs they enhance each other's effects. We find evidence that reconnection-induced processes modify the shape of the magnetopause, which in turn has and effect on the reconnection location. Therefore intrinsic processes within the magnetosphere - the <span class="hlt">magnetic</span> flux transfer to nightside and the subsequent return of the closed flux - can influence the basic reconnection processes within the dayside magnetopause.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSMSM33A..02W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSMSM33A..02W"><span id="translatedtitle">The Ionospheric Convection and Birkeland Current Response to an Impulse in the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field BY Component</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilder, F. D.; Eriksson, S.; Korth, H.; Baker, J. B.; Hairston, M. R.; Heinselman, C. J.; Anderson, B. J.</p> <p>2013-05-01</p> <p>When the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) is dawnward or duskward, <span class="hlt">magnetic</span> merging between the IMF and the geomagnetic field occurs near the cusp on the dayside flanks of the magnetosphere. During these intervals, sunward flow channels on open field lines with velocities in excess of 2 km/s are generated in the polar ionosphere, which can deposit large amounts of energy into the cusp-region thermosphere. In this study, we analyze an interval on 5 April 2010 where there was a strong dawnward impulse in the IMF, followed by a gradual decay in IMF magnitude at constant clock angle. Data from ground based radars and the DMSP spacecraft were assimilated to investigate the global convection pattern during this interval, and data from the Active Magnetospheric and Planetary Electrodynamics Response Experiment (AMPERE) were used to investigate the associated Field-Aligned Current (FAC) system. Additionally, data from AMPERE and the Sondrestrom Incoherent Scatter Radar were used to investigate the time response of the flow channel and its associated FAC pair. We find that there is a delay of approximately 1.25 hours between the arrival of the dawnward IMF impulse at the magnetopause and the speed of the flow channel and strength of the FACs flanking it. In addition to correlation between the dawnward component of the IMF and the flanking FAC strength, we also find that there is inverse correlation between the flanking FAC strength and both the SYM-H index and Solar Wind Alfvenic Mach Number. No statistically significant correlation is found between the flanking FAC strength and solar wind dynamic pressure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013GeoRL..40.2489W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013GeoRL..40.2489W"><span id="translatedtitle">Field-aligned current reconfiguration and magnetospheric response to an impulse in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field BY component</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilder, F. D.; Eriksson, S.; Korth, H.; Baker, J. B. H.; Hairston, M. R.; Heinselman, C.; Anderson, B. J.</p> <p>2013-06-01</p> <p>the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) is dawnward or duskward, <span class="hlt">magnetic</span> merging between the IMF and the geomagnetic field occurs near the cusp on the dayside flanks of the magnetosphere. During these intervals, flow channels in the ionosphere with velocities in excess of 2 km/s have been observed, which can deposit large amounts of energy into the high-latitude thermosphere. In this study, we analyze an interval on 5 April 2010 where there was a strong dawnward impulse in the IMF, followed by a gradual decay in IMF magnitude at constant clock angle. Data from the Sondrestrom incoherent scatter radar and the Defense Meteorological Satellite Program spacecraft were used to investigate ionospheric convection during this interval, and data from the Active Magnetospheric and Planetary Electrodynamics Response Experiment (AMPERE) were used to investigate the associated Field-Aligned Current (FAC) system. Additionally, data from AMPERE were used to investigate the time response of the dawnside FAC pair. We find there is a delay of approximately 1.25 h between the arrival of the dawnward IMF impulse at the magnetopause and strength of the dawnward FAC pair, which is comparable to substorm growth and expansion time scales under southward IMF. Additionally, we find at the time of the peak FAC, there is evidence of a reconfiguring four-sheet FAC system in the morning local time sector of the ionosphere. Additionally, we find an inverse correlation between the dawn FAC strength and both the solar wind Alfvnic Mach number and the SYM-H index. No statistically significant correlation between the FAC strength and the solar wind dynamic pressure was found.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM41B2238W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM41B2238W"><span id="translatedtitle">Field-Aligned Current Reconfiguration and Magnetospheric Response to an Impulse in the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field BY Component</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wilder, F. D.; Eriksson, S.; Korth, H.; Hairston, M. R.; Baker, J. B.; Heinselman, C. J.</p> <p>2013-12-01</p> <p>When the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) is dawnward or duskward, <span class="hlt">magnetic</span> merging between the IMF and the geomagnetic field occurs near the cusp on the dayside flanks of the magnetosphere. During these intervals, flow channels in the ionosphere with velocities in excess of 2 km/s have been observed, which can deposit large amounts of energy into the high-latitude thermosphere. In this study, we analyze an interval on 5 April 2010 where there was a strong dawnward impulse in the IMF, followed by a gradual decay in IMF magnitude at constant clock angle. Data from the Sondrestrom incoherent scatter radar and the DMSP spacecraft were used to investigate ionospheric convection during this interval, and data from the Active Magnetospheric and Planetary Electrodynamics Response Experiment (AMPERE) were used to investigate the associated Field-Aligned Current (FAC) system. Additionally, data from AMPERE were used to investigate the time response of the dawn-side FAC pair. We find there is a delay of approximately 1.25 hours between the arrival of the dawnward IMF impulse at the magnetopause and strength of the dawnward FAC pair, which is comparable to substorm growth and expansion time scales under southward IMF. Additionally, we find at the time of the peak FAC, there is evidence of a reconfiguring four-sheet FAC system in the morning local time sector of the ionosphere. Additionally, we find an inverse correlation between the dawn FAC strength and both the solar wind Alfvnic Mach number and the SYM-H index. No statistically significant correlation between the FAC strength and the solar wind dynamic pressure was found.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27..577M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27..577M"><span id="translatedtitle">Ring Current Decay During Northward Turnings of The <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Monreal MacMahon, R.; Llop, C.; Miranda, R.</p> <p></p> <p>The ring current formation and energization is thought to be the main consequence of geomagnetic storms and its strength is characterized by the Dst index which evolu- tion satisfies a simple and well-known differential equation introduced by Burton et al. (1975). Since then, several attempts and approaches have been done to study the evolution of the ring current whether introducing discrete values or continuous func- tions for the decay time involved. In this work, we study the character of the recovery phase of <span class="hlt">magnetic</span> storms in response to well defined northward turnings of the inter- planetary <span class="hlt">magnetic</span> field using our functional form of the decay time of ring current particles introduced previously.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_8");'>8</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li class="active"><span>10</span></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_10 --> <div id="page_11" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="201"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910040048&hterms=multifractal&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmultifractal','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910040048&hterms=multifractal&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmultifractal"><span id="translatedtitle">Multifractal structure of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field - Voyager 2 observations near 25 AU, 1987-1988</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burlaga, L. F.</p> <p>1991-01-01</p> <p>Voyager-2 measurements indicate that, for the period day 190, 1987 to day 345, 1988, the large-scale fluctuations of the IMF between 23.3 AU and 27.8 AU have the symmetry properties of a multifractal over scales from 16 hours to 21 days. This suggests the existence of scaling symmetries for the higher moments of the fluctuations of the <span class="hlt">magnetic</span> field strength.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910070191&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dluhmann','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910070191&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dluhmann"><span id="translatedtitle">Venus ionospheric tail rays - Spatial distributions and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field control</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ong, M.; Luhmann, J. G.; Russell, C. T.; Strangeway, R. J.; Brace, L. H.</p> <p>1991-01-01</p> <p>The overall properties of Venus ionospheric tail rays (such as density, spatial extent, and distribution) and their relationship to the draped <span class="hlt">magnetic</span> field configuration behind the planet were investigated using measurements obtained by the Pioneer Venus Orbiter Langmuir probe, a magnetometer, and a plasma-wave detector. The results suggest that tail rays are a normal feature of the steady solar wind interaction with Venus and are not generally associated with a central tail plasma sheet. The statistics of the tail rays occurrence point toward the existence of a distributed terminator ionosphere source, consistent with findings of Brace et al. (1990).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870067076&hterms=Jump&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DJump','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870067076&hterms=Jump&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DJump"><span id="translatedtitle">Spectral signatures of jumps and turbulence in <span class="hlt">interplanetary</span> speed and <span class="hlt">magnetic</span> field data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Roberts, D. A.; Goldstein, M. L.</p> <p>1987-01-01</p> <p>It is shown here that, consistent with a suggestion of Burlaga and Mish (1987), the f exp -2 spectra in the magnitudes of the <span class="hlt">magnetic</span> and velocity fields in the solar wind result from jumps due to various rapid changes in the time series for these quantities. If these jumps are removed from the data, the spectra of the resulting 'difference' time series have the f exp -5/3 form. It is concluded that f exp -2 spectra in these magnitudes arise from phase coherent structures that can be distinguished clearly from incoherent turbulent fluctuations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AdSpR..29.1489V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AdSpR..29.1489V"><span id="translatedtitle">Evolution of the source region of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> cloud of 18-20 Oct. 1995</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>van Driel-Gesztelyi, L.; Schmieder, B.; Baranyi, T.</p> <p></p> <p>We follow the evolution and activity of the reversed polarity AR 7912 using multi-wavelength observations. We find that the presence of high shear increased by flux emergence led to the occurrence of a long-duration eruptive flare on 14 October 1995, which was manifested in the SXR corona by an arcade of expanding sigmoidal loops. A twisted <span class="hlt">magnetic</span> cloud was observed at 1 AU between October 18-20. We propose that it was ejected from this reversed polarity AR, and it was associated with the expanding sigmoids.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790038772&hterms=earth+moon+distance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dearth%2Bmoon%2Bdistance','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790038772&hterms=earth+moon+distance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dearth%2Bmoon%2Bdistance"><span id="translatedtitle">Occurrence of the lobe plasma at lunar distance. [correlation with <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hardy, D. A.; Hills, H. K.; Freeman, J. W.</p> <p>1979-01-01</p> <p>Recent analysis has confirmed the existence of the lobe plasma, the extension of the 'boundary layer' and 'plasma mantle' to lunar distances. The observation of the lobe plasma is strongly correlated with the y component of the IMF. Generally, the lobe plasma is observed sporadically for a full day after the moon has entered the tail and a full day before the last magnetopause crossing as it exits the tail. An <span class="hlt">average</span> extent of approximately 8-10 earth radii inward from the magnetopause is inferred; however, the lobe plasma has been seen all across the tail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.2114V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.2114V"><span id="translatedtitle">From <span class="hlt">interplanetary</span> space to the ground: The development of <span class="hlt">magnetic</span> structures and their signatures</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Volwerk, Martin; Berchem, J.; Bogdanova, Y. V.; Constantinescu, O. D.; Dunlop, M. W.; Escoubet, P.; Faza-Kerley, A. N.; Frey, H.; Hasegawa, H.; Lavraud, B.; Panov, E. V.; Shen, C.; Shi, J. K.; Sibeck, D. G.; Taylor, M.; Wang, J.; Wild, J.</p> <p></p> <p>We use a special conjuntion of several satellites (ACE, Wind, Cluster, THEMIS, Geotail and DoubleStar) and ground based magnetometers and cameras, on 14 June 2007, to follow ro-tational <span class="hlt">magnetic</span> structures from the solar wind, via amplification through the bow shock, motion of the magnetopause and signatures on the ground. The structures crossing the quasi-perpendicular bow shock are amplified as expected ( factor 2) and further compressed when moving towards the magnetopause. Timing analysis on the structures in the magnetosheath shows that they are moving along with the magnetosheath plasma flow. The structures have slightly different characters with respect to the location of the spacecraft, either pre-or post-noon, both in the solar wind and in the magnetosheath. At the same time that these two structures are observed near Earth, there are strong poleward motions of the aurora and the THEMIS ground magnetometer stations show strong <span class="hlt">magnetic</span> activity. We will follow these structures from the solar wind to the ground and discuss the various processes that are taking place in a first time "three dimensional" view of near Earth space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930062111&hterms=magnetic+anisotropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Banisotropy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930062111&hterms=magnetic+anisotropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Banisotropy"><span id="translatedtitle">Hale cycle effects in cosmic ray east-west anisotropy and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ahluwalia, H. S.</p> <p>1993-01-01</p> <p>We have reanalyzed diurnal anisotropy data obtained with the shielded ion chamber (IC) at Cheltenham/Fredericksburg and the neutron monitor (NM) at Swarthmore/Newark. IC data are for the 1936-1977 period and NM data are for the 1965-1988 period. We have corrected IC data for the diurnal temperature effect. Application of this correction results in a better agreement between IC and other data sets, thereby making it possible to study the long-term changes in the diurnal anisotropy using IC data. The behavior of the annual mean east-west anisotropy is studied for 53 years of observations. The period encompasses more than two solar <span class="hlt">magnetic</span> (Hale) cycles. Its amplitude undergoes the expected 11 and 22 year variations, with the largest changes occurring near solar activity minima. Moreover, the data indicate the presence of the subsidiary maxima for the entire 53-year period, following the solar polar field reversals, during the declining phases of activity cycles when high-speed solar wind streams are present in the heliosphere. The data suggest that the amplitude of the subsidiary maximum is large when the solar polar <span class="hlt">magnetic</span> field points toward the sun in the Northern Hemisphere, and radial anisotropy is absent.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20120016557&hterms=statistical&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dstatistical','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20120016557&hterms=statistical&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dstatistical"><span id="translatedtitle">Using Statistical Multivariable Models to Understand the Relationship Between <span class="hlt">Interplanetary</span> Coronal Mass Ejecta and <span class="hlt">Magnetic</span> Flux Ropes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Riley, P.; Richardson, I. G.</p> <p>2012-01-01</p> <p>In-situ measurements of <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs) display a wide range of properties. A distinct subset, "<span class="hlt">magnetic</span> clouds" (MCs), are readily identifiable by a smooth rotation in an enhanced <span class="hlt">magnetic</span> field, together with an unusually low solar wind proton temperature. In this study, we analyze Ulysses spacecraft measurements to systematically investigate five possible explanations for why some ICMEs are observed to be MCs and others are not: i) An observational selection effect; that is, all ICMEs do in fact contain MCs, but the trajectory of the spacecraft through the ICME determines whether the MC is actually encountered; ii) interactions of an erupting flux rope (PR) with itself or between neighboring FRs, which produce complex structures in which the coherent <span class="hlt">magnetic</span> structure has been destroyed; iii) an evolutionary process, such as relaxation to a low plasma-beta state that leads to the formation of an MC; iv) the existence of two (or more) intrinsic initiation mechanisms, some of which produce MCs and some that do not; or v) MCs are just an easily identifiable limit in an otherwise corntinuous spectrum of structures. We apply quantitative statistical models to assess these ideas. In particular, we use the Akaike information criterion (AIC) to rank the candidate models and a Gaussian mixture model (GMM) to uncover any intrinsic clustering of the data. Using a logistic regression, we find that plasma-beta, CME width, and the ratio O(sup 7) / O(sup 6) are the most significant predictor variables for the presence of an MC. Moreover, the propensity for an event to be identified as an MC decreases with heliocentric distance. These results tend to refute ideas ii) and iii). GMM clustering analysis further identifies three distinct groups of ICMEs; two of which match (at the 86% level) with events independently identified as MCs, and a third that matches with non-MCs (68 % overlap), Thus, idea v) is not supported. Choosing between ideas i) and iv) is more challenging, since they may effectively be indistinguishable from one another by a single in-situ spacecraft. We offer some suggestions on how future studies may address this.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/7040713','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/7040713"><span id="translatedtitle">Large-scale variations of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field: Voyager 1 and 2 observations between 1-5 AU</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Burlaga, L.F.; Lepping, R.P.; Behannon, K.W.; Klein, L.W.; Neubauer, F.M.</p> <p>1982-06-01</p> <p>Observations by the Voyager 1 and 2 spacecraft of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field between 1 and 5 AU have been used to investigate the large-scale structure of the IMF in the years 1977 to 1979, a period of increasing solar activity. This complements the Pioneer 10, 11 investigation between 1 and 8.5 AU during 1972--1976 when the sun was less active. In contrast to the good agreement of the Pioneer observations with the ideal field configuration of the Parker spiral model during near solar minimum conditions, the Voyager spacecraft found notable deviations from that configuration. We attribute these deviations both to temporal variations associated with increasing solar activity, and to the effects of fluctuations of the field in the radial direction. The amplitude of the latter fluctuations was found to be large relative to the magnitude of the radial field component itself beyond approximately 3 AU. The IMF sector structure was generally not well-developed during the period of this study. Notable differences were found between Voyager 1 and 2 observations. Differences in the region 1--2 AU are attributed to the substantially different latitudes of the two spacecraft during much of the period. Later differences are most likely associated with the fact that the Voyagers moved through the region between 4 and 5 AU at different times. Both Voyager 1 and 2 observed decreases with increasing heliocentric distance in the amplitude of 'transverse' fluctuations in B that are consistent with the presence of predominantly undamped Alfven waves in the solar wind although not necessarily implying the presence of them. The presence of convective structures, compressive modes, and/or a saturated instability of Alfven waves cannot be excluded by these Voyager results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JGRA..11612215D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JGRA..11612215D"><span id="translatedtitle">Solar wind energy input during prolonged, intense northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields: A new coupling function</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Du, A. M.; Tsurutani, B. T.; Sun, W.</p> <p>2011-12-01</p> <p>Sudden energy release (ER) events in the midnight sector auroral zone during intense (B > 10 nT), long-duration (T > 3 h), northward (N = Bz > 0 nT) IMF <span class="hlt">magnetic</span> clouds (MCs) during solar cycle 23 (SC23) have been examined in detail. The MCs with northward-then-southward (NS) IMFs were analyzed separately from MCs with southward-then-northward (SN) configurations. It is found that there is a lack of ER/substorms during the N field intervals of NS clouds. In sharp contrast, ER events do occur during the N field portions of SN MCs. From the above two results it is reasonable to conclude that the latter ER events represent residual energy remaining from the preceding S portions of the SN MCs. We derive a new solar wind-magnetosphere coupling function during northward IMFs: ENIMF = ? N-1/12 V7/3 B1/2 + ? V |Dstmin|. The first term on the right-hand side of the equation represents the energy input via viscous interaction, and the second term indicates the residual energy stored in the magnetotail. It is empirically found that the magnetotail/magnetosphere/ionosphere can store energy for a maximum of 4 h before it has dissipated away. This concept is defining one for ER/substorm energy storage. Our scenario indicates that the rate of solar wind energy injection into the magnetotail/magnetosphere/ionosphere for storage determines the potential form of energy release into the magnetosphere/ionosphere. This may be more important to understand solar wind-magnetosphere coupling than the dissipation mechanism itself (in understanding the form of the release). The concept of short-term energy storage is also applied for the solar case. It is argued that it may be necessary to identify the rate of energy input into solar <span class="hlt">magnetic</span> loop systems to be able to predict the occurrence of solar flares.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.4860D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.4860D"><span id="translatedtitle">Solar Wind Energy Input during Prolonged, Intense Northward <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Fields: A New Coupling Function</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Du, A. M.; Tsurutani, B. T.; Sun, W.</p> <p>2012-04-01</p> <p>Sudden energy release (ER) events in the midnight sector at auroral zone latitudes during intense (B > 10 nT), long-duration (T > 3 hr), northward (Bz > 0 nT = N) IMF <span class="hlt">magnetic</span> clouds (MCs) during solar cycle 23 (SC23) have been examined in detail. The MCs with northward-then-southward (NS) IMFs were analyzed separately from MCs with southward-then-northward (SN) configurations. It is found that there is a lack of substorms during the N field intervals of NS clouds. In sharp contrast, ER events do occur during the N field portions of SN MCs. From the above two results it is reasonable to conclude that the latter ER events represent residual energy remaining from the preceding S portions of the SN MCs. We derive a new solar wind-magnetosphere coupling function during northward IMFs: ENIMF = ? N-1/12V 7/3B1/2 + ? V |Dstmin|. The first term on the right-hand side of the equation represents the energy input via "viscous interaction", and the second term indicates the residual energy stored in the magnetotail. It is empirically found that the magnetosphere/magnetotail can store energy for a maximum of ~ 4 hrs before it has dissipated away. This concept is defining one for ER/substorm energy storage. Our scenario indicates that the rate of solar wind energy injection into the magnetosphere/magnetotail determines the form of energy release into the magnetosphere/ionosphere. This may be more important than the dissipation mechanism itself (in understanding the form of the release). The concept of short-term energy storage is applied for the solar case. It is argued that it may be necessary to identify the rate of energy input into solar <span class="hlt">magnetic</span> loop systems to be able to predict the occurrence of solar flares.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140010294','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140010294"><span id="translatedtitle">Source Regions of the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field and Variability in Heavy-Ion Elemental Composition in Gradual Solar Energetic Particle Events</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ko, Yuan-Kuen; Tylka, Allan J.; Ng, Chee K.; Wang, Yi-Ming; Dietrich, William F.</p> <p>2013-01-01</p> <p>Gradual solar energetic particle (SEP) events are those in which ions are accelerated to their observed energies by interactions with a shock driven by a fast coronal mass-ejection (CME). Previous studies have shown that much of the observed event-to-event variability can be understood in terms of shock speed and evolution in the shock-normal angle. But an equally important factor, particularly for the elemental composition, is the origin of the suprathermal seed particles upon which the shock acts. To tackle this issue, we (1) use observed solar-wind speed, magnetograms, and the PFSS model to map the Sun-L1 <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) line back to its source region on the Sun at the time of the SEP observations; and (2) then look for correlation between SEP composition (as measured by Wind and ACE at approx. 2-30 MeV/nucleon) and characteristics of the identified IMF-source regions. The study is based on 24 SEP events, identified as a statistically-significant increase in approx. 20 MeV protons and occurring in 1998 and 2003-2006, when the rate of newly-emergent solar <span class="hlt">magnetic</span> flux and CMEs was lower than in solar-maximum years and the field-line tracing is therefore more likely to be successful. We find that the gradual SEP Fe/O is correlated with the field strength at the IMF-source, with the largest enhancements occurring when the footpoint field is strong, due to the nearby presence of an active region. In these cases, other elemental ratios show a strong charge-to-mass (q/M) ordering, at least on <span class="hlt">average</span>, similar to that found in impulsive events. These results lead us to suggest that <span class="hlt">magnetic</span> reconnection in footpoint regions near active regions bias the heavy-ion composition of suprathermal seed ions by processes qualitatively similar to those that produce larger heavy-ion enhancements in impulsive SEP events. To address potential technical concerns about our analysis, we also discuss efforts to exclude impulsive SEP events from our event sample.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22270776','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22270776"><span id="translatedtitle">SOURCE REGIONS OF THE <span class="hlt">INTERPLANETARY</span> <span class="hlt">MAGNETIC</span> FIELD AND VARIABILITY IN HEAVY-ION ELEMENTAL COMPOSITION IN GRADUAL SOLAR ENERGETIC PARTICLE EVENTS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ko, Yuan-Kuen; Wang, Yi-Ming; Tylka, Allan J.; Ng, Chee K.; Dietrich, William F.</p> <p>2013-10-20</p> <p>Gradual solar energetic particle (SEP) events are those in which ions are accelerated to their observed energies by interactions with a shock driven by a fast coronal mass ejection (CME). Previous studies have shown that much of the observed event-to-event variability can be understood in terms of shock speed and evolution in the shock-normal angle. However, an equally important factor, particularly for the elemental composition, is the origin of the suprathermal seed particles upon which the shock acts. To tackle this issue, we (1) use observed solar-wind speed, magnetograms, and the potential-field source-surface model to map the Sun-L1 <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) line back to its source region on the Sun at the time of the SEP observations and (2) then look for a correlation between SEP composition (as measured by Wind and Advanced Composition Explorer at ?2-30 MeV nucleon{sup 1}) and characteristics of the identified IMF source regions. The study is based on 24 SEP events, identified as a statistically significant increase in ?20 MeV protons and occurring in 1998 and 2003-2006, when the rate of newly emergent solar <span class="hlt">magnetic</span> flux and CMEs was lower than in solar-maximum years, and the field-line tracing is therefore more likely to be successful. We find that the gradual SEP Fe/O is correlated with the field strength at the IMF source, with the largest enhancements occurring when the footpoint field is strong due to the nearby presence of an active region (AR). In these cases, other elemental ratios show a strong charge-to-mass (q/M) ordering (at least on <span class="hlt">average</span>), similar to that found in impulsive events. Such results lead us to suggest that <span class="hlt">magnetic</span> reconnection in footpoint regions near ARs bias the heavy-ion composition of suprathermal seed ions by processes qualitatively similar to those that produce larger heavy-ion enhancements in impulsive SEP events. To address potential technical concerns about our analysis, we also discuss efforts to exclude impulsive SEP events from our event sample.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040031460&hterms=magnetic+signature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dmagnetic%2Bsignature','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040031460&hterms=magnetic+signature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dmagnetic%2Bsignature"><span id="translatedtitle">Spatial Relationship of Signatures of <span class="hlt">Interplanetary</span> Coronal Mass Ejections</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richardson, I. G.; Cane, H. V.; Lepri, S. T.; Zurbuchen, T. H.; Gosling, J. T.</p> <p>2003-01-01</p> <p><span class="hlt">Interplanetary</span> coronal mass ejections (ICMEs) are characterized by a number of signatures. In particular, we examine the relationship between Fe charge states and other signatures during ICMEs in solar cycle 23. Though enhanced Fe charge states characterize many ICMEs, <span class="hlt">average</span> charge states vary from event to event, are more likely to be enhanced in faster or flare-related ICMEs, and do not appear to depend on whether the ICME is a <span class="hlt">magnetic</span> cloud.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900035884&hterms=1087&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2526%25231087','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900035884&hterms=1087&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2526%25231087"><span id="translatedtitle">Heliocentric distance and temporal dependence of the <span class="hlt">interplanetary</span> density-<span class="hlt">magnetic</span> field magnitude correlation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Roberts, D. A.</p> <p>1990-01-01</p> <p>The Helios, IMP 8, ISEE 3, ad Voyager 2 spacecraft are used to examine the solar cycle and heliocentric distance dependence of the correlation between density n and <span class="hlt">magnetic</span> field magnitude B in the solar wind. Previous work had suggested that this correlation becomes progressively more negative with heliocentric distance out to 9.5 AU. Here it is shown that this evolution is not a solar cycle effect, and that the correlations become even more strongly negative at heliocentric distance larger than 9.5 AU. There is considerable variability in the distributions of the correlations at a given heliocentric distance, but this is not simply related to the solar cycle. Examination of the evolution of correlations between density and speed suggest that most of the structures responsible for evolution in the anticorrelation between n and B are not slow-mode waves, but rather pressure balance structures. The latter consist of both coherent structures such as tangential discontinuities and the more generally pervasive 'pseudosound' which may include the coherent structures as a subset.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22133988','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22133988"><span id="translatedtitle">INTERVALS OF RADIAL <span class="hlt">INTERPLANETARY</span> <span class="hlt">MAGNETIC</span> FIELDS AT 1 AU, THEIR ASSOCIATION WITH RAREFACTION REGIONS, AND THEIR APPARENT <span class="hlt">MAGNETIC</span> FOOT POINTS AT THE SUN</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Orlove, Steven T.; Smith, Charles W.; Vasquez, Bernard J.; Schwadron, Nathan A.; Skoug, Ruth M.; Zurbuchen, Thomas H.; Zhao Liang E-mail: Charles.Smith@unh.edu E-mail: N.Schwadron@unh.edu E-mail: thomasz@umich.edu</p> <p>2013-09-01</p> <p>We have examined 226 intervals of nearly radial <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field orientations at 1 AU lasting in excess of 6 hr. They are found within rarefaction regions as are the previously reported high-latitude observations. We show that these rarefactions typically do not involve high-speed wind such as that seen by Ulysses at high latitudes during solar minimum. We have examined both the wind speeds and the thermal ion composition before, during and after the rarefaction in an effort to establish the source of the flow that leads to the formation of the rarefaction. We find that the bulk of the measurements, both fast- and slow-wind intervals, possess both wind speeds and thermal ion compositions that suggest they come from typical low-latitude sources that are nominally considered slow-wind sources. In other words, we find relatively little evidence of polar coronal hole sources even when we examine the faster wind ahead of the rarefaction regions. While this is in contrast to high-latitude observations, we argue that this is to be expected of low-latitude observations where polar coronal hole sources are less prevalent. As with the previous high-latitude observations, we contend that the best explanation for these periods of radial <span class="hlt">magnetic</span> field is interchange reconnection between two sources of different wind speed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890001307','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890001307"><span id="translatedtitle"><span class="hlt">Interplanetary</span> medium data book: Supplement 3A, 1977-1985</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Couzens, David A.; King, Joseph H.</p> <p>1986-01-01</p> <p>Supplement 3 of the <span class="hlt">Interplanetary</span> Medium Data Book contains a detailed discussion of a data set compilation of hourly <span class="hlt">averaged</span> <span class="hlt">interplanetary</span> plasma and <span class="hlt">magnetic</span> field parameters. The discussion addresses data sources, systematic and random differences, time shifting of ISEE 3 data, and plasma normalizations. Supplement 3 also contains solar rotation plots of field and plasma parameters. Supplement 3A contains computer-generated listings of selected parameters from the composite data set. These parameters are bulk speed (km/sec), density (per cu cm), temperature (in units of 1000 K) and the IMF parameters: <span class="hlt">average</span> magnitude, latitude and longitude angles of the vector made up of the <span class="hlt">average</span> GSE components, GSM Cartesian components, and the vector standard deviation. The units of field magnitude, components, and standard deviation are gammas, while the units of field direction angles and degrees.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AnGeo..25.2641L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AnGeo..25.2641L"><span id="translatedtitle">Comparison of <span class="hlt">magnetic</span> field observations of an <span class="hlt">average</span> <span class="hlt">magnetic</span> cloud with a simple force free model: the importance of field compression and expansion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lepping, R. P.; Narock, T. W.; Chen, H.</p> <p>2007-12-01</p> <p>We investigate the ability of the cylindrically symmetric force-free <span class="hlt">magnetic</span> cloud (MC) fitting model of Lepping et al. (1990) to faithfully reproduce actual <span class="hlt">magnetic</span> field observations by examining two quantities: (1) a difference angle, called ?, i.e., the angle between the direction of the observed <span class="hlt">magnetic</span> field (Bobs) and the derived force free model field (Bmod) and (2) the difference in magnitudes between the observed and modeled fields, i.e., ?B(=|Bobs|-|Bmod|), and a normalized ?B (i.e., ?B/) is also examined, all for a judiciously chosen set of 50 WIND <span class="hlt">interplanetary</span> MCs, based on quality considerations. These three quantities are developed as a percent of MC duration and <span class="hlt">averaged</span> over this set of MCs to obtain <span class="hlt">average</span> profiles. It is found that, although <?B> and its normalize version are significantly enhanced (from a broad central <span class="hlt">average</span> value) early in an <span class="hlt">average</span> MC (and to a lesser extent also late in the MC), the angle <?> is small (less than 8) and approximately constant all throughout the MC. The field intensity enhancements are due mainly to interaction of the MC with the surrounding solar wind plasma causing field compression at front and rear. For example, for a typical MC, ?B/ is: 0.210.27 very early in the MC, -0.110.10 at the center (and -0.0850.12 <span class="hlt">averaged</span> over the full "central region," i.e., for 30% to 80% of duration), and 0.050.29 very late in the MC, showing a double sign change as we travel from front to center to back, in the MC. When individual MCs are examined we find that over 80% of them possess field enhancements within several to many hours of the front boundary, but only about 30% show such enhancements at their rear portions. The enhancement of the MC's front field is also due to MC expansion, but this is usually a lesser effect compared to compression. It is expected that this compression is manifested as significant distortion to the MC's cross-section from the ideal circle, first suggested by Crooker et al. (1990), into a more elliptical/oval shape, as some global MC studies seem to confirm (e.g., Riley and Crooker, 2004) and apparently also as confirmed for local studies of MCs (e.g., Hidalgo et al., 2002; Nieves-Chinchilla et al., 2005).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950029559&hterms=Taguchi&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DTaguchi','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950029559&hterms=Taguchi&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DTaguchi"><span id="translatedtitle">By-controlled convection and field-aligned currents near midnight auroral oval for northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Taguchi, S.; Sugiura, M.; Iyemori, T.; Winningham, J. D.; Slavin, J. A.</p> <p>1994-01-01</p> <p>Using the Dynamics Explorer (DE) 2 <span class="hlt">magnetic</span> and electric field and plasma data, B(sub y)- controlled convection and field-aligned currents in the midnight sector for northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) are examined. The results of an analysis of the electric field data show that when IMF is stable and when its magnitude is large, a coherent B(sub y)-controlled convection exists near the midnight auroral oval in the ionosphere having adequate conductivities. When B(sub y) is negative, the convection consists of a westward (eastward) plasma flow at the lower latitudes and an eastward (westward) plasma flow at the higher latitudes in the midnight sector in the northern (southern) ionosphere. When B(sub y) is positive, the flow directions are reversed. The distribution of the field-aligned currents associated with the B(sub y)-controlled convection, in most cases, shows a three-sheet structure. In accordance with the convection the directions of the three sheets are dependent on the sign of B(sub y). The location of disappearance of the precipitating intense electrons having energies of a few keV is close to the convection reversal surface. However, the more detailed relationship between the electron precipitation boundary and the convection reversal surface depends on the case. In some cases the precipitating electrons extend beyond the convection reversal surface, and in others the poleward boundary terminates at a latitude lower than the reversal surface. Previous studies suggest that the poleward boundary of the electrons having energies of a few keV is not necessarily coincident with an open/closed bounary. Thus the open/closed boundary may be at a latitude higher than the poleward boundary of the electron precipitation, or it may be at a latitude lower than the poleward boundary of the electron precipitation. We discuss relationships between the open/closed boundary and the convection reversal surface. When as a possible choice we adopt a view that the open/closed boundary agrees with the convection reversal surface, we can explain qualitatively the configuration of the B(sub y)-controlled convection on the open and close field line regions by proposing a mapping modified in accordance with IMF B(sub y).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880012611','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880012611"><span id="translatedtitle"><span class="hlt">Magnetic</span> field hourly <span class="hlt">averages</span> from the Rome-GSFC experiment aboard Helios 1 and Helio 2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mariani, F.; Ness, N. F.; Bavassano, B.; Bruno, R.; Buccellato, R.; Burlaga, L. F.; Cantarano, S.; Scearce, C. S.; Terenzi, R.; Villante, U.</p> <p>1987-01-01</p> <p>Plots of all the hourly <span class="hlt">averages</span> computed from the solar <span class="hlt">magnetic</span> field measurements obtained during the mission are given separately for Helios 1 and Helios 2. The magnitude and the direction of the <span class="hlt">averaged</span> field are plotted versus the number of solar rotations as seen from Helios, counted from launch.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_9");'>9</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li class="active"><span>11</span></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_11 --> <div id="page_12" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="221"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920045478&hterms=earth+events&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dearth%2Bevents','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920045478&hterms=earth+events&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dearth%2Bevents"><span id="translatedtitle">Prediction of <span class="hlt">magnetic</span> orientation in driver gas associated -Bz events. [in <span class="hlt">interplanetary</span> medium observed at earth when solar source is identified</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hoeksema, J. T.; Zhao, Xuepu</p> <p>1992-01-01</p> <p>The source regions of five strong -Bz events detected at 1 AU for which solar sources were identified by Tang et al. (1989) and Tsurutani et al. (1992) are investigated in order to determine whether the <span class="hlt">magnetic</span> orientation of driver gas in the <span class="hlt">interplanetary</span> medium observed at the earth can be predicted when its solar source is identified. Three -Bz events were traced to flare-associated coronal mass ejections (CMEs), one to an eruptive prominence associated CME, and one to three possible solar sources. The computed <span class="hlt">magnetic</span> orientations at the candidate 'release height' (the height where the front of a CME ceases to accelerate) above the flare sites associated with CMEs show the existence of the expected southward field component. It is concluded that the <span class="hlt">magnetic</span> orientation in flare-associated CME generated driver gas may be predictable.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970026618','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970026618"><span id="translatedtitle">Upper Thermosphere Winds and Temperatures in the Geomagnetic Polar Cap: Solar Cycle, Geomagnetic Activity, and <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Dependencies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Killeen, T. L.; Won, Y.-I.; Niciejewski, R. J.; Burns, A. G.</p> <p>1995-01-01</p> <p>Ground-based Fabry-Perot interferometers located at Thule, Greenland (76.5 deg. N, 69.0 deg. W, lambda = 86 deg.) and at Sondre Stromfjord, Greenland (67.0 deg. N, 50.9 deg. W, lambda = 74 deg.) have monitored the upper thermospheric (approx. 240-km altitude) neutral wind and temperature over the northern hemisphere geomagnetic polar cap since 1983 and 1985, respectively. The thermospheric observations are obtained by determining the Doppler characteristics of the (OI) 15,867-K (630.0-nm) emission of atomic oxygen. The instruments operate on a routine, automatic, (mostly) untended basis during the winter observing seasons, with data coverage limited only by cloud cover and (occasional) instrument failures. This unique database of geomagnetic polar cap measurements now extends over the complete range of solar activity. We present an analysis of the measurements made between 1985 (near solar minimum) and 1991 (near solar maximum), as part of a long-term study of geomagnetic polar cap thermospheric climatology. The measurements from a total of 902 nights of observations are compared with the predictions of two semiempirical models: the Vector Spherical Harmonic (VSH) model of Killeen et al. (1987) and the Horizontal Wind Model (HWM) of Hedin et al. (1991). The results are also analyzed using calculations of thermospheric momentum forcing terms from the Thermosphere-ionosphere General Circulation Model TGCM) of the National Center for Atmospheric Research (NCAR). The experimental results show that upper thermospheric winds in the geomagnetic polar cap have a fundamental diurnal character, with typical wind speeds of about 200 m/s at solar minimum, rising to up to about 800 m/s at solar maximum, depending on geomagnetic activity level. These winds generally blow in the antisunward direction, but are interrupted by episodes of modified wind velocity and altered direction often associated with changes in the orientation of the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field (IMF). The central polar cap (greater than approx. 80 <span class="hlt">magnetic</span> latitude) antisunward wind speed is found to be a strong function of both solar and geomagnetic activity. The polar cap temperatures show variations in both solar and geomagnetic activity, with temperatures near 800 K for low K(sub p) and F(sub 10.7) and greater than about 2000 K for high K(sub p) and F(sub 10.7). The observed temperatures are significantly greater than those predicted by the mass spectrometer/incoherent scatter model for high activity conditions. Theoretical analysis based on the NCAR TIGCM indicates that the antisunward upper thermospheric winds, driven by upstream ion drag, basically 'coast' across the polar cap. The relatively small changes in wind velocity and direction within the polar cap are induced by a combination of forcing terms of commensurate magnitude, including the nonlinear advection term, the Coriolis term, and the pressure gradient force term. The polar cap thennospheric thermal balance is dominated by horizontal advection, and adiabatic and thermal conduction terms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740009007','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740009007"><span id="translatedtitle"><span class="hlt">Average</span> daily variations in the <span class="hlt">magnetic</span> field as observed by ATS-5</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Skillman, T. L.</p> <p>1974-01-01</p> <p>Hourly <span class="hlt">averages</span> of the <span class="hlt">magnetic</span> field components are determined and analyzed using the measurements of the <span class="hlt">magnetic</span> field monitor aboard the ATS-5. The data covering the time period of September 1969 through September 1971 are sorted and analyzed for various Kp values, geomagnetic latitude of the subsolar point, and local time. Local time variations are harmonically analyzed, and amplitudes and phases are given up to the fourth harmonic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720022697','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720022697"><span id="translatedtitle"><span class="hlt">Average</span> daily variations in the <span class="hlt">magnetic</span> field as observed by ATS-5</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Skillman, T. L.</p> <p>1972-01-01</p> <p>Hourly <span class="hlt">averages</span> of the <span class="hlt">magnetic</span> field components are determined and analyzed using the measurements, by the <span class="hlt">magnetic</span> field monitor (MFM) aboard the ATS-5 satellite. The data covering the time period of September 1969 through September 1971 are sorted and analyzed for various Kp values, geomagnetic latitude of the subsolar point, and local time. Local time variations are harmonically analyzed, and amplitudes and phases are given up to the fourth harmonic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMMM..394..195S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMMM..394..195S"><span id="translatedtitle">The effect of stress and incentive <span class="hlt">magnetic</span> field on the <span class="hlt">average</span> volume of <span class="hlt">magnetic</span> Barkhausen jump in iron</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shu, Di; Guo, Lei; Yin, Liang; Chen, Zhaoyang; Chen, Juan; Qi, Xin</p> <p>2015-11-01</p> <p>The <span class="hlt">average</span> volume of <span class="hlt">magnetic</span> Barkhausen jump (AVMBJ) v bar generated by <span class="hlt">magnetic</span> domain wall irreversible displacement under the effect of the incentive <span class="hlt">magnetic</span> field H for ferromagnetic materials and the relationship between irreversible <span class="hlt">magnetic</span> susceptibility ?irr and stress ? are adopted in this paper to study the theoretical relationship among AVMBJ v bar(magneto-elasticity noise) and the incentive <span class="hlt">magnetic</span> field H. Then the numerical relationship among AVMBJ v bar, stress ? and the incentive <span class="hlt">magnetic</span> field H is deduced. Utilizing this numerical relationship, the displacement process of <span class="hlt">magnetic</span> domain wall for single crystal is analyzed and the effect of the incentive <span class="hlt">magnetic</span> field H and the stress ? on the AVMBJ v bar (magneto-elasticity noise) is explained from experimental and theoretical perspectives. The saturation velocity of Barkhausen jump characteristic value curve is different when tensile or compressive stress is applied on ferromagnetic materials, because the resistance of <span class="hlt">magnetic</span> domain wall displacement is different. The idea of critical <span class="hlt">magnetic</span> field in the process of <span class="hlt">magnetic</span> domain wall displacement is introduced in this paper, which solves the supersaturated calibration problem of AVMBJ - ? calibration curve.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMGP51B3724E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMGP51B3724E"><span id="translatedtitle">Implications of Depth Determination from Second Moving <span class="hlt">Average</span> Residual <span class="hlt">Magnetic</span> Anomalies on Mars</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Essa, K. S.; Kletetschka, G.</p> <p>2014-12-01</p> <p>Mars total <span class="hlt">magnetic</span> data obtained by Mars Global Surveyor mission from 400 km altitude were processed using a second moving <span class="hlt">average</span> method (SMAM) to estimate the depth of the buried sources. Five profiles were chosen across major <span class="hlt">magnetic</span> areas. Each profile was subjected to a separation technique using the SMAM. Second moving <span class="hlt">average</span> residual anomalies (SMARA) were obtained from <span class="hlt">magnetic</span> data using filters of successive spacing. The depth estimate is monitored by the standard deviation of the depths determined from all SMARA for various value of the shape factor (SF) that includes dike, cylinder, and sphere. The standard deviation along with depth estimate is considered to be a new criterion for determining the correct depth and shape of the buried structures on Mars.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM33A2168L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM33A2168L"><span id="translatedtitle">Adiabatic and nonadiabatic responses of the radiation belt relativistic electrons to the external changes in solar wind dynamic pressure and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, L.</p> <p>2013-12-01</p> <p>By removing the influences of 'magnetopause shadowing' (r0>6.6RE) and geomagnetic activities, we investigated statistically the responses of <span class="hlt">magnetic</span> field and relativistic (>0.5MeV) electrons at geosynchronous orbit to 201 <span class="hlt">interplanetary</span> perturbations during 6 years from 2003 (solar maximum) to 2008 (solar minimum). The statistical results indicate that during geomagnetically quiet times (HSYM ≥-30nT, and AE<200nT), ~47.3% changes in the geosynchronous <span class="hlt">magnetic</span> field and relativistic electron fluxes are caused by the combined actions of the enhancement of solar wind dynamic pressure (Pd) and the southward turning of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) (ΔPd>0.4 nPa, and IMF Bz<0 nT), and only ~18.4% changes are due to single dynamic pressure increase (ΔPd >0.4 nPa, but IMF Bz>0 nT), and ~34.3% changes are due to single southward turning of IMF (IMF Bz<0 nT, but |ΔPd|<0.4 nPa). Although the responses of <span class="hlt">magnetic</span> field and relativistic electrons to the southward turning of IMF are weaker than their responses to the dynamic pressure increase, the southward turning of IMF can cause the dawn-dusk asymmetric perturbations that the <span class="hlt">magnetic</span> field and the relativistic electrons tend to increase on the dawnside (LT~00:00-12:00) but decrease on the duskside (LT~13:00-23:00). Furthermore, the variation of relativistic electron fluxes is adiabatically controlled by the magnitude and elevation angle changes of <span class="hlt">magnetic</span> field during the single IMF southward turnings. However, the variation of relativistic electron fluxes is independent of the change in <span class="hlt">magnetic</span> field in some compression regions during the enhancement of solar wind dynamic pressure (including the single pressure increases and the combined external perturbations), indicating that nonadiabatic dynamic processes of relativistic electrons occur there. Acknowledgments. This work is supported by NSFC (grants 41074119 and 40604018). Liuyuan Li is grateful to the staffs working for the data from GOES 8-12 satellites and OMNI database in CDAWeb.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930015892','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930015892"><span id="translatedtitle">Anomalous aspects of magnetosheath flow and of the shape and oscillations of the magnetopause during an interval of strongly northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chen, Sheng-Hsien; Kivelson, Margaret G.; Gosling, Jack T.; Walker, Raymond T.; Lazarus, Allan J.</p> <p>1992-01-01</p> <p>On 15 Feb. 1978, the orientation of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) remained steadily northward for more than 12 hours. The ISEE 1 and 2 spacecraft were located near apogee on the dawn side flank of the magnetotail. IMP 8 was almost symmetrically located in the magnetosheath on the dusk flank and IMP 7 was upstream in the solar wind. Using plasma and <span class="hlt">magnetic</span> field data, we show the following: (1) the magnetosheath flow speed on the flanks of the magnetotail steadily exceeded the solar wind speed by 20 percent; (2) surface waves with approximately a 5-min period and very non-sinusoidal waveform were persistently present on the dawn magnetopause and waves of similar period were present in the dusk magnetosheath; and (3) the magnetotail ceased to flare at an antisunward distance of 15 R(sub E). We propose that the acceleration of the magnetosheath flow is achieved by <span class="hlt">magnetic</span> tension in the draped field configuration for northward IMF and that the reduction of tail flaring is consistent with a decreased amount of open <span class="hlt">magnetic</span> flux and a larger standoff distance of the subsolar magnetopause. Results of a three-dimensional magnetohydrodynamic simulation support this phenomenological model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6306067','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6306067"><span id="translatedtitle">Anomalous aspects of magnetosheath flow and of the shape and oscillations of the magnetopause during an interval of strongly northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chen, S.; Kivelson, M.G.; Gosling, J.T.; Walker, R.T.; Lazarus, A.J.</p> <p>1992-09-01</p> <p>On 15 Feb. 1978, the orientation of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) remained steadily northward for more than 12 hours. The ISEE 1 and 2 spacecraft were located near apogee on the dawn side flank of the magnetotail. IMP 8 was almost symmetrically located in the magnetosheath on the dusk flank and IMP 7 was upstream in the solar wind. Using plasma and <span class="hlt">magnetic</span> field data, the authors show the following: (1) the magnetosheath flow speed on the flanks of the magnetotail steadily exceeded the solar wind speed by 20 percent; (2) surface waves with approximately a 5-min period and very non-sinusoidal waveform were persistently present on the dawn magnetopause and waves of similar period were present in the dusk magnetosheath; and (3) the magnetotail ceased to flare at an antisunward distance of 15 R(sub E). They propose that the acceleration of the magnetosheath flow is achieved by <span class="hlt">magnetic</span> tension in the draped field configuration for northward IMF and that the reduction of tail flaring is consistent with a decreased amount of open <span class="hlt">magnetic</span> flux and a larger standoff distance of the subsolar magnetopause. Results of a three-dimensional magnetohydrodynamic simulation support this phenomenological model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SuMi...88..204L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SuMi...88..204L"><span id="translatedtitle">Manipulating spin spatial splitter in a ?-doped semiconductor nanostructure with zero <span class="hlt">average</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Gui-Xiang; Ma, Wen-Yue; Shen, Li-Hua</p> <p>2015-12-01</p> <p>Recently, based on a novel <span class="hlt">magnetic</span> nanostructure with zero <span class="hlt">average</span> <span class="hlt">magnetic</span> field, a spin spatial splitter with a considerable spin-polarized lateral displacement was proposed [Appl. Surf. Sci. 313 (2014) 545]. To further manipulate its spin-polarized behaviour, in this work, we introduce a tunable ?-potential into the device by the atomic layer doping, and calculated its effect on spin-polarized lateral displacement of the electron. Both magnitude and sign of spin polarization are found to be sensitive to the ?-doping. Therefore, such a device can serve as a structurally-controllable spin-polarized source for spintronics applications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20110007246&hterms=consequence+many&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dconsequence%2Bmany','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110007246&hterms=consequence+many&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dconsequence%2Bmany"><span id="translatedtitle">Erratum to "Solar Sources and Geospace Consequences of <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Clouds Observed During Solar Cycle 23-Paper 1" [J. Atmos. Sol.-Terr. Phys. 70(2-4) (2008) 245-253</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gopalswamy, N.; Akiyama, S.; Yashiro, S.; Michalek, G.; Lepping, R. P.</p> <p>2009-01-01</p> <p>One of the figures (Fig. 4) in "Solar sources and geospace consequences of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> Clouds observed during solar cycle 23 -- Paper 1" by Gopalswamy et al. (2008, JASTP, Vol. 70, Issues 2-4, February 2008, pp. 245-253) is incorrect because of a software error in t he routine that was used to make the plot. The source positions of various <span class="hlt">magnetic</span> cloud (MC) types are therefore not plotted correctly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014IAUS..300..297W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014IAUS..300..297W"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Disturbances Affecting Space Weather</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wimmer-Schweingruber, Robert F.</p> <p>2014-01-01</p> <p>The Sun somehow accelerates the solar wind, an incessant stream of plasma originating in coronal holes and some, as yet unidentified, regions. Occasionally, coronal, and possibly sub-photospheric structures, conspire to energize a spectacular eruption from the Sun which we call a coronal mass ejection (CME). These can leave the Sun at very high speeds and travel through the <span class="hlt">interplanetary</span> medium, resulting in a large-scale disturbance of the ambient background plasma. These <span class="hlt">interplanetary</span> CMEs (ICMEs) can drive shocks which in turn accelerate particles, but also have a distinct intrinsic <span class="hlt">magnetic</span> structure which is capable of disturbing the Earth's <span class="hlt">magnetic</span> field and causing significant geomagnetic effects. They also affect other planets, so they can and do contribute to space weather throughout the heliosphere. This paper presents a historical review of early space weather studies, a modern-day example, and discusses space weather throughout the heliosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6416734','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6416734"><span id="translatedtitle">Use of induction linacs with nonlinear <span class="hlt">magnetic</span> drive as high <span class="hlt">average</span> power accelerators</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Birx, D.L.; Cook, E.G.; Hawkins, S.A.; Newton, M.A.; Poor, S.E.; Reginato, L.L.; Schmidt, J.A.; Smith, M.W.</p> <p>1984-08-20</p> <p>The marriage of induction linac technology with Nonlinear <span class="hlt">Magnetic</span> Modulators has produced some unique capabilities. It appears possible to produce electron beams with <span class="hlt">average</span> currents measured in amperes, at gradients exceeding 1 Mev/meter, and with power efficiencies approaching 50%. A 2 MeV, 5 kA electron accelerator is under construction at Lawrence Livermore National Laboratory (LLNL) to allow us to demonstrate some of these concepts. Progress on this project is reported here.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950047166&hterms=earth+layers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dearth%2527s%2Blayers','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950047166&hterms=earth+layers&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dearth%2527s%2Blayers"><span id="translatedtitle">The Earth's magnetosphere is 165 R(sub E) long: Self-consistent currents, convection, magnetospheric structure, and processes for northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fedder, J. A.; Lyon, J. G.</p> <p>1995-01-01</p> <p>The subject of this paper is a self-consistent, magnetohydrodynamic numerical realization for the Earth's magnetosphere which is in a quasi-steady dynamic equilibrium for a due northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). Although a few hours of steady northward IMF are required for this asymptotic state to be set up, it should still be of considerable theoretical interest because it constitutes a 'ground state' for the solar wind-magnetosphere interaction. Moreover, particular features of this ground state magnetosphere should be observable even under less extreme solar wind conditions. Certain characteristics of this magnetosphere, namely, NBZ Birkeland currents, four-cell ionospheric convection, a relatively weak cross-polar potential, and a prominent flow boundary layer, are widely expected. Other characteristics, such as no open tail lobes, no Earth-connected <span class="hlt">magnetic</span> flux beyond 155 R(sub E) downstream, <span class="hlt">magnetic</span> merging in a closed topology at the cusps, and a 'tadpole' shaped magnetospheric boundary, might not be expected. In this paper, we will present the evidence for this unusual but interesting magnetospheric equilibrium. We will also discuss our present understanding of this singular state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/85412','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/85412"><span id="translatedtitle">The Earth`s magnetosphere is 165 R{sub E} long: Self-consistent currents, convection, magnetospheric structure, and processes for northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fedder, J.A.; Lyon, J.G.</p> <p>1995-03-01</p> <p>The subject of this paper is a self-consistent, magnetohydrodynamic numerical realization for the Earth`s magnetosphere which is in a quasi-steady dynamic equilibrium for a due northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). Although a few hours of steady northward IMF are required for this asymptotic state to be set up, it should still be of considerable theoretical interest because it constitutes a `ground state` for the solar wind-magnetosphere interaction. Moreover, particular features of this ground state magnetosphere should be observable even under less extreme solar wind conditions. Certain characteristics of this magnetosphere, namely, NBZ Birkeland currents, four-cell ionospheric convection, a relatively weak cross-polar potential, and a prominent flow boundary layer, are widely expected. Other characteristics, such as no open tail lobes, no Earth-connected <span class="hlt">magnetic</span> flux beyond 155 R(sub E) downstream, <span class="hlt">magnetic</span> merging in a closed topology at the cusps, and a `tadpole` shaped magnetospheric boundary, might not be expected. In this paper, we will present the evidence for this unusual but interesting magnetospheric equilibrium. We will also discuss our present understanding of this singular state.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870041528&hterms=magnetic+anisotropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Banisotropy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870041528&hterms=magnetic+anisotropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Banisotropy"><span id="translatedtitle">Properties of a large-scale <span class="hlt">interplanetary</span> loop structure as deduced from low-energy proton anisotropy and <span class="hlt">magnetic</span> field measurements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tranquille, C.; Sanderson, T. R.; Marsden, R. G.; Wenzel, K.-P.; Smith, E. J.</p> <p>1987-01-01</p> <p>Correlated particle and <span class="hlt">magnetic</span> field measurements by the ISEE 3 spacecraft are presented for the loop structure behind the <span class="hlt">interplanetary</span> traveling shock event of Nov. 12, 1978. Following the passage of the turbulent shock region, strong bidirectional streaming of low-energy protons is observed for approximately 6 hours, corresponding to a loop thickness of about 0.07 AU. This region is also characterized by a low relative variance of the <span class="hlt">magnetic</span> field, a depressed proton intensity, and a reduction in the <span class="hlt">magnetic</span> power spectral density. Using quasi-linear theory applied to a slab model, a value of 3 AU is derived for the mean free path during the passage of the closed loop. It is inferred from this observation that the proton regime associated with the loop structure is experiencing scatter-free transport and that either the length of the loop is approximately 3 AU between the sun and the earth or else the protons are being reflected at both ends of a smaller loop.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.1624K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.1624K"><span id="translatedtitle">Investigation of influence of hypomagnetic conditions closely similar to <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> filed on behavioral and vegetative reactions of higher mammals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Krivova, Natalie; Trukhanov, Kiril; Zamotshina, Tatyana; Zaeva, Olga; Khodanovich, Marina; Misina, Tatyana; Tukhvatulin, Ravil; Suhko, Valery</p> <p></p> <p>To study the influence of long being under reduced <span class="hlt">magnetic</span> field on behavioral and vegetative reactions of higher mammals the white rat males were put into the 700-1000 times reduced geomagnetic field (50-70 nT) for 25 days. Such field was obtained by using automatic compensation of the horizontal and vertical components of the GMF at a frequencies up to 10 Hz by means of solenoids of the experimental <span class="hlt">magnetic</span> system. Control animals were located in the same room under usual laboratory GMF conditions (52 uT). Two days before the experiment the behavioral reactions were studied in the "open field" by means of a set of tests, characterizing the level of emotionality, moving and orientational-investigative activities of the animals under conditions of unimpeded behavior. 60 white underbred rat males with the initial body mass of 200 g were divided into three clusters. Animals with <span class="hlt">average</span> indices were selected for the experiment. We have judged behavioral reaction disturbances of the rats under hypomagnetic conditions using videotape recordings carried out in the entire course of the chronic experiment. According to the obtained results during the period of maximum activity (from 230 to 330 a.m.) the number of interrelations between the individuals increased appreciably for experimental rats including interrelations with aggressive character. This was real during all 25 days of observation. We observed a certain dynamics of this index differed from that of the control group. We have also analyzed the final period of observation from the 21th to the 25th days. In this period we studied the 24 hours' dynamics of interrelations which were noted during 5 minutes in every hour around the clock. In the control group the number of interrelation was at a constantly low level. For experimental animals the number of interrelations was higher in the night hours than in the day ones. Moreover it exceeded the similar indexes observed from the 1st to the 20th day. For example from 300 to 305 a.m. on the 23th day we recorded 27 contacts of aggressive character between the individuals. So, in hypomagnetic field conditions the irritability of the animals' central nervous system grows, that expresses itself in the increase of contacts of aggressive and non-aggressive character between the individuals. Also we have carried out the Spirman correlation analysis between studied indices of moving activity and chemiluminescence of blood plasma and urine, electrolytic composition of urine and muscles. For control animals the quantity of correlation connections between electrolyte concentrations in studied substrata was higher than for experimental animals. The physiological sense of these correlation connections is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://pubs.er.usgs.gov/publication/70011277','USGSPUBS'); return false;" href="http://pubs.er.usgs.gov/publication/70011277"><span id="translatedtitle">Statistical <span class="hlt">averaging</span> of marine <span class="hlt">magnetic</span> anomalies and the aging of oceanic crust.</span></a></p> <p><a target="_blank" href="http://pubs.er.usgs.gov/pubs/index.jsp?view=adv">USGS Publications Warehouse</a></p> <p>Blakely, R.J.</p> <p>1983-01-01</p> <p>Visual comparison of Mesozoic and Cenozoic <span class="hlt">magnetic</span> anomalies in the North Pacific suggests that older anomalies contain less short-wavelength information than younger anomalies in this area. To test this observation, <span class="hlt">magnetic</span> profiles from the North Pacific are examined from crust of three ages: 0-2.1, 29.3-33.1, and 64.9-70.3Ma. For each time period, at least nine profiles were analyzed by 1) calculating the power density spectrum of each profile, 2) <span class="hlt">averaging</span> the spectra together, and 3) computing a 'recording filter' for each time period by assuming a hypothetical seafloor model. The model assumes that the top of the source is acoustic basement, the source thickness is 0.5km, and the time scale of geomagnetic reversals is according to Ness et al. (1980). The calculated power density spectra of the three recording filters are complex in shape but show an increase of attenuation of short-wavelength information as the crust ages. These results are interpreted using a multilayer model for marine <span class="hlt">magnetic</span> anomalies in which the upper layer, corresponding to pillow basalt of seismic layer 2A, acts as a source of noise to the <span class="hlt">magnetic</span> anomalies. As the ocean crust ages, this noisy contribution by the pillow basalts becomes less significant to the anomalies. Consequently, <span class="hlt">magnetic</span> sources below layer 2A must be faithful recorders of geomagnetic reversals.-AuthorPacific power density spectrum</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983JGR....88.2289B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983JGR....88.2289B"><span id="translatedtitle">Statistical <span class="hlt">averaging</span> of marine <span class="hlt">magnetic</span> anomalies and the aging of oceanic crust</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Blakely, Richard J.</p> <p>1983-03-01</p> <p>Visual comparison of Mesozoic and Cenozoic <span class="hlt">magnetic</span> anomalies in the North Pacific suggests that older anomalies contain less short-wavelength information than younger anomalies in this area. To test this observation, <span class="hlt">magnetic</span> profiles from the North Pacific are examined from crust of three ages: 0-2.1, 29.3-33.1, and 64.9-70.3 m.y, B.P. For each time period, at least nine profiles were analyzed by (1) calculating the power density spectrum of each profile, (2) <span class="hlt">averaging</span> the spectra together, and (3) computing a `recording filter' for each time period by assuming a hypothetical seafloor model. The model assumes that the top of the source is acoustic basement, the source thickness is 0.5 km, and the time scale of geomagnetic reversals is according to Ness et al. (1980). The calculated power density spectra of the three recording filters are complex in shape but show an increase of attenuation of short-wavelength information as the crust ages. These results are interpreted using a multilayer model for marine <span class="hlt">magnetic</span> anomalies in which the upper layer, corresponding to pillow basalt of seismic layer 2A, acts as a source of noise to the <span class="hlt">magnetic</span> anomalies. As the ocean crust ages, this noisy contribution by the pillow basalts becomes less significant to the anomalies. Consequently, <span class="hlt">magnetic</span> sources below layer 2A must be faithful recorders of geomagnetic reversals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6584334','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6584334"><span id="translatedtitle">Anomalous aspects of magnetosheath flow and of the shape and oscillations of the magnetopause during an interval of strongly northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chen, Shenghsien; Kivelson, M.G.; Walker, R.J. ); Gosling, J.T. ); Lazarus, A.J. )</p> <p>1993-04-01</p> <p>The authors address the question of the flow of the magnetosheath, and its coupling to the magnetopause, in particular along the flanks of the magnetotail. There was a greater than 12 hour period on February 15, 1978, when the orientation of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field remained northward. Several satellites observed this occurance. The ISEE 1 and 2 satellites were on the dawnside edge of the magnetotail. IMP 8 was on the duskside edge of the magnetosheath almost symmetric from the ISEE satellites. IMP 7 was at an upsteam location in the solar wind. The authors use plasma and <span class="hlt">magnetic</span> field measurement data to propose a model which they then support with three-dimensional magnetohydrodynamic simulations. They observe that the flow speed of the magnetosheath on the edges of the magnetotail exceeds the solar wind speed by roughly 20%. Plasma surface wave with roughly 5 minute periods were observed in the magnetopause and magnetosphere. Flaring of the magnetotail ceased at an antisunward distance of roughly 15R[sub E].</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_10");'>10</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li class="active"><span>12</span></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_12 --> <div id="page_13" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="241"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950053481&hterms=plasma+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dplasma%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950053481&hterms=plasma+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dplasma%2Bfield"><span id="translatedtitle">Penetration of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field B(sub y) magnetosheath plasma into the magnetosphere: Implications for the predominant magnetopause merging site</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Newell, Patrick T.; Sibeck, David G.; Meng, Ching-I</p> <p>1995-01-01</p> <p>Magnetosheath plasma peertated into the magnetospere creating the particle cusp, and similarly the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) B(sub y) component penetrates the magnetopause. We reexamine the phenomenology of such penetration to investigate implications for the magnetopause merging site. Three models are popular: (1) the 'antiparallel' model, in which merging occurs where the local <span class="hlt">magnetic</span> shear is largest (usually high <span class="hlt">magnetic</span> latitude); (2) a tilted merging line passing through the subsolar point but extending to very high latitudes; or (3) a tilted merging line passing through the subsolar point in which most merging occurs within a few Earth radii of the equatorial plane and local noon (subsolar merging). It is difficult to distinguish between the first two models, but the third implies some very different predictions. We show that properties of the particle cusp imply that plasma injection into the magnetosphere occurs most often at high <span class="hlt">magnetic</span> latitudes. In particular, we note the following: (1) The altitude of the merging site inferred from midaltitude cusp ion pitch angle dispersion is typically 8-12 R(sub E). (2) The highest ion energy observable when moving poleward through the cusp drops long before the bulk of the cusp plasma is reached, implying that ions are swimming upstream against the sheath flow shortly after merging. (3) Low-energy ions are less able to enter the winter cusp than the summer cusp. (4) The local time behavior of the cusp as a function of B(sub y) and B(sub z) corroborates predictions of the high-latitude merging models. We also reconsider the penetration of the IMF B(sub y) component onto closed dayside field lines. Our approach, in which closed field lines ove to fill in flux voids created by asymmetric magnetopause flux erosion, shows that strich subsolar merging cannot account for the observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870017315&hterms=Giotto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DGiotto','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870017315&hterms=Giotto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DGiotto"><span id="translatedtitle">Macroscopic perturbations of the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field (IMF) by P/Halley as seen by the Giotto magnetometer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Raeder, J.; Neubauer, F. M.; Ness, N.; Burlaga, L. F.</p> <p>1986-01-01</p> <p>Giotto <span class="hlt">magnetic</span> field data were used to analyze the macroscopic field structure in the vicinity of P/Halley. During the Giotto flyby at comet P/Halley the IMF showed a quite stable away polarity. Draping of <span class="hlt">magnetic</span> field lines is clearly observed along the outbound leg of the trajectory. Inside the <span class="hlt">magnetic</span> pile-up region the field reverses its polarity several times. A symmetry of oppositely <span class="hlt">magnetized</span> sheets with respect to the nucleus is found and explained in terms of convected IMF features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080014138&hterms=Weber&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D60%26Ntt%3DWeber','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080014138&hterms=Weber&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D60%26Ntt%3DWeber"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Network Directorate</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Weber, William J.</p> <p>2004-01-01</p> <p>This viewgraph presentation reviews the work of the <span class="hlt">Interplanetary</span> Network Directorate at NASA's Jet Propulsion Laboratory. The attributes of the <span class="hlt">interplanetary</span> network are reviewed, and the expansion of the current Deep Space Network for future mission support is described. Points of interest to the industry are emphasized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ExG....47...58A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ExG....47...58A"><span id="translatedtitle">Depth and shape solutions from second moving <span class="hlt">average</span> residual <span class="hlt">magnetic</span> anomalies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Abdelrahman, El-Sayed M.; Essa, Khalid S.; El-Araby, Tarek M.; Abo-Ezz, Eid R.</p> <p>2016-02-01</p> <p>We have developed a simple and fast numerical method to simultaneously determine the depth and shape of a buried structure from second moving <span class="hlt">average</span> residual anomalies obtained from <span class="hlt">magnetic</span> data with filters of successive window lengths. The method is similar to Euler deconvolution, but it solves for depth and shape independently. The method involves using a nonlinear relationship between the depth to the source and the shape factor, and a combination of observations at five points with respect to the coordinate of the source centre with a free parameter (window length). The method is based on computing the standard deviation of the depths determined from all second moving <span class="hlt">average</span> residual anomalies for each value of the shape factor. The standard deviation may generally be considered a criterion for determining the correct depth and shape of the buried structure. When the correct shape factor is used, the standard deviation of the depths is less than the standard deviation using incorrect values of the shape factor. This method can be applied to residuals, as well as the observed <span class="hlt">magnetic</span> data consisting of the combined effect of a residual component due to a purely local structure and a regional component represented by a polynomial of up to fourth-order. The method is applied to synthetic data, with and without random errors, and tested on a field example from Brazil. In all cases, the shape and depth of the buried structures are found in good agreement with the actual ones.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhyE...71...39S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhyE...71...39S"><span id="translatedtitle">A structurally-controllable spin filter in a δ-doped <span class="hlt">magnetically</span> modulated semiconductor nanostructure with zero <span class="hlt">average</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shen, Li-Hua; Ma, Wen-Yue; Zhang, Gui-Lian; Yang, Shi-Peng</p> <p>2015-07-01</p> <p>We report on a theoretical investigation of spin-polarized transport in a δ-doped <span class="hlt">magnetically</span> modulated semiconductor nanostructure, which can be experimentally realized by depositing a ferromagnetic stripe on the top of a semiconductor heterostructure and by using the atomic layer doping technique such as molecular beam epitaxy (MBE). It is shown that although such a nanostructure has a zero <span class="hlt">average</span> <span class="hlt">magnetic</span> filed, a sizable spin polarization exists due to the Zeeman splitting mechanism. It is also shown that the degree of spin polarization varies sensitively with the weight and/or position of the δ-doping. Therefore, one can conveniently tailor the behaviour of the spin-polarized electron by tuning the δ -doping, and such a device can be employed as a controllable spin filter for spintronics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140009615','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140009615"><span id="translatedtitle">The First in situ Observation of Kelvin-Helmholtz Waves at High-Latitude Magnetopause during Strongly Dawnward <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Conditions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hwang, K.-J.; Goldstein, M. L.; Kuznetsova, M. M.; Wang, Y.; Vinas, A. F.; Sibeck, D. G.</p> <p>2012-01-01</p> <p>We report the first in situ observation of high-latitude magnetopause (near the northern duskward cusp) Kelvin-Helmholtz waves (KHW) by Cluster on January 12, 2003, under strongly dawnward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) conditions. The fluctuations unstable to Kelvin-Helmholtz instability (KHI) are found to propagate mostly tailward, i.e., along the direction almost 90 deg. to both the magnetosheath and geomagnetic fields, which lowers the threshold of the KHI. The <span class="hlt">magnetic</span> configuration across the boundary layer near the northern duskward cusp region during dawnward IMF is similar to that in the low-latitude boundary layer under northward IMF, in that (1) both magnetosheath and magnetospheric fields across the local boundary layer constitute the lowest <span class="hlt">magnetic</span> shear and (2) the tailward propagation of the KHW is perpendicular to both fields. Approximately 3-hour-long periods of the KHW during dawnward IMF are followed by the rapid expansion of the dayside magnetosphere associated with the passage of an IMF discontinuity that characterizes an abrupt change in IMF cone angle, Phi = acos (B(sub x) / absolute value of Beta), from approx. 90 to approx. 10. Cluster, which was on its outbound trajectory, continued observing the boundary waves at the northern evening-side magnetopause during sunward IMF conditions following the passage of the IMF discontinuity. By comparing the signatures of boundary fluctuations before and after the IMF discontinuity, we report that the frequencies of the most unstable KH modes increased after the discontinuity passed. This result demonstrates that differences in IMF orientations (especially in f) are associated with the properties of KHW at the high-latitude magnetopause due to variations in thickness of the boundary layer, and/or width of the KH-unstable band on the surface of the dayside magnetopause.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUSMSH23B..02O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUSMSH23B..02O"><span id="translatedtitle">Update from the BU-CME Group: Accurate Prediction of CME Deflection and <span class="hlt">Magnetic</span> reconnection in the interior of <span class="hlt">interplanetary</span> CMEs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Opher, M.; Kay, C.; Fermo, R. L.; Drake, J. F.; Evans, R. M.</p> <p>2013-05-01</p> <p>The accurate prediction of the path of coronal mass ejections (CMEs) plays an important role in space weather forecasting, and knowing the source location of the CME does not always suffice. During solar minimum, for example, polar coronal holes (CHs) can deflect high latitude CMEs toward the ecliptic plane and when CHs extend to lower latitudes deflections in other directions can occur. To predict whether a CME will impact Earth the effects of the solar background on the CME's trajectory must be taken into account. Here we develop a model (Kay et al. 2013), called ForeCAT (Forecasting a CME's Altered Trajectory), of CME deflection close to the Sun where <span class="hlt">magnetic</span> forces dominate. Given the background solar wind conditions, the launch site of the CME, and the properties of the CME (such as its mass and size), ForeCAT predicts the deflection of the CME as well as the full trajectory as the CME propagates away from the Sun. For a <span class="hlt">magnetic</span> background where the CME is launched from an active region located in between a CH and streamer region the strong <span class="hlt">magnetic</span> gradients cause a deflection of 39.0o in latitude and 21.9o in longitude. Varying the CME's input parameters within observed ranges leads to deflections predominantly between 36.2o and 44.5o in latitude and between 19.5o and 27.9 in longitude. For all cases, the majority of the deflection occurs before the CME reaches a radial distance of 3 R?. Recent in situ observations of <span class="hlt">interplanetary</span> mass ejections (ICMEs) found signatures of reconnection exhausts in their interior or trailing edge. This result suggests that the internal <span class="hlt">magnetic</span> field reconnects with itself. To this end, we propose an approach (Fermo et al. 2013) borrowed from the fusion plasma community. Taylor (1974) showed that the lowest energy state corresponds to one in which \\grad B = ? B. Variations from this state will result in the <span class="hlt">magnetic</span> field trying to re-orient itself into the Taylor state solution, subject to the constraints that the toroidal flux and <span class="hlt">magnetic</span> helicity are invariant. In tokamaks, the result is a sawtooth crash. In an ICME, if we likewise treat the flux rope as a toroidal flux tube, any variation from the Taylor state will result in reconnection within the interior of the flux tube, in accord with the observations by Gosling et al. (2007). We present MHD and PIC simulations that shows that indeed this is the case and discuss the implications for ICMEs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820012231','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820012231"><span id="translatedtitle"><span class="hlt">Magnetic</span> field measurements at Jupiter by Voyagers 1 and 2: Daily plots of 48 second <span class="hlt">averages</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lepping, R. P.; Silverstein, M. J.; Ness, N. F.</p> <p>1981-01-01</p> <p>A series of 24 hour summary plots of the <span class="hlt">magnetic</span> field, in 48-s <span class="hlt">average</span> form, measured in the vicinity of Jupiter by the magnetometers onboard Voyagers 1 and 2 are presented. The Voyager 1 data cover the period from 27 February 1979 (day = 58) to 23 March (day = 82) inclusive, and the Voyager 2 data cover the period from 2 July 1979 (day = 183) to 14 August (day = 226) inclusive. Closest approach to the planet occurred on days 64 (AT 1205 UT) and 190 (AT 2230 UT) for Voyagers 1 and 2, respectively. Also included are: a description of the characteristics of the magnetometers, a brief description of the near-planet trajectories of the two spacecraft, a listing of the bow shock and magnetopause crossing times, and a bibliography containing Voyager-Jupiter related papers and reports.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930039184&hterms=energy+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Denergy%2Bwaves','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930039184&hterms=energy+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Denergy%2Bwaves"><span id="translatedtitle">Wave properties near the subsolar magnetopause - Pc 3-4 energy coupling for northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Song, P.; Russell, C. T.; Strangeway, R. J.; Wygant, J. R.; Cattell, C. A.; Fitzenreiter, R. J.; Anderson, R. R.</p> <p>1993-01-01</p> <p>Strong slow mode waves in the Pc 3-4 frequency range are found in the magnetosheath close to the magnetopause. We have studied these waves at one of the ISEE subsolar magnetopause crossings using the <span class="hlt">magnetic</span> field, electric field, and plasma measurements. We use the pressure balance at the magnetopause to calibrate the Fast Plasma Experiment data versus the magnetometer data. When we perform such a calibration and renormalization, we find that the slow mode structures are not in pressure balance and small scale fluctuations in the total pressure still remain in the Pc 3-4 range. Energy in the total pressure fluctuations can be transmitted through the magnetopause by boundary motions. The Poynting flux calculated from the electric and <span class="hlt">magnetic</span> field measurements suggests that a net Poynting flux is transmitted into the magnetopause. The two independent measurements show a similar energy transmission coefficient. The transmitted energy flux is about 18 percent of the <span class="hlt">magnetic</span> energy flux of the waves in the magnetosheath. Part of this transmitted energy is lost in the sheath transition layer before it enters the closed field line region. The waves reaching the boundary layer decay rapidly. Little wave power is transmitted into the magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH52A..06T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH52A..06T"><span id="translatedtitle">On the Estimate of Frequency Break and Spectral Index at Ion Scales for <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Fluctuations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Telloni, D.; Bruno, R.; Trenchi, L.</p> <p>2014-12-01</p> <p>We exploited radial alignments between MESSENGER and WIND spacecraft to study: 1) the radial dependence of the spectral break located at the border between fluid and kinetic regimes; 2) the dependence, if any, of the spectral slope, around the frequency break, on the type of wind, either fast or slow.We found that this spectral break moves to lower and lower frequencies as heliocentric distance increases, following a power-law dependence. Moreover, we found evidence that a cyclotron-resonant dissipation mechanism must participate into the spectral energy cascade together with other possible kinetic noncyclotron-resonant mechanisms.On the other hand, the spectral slope shows a large variability between -3.75 and -1.75 with an <span class="hlt">average</span> value around -2.8 and a robust tendency for this parameter to be steeper within the trailing edge of high speed streams and to be flatter within the subsequent slower wind, following a gradual transition between these two states. The value of the spectral index seems to depend firmly on the power associated to the fluctuations within the inertial range, higher the power steeper the slope. Research partially supported by the Agenzia Spaziale Italiana, contract ASI/INAF I/013/12/0 and by the European Community's Seventh Framework Programme (FP7/2007-2013) under grant agreement n 313038/STORM</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AIPC..974...52Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AIPC..974...52Z"><span id="translatedtitle">Ionospheric Response to the <span class="hlt">Interplanetary</span> Shock</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zong, Q.-G.; Reinisch, B. W.; Song, P.; Galkin, I.; Liu, X. J.</p> <p>2008-02-01</p> <p>The Cluster spacecraft and ground-based Digisonde network observed on November 7, 2004 a strong <span class="hlt">interplanetary</span> shock interaction with Earth's magnetosphere which initiated a strong <span class="hlt">magnetic</span> storm with Dst = -373 nT. When the <span class="hlt">interplanetary</span> shock encountered the Earth system, the Cluster fleet was traveling in the inner magnetosphere region (L shell = 4.2) at almost exactly the Cluster's perigee (around 0900 MLT). This event offers an excellent opportunity to study the geospace response to a powerful <span class="hlt">interplanetary</span> shock. The angle between the sun-Earth line and the normal direction of the shock front is only 3.0 degree indicating that the shock hit the geospace at ~12 LT initially. It is found that energetic particle fluxes are strongly enhanced and the shock related ionospheric phenomena have obvious longitudinal and latitudinal distribution. The <span class="hlt">interplanetary</span> shock has a significant influence on the dayside mid-high latitude stations, e.g., Millstone Hill, Wallops Island, etc. whereas the stations in the night sector show no immediate response to the <span class="hlt">interplanetary</span> shock.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.P34B..05J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.P34B..05J"><span id="translatedtitle">Mercury's Time-<span class="hlt">Averaged</span> and Induced <span class="hlt">Magnetic</span> Fields from MESSENGER Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johnson, C. L.; Winslow, R. M.; Anderson, B. J.; Purucker, M. E.; Korth, H.; Al Asad, M. M.; Slavin, J. A.; Baker, D. N.; Hauck, S. A.; Phillips, R. J.; Zuber, M. T.; Solomon, S. C.</p> <p>2012-12-01</p> <p>Observations from MESSENGER's Magnetometer (MAG) have allowed the construction of a baseline, time-<span class="hlt">averaged</span> model for Mercury's magnetosphere. The model, constructed with the approximation that the magnetospheric shape can be represented as a paraboloid, includes two external (magnetopause and magnetotail) current systems and an internal (dipole) field. We take advantage of the geometry of the orbital MAG data to constrain all but one of the model parameters, and their ranges, directly from the observations. These parameters are then used as a priori constraints in the magnetospheric model, and the remaining parameter, the dipole moment, is estimated from a grid search. The model provides an excellent fit to the MAG observations, with a root-mean-square misfit of less than 20 nT globally. The mean distance from the planetary dipole origin to the magnetopause subsolar point, RSS, is 1.45 RM (where RM = 2440 km) and the mean planetary dipole moment is 190 nT- RM3. Temporal variations in the global-scale <span class="hlt">magnetic</span> fields result from changes in solar wind ram pressure, Pram, at Mercury that arise from the planet's 88-day eccentric orbit around the Sun and from transient, rapid changes in solar wind conditions. For a constant planetary dipole moment, RSS varies as Pram-1/6. However, magnetopause crossings obtained from several Mercury years of MESSENGER observations indicate that RSS is proportional to Pram-1/a where a is greater than 6, suggesting induction in Mercury's highly conducting metallic interior. We obtain an effective dipole moment that varies by up to ˜15% about its mean value. We further investigate the periodic 88-day induction signature and use the paraboloid model to describe the spatial structure in the inducing magnetopause field, together with estimates for the outer radius of Mercury's liquid core and possible overlying solid iron sulfide layer, to calculate induced core fields. The baseline magnetospheric model is adapted to include the 88-day periodic induction signature, and residuals to this time-varying global model from <span class="hlt">magnetically</span> quiet orbits are then used to investigate structure at higher degree and order in the internal and external fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121...42L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121...42L"><span id="translatedtitle">A new approach to identify <span class="hlt">interplanetary</span> Alfvn waves and to obtain their frequency properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, H.; Wang, C.; Chao, J. K.; Hsieh, W. C.</p> <p>2016-01-01</p> <p>Conventional diagnosis of <span class="hlt">interplanetary</span> Alfvn waves requires an accurately determined de Hoffmann-Teller (HT) frame or background <span class="hlt">magnetic</span> field. For simplicity, the <span class="hlt">averaged</span> HT frame and the mean value of the <span class="hlt">magnetic</span> field are often used in the literature. However, HT frame can change quite fast in high-speed solar wind streams, and it is not always appropriate to take the <span class="hlt">average</span> value of the <span class="hlt">magnetic</span> field to be the background state. In order to reduce the uncertainty introduced by determining HT frame and background <span class="hlt">magnetic</span> field, we propose a new approach for identifying large-amplitude <span class="hlt">interplanetary</span> Alfvn waves. This new approach is independent of HT frame and of background <span class="hlt">magnetic</span> field. Instead of the original data sets, the band-pass filtered signals of plasma velocity and <span class="hlt">magnetic</span> field observations are used to check the Waln relation. The robustness of this technique is verified by applying to simulated pure Alfvn waves with two separate frequencies and contaminated by pink colored noises in a varying solar wind stream. Furthermore, in our approach, more properties of Alfvn waves in frequency domain can be obtained, which have been rarely discussed before. Our analysis technique is applied to two intervals of solar wind high-speed streams, and it is shown that large-amplitude Alfvn waves near 1 AU are frequently found during these two intervals.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22408061','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22408061"><span id="translatedtitle">Orbit-<span class="hlt">averaged</span> quantities, the classical Hellmann-Feynman theorem, and the <span class="hlt">magnetic</span> flux enclosed by gyro-motion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Perkins, R. J. Bellan, P. M.</p> <p>2015-02-15</p> <p>Action integrals are often used to <span class="hlt">average</span> a system over fast oscillations and obtain reduced dynamics. It is not surprising, then, that action integrals play a central role in the Hellmann-Feynman theorem of classical mechanics, which furnishes the values of certain quantities <span class="hlt">averaged</span> over one period of rapid oscillation. This paper revisits the classical Hellmann-Feynman theorem, rederiving it in connection to an analogous theorem involving the time-<span class="hlt">averaged</span> evolution of canonical coordinates. We then apply a modified version of the Hellmann-Feynman theorem to obtain a new result: the <span class="hlt">magnetic</span> flux enclosed by one period of gyro-motion of a charged particle in a non-uniform <span class="hlt">magnetic</span> field. These results further demonstrate the utility of the action integral in regards to obtaining orbit-<span class="hlt">averaged</span> quantities and the usefulness of this formalism in characterizing charged particle motion.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20090019739&hterms=higa&qs=N%3D0%26Ntk%3DAuthor-Name%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dhiga','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20090019739&hterms=higa&qs=N%3D0%26Ntk%3DAuthor-Name%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dhiga"><span id="translatedtitle">Mars Reconnaissance Orbiter <span class="hlt">Interplanetary</span> Navigation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>You, Tung-Han; Halsell, Allen; Graat, Eric J.; Highsmith, Dolan E.; Demcak, Stuart; Long, Stacia M.; Bhat, Ramachand S.; Mottinger, Neil A.; Higa, Earl; Jah, Moriba K.</p> <p>2007-01-01</p> <p>This viewgraph presentation reviews the Mars Reconnaissance Orbiter (MRO) <span class="hlt">interplanetary</span> navigation. An <span class="hlt">interplanetary</span> overview including dynamic models of outgassing, small force calibration and trending, solar radiation pressure and trajectory correction maneuvers are also described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740004975','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740004975"><span id="translatedtitle">High latitude ionospheric winds related to solar-<span class="hlt">interplanetary</span> conditions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Heppner, J. P.</p> <p>1973-01-01</p> <p>Treated jointly, two recent results imply that the distribution of winds in the polar ionosphere should change as a function of the direction of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. (1) From the motions of chemically released ion and neutral clouds, it is apparent that neutral winds in the high latitude ionosphere are driven principally by ion drag forces. (2) OGO-6 electric field measurements have demonstrated that there are definite relationships between the time-latitude distribution of ionospheric plasma convection and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field parameters, and also that the distribution is most sensitive to the azimuthal angle of the <span class="hlt">interplanetary</span> field. Although direct neutral wind to <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field comparisons are not available, logic clearly implies a close relationship. The lower altitude, meteorological effects of these externally driven ionospheric winds are not known. However, observations of infrasonic waves following sudden ionization enhancements indicate the existence of momentum transfer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.1509M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.1509M"><span id="translatedtitle">Comparisons between in situ measurements of the <span class="hlt">magnetic</span> shadowing of high energy ions at Mars and hybrid model simulations, using contemporary particle and field measurements to define the upstream <span class="hlt">interplanetary</span> conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McKenna-Lawlor, S.; Kallio, E.; Alho, M.; Jarvinen, R.; Afonin, V.</p> <p>2012-04-01</p> <p>Energetic particle data recorded by the SLED instrument aboard Phobos-2 while in circular orbit about Mars in March, 1989 showed the presence of <span class="hlt">magnetic</span> shadowing. A 3-D, self consistent, hybrid model (HYB-Mars) supplemented by test particle simulations was developed to study the response of the Martian plasma environment to solar disturbances and to interpret, in particular, the SLED observations. The <span class="hlt">magnetic</span> and electric fields, as well as the properties of high energy ions, present at Mars under conditions of extreme solar disturbance can be derived from HYB-Mars. Our initial study [McKenna-Lawlor et al., EPS 2011, in press] showed that the HYB-Mars model predicted an already well-documented plasma phenomenon at the planet, namely 'sw-flow shadowing (identified in the measurements of the ASPERA (plasma) experiment aboard Phobos-2). HYB further, importantly, predicted the occurrence of <span class="hlt">magnetic</span> shadowing which is qualitatively similar to that recorded by SLED. The simulations in addition suggested that the configuration of a <span class="hlt">magnetic</span> shadow depends on the pertaining solar wind density and velocity, and on the magnitude and direction of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. The present work presents a more detailed study where plasma and <span class="hlt">magnetic</span> field inputs to the HYB model come from measurements made aboard Phobos-2 contemporaneously with the SLED observations. In this way it is possible to realistically match the upstream <span class="hlt">interplanetary</span> conditions with the configuration of the <span class="hlt">magnetic</span> shadow recorded at various energies in the SLED data. One-to-one comparisons between the SLED observations and simulated high energy H+ fluxes will be presented in this context and similarities and differences between the observations and simulations discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996JGR...10110919R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996JGR...10110919R"><span id="translatedtitle">Characterization of the dynamic variations of the dayside high-latitude ionospheric convection reversal boundary and relationship to <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field orientation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ridley, A. J.; Clauer, C. R.</p> <p>1996-05-01</p> <p>We present initial results from observations of the northern summer polar ionospheric convection reversal boundary using ground- and satellite-based instrumentation. Ionospheric convection measurements obtained using the Sondrestrom radar are used to locate and observe the boundary. The flow around the reversal is compared to three different modeled low patterns. The first is a shear reversal (oppositely directed flows with no flow across the boundary). The second is a shear reversal combined with uniform poleward flow. The final flow pattern observed is a rotational reversal, where flows gradually turn from one direction to the opposite over distances on the order of 200-400 km. The convection reversals observed were categorized into three different classes: (1) stationary and steady, (2) nonstationary, and (3) oscillating. A stationary and steady boundary remains at the same invariant latitude for long periods of time and demonstrates no observable motion. A nonstationary boundary will propagate northward or southward, generally remaining parallel to a line of invariant latitude. The oscillating reversal boundary (ORB) will have wave-like motions of the local boundary location. A number of different reversals were classified and then studied further using other instrumentation, which include the Greenland coastal and MAGIC chains of magnetometers, the drift meter and particle precipitation instruments from the DMSP F9, F10, and F11 satellites, and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) measurements from the IMP 8 satellite. A stationary and steady reversal has been observed during a time of magnitude variations in the By and Bz components of the IMF, but no sign changes in either of the components. The nonstationary reversals have been observed to be a response to both sign changes and magnitude changes with no sign changes in IMF components. Of the two ORBs reported here, one has been determined to be a ULF wave propagating along the convection reversal boundary, which maps to the magnetospheric low latitude boundary layer. The other ORB has little coherence between longitudinally spaced magnetometer stations, implying that the propagating waves are changing form between the stations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008GMS...181...99T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008GMS...181...99T"><span id="translatedtitle"><span class="hlt">Interplanetary</span> causes of middle latitude ionospheric disturbances</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsurutani, Bruce T.; Echer, Ezequiel; Guarnieri, Fernando L.; Verkhoglyadova, Olga P.</p> <p></p> <p>The solar and <span class="hlt">interplanetary</span> causes of major middle latitude ionospheric disturbances are reviewed. Solar flare photons can cause abrupt (within ˜5 min), 30% increases in ionospheric total electron content, a feature that can last for tens of minutes to hours, depending on the altitude of concern. Fast <span class="hlt">interplanetary</span> coronal mass ejection sheath fields and <span class="hlt">magnetic</span> clouds can cause intense <span class="hlt">magnetic</span> storms if the field in either region is intensely southward for several hours or more. If the field conditions in both regions are southward, "double storms" will occur. Multiple <span class="hlt">interplanetary</span> fast forward shocks "pump up" the sheath <span class="hlt">magnetic</span> field, leading to conditions that can lead to superstorms. <span class="hlt">Magnetic</span> storm auroral precipitation and Joule heating cause pressure waves that propagate from subauroral latitudes to middle and equatorial latitudes. Shocks can create middle latitude dayside auroras as well as trigger nightside subauroral supersubstorms. Solar wind ram pressure increases after fast shocks can lead to the formation of new radiation belts under proper conditions. Prompt penetration electric fields can cause a dayside ionospheric superfountain, leading to plasma transport from the equatorial region to middle latitudes. The large amplitude Alfvén waves present in solar wind high-speed streams cause sporadic <span class="hlt">magnetic</span> reconnection, plasma injections, and electromagnetic chorus wave generation. Energetic electrons interacting with chorus (and PC5) waves are accelerated to hundreds of keV up to MeV energies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1993SoPh..143..345U','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1993SoPh..143..345U"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field structure and solar wind parameters as inferred from solar <span class="hlt">magnetic</span> field observations and by using a numerical 2-D MHD model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Usmanov, A. V.</p> <p>1993-02-01</p> <p>A numerical, self-consistent MHD simulation is used to determine the parameters of the solar corona and the solar wind. Observations of the large-scale <span class="hlt">magnetic</span> field at the sun are used to find the boundary conditions for the <span class="hlt">magnetic</span> field. The planar model used for the solar wind flow consists of two regions. Region I, covering the distance from the solar surface to 10 solar radii, is the region of transonic flow. Region II extends from 10 solar radii to the earth's orbit, and is the region of supersonic, super-Alfvenic flow. Region I is treated as a mixed initial-boundary value problem. For region II, solar rotation is taken into consideration, so that the interaction between fast and slow solar wind streams is treated self-consistently. The calculated solar wind velocity, radial <span class="hlt">magnetic</span> field, and number density are compared with space-based observations.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_11");'>11</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li class="active"><span>13</span></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_13 --> <div id="page_14" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="261"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015PhFl...27i3101M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015PhFl...27i3101M"><span id="translatedtitle">The <span class="hlt">average</span> stress in a suspension of cube-shaped <span class="hlt">magnetic</span> particles subject to shear and <span class="hlt">magnetic</span> fields</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mallavajula, Rajesh K.; Archer, Lynden A.; Koch, Donald L.</p> <p>2015-09-01</p> <p>The effect of a homogeneous <span class="hlt">magnetic</span> field (H) on the bulk stress in a dilute suspension of weakly Brownian, <span class="hlt">magnetic</span> cubes suspended in a Newtonian fluid subjected to a linear shear flow is studied. The stresslet on each cube is anisotropic and depends on its orientation. Application of a <span class="hlt">magnetic</span> field results in anisotropy in the orientation distribution. The steady-state orientation distribution is derived as a function of the angle between the directions of the <span class="hlt">magnetic</span> field and the fluid vorticity vector and the ratio of the <span class="hlt">magnetic</span> torque to the viscous torque. Knowledge of the distribution function is used to derive a general expression for the bulk stress in a general linear flow field and a <span class="hlt">magnetic</span> field. Specific numerical results are obtained for the intrinsic viscosity in a simple shear flow when the <span class="hlt">magnetic</span> field is either parallel or perpendicular to the vorticity. When the <span class="hlt">magnetic</span> field is perpendicular to vorticity, we find that the intrinsic viscosity increases at first with increasing shear rate passes through a maximum and then shear thins. The intrinsic viscosity can vary from 3.25 to 5.5 in response to changes in the relative strengths of the shear and <span class="hlt">magnetic</span> fields. The maximum value of 5.5 is obtained when the <span class="hlt">magnetic</span> moment of the cube, which is assumed to be parallel to the normal of one of the faces, lies in the flow gradient plane at an angle of ?/4 from the flow direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.4503K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.4503K"><span id="translatedtitle">Modular model for Mercury's magnetospheric <span class="hlt">magnetic</span> field confined within the <span class="hlt">average</span> observed magnetopause</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Korth, Haje; Tsyganenko, Nikolai A.; Johnson, Catherine L.; Philpott, Lydia C.; Anderson, Brian J.; Al Asad, Manar M.; Solomon, Sean C.; McNutt, Ralph L.</p> <p>2015-06-01</p> <p>Accurate knowledge of Mercury's magnetospheric <span class="hlt">magnetic</span> field is required to understand the sources of the planet's internal field. We present the first model of Mercury's magnetospheric <span class="hlt">magnetic</span> field confined within a magnetopause shape derived from Magnetometer observations by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging spacecraft. The field of internal origin is approximated by a dipole of magnitude 190 nT RM3, where RM is Mercury's radius, offset northward by 479 km along the spin axis. External field sources include currents flowing on the magnetopause boundary and in the cross-tail current sheet. The cross-tail current is described by a disk-shaped current near the planet and a sheet current at larger (≳ 5 RM) antisunward distances. The tail currents are constrained by minimizing the root-mean-square (RMS) residual between the model and the <span class="hlt">magnetic</span> field observed within the magnetosphere. The magnetopause current contributions are derived by shielding the field of each module external to the magnetopause by minimizing the RMS normal component of the <span class="hlt">magnetic</span> field at the magnetopause. The new model yields improvements over the previously developed paraboloid model in regions that are close to the magnetopause and the nightside <span class="hlt">magnetic</span> equatorial plane. <span class="hlt">Magnetic</span> field residuals remain that are distributed systematically over large areas and vary monotonically with <span class="hlt">magnetic</span> activity. Further advances in empirical descriptions of Mercury's magnetospheric external field will need to account for the dependence of the tail and magnetopause currents on <span class="hlt">magnetic</span> activity and additional sources within the magnetosphere associated with Birkeland currents and plasma distributions near the dayside magnetopause.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMSH41B0758O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMSH41B0758O"><span id="translatedtitle">Electron Distribution Functions Near <span class="hlt">Interplanetary</span> Shocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ogilvie, K. W.; Fitzenreiter, R. J.; Bale, S. D.; Szabo, A.</p> <p>2001-12-01</p> <p>This paper examines the signatures of electron velocity distribution functions near several <span class="hlt">interplanetary</span> shocks as observed by the Vector Electron Spectrometer on the WIND spacecraft. These <span class="hlt">interplanetary</span> shocks are moderate in strength and have values of thetabn between 60 and 90 degrees. We concentrate on a quasi-perpendicular shock observed by WIND on August 26, 1998 which was associated with an <span class="hlt">interplanetary</span> type II radio burst. WIND observations of this shock have previously been studied by Bale et al. [GRL, June 1, 1999] who found the first evidence for electron beams in the source region of a type II burst in the upstream region of this shock. Our focus will be on comparing the electron distribution functions before and after the WIND encounter with the shock, showing the evidence for electron acceleration and heating from the shapes of the distributions. In the upstream, loss cone and bump on tail distributions are observed that are characteristic of <span class="hlt">magnetic</span> mirroring in the rising <span class="hlt">magnetic</span> field of the shock layer. The dispersion in arrival times of the upstream electrons has been used to measure the distance along the <span class="hlt">magnetic</span> field lines connecting the spacecraft and the shock. On traversing the shock layer from the upstream to the downstream, the distributions broaden, first in the direction perpendicular to the <span class="hlt">magnetic</span> field, followed by broadening of the parallel distribution and the formation of parallel beams until the distribution is nearly isotropic. The downstream distributions of this shock, as well as several of the other stronger <span class="hlt">interplanetary</span> shocks in this study, have the typical flat top signature of electron heating and the electron beams found immediately downstream of the Earth's bow shock. Observations by the WAVES experiment on WIND also show typical broadband, impulsive signatures in the shock. Further downstream the distributions again become slightly anisotropic with the perpendicular temperature exceeding the parallel. We compare the observed distributions with results of theoretical works, particularly the recent work of Hull et al. [JGR, August 1, 2001].</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910048949&hterms=inertia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dinertia','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910048949&hterms=inertia&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dinertia"><span id="translatedtitle">Viscosity and inertia in cosmic-ray transport - Effects of an <span class="hlt">average</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Williams, L. L.; Jokipii, J. R.</p> <p>1991-01-01</p> <p>A generalized transport equation is introduced which describes the transport and propagation of cosmic rays in a <span class="hlt">magnetized</span>, collisionless medium. The equation is valid if the cosmic-ray distribution function is nearly isotropic in momentum, if the ratio of fluid speed to fluid-flow particle speed is small, and if the ratio of collision time to time for change in the macroscopic flow is small. Five independent cosmic-ray viscosity coefficients are found, and the ralationship of this viscosity to particle orbits in a <span class="hlt">magnetic</span> field is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730021133','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730021133"><span id="translatedtitle"><span class="hlt">Interplanetary</span> charged particle environments</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Divine, T. N.</p> <p>1973-01-01</p> <p>Current state-of-the-art knowledge of the solar wind, solar particle events, and galactic cosmic rays is reviewed for the development of space vehicle design criteria based on these <span class="hlt">interplanetary</span> environments. These criteria are described quantitatively in terms of intensity, flux and fluence, and their dependences on time, position and energy, and the associated probabilities and related parameters, for electrons, protons and other ions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740008403','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740008403"><span id="translatedtitle">Observations of interactions between <span class="hlt">interplanetary</span> and geomagnetic fields</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burch, J. L.</p> <p>1973-01-01</p> <p>Magnetospheric effects associated with variations of the north-south component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field are examined in light of recent recent experimental and theoretical results. Although the occurrence of magnetospheric substorms is statistically related to periods of southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field, the details of the interaction are not understood. In particular, attempts to separate effects resulting directly from the interaction between the <span class="hlt">interplanetary</span> and geomagnetic fields from those associated with substorms have produced conflicting results. The transfer of <span class="hlt">magnetic</span> flux from the dayside to the nightside magnetosphere is evidenced by equatorward motion of the polar cusp and increases of the <span class="hlt">magnetic</span> energy density in the lobes of the geomagnetic tail. The formation of a macroscopic X-type neutral line at tail distances less than 35 R sub E appears to be a substorm phenomenon.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830025541','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830025541"><span id="translatedtitle">Electron heating at <span class="hlt">interplanetary</span> shocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Feldman, W. C.; Asbridge, J. R.; Bame, S. J.; Gosling, J. T.; Zwickl, R. D.</p> <p>1982-01-01</p> <p>Data for 41 forward <span class="hlt">interplanetary</span> shocks show that the ratio of downstream to upstream electron temperatures, T/sub e/(d/u) is variable in the range between 1.0 (isothermal) and 3.0. On <span class="hlt">average</span>, (T/sub e/(d/u) = 1.5 with a standard deviation, sigma e = 0.5. This ratio is less than the <span class="hlt">average</span> ratio of proton temperatures across the same shocks, (T/sub p/(d/u)) = 3.3 with sigma p = 2.5 as well as the <span class="hlt">average</span> ratio of electron temperatures across the Earth's bow shock. Individual samples of T/sub e/(d/u) and T/sub p/(d/u) appear to be weakly correlated with the number density ratio. However the amounts of electron and proton heating are well correlated with each other as well as with the bulk velocity difference across each shock. The stronger shocks appear to heat the protons relatively more efficiently than they heat the electrons.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021484&hterms=solar+activity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dsolar%2Bactivity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021484&hterms=solar+activity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dsolar%2Bactivity"><span id="translatedtitle">Statistical analysis of <span class="hlt">interplanetary</span> shock waves observed during a complete solar activity cycle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Khalisi, E.; Schwenn, R.</p> <p>1995-01-01</p> <p>During the Helios mission a total of 391 fast forward non-corotating <span class="hlt">interplanetary</span> shock waves was identified. For most of the 12 years between 1974 and 1986 unique shock detection was possible for more than 80 % of the time. The occurrence rate (in shocks per day) varied from 0.02 at activity minimum in 1976 to 0.17 in 1979 and 0.22 in 1982 with a significant drop to 0.13 in 1980, i.e. right at activity maximum. The <span class="hlt">average</span> properties of all events as functions of solar distance. phase in the solar cycle, heliographic and -<span class="hlt">magnetic</span> latitude and others are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JASS...32..181P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JASS...32..181P"><span id="translatedtitle">Storm Sudden Commencements Without <span class="hlt">Interplanetary</span> Shocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Park, Wooyeon; Lee, Jeongwoo; Yi, Yu; Ssessanga, Nicholas; Oh, Suyeon</p> <p>2015-09-01</p> <p>Storm sudden commencements (SSCs) occur due to a rapid compression of the Earth's <span class="hlt">magnetic</span> field. This is generally believed to be caused by <span class="hlt">interplanetary</span> (IP) shocks, but with exceptions. In this paper we explore possible causes of SSCs other than IP shocks through a statistical study of geomagnetic storms using SYM-H data provided by the World Data Center for Geomagnetism ? Kyoto and by applying a superposed epoch analysis to simultaneous solar wind parameters obtained with the Advanced Composition Explorer (ACE) satellite. We select a total of 274 geomagnetic storms with minimum SYM-H of less than ?30nT during 1998-2008 and regard them as SSCs if SYM-H increases by more than 10 nT over 10 minutes. Under this criterion, we found 103 geomagnetic storms with both SSC and IP shocks and 28 storms with SSC not associated with IP shocks. Storms in the former group share the property that the strength of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF), proton density and proton velocity increase together with SYM-H, implying the action of IP shocks. During the storms in the latter group, only the proton density rises with SYM-H. We find that the density increase is associated with either high speed streams (HSSs) or <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs), and suggest that HSSs and ICMEs may be alternative contributors to SSCs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050070873','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050070873"><span id="translatedtitle">The "Approximate 150 Day Quasi-Periodicity" in <span class="hlt">Interplanetary</span> and Solar Phenomena During Cycle 23</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richardson, I. G.; Cane, H. V.</p> <p>2004-01-01</p> <p>A"quasi-periodicity" of approx. 150 days in various solar and <span class="hlt">interplanetary</span> phenomena has been reported in earlier solar cycles. We suggest that variations in the occurrence of solar energetic particle events, <span class="hlt">inter-planetary</span> coronal mass ejections, and geomagnetic storm sudden commenceents during solar cycle 23 show evidence of this quasi-periodicity, which is also present in the sunspot number, in particular in the northern solar hemisphere. It is not, however, prominent in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field strength.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSH22B...5K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSH22B...5K"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Shocks Observed by the DSCOVR Spacecraft</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Koval, A.; Wilson, L. B., III; Szabo, A.; Kasper, J. C.; Stevens, M.; Case, A.; Biesecker, D.</p> <p>2015-12-01</p> <p>We are examining <span class="hlt">magnetic</span> field fluctuations in and around <span class="hlt">interplanetary</span> shocks observed by the DSCOVR spacecraft. The DSCOVR spacecraft, launched in February 2015 and currently in an orbit about L1, provides very high cadence measurements of the <span class="hlt">magnetic</span> field (50 Hz) and ion velocity distribution functions (1 Hz). Observations suggest the fluctuations near the shock ramps are whistler precursors. The properties of both the precursor waves and the shock ramp structure are compared to the shock geometry and strength. The observations are compared with the observations by the Wind spacecraft, also in an orbit about L1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990079403&hterms=hugoniot&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhugoniot','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990079403&hterms=hugoniot&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhugoniot"><span id="translatedtitle">Multi-Spacecraft Observations of <span class="hlt">Interplanetary</span> Shocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Szabo, A.; Smith, C. W.; Tokar, R. L.; Skoug, R. M.</p> <p>1999-01-01</p> <p>Using multi-spacecraft observations primarily from ACE and WIND, and from IMP 8 and Geotail when available, the 3-dimensional structure of <span class="hlt">interplanetary</span> shocks on the hundred Earth radii scale will be discussed. The complete <span class="hlt">magnetic</span> field, and solar wind ion and electron data sets were used to fit the shocks with a full non-linear least squares fit "Rankine-Hugoniot" technique yielding the local shock surface normals and speeds with associated uncertainties. Multi-spacecraft results reveal that on the distance scale of ACE's L1 halo orbit the shocks deviate significantly from a simple planar geometry. This result has important consequences for the prediction of the exact arrival times of <span class="hlt">interplanetary</span> shocks at the Earth's magnetosphere, and hence, on the reliability of space weather predictions. It also has implications on the coherence scale of solar wind structures and their evolution from the Sun to Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000032153&hterms=hugoniot&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhugoniot','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000032153&hterms=hugoniot&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dhugoniot"><span id="translatedtitle">Multi-Spacecraft Observations of <span class="hlt">Interplanetary</span> Shocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, C. W.; Tokar, R. L.; Skoug, R. M.; Szabo, A.</p> <p>1999-01-01</p> <p>Using multi-spacecraft observations primarily from ACE and WIND and from IMP 8 and Geotail when available, the 3-dimensional structure of <span class="hlt">interplanetary</span> shocks on the hundred Earth radii scale will be discussed. The complete <span class="hlt">magnetic</span> field, and solar wind ion and electron data sets were used to fit the shocks with a full non-linear least squares fitting "Rankine-Hugoniot" technique yielding the local shock surface normals and speeds with associated uncertainties. Multi-spacecraft results reveal that on the distance scale of ACE's L1 halo orbit the shocks deviate from a simple planar geometry. This result has important consequences for the prediction of the exact arrival times of <span class="hlt">interplanetary</span> shocks at the Earth's magnetosphere, and hence, on the reliability of space weather predictions. It also has implications on the coherence scale of solar wind structures and their evolution from the Sun to Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/26437746','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/26437746"><span id="translatedtitle">The role of size polydispersity in <span class="hlt">magnetic</span> fluid hyperthermia: <span class="hlt">average</span> vs. local infra/over-heating effects.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Munoz-Menendez, Cristina; Conde-Leboran, Ivan; Baldomir, Daniel; Chubykalo-Fesenko, Oksana; Serantes, David</p> <p>2015-11-01</p> <p>An efficient and safe hyperthermia cancer treatment requires the accurate control of the heating performance of <span class="hlt">magnetic</span> nanoparticles, which is directly related to their size. However, in any particle system the existence of some size polydispersity is experimentally unavoidable, which results in a different local heating output and consequently a different hyperthermia performance depending on the size of each particle. With the aim to shed some light on this significant issue, we have used a Monte Carlo technique to study the role of size polydispersity in heat dissipation at both the local (single particle) and global (macroscopic <span class="hlt">average</span>) levels. We have systematically varied size polydispersity, temperature and interparticle dipolar interaction conditions, and evaluated local heating as a function of these parameters. Our results provide a simple guide on how to choose, for a given polydispersity degree, the more adequate <span class="hlt">average</span> particle size so that the local variation in the released heat is kept within some limits that correspond to safety boundaries for the <span class="hlt">average</span>-system hyperthermia performance. All together we believe that our results may help in the design of more effective <span class="hlt">magnetic</span> hyperthermia applications. PMID:26437746</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1082462','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1082462"><span id="translatedtitle">Determination of the <span class="hlt">Average</span> Aromatic Cluster Size of Fossil Fuels by Solid-State NMR at High <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Mao, Kanmi; Kennedy, Gordon J.; Althaus, Stacey M.; Pruski, Marek</p> <p>2013-01-07</p> <p>We show that the <span class="hlt">average</span> aromatic cluster size in complex carbonaceous materials can be accurately determined using fast magic-angle spinning (MAS) NMR at a high <span class="hlt">magnetic</span> field. To accurately quantify the nonprotonated aromatic carbon, we edited the 13C spectra using the recently reported MAS-synchronized spinecho, which alleviated the problem of rotational recoupling of 1H-13C dipolar interactions associated with traditional dipolar dephasing experiments. The dependability of this approach was demonstrated on selected Argonne Premium coal standards, for which full sets of basic structural parameters were determined with high accuracy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004ASPC..309..245G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004ASPC..309..245G"><span id="translatedtitle">Dust in <span class="hlt">Interplanetary</span> Space and in the Local Galactic Environment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grn, E.; Dikarev, V.; Frisch, P. C.; Graps, A.; Kempf, S.; Krger, H.; Landgraf, M.; Moragas-Klostermeyer, G.; Srama, R.</p> <p>2004-05-01</p> <p>The solar system is a natural laboratory, accessible by a variety of methods, for studying the astrophysics of dust. Astronomical measurements mostly at visible and infrared wavelengths, yield the large-scale distribution of dust and its <span class="hlt">average</span> composition. Examining natural surfaces deployed to the space environment, and assessing those surfaces' micro-crater distributions, reveals the size distribution of dust. Meteor observations and their corresponding measurements provide orbital information of dust grains and their genetic interrelation to the larger bodies in our solar system: comets and asteroids. From analyses of meteorites and <span class="hlt">interplanetary</span> dust particles collected in the stratosphere, we have a comprehensive understanding of the isotopic, elemental, and mineralogical composition of this primordial material. Finally, in situ dust analysis via dust detectors located in <span class="hlt">interplanetary</span> space, the most versatile method, have been providing data to determine the dust particles' mass, speed, trajectory, and chemical composition. An assortment of dust exhibiting a variety of dynamical processes has been identified in <span class="hlt">interplanetary</span> space. In Jupiter's proximity, intense streams have been observed of nanometer-sized ash particles, which are emitted from the volcanoes of Jupiter's moon Io. These particles are accelerated by the powerful Jovian <span class="hlt">magnetic</span> field to speeds of several 100 km/s, and are propelled further into <span class="hlt">interplanetary</span> and interstellar space by the solar wind <span class="hlt">magnetic</span> field. In <span class="hlt">interplanetary</span> space, concentrations of collisional debris in the asteroid belt have been identified by infrared observations. The Poynting-Robertson effect drags these particles in towards the Earth and the Sun, where they sublimate. If the giant planets did not block their inward drift, a similar fate is expected for the dust assortment that is generated by collisions in the Kuiper belt. Another dust population is the mostly sub-micron-sized dust from comets, released while the comets traverse the inner parts of our solar system. These comet particles are shed from the comet's coma and consequently, quickly driven out of the solar system by radiation pressure forces. Larger particles form trails along the orbit of the parent comet, which result in a meteor storm as the Earth crosses the trail. Furthermore, the dust of comet trails can disperse via planetary perturbations into the background zodiacal cloud. Last, but not least, an important dust population identified by in situ dust instruments is the micron-sized interstellar grains flowing through the planetary system with the interstellar gas flow being part of the local interstellar cloud. This cloud is at the edge of the local bubble of hot tenuous gas which was excavated by supernova explosions in the near-by Scorpius-Centaurus and Orion Associations. These dust populations are the target of future dust observatory missions in space. Such a dust observatory satellite carries a dust telescope, which is a combination of a dust trajectory sensor together with an analyzer for the particles' chemical composition. With accurate dust trajectory measurements, we can identify its place of origin: for example, comets, asteroids, or interstellar space. From the particles' bulk properties and their chemical composition, we can infer properties of the environments out of which the particles were formed, and in which they were subsequently altered.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5289366','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5289366"><span id="translatedtitle">Relationships between <span class="hlt">interplanetary</span> quantities and the global auroral electrojet index</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Meloni, A.; Wolfe, A.; Lanzerotti, L.J.</p> <p>1982-01-01</p> <p>We have studied, using linear cross correlation and multilinear regression analyses, statistical relations between the magnetospheric auroral electrojet intensity index AE and various parameters characterizing the <span class="hlt">interplanetary</span> plasma and <span class="hlt">magnetic</span> field. We also consider the recently proposed epsilon parameter as an independent variable. The analyses were carried out separately for twenty-eight days in mid 1975 and for each of five individual <span class="hlt">magnetic</span> storm intervals that have been previously discussed extensively in the literature. We find that when the <span class="hlt">interplanetary</span> data set is not distinguished as to the direction of the north-south component B/sub z/, the <span class="hlt">interplanetary</span> electric field -VB/sub z/ carried to the front of the magnetosphere correlates with AE substantially better than does epsilon. Considering only data during which B/sub z/ is negative gives a slightly better correlation of epsilon with AE than of the electric field with AE. The correlations are valid for the specific storm periods as well as for the unrestricted twenty-eight days of data. Our results suggest that the physical processes involved in energy transfer to the nightside magnetosphere depend upon the direction of the north-south component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field: the <span class="hlt">interplanetary</span> electric field plays an important role during northward B/sub z/ and the epsilon parameter and the electric field both provide an indication of energy transfer and substorm activity during southward B/sub z/.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140006630','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140006630"><span id="translatedtitle">Whistler Waves Associated with Weak <span class="hlt">Interplanetary</span> Shocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Velez, J. C. Ramirez; Blanco-Cano, X.; Aguilar-Rodriguez, E.; Russell, C. T.; Kajdic, P.; Jian,, L. K.; Luhmann, J. G.</p> <p>2012-01-01</p> <p>We analyze the properties of 98 weak <span class="hlt">interplanetary</span> shocks measured by the dual STEREO spacecraft over approximately 3 years during the past solar minimum. We study the occurrence of whistler waves associated with these shocks, which on <span class="hlt">average</span> are high beta shocks (0.2 < Beta < 10). We have compared the waves properties upstream and downstream of the shocks. In the upstream region the waves are mainly circularly polarized, and in most of the cases (approx. 75%) they propagate almost parallel to the ambient <span class="hlt">magnetic</span> field (<30 deg.). In contrast, the propagation angle with respect to the shock normal varies in a broad range of values (20 deg. to 90 deg.), suggesting that they are not phase standing. We find that the whistler waves can extend up to 100,000 km in the upstream region but in most cases (88%) are contained in a distance within 30,000 km from the shock. This corresponds to a larger region with upstream whistlers associated with IP shocks than previously reported in the literature. The maximum amplitudes of the waves are observed next to the shock interface, and they decrease as the distance to the shock increases. In most cases the wave propagation direction becomes more aligned with the <span class="hlt">magnetic</span> field as the distance to the shock increases. These two facts suggest that most of the waves in the upstream region are Landau damping as they move away from the shock. From the analysis we also conclude that it is likely that the generation mechanism of the upstream whistler waves is taking place at the shock interface. In the downstream region, the waves are irregularly polarized, and the fluctuations are very compressive; that is, the compressive component of the wave clearly dominates over the transverse one. The majority of waves in the downstream region (95%) propagate at oblique angles with respect to the ambient <span class="hlt">magnetic</span> field (>60 deg.). The wave propagation with respect to the shock-normal direction has no preferred direction and varies similarly to the upstream case. It is possible that downstream fluctuations are generated by ion relaxation as suggested in previous hybrid simulation shocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7764K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7764K"><span id="translatedtitle">Observations of <span class="hlt">interplanetary</span> shocks with multiple spacecraft</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kajdi?, Primo; Blanco-Cano, Xochitl; Lavraud, Benoit</p> <p>2015-04-01</p> <p><span class="hlt">Interplanetary</span> (IP) shocks in the heliosphere are often driven by Coronal Mass Ejections and Stream Interaction Regions. They are one of the main accelerators of suprathermal and energetic particles in the <span class="hlt">interplanetary</span> space. The acceleration mechanisms of these collisionless shocks depend on their Mach numbers and also on the angle between the upstream <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and the local normal to the shock. It has been recognized in the past that the latter varies along the shock surface. Observations with multiple spacecraft have shown that the local shock normal is oriented differently at different points in space. However this has been done for spacecraft separations of at least several Earth radii. Here we present observations of IP shocks with multiple spacecraft and missions for much smaller inter-spacecraft separations. In the case of observations with Cluster mission, these separations can be as small as 40 km. Even on these scales we find that the observed shock profiles may be slightly different. We have elaborated a catalog of ~80 shocks observed with two or more spacecraft in orbit around Earth. Here we present this catalog as well as some of the most interesting case events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.2392P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.2392P"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Scintillation and Geomagnetic Activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perez-Enriquez, Roman; Carrillo-Vargas, Armando; Kotsarenko, Anatoly; Lopez Cruz-Abeyro, Jose Antonio</p> <p></p> <p>In this paper the daily values of the global index of <span class="hlt">interplanetary</span> scintillation, G, obtained from the g-maps of Cambridge Observatory, UK, were analyzed for the period 1991-1994 in relation with the geomagnetic index DST, to determine the possible impact of both large scale events and small scale <span class="hlt">magnetic</span> irregularities on the magnetosphere of our planet. The analysis consisted of the comparison of the two time series G and DST, as well as a superposed epoch analysis of G with respect to the ocurrence of 16 events where the DST index dropped to less than -70 nT. While the cross-correlation shows that there is a marked anti-correlation with a lag of 2 days, the superposed epoch analysis showed a peak at day zero of 2.93 sigmas that start 2 days before. No peak was found when the analysis was performed on 16 randomly chosen dates in the period. The results indicate that the state of the inner heliosphere as given by the G index may be important in the study of the solar wind related magnetospheric activity.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_12");'>12</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li class="active"><span>14</span></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_14 --> <div id="page_15" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="281"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AdSpR..29.1467A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AdSpR..29.1467A"><span id="translatedtitle">Observation of travelling <span class="hlt">interplanetary</span> disturbances</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ananthakrishnan, S.; Tokumaru, M.; Kojima, M.</p> <p></p> <p>A travelling <span class="hlt">interplanetary</span> disturbance (IPD) was detected by the four station <span class="hlt">interplanetary</span> scintillation (IPS) system of the Nagoya University on October 21, 1995 which has good time agreement with an energetic proton flare on the Sun (>20 Mev) on October 20, associated with AR 7912. The estimated shock speed of the accompanying metric type II burst, by ground radio observatories, agrees well with that measured by the IPS system. Hence, it appears that coronal type II shocks may be propagating in the <span class="hlt">interplanetary</span> medium at least in some cases. This is in contrast to the recent statement in the literature, that 'metric type II bursts may not be considered as predictors of <span class="hlt">interplanetary</span> shocks' (Gopalswamy et al., 1998). The event under discussion indicates that their general suggestion may not be universally appropriate in all cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5029174','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5029174"><span id="translatedtitle">The configuration of the auroral distribution for <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field B sub z northward. 1. IMF B sub x and B sub y dependencies as observed by the Viking satellite</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Eliphinstone, R.D.; Jankowska, K.; Murphree, J.S.; Cogger, L.L. )</p> <p>1990-05-01</p> <p>Viking images obtained throughout 1986 have been utilized in combination with IMP 8 satellite measurements of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields (IMF) to determine typical northern hemisphere auroral distributions for a variety of IMF B{sub z} positive conditions. Varying B{sub y} has an effect which is consistent with expected results. That is, B{sub y} positive implies high-latitude auroral arcs in the dusk sector while negative B{sub y} gives dawn sector polar arcs. A new result gives significant importance to the B{sub x} component of the IMF. B{sub x} toward the Sun (B{sub y} = 0) gives polar arcs on both dawn and dusk with comparatively weak UV emissions. With B{sub x} away from the Sun (B{sub y} = 0) a single Sun-aligned morning sector polar arc dominates the auroral distribution. Azimuthal angle changes to the IMF of only 45{degree} seem to affect the global auroral distribution with time scales of less than 2-3 hours. Poleward boundaries of the aurora were found to have a strong dependence on the IMF azimuthal angle which varied according to the <span class="hlt">magnetic</span> local time investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25254955','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25254955"><span id="translatedtitle">An in vivo three-dimensional <span class="hlt">magnetic</span> resonance imaging-based <span class="hlt">averaged</span> brain collection of the neonatal piglet (Sus scrofa).</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Conrad, Matthew S; Sutton, Bradley P; Dilger, Ryan N; Johnson, Rodney W</p> <p>2014-01-01</p> <p>Due to the fact that morphology and perinatal growth of the piglet brain is similar to humans, use of the piglet as a translational animal model for neurodevelopmental studies is increasing. <span class="hlt">Magnetic</span> resonance imaging (MRI) can be a powerful tool to study neurodevelopment in piglets, but many of the MRI resources have been produced for adult humans. Here, we present an <span class="hlt">average</span> in vivo MRI-based atlas specific for the 4-week-old piglet. In addition, we have developed probabilistic tissue classification maps. These tools can be used with brain mapping software packages (e.g. SPM and FSL) to aid in voxel-based morphometry and image analysis techniques. The atlas enables efficient study of neurodevelopment in a highly tractable translational animal with brain growth and development similar to humans. PMID:25254955</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012PhDT.......113C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012PhDT.......113C"><span id="translatedtitle">Autonomous <span class="hlt">interplanetary</span> constellation design</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chow, Cornelius Channing, II</p> <p></p> <p>According to NASA's integrated space technology roadmaps, space-based infrastructures are envisioned as necessary ingredients to a sustained effort in continuing space exploration. Whether it be for extra-terrestrial habitats, roving/cargo vehicles, or space tourism, autonomous space networks will provide a vital communications lifeline for both future robotic and human missions alike. Projecting that the Moon will be a bustling hub of activity within a few decades, a near-term opportunity for in-situ infrastructure development is within reach. This dissertation addresses the anticipated need for in-space infrastructure by investigating a general design methodology for autonomous <span class="hlt">interplanetary</span> constellations; to illustrate the theory, this manuscript presents results from an application to the Earth-Moon neighborhood. The constellation design methodology is formulated as an optimization problem, involving a trajectory design step followed by a spacecraft placement sequence. Modeling the dynamics as a restricted 3-body problem, the investigated design space consists of families of periodic orbits which play host to the constellations, punctuated by arrangements of spacecraft autonomously guided by a navigation strategy called LiAISON (Linked Autonomous <span class="hlt">Interplanetary</span> Satellite Orbit Navigation). Instead of more traditional exhaustive search methods, a numerical continuation approach is implemented to map the admissible configuration space. In particular, Keller's pseudo-arclength technique is used to follow folding/bifurcating solution manifolds, which are otherwise inaccessible with other parameter continuation schemes. A succinct characterization of the underlying structure of the local, as well as global, extrema is thus achievable with little a priori intuition of the solution space. Furthermore, the proposed design methodology offers benefits in computation speed plus the ability to handle mildly stochastic systems. An application of the constellation design methodology to the restricted Earth-Moon system, reveals optimal pairwise configurations for various L1, L2, and L5 (halo, axial, and vertical) periodic orbit families. Navigation accuracies, ranging from O (10+/-1) meters in position space, are obtained for the optimal Earth-Moon constellations, given measurement noise on the order of 1 meter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5619090','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5619090"><span id="translatedtitle">Laser-fusion rocket for <span class="hlt">interplanetary</span> propulsion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hyde, R.A.</p> <p>1983-09-27</p> <p>A rocket powered by fusion microexplosions is well suited for quick <span class="hlt">interplanetary</span> travel. Fusion pellets are sequentially injected into a <span class="hlt">magnetic</span> thrust chamber. There, focused energy from a fusion Driver is used to implode and ignite them. Upon exploding, the plasma debris expands into the surrounding <span class="hlt">magnetic</span> field and is redirected by it, producing thrust. This paper discusses the desired features and operation of the fusion pellet, its Driver, and <span class="hlt">magnetic</span> thrust chamber. A rocket design is presented which uses slightly tritium-enriched deuterium as the fusion fuel, a high temperature KrF laser as the Driver, and a thrust chamber consisting of a single superconducting current loop protected from the pellet by a radiation shield. This rocket can be operated with a power-to-mass ratio of 110 W gm/sup -1/, which permits missions ranging from occasional 9 day VIP service to Mars, to routine 1 year, 1500 ton, Plutonian cargo runs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060037420&hterms=solar+activity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsolar%2Bactivity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060037420&hterms=solar+activity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsolar%2Bactivity"><span id="translatedtitle">The Solar and <span class="hlt">Interplanetary</span> Causes of Geomagnetic Activity and Quiet</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gonzalez, W. D.; Tsurutani, B. T.; Tang, F.</p> <p>1995-01-01</p> <p>This presentation will show that the three distinct phases of <span class="hlt">magnetic</span> storms (initial, main, recovery) can each have considerably different characteristics during solar minimum and solar maximum. Illustrated will be the <span class="hlt">interplanetary</span> causes of these differences; and, that a year during the descending phase of the solar cycle had significantly greater auroral activity than a year of solar maximum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120009632','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120009632"><span id="translatedtitle">Search Coil vs. Fluxgate Magnetometer Measurements at <span class="hlt">Interplanetary</span> Shocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, L.B., III</p> <p>2012-01-01</p> <p>We present <span class="hlt">magnetic</span> field observations at <span class="hlt">interplanetary</span> shocks comparing two different sample rates showing significantly different results. Fluxgate magnetometer measurements show relatively laminar supercritical shock transitions at roughly 11 samples/s. Search coil magnetometer measurements at 1875 samples/s, however, show large amplitude (dB/B as large as 2) fluctuations that are not resolved by the fluxgate magnetometer. We show that these fluctuations, identified as whistler mode waves, would produce a significant perturbation to the shock transition region changing the interpretation from laminar to turbulent. Thus, previous observations of supercritical <span class="hlt">interplanetary</span> shocks classified as laminar may have been under sampled.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19720004688','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720004688"><span id="translatedtitle"><span class="hlt">Magnetic</span> field measurements by Pioneer 7. 1: Hourly <span class="hlt">averages</span> of the field elements from 17 August 1966 to 29 October 1967 (Bartel's Solar Rotation 1820 to 1836)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ness, N. F.; Ottens, F. W.</p> <p>1971-01-01</p> <p>The <span class="hlt">magnetic</span> observations of Pioneer 7, located in the aftward portion of the disturbed solar plasma caused by interaction with the geomagnetic field, are summarized in graphical form. Hourly <span class="hlt">averages</span> of the <span class="hlt">magnetic</span> field elements for Bartel's solar rotation number are shown for each month from August 1966 to October 1967.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850026502','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850026502"><span id="translatedtitle">Determination of the pitch-angle distribution and transverse anisotropy of <span class="hlt">interplanetary</span> particles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ng, C. K.</p> <p>1985-01-01</p> <p>A method to determine the directional differential intensity (d.d.i.), expressed in terms of spherical harmonics, from sectored particle data, concurrent <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) and solar wind velocity is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.7307K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.7307K"><span id="translatedtitle">Estimation of <span class="hlt">interplanetary</span> electric field conditions for historical geomagnetic storms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kumar, Sandeep; Veenadhari, B.; Tulasi Ram, S.; Selvakumaran, R.; Mukherjee, Shyamoli; Singh, Rajesh; Kadam, B. D.</p> <p>2015-09-01</p> <p>Ground <span class="hlt">magnetic</span> measurements provide a unique database in understanding space weather. The continuous geomagnetic records from Colaba-Alibag observatories in India contain historically longest and continuous observations from 1847 to present date. Some of the super intense geomagnetic storms that occurred prior to 1900 have been revisited and investigated in order to understand the probable <span class="hlt">interplanetary</span> conditions associated with intense storms. Following Burton et al. (1975), an empirical relationship is derived for estimation of <span class="hlt">interplanetary</span> electric field (IEFy) from the variations of Dst index and ?H at Colaba-Alibag observatories. The estimated IEFy values using Dst and ?HABG variations agree well with the observed IEFy, calculated using Advanced Composition Explorer (ACE) satellite observations for intense geomagnetic storms in solar cycle 23. This study will provide the uniqueness of each event and provide important insights into possible <span class="hlt">interplanetary</span> conditions for intense geomagnetic storms and probable frequency of their occurrence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990053118&hterms=rubidium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Drubidium','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990053118&hterms=rubidium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Drubidium"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Microlaser Transponders</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Degnan, John J.</p> <p>1999-01-01</p> <p>The feasibility of an asynchronous (i.e. independently firing) <span class="hlt">interplanetary</span> laser transponder, capable of ranging between Earth and Mars and using the automated SLR2000 Satellite Laser Ranging (SLR) system as an Earth base station, has been suggested. Since that time, we have received a small amount of discretionary funding to further explore the transponder concept and to develop and test an engineering breadboard. Candidate operational scenarios for acquiring and tracking the opposite laser terminal over <span class="hlt">interplanetary</span> distances have been developed, and breadboard engineering parameters were chosen to reflect the requirements of an Earth-Mars link Laboratory tests have been devised to simulate the Earth- Mars link between two independent SLR2000 transceivers and to demonstrate the transfer of range and time in single photon mode. The present paper reviews the concept of the asynchronous microlaser transponder, the transponder breadboard design, an operational scenario recently developed for an asteroid rendezvous, and the laboratory test setup. The optical head of the transponder breadboard fits within a cylinder roughly 15 cm in diameter and 32 cm in length and is mounted in a commercial two axis gimbal driven by two computer-controlled stepper motors which allows the receiver optical axis to be centered on a simulated Earth image. The optical head is built around a small optical bench which supports a 14.7 cm diameter refractive telescope, a prototype 2 kHz SLR2000 microlaser transmitter, a quadrant microchannel plate photomultiplier (MCP/PMT), a CCD array camera, spatial and spectral filters, assorted lenses and mirrors, and protective covers and sun shields. The microlaser is end-pumped by a fiber-coupled diode laser array. An annular mirror is employed as a passive transmit/receive (T/R) switch in an aperture-sharing arrangement wherein the transmitted beam passes through the central hole and illuminates only the central 2.5 cm of the common telescope (adequate to achieve a 10 arcsecond full laser beam divergence) while the receiver uses the remainder of the 14.7 cm aperture. Additional electronic instrumentation includes the diode pump array and associated heat sink and current drivers, rubidium frequency standard, timing distribution module, range gate generator, a recently developed all-digital correlation range receiver, and system computer. Acquisition of the opposite transponder terminal requires a search within a three-dimensional volume determined by the initial pointing uncertainty and a maximum 500 microsecond uncertainty in the laser time of fire at the opposite terminal for totally uncorrelated Earth and spacecraft clocks. The angular search is aided by a sensitive CCD array capable of imaging the Earth, Moon, and surrounding stars within the nominal + 0.5 degree cone of uncertainty associated with the initial pointing of a spacecraft body or microwave communications dish.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840005055&hterms=properties+gas&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dproperties%2Bgas','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840005055&hterms=properties+gas&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dproperties%2Bgas"><span id="translatedtitle">Plasma properties of driver gas following <span class="hlt">interplanetary</span> shocks observed by ISEE-3</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zwickl, R. D.; Asbridge, J. R.; Bame, S. J.; Feldman, W. C.; Gosling, J. T.; Smith, E. J.</p> <p>1983-01-01</p> <p>Plasma fluid parameters calculated from solar wind and <span class="hlt">magnetic</span> field data to determine the characteristic properties of driver gas following a select subset of <span class="hlt">interplanetary</span> shocks were studied. Of 54 shocks observed from August 1978 to February 1980, 9 contained a well defined driver gas that was clearly identifiable by a discontinuous decrease in the <span class="hlt">average</span> proton temperature. While helium enhancements were present downstream of the shock in all 9 of these events, only about half of them contained simultaneous changes in the two quantities. Simultaneous with the drop in proton temperature the helium and electron temperature decreased abruptly. In some cases the proton temperature depression was accompanied by a moderate increase in <span class="hlt">magnetic</span> field magnitude with an unusually low variance, by a small decrease in the variance of the bulk velocity, and by an increase in the ratio of parallel to perpendicular temperature. The cold driver gas usually displayed a bidirectional flow of suprathermal solar wind electrons at higher energies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830025554','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830025554"><span id="translatedtitle">Plasma properties of driver gas following <span class="hlt">interplanetary</span> shocks observed by ISEE-3</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zwickl, R. D.; Ashbridge, J. R.; Bame, S. J.; Feldman, W. C.; Gosling, J. T.; Smith, E. J.</p> <p>1982-01-01</p> <p>Plasma fluid parameters calculated from solar wind and <span class="hlt">magnetic</span> field data obtained on ISEE 3 were studied. The characteristic properties of driver gas following <span class="hlt">interplanetary</span> shocks was determined. Of 54 shocks observed from August 1978 to February 1980, nine contained a well defined driver gas that was clearly identifiable by a discontinuous decrease in the <span class="hlt">average</span> proton temperature across a tangential discontinuity. While helium enhancements were present in all of nine of these events, only about half of them contained simultaneous changes in the two quantities. Often the He/H ratio changed over a period of minutes. Simultaneous with the drop in proton temperature the helium and electron temperature decreased abruptly. In some cases the proton temperature depression was accompanied by a moderate increase in <span class="hlt">magnetic</span> field magnitude with an unusually low variance and by an increase in the ratio of parallel to perpendicular temperature. The drive gas usually displayed a bidirectional flow of suprathermal solar wind electrons at higher energies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMSM44A..02Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMSM44A..02Z"><span id="translatedtitle">Magnetospheric and Ionospheric Response to the <span class="hlt">Interplanetary</span> Shocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zong, Q.; Wang, Y.; Zhou, X.; Song, P.; Li, X.; Fritz, T.; Korth, A.</p> <p>2008-12-01</p> <p>The Cluster spacecraft and ground-based Digisonde network observed on November 7, 2004 a strong <span class="hlt">interplanetary</span> shock interaction with Earth's magnetosphere which initiated a strong <span class="hlt">magnetic</span> storm with Dst = -373 nT. When this <span class="hlt">interplanetary</span> shock encountered the Earth system, the Cluster fleet were traveling in the inner magnetosphere region (L shell = 4.2) at almost exactly the Cluster's perigee (around 0900 MLT). This event provides an excellent opportunity to study the geospace response to a powerful <span class="hlt">interplanetary</span> shock. The angle between the sun-Earth line and the normal direction of the shock front is only 3.0 degree indicating that the shock hit the geospace at ~12LT (local time) initially. It is found that energetic particle fluxes are enhanced strongly and the shock related ionospheric phenomena have obvious longitudinal and latitudinal distribution. The <span class="hlt">interplanetary</span> shock has a significant influence on the dayside mid-high latitude stations, e.g. Millstone Hill, Wallops Island, etc. whereas the stations at the night sector do not seem to respond to the <span class="hlt">interplanetary</span> shock immediately.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760017031','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760017031"><span id="translatedtitle">Proceedings of the Symposium on the Study of the Sun and <span class="hlt">Interplanetary</span> Medium in Three Dimensions. [space mission planning and <span class="hlt">interplanetary</span> trajectories by NASA and ESA to better observe the sun and solar system</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fisk, L. A. (Editor); Axford, W. I. (Editor)</p> <p>1976-01-01</p> <p>A series of papers are presented from a symposium attended by over 200 European and American scientists to examine the importance of exploring the <span class="hlt">interplanetary</span> medium and the sun by out-of-the-ecliptic space missions. The likely scientific returns of these missions in the areas of solar, <span class="hlt">interplanetary</span>, and cosmic ray physics is examined. Theoretical models of the solar wind and its interaction with <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.3758V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.3758V"><span id="translatedtitle">Heliospheric Consecuences of Solar Activity In Several <span class="hlt">Interplanetary</span> Phenomena</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Valds-Galicia, J. F.; Mendoza, B.; Lara, A.; Maravilla, D.</p> <p></p> <p>We have done an analysis of several phenomena related to solar activity such as the total <span class="hlt">magnetic</span> flux, coronal hole area and sunspots, investigated its long trend evolu- tion over several solar cycles and its possible relationships with <span class="hlt">interplanetary</span> shocks, sudden storm commencements at earth and cosmic ray variations. Our results stress the physical connection between the solar <span class="hlt">magnetic</span> flux emergence and the interplan- etary medium dynamics, in particular the importance of coronal hole evolution in the structuring of the heliosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20050131826&hterms=hugoniot&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhugoniot','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20050131826&hterms=hugoniot&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dhugoniot"><span id="translatedtitle">Multi-Spacecraft Observations of <span class="hlt">Interplanetary</span> Shocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Szabo, Adam</p> <p>2005-01-01</p> <p>Multi-spacecraft solar wind observations reveal that many <span class="hlt">interplanetary</span> shocks deviate significantly from exact planarity on scale length of the magnetospheric cross section. A number of different IP shock observations with four spacecraft will be presented to demonstrate quantitatively the angular deviations between shock normals obtained from 4-spacecraft methods, using only the time and position information of shock observations but assuming a exactly planar geometry, and those obtained from a non-linear least squares fitting of the "Rankine-Hugoniot" conservation equations at each spacecraft. Moreover, the curvature of the shock fronts is strongly related to its driver, typically <span class="hlt">magnetic</span> clouds. It will be demonstrated that small and slower moving <span class="hlt">magnetic</span> clouds drive shocks with significantly more irregular surface geometries.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930049293&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930049293&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dlazarus"><span id="translatedtitle">Anomalous aspects of magnetosheath flow and of the shape and oscillations of the magnetopause during an interval of strongly northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chen, Sheng-Hsien; Kivelson, Margaret G.; Gosling, Jack T.; Walker, Raymond J.; Lazarus, Allan J.</p> <p>1993-01-01</p> <p>On February 15, 1978, the orientation of the IMF remained steadily northward for more than 12 hours. Using plasma and <span class="hlt">magnetic</span> field data from ISEE 1 and 2, IMP 8, and IMP 7, we show that (1) the magnetosheath flow speed on the flanks of the magnetotail steadily exceeded the solar wind speed by 20 percent, (2) surface waves of about 5-min period and very nonsinusoidal waveform were persistently present on the dawn magnetopause and waves of similar period were present in the dusk magnetosheath, and (3) the magnetotail ceased to flare at an antisunward distance of 15 earth radii. We propose that the acceleration of the magnetosheath flow is achieved by <span class="hlt">magnetic</span> tension in the draped field configuration for northward IMP; the reduction of tail flaring is consistent with a decreased amount of open <span class="hlt">magnetic</span> flux and a larger standoff distance of the subsolar magnetopause. Results of a 3D MHD simulation support this phenomenological model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1200613-bounce-mlt-averaged-diffusion-coefficients-physics-based-magnetic-field-geometry-obtained-from-ram-scb-march-storm','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1200613-bounce-mlt-averaged-diffusion-coefficients-physics-based-magnetic-field-geometry-obtained-from-ram-scb-march-storm"><span id="translatedtitle">Bounce- and MLT-<span class="hlt">averaged</span> diffusion coefficients in a physics-based <span class="hlt">magnetic</span> field geometry obtained from RAM-SCB for the March 17 2013 storm</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Zhao, Lei; Yu, Yiqun; Delzanno, Gian Luca; Jordanova, Vania K.</p> <p>2015-04-01</p> <p>Local acceleration via whistler wave and particle interaction plays a significant role in particle dynamics in the radiation belt. In this work we explore gyro-resonant wave-particle interaction and quasi-linear diffusion in different <span class="hlt">magnetic</span> field configurations related to the March 17 2013 storm. We consider the Earth's <span class="hlt">magnetic</span> dipole field as a reference and compare the results against non-dipole field configurations corresponding to quiet and stormy conditions. The latter are obtained with the ring current-atmosphere interactions model with a self-consistent <span class="hlt">magnetic</span> field RAM-SCB, a code that models the Earth's ring current and provides a realistic modeling of the Earth's <span class="hlt">magnetic</span> field.more » By applying quasi-linear theory, the bounce- and MLT-<span class="hlt">averaged</span> electron pitch angle, mixed term, and energy diffusion coefficients are calculated for each <span class="hlt">magnetic</span> field configuration. For radiation belt (~1 MeV) and ring current (~100 keV) electrons, it is shown that at some MLTs the bounce-<span class="hlt">averaged</span> diffusion coefficients become rather insensitive to the details of the <span class="hlt">magnetic</span> field configuration, while at other MLTs storm conditions can expand the range of equatorial pitch angles where gyro-resonant diffusion occurs and significantly enhance the diffusion rates. When MLT <span class="hlt">average</span> is performed at drift shell L = 4.25 (a good approximation to drift <span class="hlt">average</span>), the diffusion coefficients become quite independent of the <span class="hlt">magnetic</span> field configuration for relativistic electrons, while the opposite is true for lower energy electrons. These results suggest that, at least for the March 17 2013 storm and for L ≲ 4.25, the commonly adopted dipole approximation of the Earth's <span class="hlt">magnetic</span> field can be safely used for radiation belt electrons, while a realistic modeling of the <span class="hlt">magnetic</span> field configuration is necessary to describe adequately the diffusion rates of ring current electrons.« less</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1200613','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1200613"><span id="translatedtitle">Bounce- and MLT-<span class="hlt">averaged</span> diffusion coefficients in a physics-based <span class="hlt">magnetic</span> field geometry obtained from RAM-SCB for the March 17 2013 storm</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zhao, Lei; Yu, Yiqun; Delzanno, Gian Luca; Jordanova, Vania K.</p> <p>2015-04-01</p> <p>Local acceleration via whistler wave and particle interaction plays a significant role in particle dynamics in the radiation belt. In this work we explore gyro-resonant wave-particle interaction and quasi-linear diffusion in different <span class="hlt">magnetic</span> field configurations related to the March 17 2013 storm. We consider the Earth's <span class="hlt">magnetic</span> dipole field as a reference and compare the results against non-dipole field configurations corresponding to quiet and stormy conditions. The latter are obtained with the ring current-atmosphere interactions model with a self-consistent <span class="hlt">magnetic</span> field RAM-SCB, a code that models the Earth's ring current and provides a realistic modeling of the Earth's <span class="hlt">magnetic</span> field. By applying quasi-linear theory, the bounce- and MLT-<span class="hlt">averaged</span> electron pitch angle, mixed term, and energy diffusion coefficients are calculated for each <span class="hlt">magnetic</span> field configuration. For radiation belt (~1 MeV) and ring current (~100 keV) electrons, it is shown that at some MLTs the bounce-<span class="hlt">averaged</span> diffusion coefficients become rather insensitive to the details of the <span class="hlt">magnetic</span> field configuration, while at other MLTs storm conditions can expand the range of equatorial pitch angles where gyro-resonant diffusion occurs and significantly enhance the diffusion rates. When MLT <span class="hlt">average</span> is performed at drift shell L = 4.25 (a good approximation to drift <span class="hlt">average</span>), the diffusion coefficients become quite independent of the <span class="hlt">magnetic</span> field configuration for relativistic electrons, while the opposite is true for lower energy electrons. These results suggest that, at least for the March 17 2013 storm and for L ≲ 4.25, the commonly adopted dipole approximation of the Earth's <span class="hlt">magnetic</span> field can be safely used for radiation belt electrons, while a realistic modeling of the <span class="hlt">magnetic</span> field configuration is necessary to describe adequately the diffusion rates of ring current electrons.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008GeofI..47..301B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008GeofI..47..301B"><span id="translatedtitle">Transport in the <span class="hlt">interplanetary</span> medium of coronal mass ejections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Borgazzi, A.; Lara, A.; Romero-Salazar, L.; Ventura, A.</p> <p>2008-07-01</p> <p>Coronal mass ejections (CMEs) are large scale structures of plasma and <span class="hlt">magnetic</span> field expelled from the Sun to the <span class="hlt">interplanetary</span> medium and generally observed in white light coronagraphs. During their travel, in the <span class="hlt">interplanetary</span> medium these structures named <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs), suffer acceleration or deceleration due to the interaction with the ambient solar wind. This process can be understood as a transference of momentum between the <span class="hlt">interplanetary</span> CME (ICME) and the solar wind. This process seems to be fundamentally different for `slow' and `fast' ICMEs (compared with the ambient solar wind velocity). In this work, we approach the problem from the fluid dynamics point of view and consider the ICMEs - solar wind system as two interacting fluids under the action of viscous forces. We note that this interaction is a special case of interaction between low density plasmas. Using these viscous forces in the Newtons Second Law, we obtained an analytical solution for the ICME velocity as a function of time. By comparing our analytic results with empirical models found in recent literature, we suggested values for the viscosity and drag parameters in this system. In this first approximation we have neglected the <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21300682','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21300682"><span id="translatedtitle">THREE-DIMENSIONAL FEATURES OF THE OUTER HELIOSPHERE DUE TO COUPLING BETWEEN THE INTERSTELLAR AND <span class="hlt">INTERPLANETARY</span> <span class="hlt">MAGNETIC</span> FIELDS. III. THE EFFECTS OF SOLAR ROTATION AND ACTIVITY CYCLE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pogorelov, Nikolai V.; Borovikov, Sergey N.; Zank, Gary P.; Ogino, Tatsuki E-mail: snb0003@uah.edu E-mail: ogino@stelab.nagoya-u.ac.jp</p> <p>2009-05-10</p> <p>We investigate the effects of the 11 year solar cycle and 25 day rotation period of the Sun on the interaction of the solar wind (SW) with the local interstellar medium (LISM). Our models take into account the partially ionized character of the LISM and include momentum and energy transfer between the ionized and neutral components. We assume that the interstellar <span class="hlt">magnetic</span> field vector belongs to the hydrogen deflection plane as discovered in the SOHO SWAN experiment. This plane is inclined at an angle of about 60 deg. toward the ecliptic plane of the Sun, as suggested in recent publications relating the local interstellar cloud properties to the radio emission observed by Voyager 1. It is assumed that the latitudinal extent of the boundary between the slow and fast SW regions, as well as the angle between the Sun's rotation and <span class="hlt">magnetic</span>-dipole axes, are periodic functions of time, while the polarity of the interstellar <span class="hlt">magnetic</span> field changes sign every 11 years at the solar maximum. The global variation of the SW-LISM interaction pattern, the excursions of the termination shock and the heliopause, and parameter distributions in certain directions are investigated. The analysis of the behavior of the wavy heliospheric current sheet in the supersonic SW region shows the importance of neutral atoms on its dynamics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19870005698','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19870005698"><span id="translatedtitle">Evolution and interaction of large <span class="hlt">interplanetary</span> streams</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Whang, Y. C.; Burlaga, L. F.</p> <p>1985-01-01</p> <p>A computer simulation for the evolution and interaction of large <span class="hlt">interplanetary</span> streams based on multi-spacecraft observations and an unsteady, one-dimensional MHD model is presented. Two events, each observed by two or more spacecraft separated by a distance of the order of 10 AU, were studied. The first simulation is based on the plasma and <span class="hlt">magnetic</span> field observations made by two radially-aligned spacecraft. The second simulation is based on an event observed first by Helios-1 in May 1980 near 0.6 AU and later by Voyager-1 in June 1980 at 8.1 AU. These examples show that the dynamical evolution of large-scale solar wind structures is dominated by the shock process, including the formation, collision, and merging of shocks. The interaction of shocks with stream structures also causes a drastic decrease in the amplitude of the solar wind speed variation with increasing heliocentric distance, and as a result of interactions there is a large variation of shock-strengths and shock-speeds. The simulation results shed light on the interpretation for the interaction and evolution of large <span class="hlt">interplanetary</span> streams. Observations were made along a few limited trajectories, but simulation results can supplement these by providing the detailed evolution process for large-scale solar wind structures in the vast region not directly observed. The use of a quantitative nonlinear simulation model including shock merging process is crucial in the interpretation of data obtained in the outer heliosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970021679','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970021679"><span id="translatedtitle">Latitudinal Dependence of the Radial IMF Component - <span class="hlt">Interplanetary</span> Imprint</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Suess, S. T.; Smith, E. J.; Phillips, J.; Goldstein, B. E.; Nerney, S.</p> <p>1996-01-01</p> <p>Ulysses measurements have confirmed that there is no significant gradient with respect to heliomagnetic latitude in the radial component, B(sub r,), of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. There are two processes responsible for this observation. In the corona, the plasma beta is much less than 1, except directly above streamers, so both longitudinal and latitudinal (meridional) gradients in field strength will relax, due to the transverse <span class="hlt">magnetic</span> pressure gradient force, as the solar wind carries <span class="hlt">magnetic</span> flux away from the Sun. This happens so quickly that the field is essentially uniform by 5 solar radius. Beyond 10 solar radius, beta is greater than 1 and it is possible for a meridional thermal pressure gradient to redistribute <span class="hlt">magnetic</span> flux - an effect apparently absent in Ulysses and earlier ICE and <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Physics (IMP) data. We discuss this second effect here, showing that its absence is mainly due to the perpendicular part of the anisotropic thermal pressure gradient in the <span class="hlt">interplanetary</span> medium being too small to drive significant meridional transport between the Sun and approx. 4 AU. This is done using a linear analytic estimate of meridional transport. The first effect was discussed in an earlier paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4765993','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4765993"><span id="translatedtitle">Phase Error Correction in Time-<span class="hlt">Averaged</span> 3D Phase Contrast <span class="hlt">Magnetic</span> Resonance Imaging of the Cerebral Vasculature</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>MacDonald, M. Ethan; Forkert, Nils D.; Pike, G. Bruce; Frayne, Richard</p> <p>2016-01-01</p> <p>Purpose Volume flow rate (VFR) measurements based on phase contrast (PC)-<span class="hlt">magnetic</span> resonance (MR) imaging datasets have spatially varying bias due to eddy current induced phase errors. The purpose of this study was to assess the impact of phase errors in time <span class="hlt">averaged</span> PC-MR imaging of the cerebral vasculature and explore the effects of three common correction schemes (local bias correction (LBC), local polynomial correction (LPC), and whole brain polynomial correction (WBPC)). Methods Measurements of the eddy current induced phase error from a static phantom were first obtained. In thirty healthy human subjects, the methods were then assessed in background tissue to determine if local phase offsets could be removed. Finally, the techniques were used to correct VFR measurements in cerebral vessels and compared statistically. Results In the phantom, phase error was measured to be <2.1 ml/s per pixel and the bias was reduced with the correction schemes. In background tissue, the bias was significantly reduced, by 65.6% (LBC), 58.4% (LPC) and 47.7% (WBPC) (p < 0.001 across all schemes). Correction did not lead to significantly different VFR measurements in the vessels (p = 0.997). In the vessel measurements, the three correction schemes led to flow measurement differences of -0.04 ± 0.05 ml/s, 0.09 ± 0.16 ml/s, and -0.02 ± 0.06 ml/s. Although there was an improvement in background measurements with correction, there was no statistical difference between the three correction schemes (p = 0.242 in background and p = 0.738 in vessels). Conclusions While eddy current induced phase errors can vary between hardware and sequence configurations, our results showed that the impact is small in a typical brain PC-MR protocol and does not have a significant effect on VFR measurements in cerebral vessels. PMID:26910600</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850026534','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850026534"><span id="translatedtitle">Differential measurement of cosmic-ray gradient with respect to <span class="hlt">interplanetary</span> current sheet</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Christon, S. P.; Cummings, A. C.; Stone, E. C.; Behannon, K. W.; Burlaga, L. F.</p> <p>1985-01-01</p> <p>Simultaneous <span class="hlt">magnetic</span> field and charged particle measurements from the Voyager spacecraft at heliographic latitude separations from 10 deg. to 21 deg. are used to determine the latitude gradient of the galactic cosmic ray flux with respect to the <span class="hlt">interplanetary</span> current sheet. By comparing the ratio of cosmic ray flux at Voyager 1 to that a Voyager 2 during periods when both spacecraft are first nort and then south of the <span class="hlt">interplanetary</span> current sheet, we find an estimate of the latitudinal gradient with respect to the current sheet of approximately -0.15 + or 0.05% deg under restricted <span class="hlt">interplanetary</span> conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22270672','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22270672"><span id="translatedtitle">USING COORDINATED OBSERVATIONS IN POLARIZED WHITE LIGHT AND FARADAY ROTATION TO PROBE THE SPATIAL POSITION AND <span class="hlt">MAGNETIC</span> FIELD OF AN <span class="hlt">INTERPLANETARY</span> SHEATH</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Xiong, Ming; Feng, Xueshang; Liu, Ying D.; Davies, Jackie A.; Harrison, Richard A.; Owens, Mathew J.; Davis, Chris J.</p> <p>2013-11-01</p> <p>Coronal mass ejections (CMEs) can be continuously tracked through a large portion of the inner heliosphere by direct imaging in visible and radio wavebands. White light (WL) signatures of solar wind transients, such as CMEs, result from Thomson scattering of sunlight by free electrons and therefore depend on both viewing geometry and electron density. The Faraday rotation (FR) of radio waves from extragalactic pulsars and quasars, which arises due to the presence of such solar wind features, depends on the line-of-sight <span class="hlt">magnetic</span> field component B{sub ?} and the electron density. To understand coordinated WL and FR observations of CMEs, we perform forward magnetohydrodynamic modeling of an Earth-directed shock and synthesize the signatures that would be remotely sensed at a number of widely distributed vantage points in the inner heliosphere. Removal of the background solar wind contribution reveals the shock-associated enhancements in WL and FR. While the efficiency of Thomson scattering depends on scattering angle, WL radiance I decreases with heliocentric distance r roughly according to the expression I?r {sup 3}. The sheath region downstream of the Earth-directed shock is well viewed from the L4 and L5 Lagrangian points, demonstrating the benefits of these points in terms of space weather forecasting. The spatial position of the main scattering site r{sub sheath} and the mass of plasma at that position M{sub sheath} can be inferred from the polarization of the shock-associated enhancement in WL radiance. From the FR measurements, the local B{sub ?sheath} at r{sub sheath} can then be estimated. Simultaneous observations in polarized WL and FR can not only be used to detect CMEs, but also to diagnose their plasma and <span class="hlt">magnetic</span> field properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19760053294&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760053294&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dlazarus"><span id="translatedtitle">Suprathermal protons in the <span class="hlt">interplanetary</span> solar wind</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goodrich, C. C.; Lazarus, A. J.</p> <p>1976-01-01</p> <p>Using the Mariner 5 solar wind plasma and <span class="hlt">magnetic</span> field data, we present observations of field-aligned suprathermal proton velocity distributions having pronounced high-energy shoulders. These observations, similar to the interpenetrating stream observations of Feldman et al. (1974), are clear evidence that such proton distributions are <span class="hlt">interplanetary</span> rather than bow shock associated phenomena. Large Alfven speed is found to be a requirement for the occurrence of suprathermal proton distribution; further, we find the proportion of particles in the shoulder to be limited by the magnitude of the Alfven speed. It is suggested that this last result could indicate that the proton thermal anisotropy is limited at times by wave-particle interactions</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22270645','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22270645"><span id="translatedtitle">MAGNETOHYDRODYNAMIC SIMULATIONS OF <span class="hlt">INTERPLANETARY</span> CORONAL MASS EJECTIONS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lionello, Roberto; Downs, Cooper; Linker, Jon A.; Török, Tibor; Riley, Pete; Mikić, Zoran E-mail: cdowns@predsci.com E-mail: tibor@predsci.com E-mail: mikic@predsci.com</p> <p>2013-11-01</p> <p>We describe a new MHD model for the propagation of <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs) in the solar wind. Accurately following the propagation of ICMEs is important for determining space weather conditions. Our model solves the MHD equations in spherical coordinates from a lower boundary above the critical point to Earth and beyond. On this spherical surface, we prescribe the <span class="hlt">magnetic</span> field, velocity, density, and temperature calculated typically directly from a coronal MHD model as time-dependent boundary conditions. However, any model that can provide such quantities either in the inertial or rotating frame of the Sun is suitable. We present two validations of the technique employed in our new model and a more realistic simulation of the propagation of an ICME from the Sun to Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003TrGeo...1..689B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003TrGeo...1..689B"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Dust Particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bradley, J. P.</p> <p>2003-12-01</p> <p>One of the fundamental goals of the study of meteorites is to understand how the solar system and planetary systems around other stars formed. It is known that the solar system formed from pre-existing (presolar) interstellar dust grains and gas. The grains originally formed in the circumstellar outflows of other stars. They were modified to various degrees, ranging from negligible modification to complete destruction and reformation during their ˜108 yr lifetimes in the interstellar medium (ISM) (Seab, 1987; Mathis, 1993). Finally, they were incorporated into the solar system. Submicrometer-sized silicates and carbonaceous material are believed to be the most common grains in the ISM ( Mathis, 1993; Sandford, 1996), but it is not known how much of this presolar particulate matter was incorporated into the solar system, to what extent it has survived, and how it might be distinguished from solar system grains. In order to better understand the process of solar system formation, it is important to identify and analyze these solid grains. Since all of the alteration processes that modified solids in the solar nebula presumably had strong radial gradients, the logical place to find presolar grains is in small primitive bodies like comets and asteroids that have undergone little, if any, parent-body alteration.Trace quantities of refractory presolar grains (e.g., SiC and Al2O3) survive in the matrices of the most primitive carbon-rich chondritic meteorites (Anders and Zinner, 1993; Bernatowicz and Zinner, 1996; Bernatowicz and Walker, 1997; Hoppe and Zinner, 2000; see Chapter 1.02). Chondritic meteorites are believed to be from the asteroid belt, a narrow region between 2.5 and 3.5 astronomical units (AU) that marks the transition from the terrestrial planets to the giant gas-rich planets. The spectral properties of the asteroids suggest a gradation in properties with some inner and main belt C and S asteroids (the source region of most meteorites and polar micrometeorites) containing layer silicates indicative of parent-body aqueous alteration and the more distant anhydrous P and D asteroids exhibiting no evidence of (aqueous) alteration (Gradie and Tedesco, 1982). This gradation in spectral properties presumably extends several hundred AU out to the Kuiper belt, the source region of most short-period comets, where the distinction between comets and outer asteroids may simply be one of the orbital parameters ( Luu, 1993; Brownlee, 1994; Jessberger et al., 2001). The mineralogy and petrography of meteorites provides direct confirmation of aqueous alteration, melting, fractionation, and thermal metamorphism among the inner asteroids ( Zolensky and McSween, 1988; Farinella et al., 1993; Brearley and Jones, 1998). Because the most common grains in the ISM (silicates and carbonaceous matter) are not as refractory as those found in meteorites, it is unlikely that they have survived in significant quantities in meteorites. Despite a prolonged search, not a single presolar silicate grain has yet been identified in any meteorite.<span class="hlt">Interplanetary</span> dust particles (IDPs) are the smallest and most fine-grained meteoritic objects available for laboratory investigation (Figure 1). In contrast to meteorites, IDPs are derived from a broad range of dust-producing bodies extending from the inner main belt of the asteroids to the Kuiper belt (Flynn, 1996, 1990; Dermott et al., 1994; Liou et al., 1996). After release from their asteroidal or cometary parent bodies the orbits of IDPs evolve by Poynting-Robertson (PR) drag (the combined influence of light pressure and radiation drag) ( Dermott et al., 2001). Irrespective of the location of their parent bodies nearly all IDPs under the influence of PR drag can eventually reach Earth-crossing orbits. IDPs are collected in the stratosphere at 20-25 km altitude using NASA ER2 aircraft ( Sandford, 1987; Warren and Zolensky, 1994). Laboratory measurements of implanted rare gases, solar flare tracks ( Figure 2), and isotope abundances have confirmed that the collected particles are indeed extraterrestrial and that, prior to atmospheric entry, they spent 104-105 yr as small particles orbiting the Sun (Rajan et al., 1977; Hudson et al., 1981; Bradley et al., 1984a; McKeegan et al., 1985; Messenger, 2000). (21K)Figure 1. (a)-(c) Secondary electron images. (a) Anhydrous CP IDP. (b) Hydrated CS IDP (RB12A44). (c) Single-mineral forsterite grain with adhering chondritic material. (d) Optical micrograph (transmitted light) of giant cluster IDP (U220GCA) in silicone oil on ER2 collection flag. (14K)Figure 2. Darkfield transmission electron micrographs. (a) Solar-wind sputtered rim on exterior surface plus implanted solar flare tracks in chondritic IDP U220A19 (from Bradley and Brownlee, 1986). (b) Solar flare tracks in a forsterite crystal in chondritic IDP U220B11 (from Bradley et al., 1984a). The track densities in both IDPs are ˜1010-1011 cm2 corresponding to an orbital exposure age of ˜104yr. During atmospheric entry most IDPs are frictionally heated to within 100 °C of their peak heating temperature for ˜1 s and, to a first-order approximation, the smallest particles are the least strongly heated. Although some IDPs may experience thermal pulses in excess of 1,000 °C for up to 10 s (depending on particle size, mass, entry angle, and speed) (Love and Brownlee, 1991, 1996), the presence of solar flare tracks in an IDP establishes that it was not heated above ˜650 °C ( Bradley et al., 1984a). Since IDPs decelerate from cosmic velocities at altitudes >90 km, where the maximum aerodynamic ram pressure is a factor of ˜103 less than that exerted on conventional meteorites, extremely fragile meteoritic materials that cannot survive as large objects can survive as small IDPs (Figure 1(a)) ( Brownlee, 1994). Such fragile materials are suspected to be among the most primitive objects and potentially the most informative regarding early solar system and presolar processes. (Conventional meteorites penetrate deep into the atmosphere such that only relatively well-indurated rocks can survive.) Collected IDPs are briefly exposed to the terrestrial environment but since their residence time in the stratosphere is short (˜2 weeks), they are not subjected to longer-term weathering that affects the surfaces of most meteorites (Flynn, 1994a).This chapter examines the compositions, mineralogy, sources, and geochemical significance of IDPs. Additional reading can be found in reviews by Fraundorf (1981), Brownlee (1985), Sandford (1987), Bradley et al. (1988), Jessberger et al. (2001), Rietmeijer (1998), and the book edited by Zolensky et al. (1994). Despite their micrometer-scale dimensions and nanogram masses it is now possible, primarily as a result of advances in small particle handling techniques and analytical instrumentation, to examine IDPs at close to atomic-scale resolution. The most widely used instruments for IDP studies are presently the analytical electron microscope, synchrotron facilities, and the ion microprobe. These laboratory analytical techniques are providing fundamental insights about IDP origins, mechanisms of formation, and grain processing phenomena that were important in the early solar system and presolar environments. At the same time, laboratory data from IDPs are being compared with astronomical data from dust in comets, circumstellar disks, and the ISM. The direct comparison of grains in the laboratory with grains in astronomical environments defines the new discipline of "astromineralogy" ( Jaeger et al., 1998; Bradley et al., 1999a, b; Molster et al., 2001; Keller et al., 2001; Flynn et al., 2002). ,</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012RScI...83j5108C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012RScI...83j5108C"><span id="translatedtitle">On the performance enhancement of adaptive signal <span class="hlt">averaging</span>: A means for improving the sensitivity and rate of data acquisition in <span class="hlt">magnetic</span> resonance and other analytical measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cochrane, C. J.</p> <p>2012-10-01</p> <p>A few years back, our lab developed a signal <span class="hlt">averaging</span> technique that greatly reduces the number of scans required to achieve a comparable signal-to-noise ratio to that of conventional signal <span class="hlt">averaging</span> for continuous wave <span class="hlt">magnetic</span> resonance measurements. We utilize an adaptive filter in a signal <span class="hlt">averaging</span> scheme without any prior knowledge of the signal under observation. We termed this technique adaptive signal <span class="hlt">averaging</span> (ASA). The technique was successful in reducing the noise variance by a factor of at least 10 in a single trace and is shown to converge in time by the same factor. ASA can also be useful in many other applications where signal <span class="hlt">averaging</span> is utilized, such as medical imaging, electrocardiography, or electroencephalography. The purpose of this paper is to describe the advancements made to the technique, present a derivation of its performance enhancement, and illustrate the power of the technique through a set of simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840053292&hterms=association+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dassociation%2Banalysis','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840053292&hterms=association+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dassociation%2Banalysis"><span id="translatedtitle">Spectral analysis of magnetohydrodynamic fluctuations near <span class="hlt">interplanetary</span> shocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vinas, A. F.; Goldstein, M. L.; Acuna, M. H.</p> <p>1984-01-01</p> <p>Preliminary results of an investigation of <span class="hlt">magnetic</span> fluctuations seen upstream of two <span class="hlt">interplanetary</span> shocks are presented. The spectral analysis includes calculation of the normalized reduced <span class="hlt">magnetic</span> helicity spectrum, the normalized reduced cross-helicity spectrum, and the Alfven ratio as discussed by Matthaeus and Goldstein (1982). Minimum variance methods are used to compute wave polarization as a function of frequency. The Taylor 'frozen in flow' hypothesis is assumed to convert frequencies to wave vectors. Some of the basic properties of the waves, including the probable mode of propagation in association with both quasi-parallel forward and reverse shocks, are described. A comparison with previous results on the generation of waves at <span class="hlt">interplanetary</span> and planetary shocks is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850026461','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850026461"><span id="translatedtitle">Particle acceleration due to shocks in the <span class="hlt">interplanetary</span> field: High time resolution data and simulation results</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kessel, R. L.; Armstrong, T. P.; Nuber, R.; Bandle, J.</p> <p>1985-01-01</p> <p>Data were examined from two experiments aboard the Explorer 50 (IMP 8) spacecraft. The Johns Hopkins University/Applied Lab Charged Particle Measurement Experiment (CPME) provides 10.12 second resolution ion and electron count rates as well as 5.5 minute or longer <span class="hlt">averages</span> of the same, with data sampled in the ecliptic plane. The high time resolution of the data allows for an explicit, point by point, merging of the <span class="hlt">magnetic</span> field and particle data and thus a close examination of the pre- and post-shock conditions and particle fluxes associated with large angle oblique shocks in the <span class="hlt">interplanetary</span> field. A computer simulation has been developed wherein sample particle trajectories, taken from observed fluxes, are allowed to interact with a planar shock either forward or backward in time. One event, the 1974 Day 312 shock, is examined in detail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22140113','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22140113"><span id="translatedtitle">THREE-DIMENSIONAL FEATURES OF THE OUTER HELIOSPHERE DUE TO COUPLING BETWEEN THE INTERSTELLAR AND <span class="hlt">INTERPLANETARY</span> <span class="hlt">MAGNETIC</span> FIELDS. IV. SOLAR CYCLE MODEL BASED ON ULYSSES OBSERVATIONS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pogorelov, N. V.; Zank, G. P.; Suess, S. T.; Borovikov, S. N.; Ebert, R. W.; McComas, D. J.</p> <p>2013-07-20</p> <p>The solar cycle has a profound influence on the solar wind (SW) interaction with the local interstellar medium (LISM) on more than one timescales. Also, there are substantial differences in individual solar cycle lengths and SW behavior within them. The presence of a slow SW belt, with a variable latitudinal extent changing within each solar cycle from rather small angles to 90 Degree-Sign , separated from the fast wind that originates at coronal holes substantially affects plasma in the inner heliosheath (IHS)-the SW region between the termination shock (TS) and the heliopause (HP). The solar cycle may be the reason why the complicated flow structure is observed in the IHS by Voyager 1. In this paper, we show that a substantial decrease in the SW ram pressure observed by Ulysses between the TS crossings by Voyager 1 and 2 contributes significantly to the difference in the heliocentric distances at which these crossings occurred. The Ulysses spacecraft is the source of valuable information about the three-dimensional and time-dependent properties of the SW. Its unique fast latitudinal scans of the SW regions make it possible to create a solar cycle model based on the spacecraft in situ measurements. On the basis of our analysis of the Ulysses data over the entire life of the mission, we generated time-dependent boundary conditions at 10 AU from the Sun and applied our MHD-neutral model to perform a numerical simulation of the SW-LISM interaction. We analyzed the global variations in the interaction pattern, the excursions of the TS and the HP, and the details of the plasma and <span class="hlt">magnetic</span> field distributions in the IHS. Numerical results are compared with Voyager data as functions of time in the spacecraft frame. We discuss solar cycle effects which may be reasons for the recent decrease in the TS particles (ions accelerated to anomalous cosmic-ray energies) flux observed by Voyager 1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013LatJP..50...68A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013LatJP..50...68A"><span id="translatedtitle">Low-Amplitude Anisotropic Wave Train Events during Passage of <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Clouds / Mazas Amplit?das Anizotropiju Vi??u Par?d?bu Sec?ba Starpplan?tu Magn?tisko M?ko?u Raan?s Laik?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Agarwal, R.; Mishra, R. K.</p> <p>2013-04-01</p> <p>The work presents a continuation in the series related to the long-term space observations made by ground-based neutron monitoring stations. The cosmic ray intensity variation is considered as affected by <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds during low-amplitude anisotropic wave train (LAAWT) events. It was observed that the solar wind velocity is higher than normal (> 300 km/s) while the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) strength is lower than normal on the arrival of <span class="hlt">magnetic</span> cloud during LAAWT events. The proton density is found to remain significantly low at high solar-wind velocity, which was expected. The north/south component of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field turns southward one day before the arrival of cloud and remains in this direction after that. The cosmic ray intensity is found to increase with the solar wind velocity. It is noteworthy that the cosmic ray intensity significantly increases before and 90 h after the arrival of such a cloud, and decreases gradually after its passage. The north/south component of IMF (Bz) is found to significantly correlate with latitude angle (?) and disturbance storm time index Dst, whereas the geomagnetic activity index (Ap) significantly anti-correlates with these parameters, decreasing with (?) and Dst increasing on the arrival of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> cloud during LAAWT events. Raksts ir turpin?jums darbu s?rijai par da?d?m par?d?b?m kosmos?, kas balst?tas uz nov?rojumiem un datiem, ieg?tiem da?dos laika periodos pasaules neitronu monitoringa stacij?s (Deep River, Tokija, Maskava, u.c.). Rakst? apskat?t?s kosmisko staru intensit?tes izmai?as tiek pamatotas ar starpplan?tu magn?tisko m?ko?u par?d?anos. Tiek par?d?tas saules v?ja, magn?tisk? lauka sp?ka, v?tru pertub?ciju indeksa un citu parametru atkar?ba no magn?tisko m?ko?u par?d?an?s. Tiek atz?m?ts, ka kosmisko staru intensit?te strauji pieaug pirms m?ko?u par?d?an?s un 90 stundu laik? p?c tiem, un pak?peniski samazin?s p?c to aizieanas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19940016180&hterms=1075&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231075','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940016180&hterms=1075&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231075"><span id="translatedtitle">Helium in <span class="hlt">interplanetary</span> dust particles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nier, A. O.; Schlutter, D. J.</p> <p>1993-01-01</p> <p>Helium and neon were extracted from fragments of individual stratosphere-collected <span class="hlt">interplanetary</span> dust particles (IDP's) by subjecting them to increasing temperature by applying short-duration pulses of power in increasing amounts to the ovens containing the fragments. The experiment was designed to see whether differences in release temperatures could be observed which might provide clues as to the asteroidal or cometary origin of the particles. Variations were observed which show promise for elucidating the problem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ApJ...734....7R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ApJ...734....7R"><span id="translatedtitle">The Solar Origin of Small <span class="hlt">Interplanetary</span> Transients</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rouillard, A. P.; Sheeley, N. R., Jr.; Cooper, T. J.; Davies, J. A.; Lavraud, B.; Kilpua, E. K. J.; Skoug, R. M.; Steinberg, J. T.; Szabo, A.; Opitz, A.; Sauvaud, J.-A.</p> <p>2011-06-01</p> <p>In this paper, we present evidence for <span class="hlt">magnetic</span> transients with small radial extents ranging from 0.025 to 0.118 AU measured in situ by the Solar-Terrestrial Relations Observatory (STEREO) and the near-Earth Advanced Composition Explorer (ACE) and Wind spacecraft. The transients considered in this study are much smaller (<0.12 AU) than the typical sizes of <span class="hlt">magnetic</span> clouds measured near 1 AU (~0.23 AU). They are marked by low plasma beta values, generally lower <span class="hlt">magnetic</span> field variance, short timescale <span class="hlt">magnetic</span> field rotations, and are all entrained by high-speed streams by the time they reach 1 AU. We use this entrainment to trace the origin of these small <span class="hlt">interplanetary</span> transients in coronagraph images. We demonstrate that these <span class="hlt">magnetic</span> field structures originate as either small or large mass ejecta. The small mass ejecta often appear from the tip of helmet streamers as arch-like structures and other poorly defined white-light features (the so-called blobs). However, we have found a case of a small <span class="hlt">magnetic</span> transient tracing back to a small and narrow mass ejection erupting from below helmet streamers. Surprisingly, one of the small <span class="hlt">magnetic</span> structures traces back to a large mass ejection; in this case, we show that the central axis of the coronal mass ejection is along a different latitude and longitude to that of the in situ spacecraft. The small size of the transient is related to the in situ measurements being taken on the edges or periphery of a larger <span class="hlt">magnetic</span> structure. In the last part of the paper, an ejection with an arch-like aspect is tracked continuously to 1 AU in the STEREO images. The associated in situ signature is not that of a <span class="hlt">magnetic</span> field rotation but rather of a temporary reversal of the <span class="hlt">magnetic</span> field direction. Due to its "open-field topology," we speculate that this structure is partly formed near helmet streamers due to reconnection between closed and open <span class="hlt">magnetic</span> field lines. The implications of these observations for our understanding of the variability of the slow solar wind are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010cosp...38.1924W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.1924W"><span id="translatedtitle">Imaging <span class="hlt">Interplanetary</span> CMEs at Radio Frequency From Solar Polar Orbit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wu, Ji; Sun, Weiying; Zheng, Jianhua; Zhang, Cheng; Wang, Chi; Wang, C. B.; Wang, S.</p> <p></p> <p>Coronal mass ejections (CMEs) are violent discharges of plasma and <span class="hlt">magnetic</span> fields from the Sun's corona. They have come to be recognized as the major driver of physical conditions in the Sun-Earth system. Consequently, the detection of CMEs is important for un-derstanding and ultimately predicting space weather conditions. The Solar Polar Orbit Radio Telescope (SPORT) is a proposed mission to observe the propagation of <span class="hlt">interplanetary</span> CMEs from solar polar orbit. The main payload (radio telescope) on board SPORT will be an in-terferometric imaging radiometer working at the meter wavelength band, which will follow the propagation of <span class="hlt">interplanetary</span> CMEs from a distance of a few solar radii to near 1 AU from solar polar orbit. The SPORT spacecraft will also be equipped with a set of optical and in situ measurement instruments such as a EUV solar telescope, a solar wind plasma experiment, a solar wind ion composition instrument, an energetic particle detector, a wave detector, a mag-netometer and an <span class="hlt">interplanetary</span> radio burst tracker. In this paper, we first describe the current shortage of <span class="hlt">interplanetary</span> CME observations. Next, the scientific motivation and objectives of SPORT are introduced. We discuss the basic specifications of the main radio telescope of SPORT with reference to the radio emission mechanisms and the radio frequency band to be observed. Finally, we discuss the key technologies of the SPORT mission, including the con-ceptual design of the main telescope, the image retrieval algorithm and the solar polar orbit injection. Other payloads and their respective observation objectives are also briefly discussed. Key words: <span class="hlt">Interplanetary</span> CMEs; Interferometric imaging; Solar polar orbit; Radiometer.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013IAUS..294..487L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013IAUS..294..487L"><span id="translatedtitle">Observations of <span class="hlt">interplanetary</span> scintillation in China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Li-Jia; Peng, Bo</p> <p>2013-07-01</p> <p>The Sun affects the Earth in multiple ways. In particular, the material in <span class="hlt">interplanetary</span> space comes from coronal expansion in the form of solar wind, which is the primary source of the <span class="hlt">interplanetary</span> medium. Ground-based <span class="hlt">Interplanetary</span> Scintillation (IPS) observations are an important and effective method for measuring solar wind speed and the structures of small diameter radio sources. In this paper we will discuss the IPS observations in China.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014IAUS..300..397B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014IAUS..300..397B"><span id="translatedtitle">24 synoptic maps 1974-1982 (ascending phase of cycle XXI) of 323 prominence <span class="hlt">average</span> <span class="hlt">magnetic</span> fields measured by the Hanle effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bommier, Véronique</p> <p>2014-01-01</p> <p>The poster was made of 323 <span class="hlt">average</span> prominence <span class="hlt">magnetic</span> fields reported on 24 synoptic maps. The paper first resumes the methods for the field derivation, and the different results of the whole program of these second generation Hanle effect observations. From their conclusions, it was possible to derive a unique field vector for each of the 323 prominences. The maps put in evidence a large scale structure of the prominence <span class="hlt">magnetic</span> field, probably distorted by the differential rotation, which leads to a systematically small angle (on the order of 30°) between the field vector and the prominence long axis.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_16 --> <div id="page_17" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="321"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20070017872','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20070017872"><span id="translatedtitle">Quaternion <span class="hlt">Averaging</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Markley, F. Landis; Cheng, Yang; Crassidis, John L.; Oshman, Yaakov</p> <p>2007-01-01</p> <p>Many applications require an algorithm that <span class="hlt">averages</span> quaternions in an optimal manner. For example, when combining the quaternion outputs of multiple star trackers having this output capability, it is desirable to properly <span class="hlt">average</span> the quaternions without recomputing the attitude from the the raw star tracker data. Other applications requiring some sort of optimal quaternion <span class="hlt">averaging</span> include particle filtering and multiple-model adaptive estimation, where weighted quaternions are used to determine the quaternion estimate. For spacecraft attitude estimation applications, derives an optimal <span class="hlt">averaging</span> scheme to compute the <span class="hlt">average</span> of a set of weighted attitude matrices using the singular value decomposition method. Focusing on a 4-dimensional quaternion Gaussian distribution on the unit hypersphere, provides an approach to computing the <span class="hlt">average</span> quaternion by minimizing a quaternion cost function that is equivalent to the attitude matrix cost function Motivated by and extending its results, this Note derives an algorithm that deterniines an optimal <span class="hlt">average</span> quaternion from a set of scalar- or matrix-weighted quaternions. Rirthermore, a sufficient condition for the uniqueness of the <span class="hlt">average</span> quaternion, and the equivalence of the mininiization problem, stated herein, to maximum likelihood estimation, are shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060037611&hterms=Solar+activity+solar+cycle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DSolar%2Bactivity%2Bsolar%2Bcycle','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060037611&hterms=Solar+activity+solar+cycle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DSolar%2Bactivity%2Bsolar%2Bcycle"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Origin of Geomagnetic Activity in the Declining Phase of the Solar Cycle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tsurutani, B. T.; Gonzalez, W. D.; Gonzalez, A. L. C.; Tang, F.; Arballo, J. K.; Okada, M.</p> <p>1995-01-01</p> <p><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field and plasma data are compared with ground-based geomagnetic Dst and AE indices to determine the causes of <span class="hlt">magnetic</span> storms, substorms, and quiet during the descending phase of the solar cycle. The primary focus is on 1974 data characterized by the presence of two long-lasting corotating streams associated with coronal holes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AIPC.1670c0015K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AIPC.1670c0015K"><span id="translatedtitle">The dynamics of solar plasma events and their <span class="hlt">interplanetary</span> consequences</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kaushik, Subhash Chandra; Sharma, Giriraj</p> <p>2015-07-01</p> <p>In the present study we have analyzed the <span class="hlt">interplanetary</span> plasma / field parameter, which have initiated the complex nature intense and highly geo-effective events in the magnetosphere. It is believed that Solar wind velocity V. <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) B and Bz are the crucial drivers of these activities. However, sometimes strong geomagnetic disturbance is associated with the interaction between slow and fast solar wind streams originating from coronal holes leads to create co-rotating plasma interaction region (CIR). Thus the dynamics of the magnetospheric plasma configuration is the reflection of measured solar wind and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) conditions. While the magnetospheric plasma anomalies are generally represented by geomagnetic storms and sudden ionosphere disturbance (SIDs). The study considers 220 geomagnetic storms associated with disturbance storm time (Dst) decrease of more than -50 nT to -300 nT, observed during solar cycle 23 and the ascending phase of solar cycle 24. These have been analyzed and studied statistically. The spacecraft data acquired by space satellites and those provided by World Data Center (WDC) - A and geomagnetic stations data from WDC- C, Kyoto are utilized in the study. It is observed that the yearly occurrences of geomagnetic storm are strongly correlated with sunspot cycle, however we have not found any significant correlation between the maximum and minimum phase of solar cycle. It is also inferred from the results that solar cycle-23 was remarkable for occurrence of intense geomagnetic storms during its descending phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009EGUGA..11.6517J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009EGUGA..11.6517J"><span id="translatedtitle">Long-Term Observations of Stream Interaction Regions and <span class="hlt">Interplanetary</span> Coronal Mass Ejections: Venus, Earth, and Jupiter Orbits</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jian, L. K.; Russell, C. T.; Luhmann, J. G.; Skoug, R. M.; Steinberg, J. T.</p> <p>2009-04-01</p> <p>Two types of large-scale solar wind structures, stream interaction regions (SIRs) and <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs), can drive <span class="hlt">interplanetary</span> shocks, generate or accelerate energetic particles, and affect the planetary ionosphere and/or magnetosphere. To quantify the properties of SIRs and ICMEs at different heliocentric distances, we have identified and characterized these structures based on consistent criteria using the in situ plasma and <span class="hlt">magnetic</span> field observations. The data sets used are Pioneer Venus Orbiter at 0.72 AU (1979 - 1988), Wind/ACE at 1 AU (1995 - 2006), and three Ulysses aphelion passes at 5.3 AU (partial 1992, 1997 - 1998, 2003 - 2005, representing slices at different phases of the solar cycle). The long-term observations enable us to study the solar cycle variations of these two structures. The parameters relevant to space weather modeling, such as the structure duration, width, maximum dynamic pressure, maximum <span class="hlt">magnetic</span> field intensity, <span class="hlt">average</span> speed, speed variation, and other properties of SIRs and ICMEs are all examined at each distance. ICMEs can generally affect the planetary environment more than SIRs at Venus and Earth, especially around solar maximum. However, when they propagate to 5.3 AU, some ICMEs and SIRs merge and form hybrid events at Jupiter. In general, SIRs have greater dynamic pressure, interaction strength and field intensity than ICMEs at Jupiter, and therefore they affect the space environment more than ICMEs there.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050180487','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050180487"><span id="translatedtitle">Propagation of <span class="hlt">Interplanetary</span> Disturbances in the Outer Heliosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wang, Chi</p> <p>2005-01-01</p> <p>Contents include the following: 1. We have developed a one-dimensional, spherically symmetric, multi-fluid MHD model that includes solar wind protons and electrons, pickup ions, and interstellar neutral hydrogen. This model advances the existing solar wind models for the outer heliosphere in two important ways: one is that it distinguishes solar wind protons from pickup ions, and the other is that it allows for energy transfer from pickup ions to the solar wind protons. Model results compare favorably with the Voyager 2 observations. 2. 2. Solar wind slowdown and interstellar neutral density. The solar wind in the outer heliosphere is fundamentally different from that in the inner heliosphere since the effects of interstellar neutrals become significant. 3. ICME propagation from the inner to outer heliosphere. Large coronal mass ejections (CMEs) have major effects on the structure of the solar wind and the heliosphere. The plasma and <span class="hlt">magnetic</span> field can be compressed ahead of <span class="hlt">interplanetary</span> CMEs. 4. During the current solar cycle (Cycle 23), several major CMEs associated with solar flares produced large transient shocks which were observed by widely-separated spacecraft such as Wind at Earth and Voyager 2 beyond 60 AU. Using data from these spacecraft, we use the multi-fluid model to investigate shock propagation and interaction in the heliosphere. Specifically, we studied the Bastille Day 2000, April 2001 and Halloween 2003 events. 5. Statistical properties of the solar wind in the outer heliosphere. In a collaboration with L.F. Burlaga of GSFC, it is shown that the basic statistical properties of the solar wind in the outer heliosphere can be well produced by our model. We studied the large-scale heliospheric <span class="hlt">magnetic</span> field strength fluctuations as a function of distance from the Sun during the declining phase of a solar cycle, using our numerical model with observations made at 1 AU during 1995 as input. 6. Radial heliospheric <span class="hlt">magnetic</span> field events. The heliospheric <span class="hlt">magnetic</span> field (HMF) direction, on <span class="hlt">average</span>, conforms well to the Parker spiral.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996LPI....27.1285S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996LPI....27.1285S"><span id="translatedtitle">Porosity of <span class="hlt">Interplanetary</span> Dust Particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Strait, M. M.; Thomas, K. L.; McKay, D. S.</p> <p>1996-03-01</p> <p>We report here new information from our studies on the porosity of <span class="hlt">interplanetary</span> dust particles. We have resolved some of the problems we encountered earlier and we report new results for four hydrated IDPs and two meteorites. Determination of the porosity of IDPs is important in the dynamics of collisional and orbital evolution of small-sized particles. We are using an image analysis method to make these determinations from digitized photographs of thin-sectioned particles. Earlier determinations of porosity were derived from measures of density and suggested that particles had appreciable porosity, but that porosities were probably less than 70%.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110005580','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110005580"><span id="translatedtitle">Atypical Particle Heating at a Supercritical <span class="hlt">Interplanetary</span> Shock</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, Lynn B., III</p> <p>2010-01-01</p> <p>We present the first observations at an <span class="hlt">interplanetary</span> shock of large amplitude (> 100 mV/m pk-pk) solitary waves and large amplitude (approx.30 mV/m pk-pk) waves exhibiting characteristics consistent with electron Bernstein waves. The Bernstein-like waves show enhanced power at integer and half-integer harmonics of the cyclotron frequency with a broadened power spectrum at higher frequencies, consistent with the electron cyclotron drift instability. The Bernstein-like waves are obliquely polarized with respect to the <span class="hlt">magnetic</span> field but parallel to the shock normal direction. Strong particle heating is observed in both the electrons and ions. The observed heating and waveforms are likely due to instabilities driven by the free energy provided by reflected ions at this supercritical <span class="hlt">interplanetary</span> shock. These results offer new insights into collisionless shock dissipation and wave-particle interactions in the solar wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.642a2016M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.642a2016M"><span id="translatedtitle">Modeling solar wind with boundary conditions from <span class="hlt">interplanetary</span> scintillations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manoharan, P.; Kim, T.; Pogorelov, N. V.; Arge, C. N.; Manoharan, P. K.</p> <p>2015-09-01</p> <p><span class="hlt">Interplanetary</span> scintillations make it possible to create three-dimensional, time- dependent distributions of the solar wind velocity. Combined with the <span class="hlt">magnetic</span> field observations in the solar photosphere, they help perform solar wind simulations in a genuinely time-dependent way. <span class="hlt">Interplanetary</span> scintillation measurements from the Ooty Radio Astronomical Observatory in India provide directions to multiple stars and may assure better resolution of transient processes in the solar wind. In this paper, we present velocity distributions derived from Ooty observations and compare them with those obtained with the Wang-Sheeley-Arge (WSA) model. We also present our simulations of the solar wind flow from 0.1 AU to 1 AU with the boundary conditions based on both Ooty and WSA data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM31D4242K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM31D4242K"><span id="translatedtitle">Magnetospheric and Ground Response to a Strong <span class="hlt">Interplanetary</span> Shock</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Korotova, G. I.; Sibeck, D. G.</p> <p>2014-12-01</p> <p>We present results from a study of <span class="hlt">interplanetary</span> shock observations by eleven spacecraft and more than fifty ground stations in both hemispheres near 1650 UT on January 19, 2013. The solar wind density observed by Wind increased from 6 to 20 cm-3, and the dynamic pressure increased from 1 to 6 nPa. The IMF had a spiral orientation. We timed the propagation of the shock through <span class="hlt">interplanetary</span> space and into the inner magnetosphere. It took about 1 min for the shock to propagate from the dayside to the nightside magnetosphere where the compressions were accompanied by three cycles of toroidal Pc5 oscillations in the azimuthal component of the <span class="hlt">magnetic</span> field observed by Van Allen Probes A and B. The ground response to the shock was very pronounced, global, and depended on the location of the observing station. Some stations observed location-dependent periodic oscillations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002cosp...34E.347E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002cosp...34E.347E"><span id="translatedtitle"><span class="hlt">Interplanetary</span> shocks and sudden impulses in solar maximum (2000) and solar minimum (1995-1996)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Echer, E.; Gonzalez, W.; dal Lago, A.; Vieira, L.; Guarnieri, F.; Prestes, A.; Gonzalez, A.; Schuch, N.</p> <p></p> <p>In this work a study is presented on the correlation between fast forward <span class="hlt">interplanetary</span> shock parameters and sudden impulse (SI) amplitude in the H-component of the geomagnetic field, for periods of maximum (2000) and minimum (1995-1996) solar activity. Solar wind temperature, density and speed, and total <span class="hlt">magnetic</span> field, as well static (thermal and <span class="hlt">magnetic</span>) and dynamic pressures, were calculated in the upstream and downstream sides of the shock. The variation of the solar wind parameters and pressures was then correlated with SI amplitude. For the solar wind pressures, the difference between upstream and downstream square root values was taken, because in the balance pressure expression, the solar wind pressures are equal to the geomagnetic <span class="hlt">magnetic</span> field pressure, that is proportional to the square <span class="hlt">magnetic</span> field (and squared SI amplitude). The solar wind speed have showed good correlations with sudden impulse, with correlation coefficients higher than 0.70 both in solar maximum and solar minimum, whereas the solar wind density presented a poor correlation. The better correlated parameter with SI was the square root dynamic pressure variation, showing a higher correlation in solar maximum ( r = 0.82) than in solar minimum (r = 0.77). The correlations of SI with square root thermal and <span class="hlt">magnetic</span> pressure was lower than with the dynamic pressure, but they also present a good correlation, with r > 0.70 both in solar maximum and minimum. Multiple correlation anaylsis of SI in terms of the three pressure terms resulted in that 78% and 85% of the variance in SI at solar maximum and minimum, respectively, are explained by the three pressure variations. <span class="hlt">Average</span> sudden impulse amplitude was 25 nT in solar maximum and 20.9 nT in solar minimum, while square root dynamic pressure variation is 1.2 nPa1/2 at solar maximum and 0.9 nPa1/2 at solar minimum. Thus on <span class="hlt">average</span>, fast forward <span class="hlt">interplanetary</span> shocks are 33% stronger (in therms of squared root dynamic pressure variation) in solar maximum than in solar minimum, and the magnetospheric SI response had an amplitude 20% higher in solar maximum than in solar minimum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880052777&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dluhmann','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880052777&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dluhmann"><span id="translatedtitle">Solar and <span class="hlt">interplanetary</span> control of the location of the Venus bow shock</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Russell, C. T.; Chou, E.; Luhmann, J. G.; Gazis, P.; Brace, L. H.; Hoegy, W. R.</p> <p>1988-01-01</p> <p>The Venus bow shock location has been measured at nearly 2000 shock crossings, and its dependence on solar EUV, solar wind conditions, and the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field determined. The shock position at the terminator varies from about 2.14 Venus radii at solar minimum to 2.40 Venus radii at solar maximum. The location of the shock varies little with solar wind dynamic pressure but strongly with solar wind Mach number. The shock is farthest from Venus on the side of the planet in which newly created ions gyrate away from the ionosphere. When the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is perpendicular to the flow, the cross section of the shock is quite elliptical. This effect appears to be due to the anisotropic propagation of the fast magnetosonic wave. When the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is aligned with the flow, the bow shock cross section is circular and only weakly sensitive to changing EUV flux.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.1062B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.1062B"><span id="translatedtitle">STEREO database of <span class="hlt">interplanetary</span> Langmuir electric waveforms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Briand, C.; Henri, P.; Génot, V.; Lormant, N.; Dufourg, N.; Cecconi, B.; Nguyen, Q. N.; Goetz, K.</p> <p>2016-02-01</p> <p>This paper describes a database of electric waveforms that is available at the Centre de Données de la Physique des Plasmas (CDPP, http://cdpp.eu/). This database is specifically dedicated to waveforms of Langmuir/Z-mode waves. These waves occur in numerous kinetic processes involving electrons in space plasmas. Statistical analysis from a large data set of such waves is then of interest, e.g., to study the relaxation of high-velocity electron beams generated at <span class="hlt">interplanetary</span> shock fronts, in current sheets and <span class="hlt">magnetic</span> reconnection region, the transfer of energy between high and low frequencies, the generation of electromagnetic waves. The Langmuir waveforms were recorded by the Time Domain Sampler (TDS) of the WAVES radio instrument on board the STEREO mission. In this paper, we detail the criteria used to identify the Langmuir/Z-mode waves among the whole set of waveforms of the STEREO spacecraft. A database covering the November 2006 to August 2014 period is provided. It includes electric waveforms expressed in the normalized frame (B,B × Vsw,B × (B × Vsw)) with B and Vsw the local <span class="hlt">magnetic</span> field and solar wind velocity vectors, and the local <span class="hlt">magnetic</span> field in the variance frame, in an interval of ±1.5 min around the time of the Langmuir event. Quicklooks are also provided that display the three components of the electric waveforms together with the spectrum of E∥, together with the magnitude and components of the <span class="hlt">magnetic</span> field in the 3 min interval, in the variance frame. Finally, the distribution of the Langmuir/Z-mode waves peak amplitude is also analyzed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850012177&hterms=modulated+structures&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmodulated%2Bstructures','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850012177&hterms=modulated+structures&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dmodulated%2Bstructures"><span id="translatedtitle">Dependence of the High Latitude Middle Atmosphere Ionization on Structures in <span class="hlt">Interplanetary</span> Space</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bremer, J.; Lauter, E. A.</p> <p>1984-01-01</p> <p>The precipitation of high energetic electrons during and after strong geomagnetic storms into heights below 100 km in middle and subauroral latitudes is markedly modulated by the structure of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). Under relative quiet conditions the D-region ionization caused by high energetic particle precipitation (energies greater than 20 to 50 keV) depends on changes of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and also on the velocity of the solar wind. To test this assumption, the influence of the IMF-sector boundary crossings on ionospheric absorption data of high and middle latitudes by the superposed-epoch method was investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SoPh..290.1371M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SoPh..290.1371M"><span id="translatedtitle">Geometrical Relationship Between <span class="hlt">Interplanetary</span> Flux Ropes and Their Solar Sources</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Marubashi, K.; Akiyama, S.; Yashiro, S.; Gopalswamy, N.; Cho, K.-S.; Park, Y.-D.</p> <p>2015-05-01</p> <p>We investigated the physical connection between <span class="hlt">interplanetary</span> flux ropes (IFRs) near Earth and coronal mass ejections (CMEs) by comparing the <span class="hlt">magnetic</span> field structures of IFRs and CME source regions. The analysis is based on the list of 54 pairs of ICMEs (<span class="hlt">interplanetary</span> coronal mass ejections) and CMEs that are taken to be the most probable solar source events. We first attempted to identify the flux rope structure in each of the 54 ICMEs by fitting models with a cylinder and torus <span class="hlt">magnetic</span> field geometry, both with a force-free field structure. This analysis determined the possible geometries of the identified flux ropes. Then we compared the flux rope geometries with the <span class="hlt">magnetic</span> field structure of the solar source regions. We obtained the following results: (1) Flux rope structures are seen in 51 ICMEs out of the 54. The result implies that all ICMEs have an intrinsic flux rope structure, if the three exceptional cases are attributed to unfavorable observation conditions. (2) It is possible to find flux rope geometries with the main axis orientation close to the orientation of the <span class="hlt">magnetic</span> polarity inversion line (PIL) in the solar source regions, the differences being less than 25. (3) The helicity sign of an IFR is strongly controlled by the location of the solar source: flux ropes with positive (negative) helicity are associated with sources in the southern (northern) hemisphere (six exceptions were found). (4) Over two-thirds of the sources in the northern hemisphere are concentrated along PILs with orientations of 45 30 (measured clockwise from the east), and over two-thirds in the southern hemisphere along PILs with orientations of 135 30, both corresponding to the Hale boundaries. These results strongly support the idea that a flux rope with the main axis parallel to the PIL erupts in a CME and that the erupted flux rope propagates through the <span class="hlt">interplanetary</span> space with its orientation maintained and is observed as an IFR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021314&hterms=energy+energy+conservation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Denergy%2Benergy%2Bconservation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021314&hterms=energy+energy+conservation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Denergy%2Benergy%2Bconservation"><span id="translatedtitle"><span class="hlt">Magnetic</span> clouds, helicity conservation, and intrinsic scale flux ropes</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kumar, A.; Rust, D. M.</p> <p>1995-01-01</p> <p>An intrinsic-scale flux-rope model for <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds, incorporating conservation of <span class="hlt">magnetic</span> helicity, flux and mass is found to adequately explain clouds' <span class="hlt">average</span> thermodynamic and <span class="hlt">magnetic</span> properties. In spite their continuous expansion as they balloon into <span class="hlt">interplanetary</span> space, <span class="hlt">magnetic</span> clouds maintain high temperatures. This is shown to be due to <span class="hlt">magnetic</span> energy dissipation. The temperature of an expanding cloud is shown to pass through a maximum above its starting temperature if the initial plasma beta in the cloud is less than 2/3. Excess <span class="hlt">magnetic</span> pressure inside the cloud is not an important driver of the expansion as it is almost balanced by the tension in the helical field lines. It is conservation of <span class="hlt">magnetic</span> helicity and flux that requires that clouds expand radially as they move away from the Sun. Comparison with published data shows good agreement between measured cloud properties and theory. Parameters determined from theoretical fits to the data, when extended back to the Sun, are consistent with the origin of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds in solar filament eruptions. A possible extension of the heating mechanism discussed here to heating of the solar corona is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6000225','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6000225"><span id="translatedtitle">Remote sensing of <span class="hlt">interplanetary</span> shocks using a scintillation method</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hewish, A.</p> <p>1987-05-01</p> <p>Energetic <span class="hlt">interplanetary</span> disturbances originating at the Sun cause geomagnetic storms when they reach the Earth. The disturbances affect radio-communications, damage electrical power grid networks, increase the atmospheric density and drag on satellites, and are accompanied by showers of energetic particles which present radiation hazards to manned spacecraft. This paper describes a new ground-based method for locating and tracking transients in <span class="hlt">interplanetary</span> space long before they reach the Earth. Continuous observations of transients during a two year period near support maximum have demonstrated the potential of the technique for predicting geomagnetic storms and given new information on the zones of the solar disk from which transients originate. The latter contradicts some widely held theories in solar-terrestrial physics and shows that a major revision of ideas is needed. Contrary to expectations, it has been found that open-<span class="hlt">magnetic</span> field regions known as coronal holes are the dominant sources of the most powerful <span class="hlt">interplanetary</span> shocks. This result conflicts with the solar flare theory of geomagnetic storms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...803...96S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...803...96S"><span id="translatedtitle">First Taste of Hot Channel in <span class="hlt">Interplanetary</span> Space</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Song, H. Q.; Zhang, J.; Chen, Y.; Cheng, X.; Li, G.; Wang, Y. M.</p> <p>2015-04-01</p> <p>A hot channel (HC) is a high temperature (˜10 MK) structure in the inner corona first revealed by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory. Eruptions of HCs are often associated with flares and coronal mass ejections (CMEs). Results of previous studies have suggested that an HC is a good proxy for a <span class="hlt">magnetic</span> flux rope (MFR) in the inner corona as well as another well known MFR candidate, the prominence-cavity structure, which has a normal coronal temperature (˜1-2 MK). In this paper, we report a high temperature structure (HTS, ˜1.5 MK) contained in an <span class="hlt">interplanetary</span> CME induced by an HC eruption. According to the observations of bidirectional electrons, high temperature and density, strong <span class="hlt">magnetic</span> field, and its association with the shock, sheath, and plasma pile-up region, we suggest that the HTS is the <span class="hlt">interplanetary</span> counterpart of the HC. The scale of the measured HTS is around 14 R ⊙ , and it maintained a much higher temperature than the background solar wind even at 1 AU. It is significantly different from the typical <span class="hlt">magnetic</span> clouds, which usually have a much lower temperature. Our study suggests that the existence of a corotating interaction region ahead of the HC formed a <span class="hlt">magnetic</span> container to inhibit expansion of the HC and cool it down to a low temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EP%26S...67...11I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EP%26S...67...11I"><span id="translatedtitle">A new leveling method without the direct use of crossover data and its application in marine <span class="hlt">magnetic</span> surveys: weighted spatial <span class="hlt">averaging</span> and temporal filtering</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ishihara, Takemi</p> <p>2015-12-01</p> <p>The author has developed a new leveling method for use with <span class="hlt">magnetic</span> survey data, which consists of adjusting each measurement using the weighted spatial <span class="hlt">average</span> of its neighboring data and subsequent temporal filtering. There are two key parameters in the method: the `weight distance' represents the characteristic distance of the weight function and the `filtering width' represents the full width of the Gaussian filtering function on the time series. This new method was applied to three examples of actual marine survey data. Leveling using optimum values of these two parameters for each example was found to significantly reduce the standard deviations of crossover differences by one third to one fifth of the values before leveling. The obtained time series of correction values for each example had a good correlation with the <span class="hlt">magnetic</span> observatory data obtained relatively close to the survey areas, thus validating this new leveling method.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6141713','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6141713"><span id="translatedtitle">Infrared emission from <span class="hlt">interplanetary</span> dust</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Temi, P.; De Bernardis, P.; Masi, S.; Moreno, G.; Salama, A.</p> <p>1989-02-01</p> <p>Standard models of the <span class="hlt">interplanetary</span> dust emission fail to account satisfactorily for IR observations. A new model of the dust, based on very simple assumptions on the grain structure (spherical and homogeneous) and chemical composition (astronomical silicates, graphite, blackbodies) is developed. Updated values of the refractive indexes have been included in the analysis. The predictions of the model (absolute values of the fluxes, spectral shape, elongation dependence of the emission) have then been compared with all the available IR observations performed by the ARGO (balloon-borne experiment by University of Rome), AFGL and Zodiacal Infrared Project (ZIP) (rocket experiments by Air Force Geophysics Laboratory, Bedford, Mass.), and IRAS satellite. Good agreement is found when homogeneous data sets from single experiments (e.g., ZIP and ARGO) are considered separately. 19 references.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19910021741','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19910021741"><span id="translatedtitle">Volatiles in <span class="hlt">interplanetary</span> dust particles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bustin, Roberta</p> <p>1991-01-01</p> <p><span class="hlt">Interplanetary</span> dust particles (IDP's) collected by specially equipped aircraft flying in the stratosphere have generated a lot of interest during the last decade. These particles, consisting of primitive materials originating in small solar system bodies such as comets and asteroids, are complex heterogeneous species with a variety of components. In order to understand the past histories of IDP's, it is particularly important to know the nature of the volatiles present. Volatiles released from a number of IDP's have been studied; however, a large number of particles must be studied in order to establish trends, to classify types of IDP's, and to have comparison data for determining the origins of IDP's. This study involves the analysis of six IDP's using laser microprobe mass spectrometry.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li class="active"><span>17</span></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_17 --> <div id="page_18" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="341"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1985ASSL..119..117S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1985ASSL..119..117S"><span id="translatedtitle">The LDEF <span class="hlt">Interplanetary</span> Dust Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Singer, S. F.; Stanley, J. E.; Kassel, P.</p> <p></p> <p>The Long Duration Exposure Facility was launched for the first time on April 6, 1984 by the NASA space shuttle Challenger. An array of solid-state detectors record the arrival time and approximate direction of an impacting particle. Two levels of detector sensitivity provide an indication of particle energy and mass. The orbit of the particle cannot be obtained, except statistically. To study the fate and origin of IP (<span class="hlt">interplanetary</span>) dust, the authors measure various kinds of time variations. Among the most interesting is the secular variations, i.e., the flux in various meteor streams, as a function of the passage of a comet. One of the challenging problems will be to distinguish IP dust from man-made space debris.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110012255','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110012255"><span id="translatedtitle">CFDP for <span class="hlt">Interplanetary</span> Overlay Network</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burleigh, Scott C.</p> <p>2011-01-01</p> <p>The CCSDS (Consultative Committee for Space Data Systems) File Delivery Protocol for <span class="hlt">Interplanetary</span> Overlay Network (CFDP-ION) is an implementation of CFDP that uses IO' s DTN (delay tolerant networking) implementation as its UT (unit-data transfer) layer. Because the DTN protocols effect automatic, reliable transmission via multiple relays, CFDP-ION need only satisfy the requirements for Class 1 ("unacknowledged") CFDP. This keeps the implementation small, but without loss of capability. This innovation minimizes processing resources by using zero-copy objects for file data transmission. It runs without modification in VxWorks, Linux, Solaris, and OS/X. As such, this innovation can be used without modification in both flight and ground systems. Integration with DTN enables the CFDP implementation itself to be very simple; therefore, very small. Use of ION infrastructure minimizes consumption of storage and processing resources while maximizing safety.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JGRA..119.8188O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JGRA..119.8188O"><span id="translatedtitle">Impact angle control of <span class="hlt">interplanetary</span> shock geoeffectiveness</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oliveira, D. M.; Raeder, J.</p> <p>2014-10-01</p> <p>We use Open Geospace General Circulation Model global MHD simulations to study the nightside magnetospheric, magnetotail, and ionospheric responses to <span class="hlt">interplanetary</span> (IP) fast forward shocks. Three cases are presented in this study: two inclined oblique shocks, hereafter IOS-1 and IOS-2, where the latter has a Mach number twice stronger than the former. Both shocks have impact angles of 30 in relation to the Sun-Earth line. Lastly, we choose a frontal perpendicular shock, FPS, whose shock normal is along the Sun-Earth line, with the same Mach number as IOS-1. We find that, in the IOS-1 case, due to the north-south asymmetry, the magnetotail is deflected southward, leading to a mild compression. The geomagnetic activity observed in the nightside ionosphere is then weak. On the other hand, in the head-on case, the FPS compresses the magnetotail from both sides symmetrically. This compression triggers a substorm allowing a larger amount of stored energy in the magnetotail to be released to the nightside ionosphere, resulting in stronger geomagnetic activity. By comparing IOS-2 and FPS, we find that, despite the IOS-2 having a larger Mach number, the FPS leads to a larger geomagnetic response in the nightside ionosphere. As a result, we conclude that IP shocks with similar upstream conditions, such as <span class="hlt">magnetic</span> field, speed, density, and Mach number, can have different geoeffectiveness, depending on their shock normal orientation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM31D4226O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM31D4226O"><span id="translatedtitle">Impact Angle Control of <span class="hlt">Interplanetary</span> Shock Geoeffectiveness</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oliveira, D.; Raeder, J.</p> <p>2014-12-01</p> <p>We use OpenGGCM global MHD simulations to study the nightside magnetospheric/ magnetotail/ ionospheric responses to <span class="hlt">interplanetary</span> (IP) fast foward shocks. Three cases are presented in this study: two inclined oblique shocks, hereafter IOS-1 and IOS-2, where the latter has a Mach number twice stronger than the former. Both shocks have impact angles of 30o in relation to the Sun-Earth line. Lastly, we choose a frontal perpendicular shock, FPS, whose shock normal is along th Sun-Earth line, with the same Mach number as IOS-1. We find that, in the IOS-1 case, due to the north-south asymmetry, the magnetotail is deflected southward, leading to a mild compression. The geomagnetic activity observed in the nightside ionosphere is then weak. On the other hand, in the head-on case, the FPS compresses the magnetotail on both sides symmetrically. This compression triggers a substorm allowing a larger amount of stored energy in the magnetotail to be released to the nightside ionosphere, resulting in a larger geomagnetic activity there. By comparing IOS-2 and FPS, we find that, despite the IOS-2 having a larger Mach number, the FPS leads to larger geomagnetic responses in the ionosphere nightside. As a result, we conclude that IP shocks with similar upstream conditions, such as <span class="hlt">magnetic</span> field, speed, density, and even Mach number, can be differently geoeffective, depending on their shock normal orientation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoRL..42.6554C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoRL..42.6554C"><span id="translatedtitle"><span class="hlt">Interplanetary</span> shocks and the resulting geomagnetically induced currents at the equator</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carter, B. A.; Yizengaw, E.; Pradipta, R.; Halford, A. J.; Norman, R.; Zhang, K.</p> <p>2015-08-01</p> <p>Geomagnetically induced currents (GICs) caused by <span class="hlt">interplanetary</span> shocks represent a serious space weather threat to modern technological infrastructure. The arrival of <span class="hlt">interplanetary</span> shocks drives magnetosphere and ionosphere current systems, which then induce electric currents at ground level. The impact of these currents at high latitudes has been extensively researched, but the <span class="hlt">magnetic</span> equator has been largely overlooked. In this paper, we investigate the potential effects of <span class="hlt">interplanetary</span> shocks on the equatorial region and demonstrate that their <span class="hlt">magnetic</span> signature is amplified by the equatorial electrojet. This local amplification substantially increases the region's susceptibility to GICs. Importantly, this result applies to both geomagnetic storms and quiet periods and thus represents a paradigm shift in our understanding of adverse space weather impacts on technological infrastructure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012cosp...39.1998T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012cosp...39.1998T"><span id="translatedtitle">Shielding Structures for <span class="hlt">Interplanetary</span> Human Mission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tracino, Emanuele; Lobascio, Cesare</p> <p>2012-07-01</p> <p>Since the end of Apollo missions, human spaceflight has been limited to the Low Earth Orbit (LEO), inside the protective <span class="hlt">magnetic</span> field of the Earth, because astronauts are, to the largest degree, protected from the harsh radiation environment of the <span class="hlt">interplanetary</span> space. However, this situation will change when space exploration missions beyond LEO will become the real challenge of the human exploration program. The feasibility of these missions in the solar system is thus strongly connected to the capability to mitigate the radiation-induced biological effects on the crew during the journey and the permanence on the intended planet surface. Inside the International Space Station (ISS), the volumes in which the crew spends most of the time, namely the crew quarters are the only parts that implement dedicated additional radiation shielding made of polyethylene tiles designed for mitigating SPE effects. Furthermore, specific radiation shielding materials are often added to the described configuration to shield crew quarters or the entire habitat example of these materials are polyethylene, liquid hydrogen, etc. but, increasing the size of the exploration vehicles to bring humans beyond LEO, and without the magnetosphere protection, such approach is unsustainable because the mass involved is a huge limiting factor with the actual launcher engine technology. Moreover, shielding against GCR with materials that have a low probability of nuclear interactions and in parallel a high ionizing energy loss is not always the best solution. In particular there is the risk to increase the LET of ions arriving at the spacecraft shell, increasing their Radio-Biological Effectiveness. Besides, the production of secondary nuclei by projectile and target fragmentation is an important issue when performing an engineering assessment of materials to be used for radiation shielding. The goal of this work is to analyze different shielding solutions to increase as much as possible the radiation shielding power of the <span class="hlt">interplanetary</span> habitat structures, like the spacecraft shell, minimizing the amount of mass used. From the radiation protection point of view the spacecraft shell is an interesting spacecraft system because it surrounds almost homogeneously all the habitat and it is typically composed by the Micrometeorites and Debris Protection Systems (MDPS), the Multilayer Insulation (MLI) for thermal control purposes, and the primary structure that offers the pressure containment functionality. Nevertheless, the spacecraft internal outfitting is important to evaluate the different shielded areas in the habitat. Using Geant4 Monte Carlo simulations toolkit through GRAS (Geant4 Radiation Analysis for Space) tool, different spacecraft structures will be analyzed for their shielding behavior in terms of fluxes, dose reduction and radiation quality, and for their implementation in a real pressurized module. Effects on astronauts and electronic equipments will be also assessed with respect to the standard aluminum structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013JGRA..118.3346Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013JGRA..118.3346Y"><span id="translatedtitle">Coordinated THEMIS spacecraft and all-sky imager observations of <span class="hlt">interplanetary</span> shock effects on plasma sheet flow bursts, poleward boundary intensifications, and streamers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yue, Chao; Nishimura, Yukitoshi; Lyons, Larry R.; Angelopoulos, Vassilis; Donovan, Eric F.; Shi, Quanqi; Yao, Zhonghua; Bonnell, John W.</p> <p>2013-06-01</p> <p>order to characterize plasma sheet and nightside auroral disturbances in response to <span class="hlt">interplanetary</span> shocks, we have examined three <span class="hlt">interplanetary</span> shock events that occurred when multiple Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft were located in the plasma sheet near midnight while ground-based aurora data were available near the spacecraft footprints. Large-scale responses we found are that the magnetotail <span class="hlt">magnetic</span> pressure started to increase within ~2 min of the SYM-H jump, and the diffuse aurora near the auroral equatorward boundary intensified over a wide <span class="hlt">magnetic</span> local time range, due to the shock compressional effect, on <span class="hlt">average</span> 3 min after the shock arrival. In addition, we also identified plasma sheet and auroral disturbances that are more transient and localized. Earthward or equatorward flow bursts are observed in the near-Earth plasma sheet on <span class="hlt">average</span> 5 min after the SYM-H increase. We find that these fast flows, originating downtail of the near-Earth spacecraft, form a localized channel, since only some of the spacecraft detected the flow bursts. Poleward boundary intensifications (PBIs) and subsequent north-south directed auroral streamers are then formed, while no substorm activity was detected. Those auroral forms are also localized in space near midnight and around the footprint of the spacecraft. These results indicate that the fast flows are azimuthally localized channels and are the magnetotail counterpart of the PBIs and streamers and that such localized disturbances are triggered by the <span class="hlt">interplanetary</span> shocks in addition to the large-scale compression of the magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...813...85L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...813...85L"><span id="translatedtitle">Energetic Particle Pressure at <span class="hlt">Interplanetary</span> Shocks: STEREO-A Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lario, D.; Decker, R. B.; Roelof, E. C.; Vias, A.-F.</p> <p>2015-11-01</p> <p>We study periods of elevated energetic particle intensities observed by STEREO-A when the partial pressure exerted by energetic (?83 keV) protons (PEP) is larger than the pressure exerted by the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (PB). In the majority of cases, these periods are associated with the passage of <span class="hlt">interplanetary</span> shocks. Periods when PEP exceeds PB by more than one order of magnitude are observed in the upstream region of fast <span class="hlt">interplanetary</span> shocks where depressed <span class="hlt">magnetic</span> field regions coincide with increases of energetic particle intensities. When solar wind parameters are available, PEP also exceeds the pressure exerted by the solar wind thermal population (PTH). Prolonged periods (>12 hr) with both PEP > PB and PEP > PTH may also occur when energetic particles accelerated by an approaching shock encounter a region well upstream of the shock characterized by low <span class="hlt">magnetic</span> field magnitude and tenuous solar wind density. Quasi-exponential increases of the sum PSUM = PB + PTH + PEP are observed in the immediate upstream region of the shocks regardless of individual changes in PEP, PB, and PTH, indicating a coupling between PEP and the pressure of the background medium characterized by PB and PTH. The quasi-exponential increase of PSUM implies a radial gradient ?PSUM/?r > 0 that is quasi-stationary in the shock frame and results in an outward force applied to the plasma upstream of the shock. This force can be maintained by the mobile energetic particles streaming upstream of the shocks that, in the most intense events, drive electric currents able to generate diamagnetic cavities and depressed solar wind density regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19770018265','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770018265"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Physics Laboratory (IPL): A concept for an <span class="hlt">interplanetary</span> mission in the mid-eighties</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burlaga, L. F.; Ogilvie, K. W.; Feldman, W.</p> <p>1977-01-01</p> <p>A concept for a near-earth <span class="hlt">interplanetary</span> mission in the mid-eighties is described. The proposed objectives would be to determine the composition of the <span class="hlt">interplanetary</span> constituents and its dependence on source-conditions and to investigate energy and momentum transfer processes in the <span class="hlt">interplanetary</span> medium. Such a mission would accomplish three secondary objectives: (1) provide a baseline for deep space missions, (2) investigate variations of the solar wind with solar activity, and (3) provide input functions for magnetospheric studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770034015&hterms=calgary+alberta&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcalgary%2Balberta','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770034015&hterms=calgary+alberta&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcalgary%2Balberta"><span id="translatedtitle">Pc 3, 4 activity and <span class="hlt">interplanetary</span> field orientation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Greenstadt, E. W.; Olson, J. V.</p> <p>1976-01-01</p> <p>Analysis of Pc 3, 4 micropulsation wave forms recorded at Calgary in September 1969 shows a tendency toward signal enhancement in cases where the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is at a small angle to the sun-earth line. Scatter plots of hourly Pc 3, 4 amplitudes exhibit a definite trend toward large signals when this angle is less than 50 or 60 degrees, and a corresponding disappearance of significant amplitudes when the angle is greater than 60 degrees. There is, however, an appreciable variability in individual cases. Power density spectrograms improved the correlation of pulsation strength with low angle in some cases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19900020833','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19900020833"><span id="translatedtitle"><span class="hlt">Interplanetary</span> medium data book, supplement 4, 1985-1988</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>King, Joseph H.</p> <p>1989-01-01</p> <p>An extension is presented of the series of <span class="hlt">Interplanetary</span> Medium Data Books and supplements which have been issued by the National Space Science Data Center since 1977. This volume contains solar wind <span class="hlt">magnetic</span> field (IMF) and plasma data from the IMP 8 spacecraft for 1985 to 1988, and 1985 IMF data from the Czechoslovakian Soviet Prognoz 10 spacecraft. The normalization of the MIT plasma density and temperature, which has been discussed at length in previous volumes, is implemented as before, using the same normalization constants for 1985 to 1988 data as for the earlier data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/75631','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/75631"><span id="translatedtitle">Observations of an intermediate shock in <span class="hlt">interplanetary</span> space</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chao, J.K.; Lyu, L.H.; Wu, B.H.; Lazarus, A.J.; Chang, T.S.; Lepping, R.P.</p> <p>1993-10-01</p> <p>The authors report the observation of an intermediate shock in <span class="hlt">interplanetary</span> space by the Voyager I spacecraft on May 1, 1980. The spacecraft was at a distance of approximately 9 AU from the sun. The observational properties support the magnetohydrodynamic properties for such an intermediate shock. Simulations give profiles of the plasma velocity, density, temperature, and <span class="hlt">magnetic</span> fields, for both the pre- and post-shock plasma which are in agreement with observations. This is the first reported observation of such shocks, whose possible observation has been questioned in the literature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740023204','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740023204"><span id="translatedtitle">Post-shock spikes: A new feature of proton and alpha enhancements associated with an <span class="hlt">interplanetary</span> shock wave</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gloeckler, G.; Ipavich, F. M.; Fan, C. Y.; Hovestadt, D.</p> <p>1974-01-01</p> <p>Abrupt and prolonged enhancements in the intensities of 100 to approximately 2000 keV nucleon protons and alpha particles observed in <span class="hlt">interplanetary</span> space are interpreted as particle populations confined between an <span class="hlt">interplanetary</span> shock front and a <span class="hlt">magnetic</span> field discontinuity. Prominent intensity spikes observed only below approximately 400 keV per charge for both protons and alpha particles several hours behind the shock front suggest that some fraction of the confined particles is accelerated by an energy per charge dependent process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM31D4239M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM31D4239M"><span id="translatedtitle">The Ring Current Response to Solar and <span class="hlt">Interplanetary</span> Storm Drivers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mouikis, C.; Kistler, L. M.; Bingham, S.; Kronberg, E. A.; Gkioulidou, M.; Huang, C. L.; Farrugia, C. J.</p> <p>2014-12-01</p> <p>The ring current responds differently to the different solar and <span class="hlt">interplanetary</span> storm drivers such as coronal mass injections, (CME's), corotating interaction regions (CIR's), high-speed streamers and other structures. The resulting changes in the ring current particle pressure, in turn, change the global <span class="hlt">magnetic</span> field, controlling the transport of the radiation belts. To quantitatively determine the field changes during a storm throughout the magnetosphere, it is necessary to understand the transport, sources and losses of the particles that contribute to the ring current. Because the measured ring current energy spectra depend not only on local processes, but also on the history of the ions along their entire drift path, measurements of ring current energy spectra at two or more locations can be used to strongly constrain the time dependent <span class="hlt">magnetic</span> and electric fields. In this study we use data predominantly from the Cluster and the Van Allen Probes, covering more than a full solar cycle (from 2001 to 2014). For the period 2001-2012, the Cluster CODIF and RAPID measurements of the inner magnetosphere are the primary data set used to monitor the storm time ring current variability. After 2012, the Cluster data set complements the data from the Van Allen Probes HOPE and RBSPICE instruments, providing additional measurements from different MLT and L shells. Selected storms from this periods, allow us to study the ring current dynamics and pressure changes, as a function of L shell, <span class="hlt">magnetic</span> local time, and the type of <span class="hlt">interplanetary</span> disturbances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840004976','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840004976"><span id="translatedtitle">Spectral analysis of magnetohydrodynamic fluctuations near <span class="hlt">interplanetary</span> schocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vinas, A. F.; Goldstein, M. L.; Acuna, M. H.</p> <p>1983-01-01</p> <p>Evidence for two types of relatively large amplitude MHD waves upstream and downstream of quasi-parallel forward and reverse <span class="hlt">interplanetary</span> shocks is presented. The first mode is an Alfven wave with frequencies (in the spacecraft frame) in the range of 0.025 to 0.07 Hz. This is a left-hand polarized mode and propagates within a few degrees of the ambient <span class="hlt">magnetic</span> field. The second is a fast MHD mode with frequencies in the range of 0.025 to 0.17 Hz, right-hand polarization and propagating along the <span class="hlt">magnetic</span> field. These waves are detected principally in association with quasi-parallel shock. The Alfven waves are found to have plasma rest frame frequencies in the range of 1.1 to 6.3 mHz with wavelengths in the order of 4.8 x 10 to the 8th power to 2.7 x 10 to the 9th power cm. Similarly, the fast MHD modes have rest frame frequencies in the range 1.6 to 26 mHz with typical wavelengths about 2.19 x 10 to the 8th power cm. The <span class="hlt">magnetic</span> field power spectrum in the vicinity of these <span class="hlt">interplanetary</span> shocks is much steeper than f to the -s/3 at high frequencies. The observed spectra have a high frequency dependence of f to the -2/5 to f to the -4.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060029807&hterms=internet&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dinternet','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060029807&hterms=internet&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dinternet"><span id="translatedtitle">Operating CFDP in the <span class="hlt">Interplanetary</span> Internet</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Burleigh, S.</p> <p>2002-01-01</p> <p>This paper examines the design elements of CCSDS File Delivery Protocol and <span class="hlt">Interplanetary</span> Internet technologies that will simplify their integration and discusses the resulting new capabilities, such as efficient transmission of large files via multiple relay satellites operating in parallel.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11537855','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11537855"><span id="translatedtitle">Volatiles in <span class="hlt">interplanetary</span> dust particles: a review.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Gibson, E K</p> <p>1992-03-25</p> <p>The paper presents a review of the volatiles found within <span class="hlt">interplanetary</span> dust particles. These particles have been shown to represent primitive material from early in the solar system's formation and also may contain records of stellar processes. The organogenic elements (i.e., H, C, N, O, and S) are among the most abundant elements in our solar system, and their abundances, distributions, and isotopic compositions in early solar system materials permit workers to better understand the processes operating early in the evolutionary history of solar system materials. <span class="hlt">Interplanetary</span> dust particles have a range of elemental compositions, but generally they have been shown to be similar to carbonaceous chondrites, the solar photosphere, Comet Halley's chondritic cores, and matrix materials of chondritic chondrites. Recovery and analysis of <span class="hlt">interplanetary</span> dust particles have opened new opportunities for analysis of primitive materials, although <span class="hlt">interplanetary</span> dust particles represent major challenges to the analyst because of their small size. PMID:11537855</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100042593','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100042593"><span id="translatedtitle">TPS Ablator Technologies for <span class="hlt">Interplanetary</span> Spacecraft</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Curry, Donald M.</p> <p>2004-01-01</p> <p>This slide presentation reviews the status of Thermal Protection System (TPS) Ablator technologies and the preparation for use in <span class="hlt">interplanetary</span> spacecraft. NASA does not have adequate TPS ablatives and sufficient selection for planned missions. It includes a comparison of shuttle and <span class="hlt">interplanetary</span> TPS requirements, the status of mainline TPS charring ablator materials, a summary of JSC SBIR accomplishments in developing advanced charring ablators and the benefits of SBIR Ablator/fabrication technology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19780049575&hterms=magnetic+signature&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmagnetic%2Bsignature','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19780049575&hterms=magnetic+signature&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmagnetic%2Bsignature"><span id="translatedtitle">The statistical <span class="hlt">magnetic</span> signature of magnetospheric substorms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Caan, M. N.; Mcpherron, R. L.; Russell, C. T.</p> <p>1978-01-01</p> <p>Daily magnetograms from a midlatitude network of geomagnetic observatories were used in the analysis of approximately 1800 substorm events, and the characteristic <span class="hlt">magnetic</span> signatures of magnetospheric substorms both on the ground and in space were determined. Auroral electrojet (AE) indices and individual magnetograms at different local times in the auroral zone and at midlatitudes were analyzed with reference to onsets, and superposed epoch <span class="hlt">averages</span> of individual magnetograms and AE indices confirm the local time <span class="hlt">magnetic</span> substorm signatures. Superposed epoch <span class="hlt">averages</span> of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) associated with the onsets demonstrates both a distinct southward component prior to the onsets and a dependence of the substorm amplitude on the integrated preceding southward IMF flux. Superposed epoch <span class="hlt">averages</span> of the tail lobe <span class="hlt">magnetic</span> field magnitude and vector components are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060036609&hterms=Ulysses&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DUlysses','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060036609&hterms=Ulysses&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DUlysses"><span id="translatedtitle">(abstract) An Extensive Search for <span class="hlt">Interplanetary</span> Slow-mode Shocks: Ulysses</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sakurai, R.; Ho, C. M.; Tsurutani, B. T.; Goldstein, B. E.; Balogh, A.</p> <p>1996-01-01</p> <p>Ulysses has accumulated five years of <span class="hlt">interplanetary</span> solar wind plasma and IMF measurements. These data cover from 1 to approximately 5 AU and all the heliographic latitudes. Based on these data, we perform an extensive search for the slow-mode shocks. We find a considerable number of discontinuities that have large <span class="hlt">magnetic</span> field magnitude changes and also large field normal components.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012EGUGA..14.6435P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012EGUGA..14.6435P"><span id="translatedtitle">Cause of the exceptionally high AE <span class="hlt">average</span> for 2003</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Prestes, A.</p> <p>2012-04-01</p> <p>In this work we focus on the year of 2003 when the AE index was extremely high (AE=341nT, with peak intensity more than 2200nT), this value is almost 100 nT higher when compared with others years of the cycle 23. <span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field (IMF) and plasma data are compared with geomagnetic AE and Dst indices to determine the causes of exceptionally high AE <span class="hlt">average</span> value. Analyzing the solar wind parameters we found that the annual <span class="hlt">average</span> speed value was extremely high, approximately 542 km/s (peak value ~1074 km/s). These values were due to recurrent high-speed solar streams from large coronal holes, which stretch to the solar equator, and low-latitude coronal holes, which exist for many solar rotations. AE was found to increase with increasing solar wind speed and decrease when solar wind speed decrease. The cause of the high AE activity during 2003 is the presence of the high-speed corotating streams that contain large-amplitude Alfvn waves throughout the streams, which resulted in a large number of HILDCAAs events. When plasma and field of solar wind impinge on Earth's magnetosphere, the southward field turnings associated with the wave fluctuations cause <span class="hlt">magnetic</span> reconnection and consequential high levels of AE activity and very long recovery phases on Dst, sometimes lasting until the next stream arrives.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900060054&hterms=Chestnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DChestnut','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900060054&hterms=Chestnut&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DChestnut"><span id="translatedtitle">New <span class="hlt">interplanetary</span> proton fluence model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Feynman, Joan; Armstrong, T. P.; Dao-Gibner, L.; Silverman, S.</p> <p>1990-01-01</p> <p>A new predictive engineering model for the <span class="hlt">interplanetary</span> fluence of protons with above 10 MeV and above 30 MeV is described. The data set used is a combination of observations made from the earth's surface and from above the atmosphere between 1956 and 1963 and observations made from spacecraft in the vicinity of earth between 1963 and 1985. The data cover a time period three times as long as the period used in earlier models. With the use of this data set the distinction between 'ordinary proton events' and 'anomalously large events' made in earlier work disappears. This permitted the use of statistical analysis methods developed for 'ordinary events' on the entire data set. The greater than 10 MeV fluences at 1 AU calculated with the new model are about twice those expected on the basis of models now in use. At energies above 30 MeV, the old and new models agree. In contrast to earlier models, the results do not depend critically on the fluence from any one event and are independent of sunspot number. Mission probability curves derived from the fluence distribution are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6423826','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6423826"><span id="translatedtitle">Plasma properties of driver gas following <span class="hlt">interplanetary</span> shocks observed by ISEE-3</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Zwickl, R.D.; Asbridge, J.R.; Bame, S.J.; Feldman, W.C.; Gosling, J.T.; Smith, E.J.</p> <p>1982-01-01</p> <p>Plasma fluid parameters calculated from solar wind and <span class="hlt">magnetic</span> field data obtained on ISEE 3 were studied to determine the characteristic properties of driver gas following <span class="hlt">interplanetary</span> shocks. Of 54 shocks observed from August 1978 to February 1980, 9 contained a well defined driver gas that was clearly identifiable by a discontinuous decrease in the <span class="hlt">average</span> proton temperature across a tangential discontinuity. While helium enhancements were present in all of 9 of these events, only about half of them contained simultaneous changes in the two quantities. Often the He/H ratio changed over a period of minutes. Simultaneous with the drop in proton temperature the helium and electron temperature decreased abruptly. In some cases the proton temperature depression was accompanied by a moderate increase in <span class="hlt">magnetic</span> field magnitude with an unusually low variance and by an increase in the ratio of parallel to perpendicular temperature. The drive gas usually displayed a bi-directional flow of suprathermal solar wind electrons at higher energies (>137 eV).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EPSC...10..146L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EPSC...10..146L"><span id="translatedtitle">Mars' "Magnetospheric" Response to <span class="hlt">Interplanetary</span> Field Orientation: Inferences from Models for MAVEN Investigation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Luhmann, J. G.; Dong, C.; Ma, Y.-J.; Curry, S. M.; Alvarez, K.; Hara, T.; Halekas, J.; Brain, D. A.; Bougher, S.; Espley, J.</p> <p>2015-10-01</p> <p>Planetary space weather at Mars has attracted much interest, but the focus is usually on the response to solar activity and its related disturbances in the solar wind. While this aspect is important and may be key to understanding Mars' atmosphere evolution, an additional consideration is based on the sensitivity of Earth's magnetospheric solar wind interaction to southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields. The study described here investigates whether Mars has its own specific <span class="hlt">interplanetary</span> field orientation sensitivities that might be identified in the MAVEN data analyses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850025738','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850025738"><span id="translatedtitle">On the possibility of the determining the <span class="hlt">average</span> mass composition near 10 to the 14th power eV through the solar <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lloyd-Evans, J.</p> <p>1985-01-01</p> <p>The discovery of primary ultrahigh energy (UHE) gamma-rays has spawned plans for a new generation of air shower experiments with unprecedented directional resolution. Such accuracy permits observation of a cosmic ray shadow due to the solar disc. Particle trajectory simulations through models of the large scale solar <span class="hlt">magnetic</span> field were performed. The shadow is apparent above 10 to the 15th power eV for all cosmic ray charges /Z/ 26; at lower energies, trajectories close to the Sun are bent sufficiently for this shadow to be lost. The onset of the shadow is rigidity dependent, and occurs at an energy per nucleus of approx. Z x 10 to the 13th power eV. The possibility of determining the <span class="hlt">average</span> mass composition near 10 to the 14th power eV from 1 year's observation at a mountain altitude array is investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUSM..SH51A08H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUSM..SH51A08H"><span id="translatedtitle">Three Solar Cycles of Non-Increasing <span class="hlt">Magnetic</span> Field</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hildner, E.; Arge, N.; Pizzo, V. J.; Harvey, J. W.</p> <p>2001-05-01</p> <p>Since measurements started in the late 19th century, there has been a secular increase (with superposed ripples due to solar cycles) of the aa geomagnetic index. Starting from this observation, Lockwood, Stamper, and Wild (hereafter, LSW) conclude (Nature, 399, 1999; see also Lockwood et al., Astronomy and Geophysics, 40, 1999) that the total source's <span class="hlt">magnetic</span> flux in the Sun's atmosphere has risen by 41% since 1964\\" and by 130% in the 20th century. However, solar data over nearly three solar cycles - near-daily magnetograms from Mt Wilson, and Wilcox Solar Observatories and newly reanalyzed data from the National Solar Observatory - show no secular trend in overall photospheric flux. More importantly, the <span class="hlt">magnetic</span> field open to <span class="hlt">interplanetary</span> space (as calculated from photospheric measurements and assuming potential fields to a height of 2.5 Rsun) fails to show a secular increase over the last three solar cycles. Like LSW, we do not explicitly take account of transient events. Thus, both data and calculations imply that the Sun's <span class="hlt">average</span> coronal <span class="hlt">magnetic</span> flux has not increased over the last three solar cycles. Analysis of simulations with the potential field source surface model shows that the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> flux is not simply related to the overall, photospheric, solar <span class="hlt">magnetic</span> flux. Both results are in agreement with the findings of Wang, Lean, and Sheeley (GRL, 27, 2000). The topology, not just the strength, of the emergent solar <span class="hlt">magnetic</span> field is a major determinant of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field experienced at Earth. In principle, secular change in non-potentiality of the coronal field could lead to secular increase in <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> flux, but this seems unlikely.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790041801&hterms=Observation+solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DObservation%2Bsolar','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790041801&hterms=Observation+solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DObservation%2Bsolar"><span id="translatedtitle">Signatures of solar wind latitudinal structure in <span class="hlt">interplanetary</span> Lyman-alpha emissions - Mariner 10 observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kumar, S.; Broadfoot, A. L.</p> <p>1979-01-01</p> <p>A detailed analysis is conducted which shows that signatures in the <span class="hlt">interplanetary</span> Lyman-alpha emissions observed in three different data sets from Mariner 10 (corresponding to different locations of the spacecraft) provide firm evidence that the intensity departures are correlated with a decrease in solar wind flux with increasing latitude. It is suggested that observations of the <span class="hlt">interplanetary</span> emission can be used to monitor <span class="hlt">average</span> solar wind activity at high latitudes. The asymmetry in the solar radiation field as a source of observed departures in L-alpha data is considered and attention is given to the interstellar hydrogen and helium density.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003ICRC....6.3655P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003ICRC....6.3655P"><span id="translatedtitle">Solar and <span class="hlt">Interplanetary</span> Disturbances Causing Moderate Geomagnetic Storms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pratap Yadav, Mahendra; Kumar, Santosh</p> <p>2003-07-01</p> <p>The effect of solar and <span class="hlt">interplanetary</span> disturbances on geomagnetospheric conditions leading to one hundred twenty one moderate geomagnetic storms (MGSs) with planetary index, Ap ? 20 and horizontal component of earth's <span class="hlt">magnetic</span> field, H ? 250? have been investigated using solar geophysical data (SGD), solar wind plasma (SWP) and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) data during the period 1978-99. It is observed statistically that 64%, 36%, MGSs have occurred during maximum and minimum phase of solar cycle 21st and 22nd respectively. Further, it is observed that H?, X-ray solar flares and active prominences and disapp earing filaments (APDFs) have occurred within lower helio latitude region associated with larger number of MGSs. No significant correlation between the intensity of GMSs and importance of H?, X-ray solar flares have been observed. Maximum number of MGSs are associated with solar flares of lower importance of solar flare faint (SF). The lower importance in association with some specific characteristics i.e. location, region, duration of occurrence of event may also cause MGSs. The correlation coefficient between MGSs and sunspot numbers (SSNs) using Karl Pearson method, has been obtained 0.37 during 1978-99.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6261170','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6261170"><span id="translatedtitle">In situ observations of coronal mass ejections in <span class="hlt">interplanetary</span> space</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gosling, J.T.</p> <p>1991-01-01</p> <p>Coronal mass ejections, CMEs, in the solar wind at 1 AU generally have distinct plasma and field signatures by which they can be distinguished from the ordinary solar wind. These include one or more of the following: helium abundance enhancements, ion and electron temperature depressions, unusual ionization states, strong <span class="hlt">magnetic</span> fields, low plasma beta, low <span class="hlt">magnetic</span> field variance, coherent field rotations, counterstreaming (along the field) energetic protons, and counterstreaming suprathermal electrons. The most reliable of these appears to be counterstreaming electrons, which indicates that CMEs at 1 AU typically are closed field structures either rooted at both ends in the Sun or entirely disconnected from it as plasmoids. About 1/3 of all CMEs have sufficiently high speeds to produce transient <span class="hlt">interplanetary</span> shock disturbances at 1 AU; the remainder simply ride along with the solar wind. The frequency of occurrence of CMEs in the ecliptic plane, as distinguished by the counterstreaming electron signature, varies roughly in phase and amplitude with the 11-yr solar activity cycle. Near solar maximum they account for {approximately} 15% of all solar wind measurements, while near solar minimum they account for less than 1% of all the measurements. All but one of the 37 largest geomagnetic storms near the last solar maximum were associated with Earth-passage of <span class="hlt">interplanetary</span> disturbances driven by fast CMEs; that is, CMEs are the prime link between solar and geomagnetic activity. However, more than half of all earthward directed CMEs are relatively ineffective in a geomagnetic sense. 19 refs., 6 figs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060044310&hterms=proton&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dproton','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060044310&hterms=proton&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dproton"><span id="translatedtitle">A study of spacecraft charging due to exposure to <span class="hlt">interplanetary</span> protons</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Green, Nelson W.; Frederickson, A. Robb</p> <p>2005-01-01</p> <p>The <span class="hlt">interplanetary</span> space environment is composed mostly of plasma from the solar wind and high energy protons from solar events such as coronal mass ejections. Satellites orbiting Earth are shielded to some degree from these events by the Earth's <span class="hlt">magnetic</span> field but spacecraft traveling between planets are exposed to these solar protons directly. A major concern for spacecraft is internal electrostatic discharge (IESD), a form of spacecraft charging. The majority of research regarding IESD has been concerned with the electrons in the space environment around the Earth and at Jupiter; little research has been done on the charging of spacecraft in <span class="hlt">interplanetary</span> space due to solar event protons. This paper reviews the work done so far on IESD due to protons and provides a possible example of an anomaly due to a proton induced discharge in <span class="hlt">interplanetary</span> space on the Galileo spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMMM..384..266T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMMM..384..266T"><span id="translatedtitle">Robust solution procedure for the discrete energy-<span class="hlt">averaged</span> model on the calculation of 3D hysteretic <span class="hlt">magnetization</span> and magnetostriction of iron-gallium alloys</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tari, H.; Scheidler, J. J.; Dapino, M. J.</p> <p>2015-06-01</p> <p>A reformulation of the Discrete Energy-<span class="hlt">Averaged</span> model for the calculation of 3D hysteretic <span class="hlt">magnetization</span> and magnetostriction of iron-gallium (Galfenol) alloys is presented in this paper. An analytical solution procedure based on an eigenvalue decomposition is developed. This procedure avoids the singularities present in the existing approximate solution by offering multiple local minimum energy directions for each easy crystallographic direction. This improved robustness is crucial for use in finite element codes. Analytical simplifications of the 3D model to 2D and 1D applications are also presented. In particular, the 1D model requires calculation for only one easy direction, while all six easy directions must be considered for general applications. Compared to the approximate solution procedure, it is shown that the resulting robustness comes at no expense for 1D applications, but requires almost twice the computational effort for 3D applications. To find model parameters, we employ the <span class="hlt">average</span> of the hysteretic data, rather than anhysteretic curves, which would require additional measurements. An efficient optimization routine is developed that retains the dimensionality of the prior art. The routine decouples the parameters into exclusive sets, some of which are found directly through a fast preprocessing step to improve accuracy and computational efficiency. The effectiveness of the model is verified by comparison with existing measurement data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21394456','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21394456"><span id="translatedtitle"><span class="hlt">INTERPLANETARY</span> SHOCKS LACKING TYPE II RADIO BURSTS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gopalswamy, N.; Kaiser, M. L.; Xie, H.; Maekelae, P.; Akiyama, S.; Yashiro, S.; Howard, R. A.; Bougeret, J.-L.</p> <p>2010-02-20</p> <p>We report on the radio-emission characteristics of 222 <span class="hlt">interplanetary</span> (IP) shocks detected by spacecraft at Sun-Earth L1 during solar cycle 23 (1996 to 2006, inclusive). A surprisingly large fraction of the IP shocks ({approx}34%) was radio quiet (RQ; i.e., the shocks lacked type II radio bursts). We examined the properties of coronal mass ejections (CMEs) and soft X-ray flares associated with such RQ shocks and compared them with those of the radio-loud (RL) shocks. The CMEs associated with the RQ shocks were generally slow (<span class="hlt">average</span> speed {approx}535 km s{sup -1}) and only {approx}40% of the CMEs were halos. The corresponding numbers for CMEs associated with RL shocks were 1237 km s{sup -1} and 72%, respectively. Thus, the CME kinetic energy seems to be the deciding factor in the radio-emission properties of shocks. The lower kinetic energy of CMEs associated with RQ shocks is also suggested by the lower peak soft X-ray flux of the associated flares (C3.4 versus M4.7 for RL shocks). CMEs associated with RQ CMEs were generally accelerating within the coronagraph field of view (<span class="hlt">average</span> acceleration {approx}+6.8 m s{sup -2}), while those associated with RL shocks were decelerating (<span class="hlt">average</span> acceleration {approx}-3.5 m s{sup -2}). This suggests that many of the RQ shocks formed at large distances from the Sun, typically beyond 10 Rs, consistent with the absence of metric and decameter-hectometric (DH) type II radio bursts. A small fraction of RL shocks had type II radio emission solely in the kilometric (km) wavelength domain. Interestingly, the kinematics of the CMEs associated with the km type II bursts is similar to those of RQ shocks, except that the former are slightly more energetic. Comparison of the shock Mach numbers at 1 AU shows that the RQ shocks are mostly subcritical, suggesting that they were not efficient in accelerating electrons. The Mach number values also indicate that most of these are quasi-perpendicular shocks. The radio-quietness is predominant in the rise phase and decreases through the maximum and declining phases of solar cycle 23. About 18% of the IP shocks do not have discernible ejecta behind them. These shocks are due to CMEs moving at large angles from the Sun-Earth line and hence are not blast waves. The solar sources of the shock-driving CMEs follow the sunspot butterfly diagram, consistent with the higher-energy requirement for driving shocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20110013494&hterms=butterfly&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dbutterfly','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110013494&hterms=butterfly&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dbutterfly"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Shocks Lacking Type 2 Radio Bursts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gopalswamy, N.; Xie, H.; Maekela, P.; Akiyama, S.; Yashiro, S.; Kaiser, M. L.; Howard, R. A.; Bougeret, J.-L.</p> <p>2010-01-01</p> <p>We report on the radio-emission characteristics of 222 <span class="hlt">interplanetary</span> (IP) shocks detected by spacecraft at Sun-Earth L1 during solar cycle 23 (1996 to 2006, inclusive). A surprisingly large fraction of the IP shocks (approximately 34%) was radio quiet (RQ; i.e., the shocks lacked type II radio bursts). We examined the properties of coronal mass ejections (CMEs) and soft X-ray flares associated with such RQ shocks and compared them with those of the radio-loud (RL) shocks. The CMEs associated with the RQ shocks were generally slow (<span class="hlt">average</span> speed approximately 535 km/s) and only approximately 40% of the CMEs were halos. The corresponding numbers for CMEs associated with RL shocks were 1237 km/s and 72%, respectively. Thus, the CME kinetic energy seems to be the deciding factor in the radio-emission properties of shocks. The lower kinetic energy of CMEs associated with RQ shocks is also suggested by the lower peak soft X-ray flux of the associated flares (C3.4 versus M4.7 for RL shocks). CMEs associated with RQ CMEs were generally accelerating within the coronagraph field of view (<span class="hlt">average</span> acceleration approximately +6.8 m/s (exp 2)), while those associated with RL shocks were decelerating (<span class="hlt">average</span> acceleration approximately 3.5 m/s (exp 2)). This suggests that many of the RQ shocks formed at large distances from the Sun, typically beyond 10 Rs, consistent with the absence of metric and decameter-hectometric (DH) type II radio bursts. A small fraction of RL shocks had type II radio emission solely in the kilometric (km) wavelength domain. Interestingly, the kinematics of the CMEs associated with the km type II bursts is similar to those of RQ shocks, except that the former are slightly more energetic. Comparison of the shock Mach numbers at 1 AU shows that the RQ shocks are mostly subcritical, suggesting that they were not efficient in accelerating electrons. The Mach number values also indicate that most of these are quasi-perpendicular shocks. The radio-quietness is predominant in the rise phase and decreases through the maximum and declining phases of solar cycle 23. About 18% of the IP shocks do not have discernible ejecta behind them. These shocks are due to CMEs moving at large angles from the Sun-Earth line and hence are not blast waves. The solar sources of the shock-driving CMEs follow the sunspot butterfly diagram, consistent with the higher-energy requirement for driving shocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890058805&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dluhmann','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890058805&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dluhmann"><span id="translatedtitle">A search for the solar roots of the most disturbed <span class="hlt">interplanetary</span> field intervals of solar cycle 21</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Luhmann, J. G.; Russell, C. T.; Barnes, A.</p> <p>1989-01-01</p> <p>During the course of the Pioneer Venus Orbiter mission, fairly continuous <span class="hlt">interplanetary</span> plasma and <span class="hlt">magnetic</span> field data were obtained which span the interval from prior to the last solar maximum to the current solar minimum recovery. Within this nearly complete solar cycle interval, several periods of exceptional disturbance of the <span class="hlt">interplanetary</span> field stand out. The available solar data have been examined to determine what features, if any, distinguish these periods. Neither flare nor coronal mass ejection reports show particularly unusual behavior. However, these periods appear to occur in conjunction with marked changes in the <span class="hlt">interplanetary</span> sector structure. This suggests that heliospheric current sheet reconfiguration is an indicator of the level of <span class="hlt">interplanetary</span> disturbance distinct from the more traditional solar activity data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20100026445&hterms=Media&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DMedia','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20100026445&hterms=Media&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DMedia"><span id="translatedtitle">Propagation and Evolution of CMEs in the <span class="hlt">Interplanetary</span> Medium: Analysis of Remote Sensing and In situ Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Figueroa-Vinas, Adolfo; Nieves-Chinchilla, Teresa; Vourlidas, Angelos; Gomez-Herrero, Raul; Malandraki, Olga; Szabo, Adam; Dresing, Nina; Davila, Joseph M.</p> <p>2010-01-01</p> <p>EUV disk imagers and white light coronagraphs have provided for many years information on the early formation and evolution of corona) mass ejections (CMEs). More recently, the novel heliospheric imaging instruments aboard the STEREO mission are providing crucial remote sensing information on the <span class="hlt">interplanetary</span> evolution of these events while in situ instruments complete the overall characterization of the <span class="hlt">interplanetary</span> CMEs. In this work, we present an analysis of CMEs from the Sun to the <span class="hlt">interplanetary</span> medium using combined data from THE SOHO, STEREO, WIND, and ACE spacecraft. The events were selected to cover the widest possible spectrum of different ambient solar wind, <span class="hlt">magnetic</span> field configurations, plasma parameters, etc. to allow uncovering those aspects that are important in understanding the propagation and evolution mechanisms of CMEs in the <span class="hlt">interplanetary</span> medium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SoPh..284....5Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SoPh..284....5Y"><span id="translatedtitle">Post-Eruption Arcades and <span class="hlt">Interplanetary</span> Coronal Mass Ejections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yashiro, S.; Gopalswamy, N.; Mäkelä, P.; Akiyama, S.</p> <p>2013-05-01</p> <p>We compare the temporal and spatial properties of posteruption arcades (PEAs) associated with coronal mass ejections (CMEs) at the Sun that end up as <span class="hlt">magnetic</span> cloud (MC) and non-MC events in the solar wind. We investigate the length, width, area, tilt angle, and formation time of the PEAs associated with 22 MC and 29 non-MC events and we find no difference between the two populations. According to current ideas on the relation between flares and CMEs, the PEA is formed together with the CME flux-rope structure by <span class="hlt">magnetic</span> reconnection. Our results indicate that at the Sun flux ropes form during CMEs in association with both MC and non-MC events; however, for non-MC events the flux-rope structure is not observed in the <span class="hlt">interplanetary</span> space because of the geometry of the observation, i.e. the location of the spacecraft when the structure passes through it.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770038233&hterms=plasma+field&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dplasma%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770038233&hterms=plasma+field&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dplasma%2Bfield"><span id="translatedtitle">Plasma field characteristics of directional discontinuities in the <span class="hlt">interplanetary</span> medium</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Solodyna, C. V.; Belcher, J. W.; Sari, J. W.</p> <p>1977-01-01</p> <p>The paper examines plasma and <span class="hlt">magnetic</span>-field changes occurring across 1359 directional discontinuities taken from <span class="hlt">interplanetary</span> data spanning almost four solar rotations. The plasma field characteristics of these events exhibit a distinct variation with large-scale solar-wind velocity. At low velocities, tangential discontinuities appear to predominate. At higher velocities, a substantial and increasing fraction of directional discontinuities exhibits the plasma field properties expected of outwardly propagating rotational discontinuities. The results of Sari (1972, 1975) and of the present study suggest that in the calculation of propagation diffusion coefficients for low-energy cosmic rays, the effects of directional discontinuities should be subtracted from the <span class="hlt">magnetic</span> fluctuation spectrum during relatively quiet wind conditions. It is not clear that such subtraction is necessary during more disturbed periods.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020015931','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020015931"><span id="translatedtitle">Cosmic Rays in <span class="hlt">Interplanetary</span> Space</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Forman, Miriam A.</p> <p>2001-01-01</p> <p>The science problem I have tackled in this grant is the derivation of the diffusion tensor of energetic particles in turbulent <span class="hlt">magnetic</span> fields, with a sensible mean field. The new approach was to use quasi-linear theory with a consistent treatment of those scattering terms leading to diffusion perpendicular to the mean <span class="hlt">magnetic</span> field; and, to use modern data and formats for three-dimensional turbulence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20100011347','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20100011347"><span id="translatedtitle">International Launch Vehicle Selection for <span class="hlt">Interplanetary</span> Travel</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ferrone, Kristine; Nguyen, Lori T.</p> <p>2010-01-01</p> <p>In developing a mission strategy for <span class="hlt">interplanetary</span> travel, the first step is to consider launch capabilities which provide the basis for fundamental parameters of the mission. This investigation focuses on the numerous launch vehicles of various characteristics available and in development internationally with respect to upmass, launch site, payload shroud size, fuel type, cost, and launch frequency. This presentation will describe launch vehicles available and in development worldwide, then carefully detail a selection process for choosing appropriate vehicles for <span class="hlt">interplanetary</span> missions focusing on international collaboration, risk management, and minimization of cost. The vehicles that fit the established criteria will be discussed in detail with emphasis on the specifications and limitations related to <span class="hlt">interplanetary</span> travel. The final menu of options will include recommendations for overall mission design and strategy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5915564','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5915564"><span id="translatedtitle"><span class="hlt">Interplanetary</span> energetic ions and polar radio wave absorption</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Armstrong, T.P.; Laird, C.M. ); Venkatesan, D. ); Krishnaswamy, S.; Rosenberg, T.J. )</p> <p>1989-04-01</p> <p>This is a study of the ionization input of <span class="hlt">interplanetary</span> (including solar flare) energetic protons and alpha particles into the south polar ionosphere over the interval 1982-1985. It is well known that <span class="hlt">interplanetary</span> ions have full and prompt access to the polar ionosphere. The incremental ionization produced at 20-120 km. altitudes causes enhanced radio wave absorption which is observed by riometers operated by the University of Maryland, at South Pole, Antarctica. The authors compute the expected absorption from the vertical structure of the ionization deposited by these energetic particles and compare the computed values with the observations. The contribution of the alpha particles is found to be quite small as a percentage of the absorption except at the peak of the day 35, 1983, event, when their contribution to the absorption is about 0.6 dB out of a total of 3.4 dB. The dominant contribution to absorption at 30 MHz usually arises from protons below 10 MeV, specifically in the 2- to 4-MeV interval. They have propagated the observed fluxes and energy spectra of protons and alpha particles through a seasonally adjusted slab model of the polar atmosphere. The atmospheric ionization resulting from the slowing and stopping of protons and alpha particles is used to estimate an equilibrium vertical ionization profile which is then convolved with an absorption efficiency profile to yield a calculated absorption. There is good agreement between the computed and observed absorption when the daily <span class="hlt">averaged</span> absorption is above 0.1 dB; this shows that the <span class="hlt">interplanetary</span> ions are the dominant contributors on those days.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950056921&hterms=yamamoto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dyamamoto','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950056921&hterms=yamamoto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dyamamoto"><span id="translatedtitle">Cross-tail <span class="hlt">magnetic</span> flux ropes as observed by the GEOTAIL spacecraft</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lepping, R. P.; Fairfield, D. H.; Jones, J.; Frank, L. A.; Paterson, W. R.; Kokubun, S.; Yamamoto, T.</p> <p>1995-01-01</p> <p>Ten transient <span class="hlt">magnetic</span> structures in Earth's magnetotail, as observed in GEOTAIL measurements, selected for early 1993 (at (-) X(sub GSM) = 90 - 130 Earth radii), are shown to have helical <span class="hlt">magnetic</span> field configurations similar to those of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds at 1 AU but smaller in size by a factor of approximately = 700. Such structures are shown to be well approximated by a comprehensive <span class="hlt">magnetic</span> force-free flux-rope model. For this limited set of 10 events the rope axes are seen to be typically aligned with the Y(sub GSM) axis and the <span class="hlt">average</span> diameter of these structures is approximately = 15 Earth radii.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20150008672&hterms=navigation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dnavigation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20150008672&hterms=navigation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dnavigation"><span id="translatedtitle">Mars Science Laboratory <span class="hlt">Interplanetary</span> Navigation Performance</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Martin-Mur, Tomas J.; Kruizinga, Gerhard; Wong, Mau</p> <p>2013-01-01</p> <p>The Mars Science Laboratory spacecraft, carrying the Curiosity rover to Mars, hit the top of the Martian atmosphere just 200 meters from where it had been predicted more than six days earlier, and 2.6 million kilometers away. This un-expected level of accuracy was achieved by a combination of factors including: spacecraft performance, tracking data processing, dynamical modeling choices, and navigation filter setup. This paper will describe our best understanding of what were the factors that contributed to this excellent <span class="hlt">interplanetary</span> trajectory prediction performance. The accurate <span class="hlt">interplanetary</span> navigation contributed to the very precise landing performance, and to the overall success of the mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790055065&hterms=lorentz&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlorentz','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790055065&hterms=lorentz&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlorentz"><span id="translatedtitle">Lorentz scattering of <span class="hlt">interplanetary</span> dust</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Consolmagno, G.</p> <p>1979-01-01</p> <p>Charged dust grains in a turbulent <span class="hlt">magnetic</span> field will see a Lorentz force due to the convection of the solar <span class="hlt">magnetic</span> field past them at the solar wind velocity. Since the sign of this <span class="hlt">magnetic</span> field is randomly varying, the direction of the force will be random, and the net effect will be to randomly scatter the orbital elements of these particles. The square roots of the mean square change in semimajor axis, inclination, and eccentricity are determined as a function of the particles' original orbital elements. Particles 3 microns in radius and smaller will have their motions strongly perturbed or dominated by Lorentz scattering. This scattering will have an effect comparable to, or greater than, the Poynting-Robertson effect on these particles for time scales comparable to their Poynting-Robertson lifetimes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870039705&hterms=drift+diffusion&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Ddrift%2Bor%2Bdiffusion','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870039705&hterms=drift+diffusion&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Ddrift%2Bor%2Bdiffusion"><span id="translatedtitle">Modeling of ion acceleration through drift and diffusion at <span class="hlt">interplanetary</span> shocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Decker, R. B.; Vlahos, L.</p> <p>1986-01-01</p> <p>A test particle simulation designed to model ion acceleration through drift and diffusion at <span class="hlt">interplanetary</span> shocks is described. The technique consists of integrating along exact particle orbits in a system where the angle between the shock normal and mean upstream <span class="hlt">magnetic</span> field, the level of <span class="hlt">magnetic</span> fluctuations, and the energy of injected particles can assume a range of values. The technique makes it possible to study time-dependent shock acceleration under conditions not amenable to analytical techniques. To illustrate the capability of the numerical model, proton acceleration was considered under conditions appropriate for <span class="hlt">interplanetary</span> shocks at 1 AU, including large-amplitude transverse <span class="hlt">magnetic</span> fluctuations derived from power spectra of both ambient and shock-associated MHD waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Ge%26Ae..55..926G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Ge%26Ae..55..926G"><span id="translatedtitle">Features of the behavior of some magnetohydrodynamic structures in the <span class="hlt">interplanetary</span> space</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Grib, S. A.; Leora, S. N.</p> <p>2015-12-01</p> <p>Constant pressure structures moving together with a solar wind flux are described based on magnetohydrodynamic representations. The action of <span class="hlt">magnetic</span> hole type structures on the bow shock wave before the Earth's magnetosphere is thus considered. In the presence of a rotational discontinuity in the <span class="hlt">magnetic</span> cloud, it is shown that the decomposition of an arbitrary discontinuity generates a plateau with an increase in the density of charged particles and a decrease in the intensity of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field, which is repeatedly observed on spacecrafts. The plateau coincides with the properties of the <span class="hlt">magnetic</span> hole to a large extent but is of another origin (in fact, local).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.6101W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.6101W"><span id="translatedtitle"><span class="hlt">Interplanetary</span> coronal mass ejections from MESSENGER orbital observations at Mercury</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Winslow, Reka M.; Lugaz, Noé; Philpott, Lydia C.; Schwadron, Nathan A.; Farrugia, Charles J.; Anderson, Brian J.; Smith, Charles W.</p> <p>2015-08-01</p> <p>We use observations from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft, in orbit around Mercury, to investigate <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs) near 0.3 AU. MESSENGER is the first spacecraft since Helios 1 and 2 in the 1980s to make in situ measurements of the <span class="hlt">interplanetary</span> medium at heliocentric distances < 0.5 AU. As such, it presents a unique opportunity for observing the innermost heliosphere. It also allows for observations of ICMEs well within 1 AU to study their evolution as they expand and propagate outward, interacting with the solar wind. We catalog ICME events observed by the MESSENGER Magnetometer between 2011 and 2014 and present statistical analyses of ICME properties at Mercury. In addition, using existing data sets of ICMEs at 1 AU, we investigate key ICME property changes from Mercury to 1 AU. We find good agreement with previous studies for the <span class="hlt">magnetic</span> field strength dependence on distance, and we also find evidence that ICME deceleration continues past the orbit of Mercury. This paper describes the database of ICMEs from MESSENGER orbital observations around Mercury, which is publicly available through the supporting information (Table S1) associated with this manuscript and the Virtual Energetic Particle Observatory. Our ICME database will prove particularly useful for multipoint spacecraft studies of recent ICMEs, as well as for model validation of ICME properties.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AstL...42..126B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AstL...42..126B"><span id="translatedtitle">Particle acceleration and Alfvn wave generation by an <span class="hlt">interplanetary</span> shock</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Berezhko, E. G.; Taneev, S. N.</p> <p>2016-02-01</p> <p>Based on the event observed by ISEE 3 near the Earth's orbit at 01:21 UT on April 5, 1979, we investigate the diffusive shock acceleration of ions and the generation of Alfvn waves by accelerated particles near the quasi-parallel parts of <span class="hlt">interplanetary</span> shock fronts within a quasi-linear approach. The theory is shown to give an excessively high level of Alfvn wave generation by accelerated particles at significant deflection angles of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field from the normal to the shock front. At the Earth's orbit, the Alfv n waves produced by accelerated ions are confined within the frequency range 5 10-2-0.5 Hz, and their spectral peak with a wave amplitude ?B ? B corresponds to a frequency ? = (1-2)10-2 Hz. The high-frequency part of the wave spectrum ( ? ? 0.5 Hz) is subjected to damping on thermal protons. The calculated spectra of the accelerated ions and Alfvn waves generated by them reproduce the main features observed in experiments.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021311&hterms=electron+cloud+injection&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Delectron%2Bcloud%2Binjection','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021311&hterms=electron+cloud+injection&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Delectron%2Bcloud%2Binjection"><span id="translatedtitle">Mass ejections from the sun and their <span class="hlt">interplanetary</span> counterparts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schwenn, R.</p> <p>1995-01-01</p> <p>Since the first observations of solar mass ejection events in the early seventies from OSO 7 and Skylab a few thousand of these remarkable dynamic incidents have been observed by now, covering about two full solar activity cycles. The mass ejecta include mainly hot coronal plasma, plus cold prominence material in variable amounts. The ejecta are often recognised in the form of <span class="hlt">interplanetary</span> plasma clouds detected in the distant solar wind by appropriately located spacecraft. Clouds which have been energetic enough to drive large scale <span class="hlt">interplanetary</span> shock waves can be identified most readily, but clouds without associated shocks do also occur. The plasma clouds are characterized by a variety of signatures indicating that they actually originate from injections of different material into the ambient solar wind. Usually only a few of the signatures are found simultaneously. Apparently the bidirectional streaming of halo electrons is a most reliable criterion, indicating a <span class="hlt">magnetic</span> bottle or plasmoid topology of the clouds. The discussion of the most recent discoveries in this context will show that quite a few crucial problems still remain to be addressed by the upcoming SOHO mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.2998S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.2998S"><span id="translatedtitle">Active shielding for long duration <span class="hlt">interplanetary</span> manned missions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Spillantini, Piero</p> <p></p> <p>The problem of protecting astronauts from the cosmic rays action in unavoidable and was therefore preliminary studied by many space agencies. In Europe, in the years 2002-2004, ESA supported two works on this thematic: a topical team in the frame of the life and physical sciences' and a study, assigned by tender, of the radiation exposure and mission strategies for <span class="hlt">interplanetary</span> manned missions to Moon and Mars'. In both studies it was concluded that, while the protection from solar cosmic rays can relay on the use of passive absorbers, for long duration missions the astronauts must be protected from the much more energetic galactic cosmic rays during the whole duration of the mission. This requires the protection of a large habitat where they could live and work, and not a temporary small volume shelter, and the use of active shielding is therefore mandatory. The possibilities offered by using superconducting <span class="hlt">magnets</span> were discussed, and the needed R&D recommended. The technical development occurred in the meantime and the evolution of the panorama of the possible <span class="hlt">interplanetary</span> missions in the near future require to revise these pioneer studies and think of the problem at a scale allowing long human permanence in deep' space, and not for a relatively small number of dedicated astronauts but also for citizens conducting there normal' activities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/266935','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/266935"><span id="translatedtitle">Mass ejections from the sun and their <span class="hlt">interplanetary</span> counterparts</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Schwenn, R.</p> <p>1995-06-01</p> <p>Since the first observations of solar mass ejection events in the early seventies from OSO 7 and Skylab a few thousand of these remarkable dynamic incidents have been observed by now, covering about two full solar activity cycles. The mass ejecta include mainly hot coronal plasma, plus cold prominence material in variable amounts. The ejecta are often recognised in the form of <span class="hlt">interplanetary</span> plasma clouds detected in the distant solar wind by appropriately located spacecraft. Clouds which have been energetic enough to drive large scale <span class="hlt">interplanetary</span> shock waves can be identified most readily, but clouds without associated shocks do also occur. The plasma clouds are characterized by a variety of signatures indicating that they actually originate from injections of different material into the ambient solar wind. Usually only a few of the signatures are found simultaneously. Apparently the bidirectional streaming of halo electrons is a most reliable criterion, indicating a <span class="hlt">magnetic</span> bottle or plasmoid topology of the clouds. The discussion of the most recent discoveries in this context will show that quite a few crucial problems still remain to be addressed by the upcoming SOHO mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021336&hterms=Current+events&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DCurrent%2Bevents','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021336&hterms=Current+events&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DCurrent%2Bevents"><span id="translatedtitle">The solar/<span class="hlt">interplanetary</span> event of 14 April 1994 observed by Yohkoh/SXT</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Alexander, D.; Harvey, K. L.; Hudson, H. S.; Hoeksema, J. T.; Zhao, X.</p> <p>1995-01-01</p> <p>The polar crown event of April 14 1994 is one of the largest scale eruptive events observed by the Yohkoh/SXT. Associated with the formation of an arcade of soft X-ray loops at the Sun was the detection of an <span class="hlt">interplanetary</span> forward/reverse shock event by the Ulysses spacecraft some 4-7 days later. The relationship between the coronal and <span class="hlt">interplanetary</span> signatures of these events is important if we are to address fully the initialization and consequent acceleration of <span class="hlt">interplanetary</span> phenomena, such as CMEs and counter-streaming electrons, originating at the Sun. From detailed analysis of the energetics of the arcade formed during the eruption of April 14 1994, we find peak temperatures and emission measures of approximately 5MK and approximately 10(exp 48)cm(exp -3) respectively. The total thermal content of the arcade loop structure observed in soft X-rays is calculated to be some 5 x 10(exp 29) ergs. The development of these parameters as the event proceeds and their relationship to the dynamics of the eruption are investigated. Although spanning a longitudinal range of some 150 degrees the April 14 event displayed the typical helmet streamer structure normally associated with coronal mass ejections These helmet streamers are thought to be related to the global solar <span class="hlt">magnetic</span> field through the heliospheric current sheet (HCS). The arcade formation, together with the eruption of material into <span class="hlt">interplanetary</span> space, signifies a large-scale reconfiguration of the coronal <span class="hlt">magnetic</span> field. We examine the effects of the formation of such a coronal arcade structure on the HCS and discuss the dynamics involved with the passage of a large scale disturbance through the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012APS..DPPUP8049I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012APS..DPPUP8049I"><span id="translatedtitle">Measurements of line-<span class="hlt">averaged</span> electron density of pulsed plasmas using a He-Ne laser interferometer in a <span class="hlt">magnetized</span> coaxial plasma gun device</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Iwamoto, D.; Sakuma, I.; Kitagawa, Y.; Kikuchi, Y.; Fukumoto, N.; Nagata, M.</p> <p>2012-10-01</p> <p>In next step of fusion devices such as ITER, lifetime of plasma-facing materials (PFMs) is strongly affected by transient heat and particle loads during type I edge localized modes (ELMs) and disruption. To clarify damage characteristics of the PFMs, transient heat and particle loads have been simulated by using a plasma gun device. We have performed simulation experiments by using a <span class="hlt">magnetized</span> coaxial plasma gun (MCPG) device at University of Hyogo. The line-<span class="hlt">averaged</span> electron density measured by a He-Ne interferometer is 2x10^21 m-3 in a drift tube. The plasma velocity measured by a time of flight technique and ion Doppler spectrometer was 70 km/s, corresponding to the ion energy of 100 eV for helium. Thus, the ion flux density is 1.4x10^26 m-2s-1. On the other hand, the MCPG is connected to a target chamber for material irradiation experiments. It is important to measure plasma parameters in front of target materials in the target chamber. In particular, a vapor cloud layer in front of the target material produced by the pulsed plasma irradiation has to be characterized in order to understand surface damage of PFMs under ELM-like plasma bombardment. In the conference, preliminary results of application of the He-Ne laser interferometer for the above experiment will be shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730006137','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730006137"><span id="translatedtitle">The <span class="hlt">interplanetary</span> pioneers. Volume 1: Summary</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Corliss, W. R.</p> <p>1972-01-01</p> <p>The Pioneer Space Probe Project is explained to document the events which occurred during the project. The subjects discussed are: (1) origin and history of <span class="hlt">interplanetary</span> Pioneer program, (2) Pioneer system development and design, (3) Pioneer flight operations, and (4) Pioneer scientific results. Line drawings, circuit diagrams, illustrations, and photographs are included to augment the written material.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JASS...22..463P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JASS...22..463P"><span id="translatedtitle">Dynamic Model Development for <span class="hlt">Interplanetary</span> Navigation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Park, Eun-Seo; Song, Young-Joo; Yoo, Sung-Moon; Park, Sang-Young; Choi, Kyu-Hong; Yoon, Jae-Cheol; Yim, Jo Ryeong; Choi, Joon-Min; Kim, Byung-Kyo</p> <p>2005-12-01</p> <p>In this paper, the dynamic model development for <span class="hlt">interplanetary</span> navigation has been discussed. The Cowell method for special perturbation theories was employed to develop an <span class="hlt">interplanetary</span> trajectory propagator including the perturbations due to geopotential, the Earth's dynamic polar motion, the gravity of the Sun, the Moon and the other planets in the solar system, the relativistic effect of the Sun, solar radiation pressure, and atmospheric drag. The equations of motion in dynamic model were numerically integrated using Adams-Cowell 11th order predictor-corrector method. To compare the influences of each perturbation, trajectory propagation was performed using initial transfer orbit elements of the Mars Express mission launched in 2003, because it can be the criterion to choose proper perturbation models for navigation upon required accuracy. To investigate the performance of dynamic model developed, it was tested whether the spacecraft can reach the Mars. The <span class="hlt">interplanetary</span> navigation tool developed in this study demonstrated the spacecraft entering the Mars SOI(Sphere of Influence) and its velocity relative to the Mars was less than the escape velocity of the Mars, hence, the spacecraft can arrive at the target planet. The obtained results were also verified by using the AGI Satellite Tool Kit. It is concluded that the developed program is suitable for supporting <span class="hlt">interplanetary</span> spacecraft mission for a future Korean Mars mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19800012928','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19800012928"><span id="translatedtitle"><span class="hlt">Interplanetary</span> monitoring platform engineering history and achievements</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Butler, P. M.</p> <p>1980-01-01</p> <p>In the fall of 1979, last of ten <span class="hlt">Interplanetary</span> Monitoring Platform Satellite (IMP) missions ended a ten year series of flights dedicated to obtaining new knowledge of the radiation effects in outer space and of solar phenomena during a period of maximum solar flare activity. The technological achievements and scientific accomplishments from the IMP program are described.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012LPICo1679.4146W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012LPICo1679.4146W"><span id="translatedtitle">Hummingbird: Dramatically Reducing <span class="hlt">Interplanetary</span> Mission Cost</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wertz, J. R.; Van Allen, R. E.; Sarzi-Amade, N.; Shao, A.; Taylor, C.</p> <p>2012-06-01</p> <p>The Hummingbird <span class="hlt">interplanetary</span> spacecraft has an available delta V of 2 to 4 km/sec and a recurring cost of 2 to 3 million, depending on the payload and configuration. The baseline telescope has a resolution of 30 cm at a distance of 100 km.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005JGRA..11011105L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005JGRA..11011105L"><span id="translatedtitle">Extreme <span class="hlt">interplanetary</span> rotational discontinuities at 1 AU</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lepping, R. P.; Wu, C.-C.</p> <p>2005-11-01</p> <p>This study is concerned with the identification and description of a special subset of four Wind <span class="hlt">interplanetary</span> rotational discontinuities (from an earlier study of 134 directional discontinuities by Lepping et al. (2003)) with some "extreme" characteristics, in the sense that every case has (1) an almost planar current sheet surface, (2) a very large discontinuity angle (?), (3) at least moderately strong normal field components (>0.8 nT), and (4) the overall set has a very broad range of transition layer thicknesses, with one being as thick as 50 RE and another at the other extreme being 1.6 RE, most being much thicker than are usually studied. Each example has a well-determined surface normal (n) according to minimum variance analysis and corroborated via time delay checking of the discontinuity with observations at IMP 8 by employing the local surface planarity. From the variance analyses, most of these cases had unusually large ratios of intermediate-to-minimum eigenvalues (?I/?min), being on <span class="hlt">average</span> 32 for three cases (with a fourth being much larger), indicating compact current sheet transition zones, another (the fifth) extreme property. For many years there has been a controversy as to the relative distribution of rotational (RDs) to tangential discontinuities (TDs) in the solar wind at 1 AU (and elsewhere, such as between the Sun and Earth), even to the point where some authors have suggested that RDs with large ?Bn?s are probably not generated or, if generated, are unstable and therefore very rare. Some of this disagreement apparently has been due to the different selection criteria used, e.g., some allowed eigenvalue ratios (?I/?min) to be almost an order of magnitude lower than 32 in estimating n, usually introducing unacceptable error in n and therefore also in ?Bn?. However, we suggest that RDs may not be so rare at 1 AU, but good quality cases (where ?Bn? confidently exceeds the error in ?Bn?) appear to be uncommon, and further, cases of large ?Bn? may indeed be rare. Finally, the issue of estimating the number of RDs-to-TDs was revisited using the full 134 events of the original Lepping et al. (2003) study (which utilized the RDs' propagation speeds for this estimation, an unconventional approach) but now by considering only normal field components, the more conventional approach. This resulted in slightly different conclusions, depending on specific assumptions used, making the unconventional approach suspect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740014311','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740014311"><span id="translatedtitle">Investigations of cosmic ray anisotropies and their relationship to concurrent <span class="hlt">magnetic</span> field data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Allum, F. R.</p> <p>1974-01-01</p> <p>Investigations of cosmic ray anisotropies and their relationship to concurrent <span class="hlt">magnetic</span> field data are reported. These investigations range in scope from the examination of data very late in the decay phase of a solar particle event where long term (approximately 6 hour) <span class="hlt">averages</span> are used and definite <span class="hlt">interplanetary</span> effects sought after to an examination of the change in low energy particle anisotropy as the satellite approaches the bow shock and the magnetopause.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740038948&hterms=motion+types+motion&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmotion%2Btypes%2Bmotion','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740038948&hterms=motion+types+motion&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmotion%2Btypes%2Bmotion"><span id="translatedtitle">Motion of the sources for type II and type IV radio bursts and flare-associated <span class="hlt">interplanetary</span> disturbances</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sakurai, K.; Chao, J. K.</p> <p>1974-01-01</p> <p>Shock waves are indirectly observed as the source of type II radio bursts, whereas <span class="hlt">magnetic</span> bottles are identified as the source of moving metric type IV radio bursts. The difference between the expansion speeds of these waves and bottles is examined during their generation and propagation near the flare regions. It is shown that, although generated in the explosive phase of flares, the bottles behave quite differently from the waves and that the bottles are generally much slower than the waves. It has been suggested that the waves are related to flare-associated <span class="hlt">interplanetary</span> disturbances which produce SSC geomagnetic storms. These disturbances may, therefore, be identified as <span class="hlt">interplanetary</span> shock waves. The relationship among <span class="hlt">magnetic</span> bottles, shock waves near the sun, and flare-associated disturbances in <span class="hlt">interplanetary</span> space is briefly discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790059028&hterms=wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwind%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790059028&hterms=wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dwind%2Benergy"><span id="translatedtitle">Relationship between the growth of the ring current and the <span class="hlt">interplanetary</span> quantity. [solar wind energy-magnetospheric coupling parameter correlation with substorm AE index</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Akasofu, S.-I.</p> <p>1979-01-01</p> <p>Akasofu (1979) has reported that the <span class="hlt">interplanetary</span> parameter epsilon correlates reasonably well with the magnetospheric substorm index AE; in the first approximation, epsilon represents the solar wind coupled to the magnetosphere. The correlation between the <span class="hlt">interplanetary</span> parameter, the auroral electrojet index and the ring current index is examined for three <span class="hlt">magnetic</span> storms. It is shown that when the <span class="hlt">interplanetary</span> parameter exceeds the amount that can be dissipated by the ionosphere in terms of the Joule heat production, the excess energy is absorbed by the ring current belt, producing an abnormal growth of the ring current index.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_20 --> <div id="page_21" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="401"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19730002087&hterms=Lange&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DLange%252C%2BW','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19730002087&hterms=Lange&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DLange%252C%2BW"><span id="translatedtitle">Interstellar helium in <span class="hlt">interplanetary</span> space</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Feldman, W. C.; Lange, J. J.; Scherb, F.</p> <p>1972-01-01</p> <p>The velocity distribution function of He(+) in the solar wind at 1 AU is calculated with the assumption that the source is photoionization of a cold (T = 100 K), neutral interstellar wind. If the spiral <span class="hlt">magnetic</span> field is noise free, the velocity distribution is diffuse and would not produce a peak at 4(E over Q) sub H in an E over Q particle spectrum. If the velocity of the interstellar wind with respect to the sun lies in the ecliptic, a large variation of the He(+) number density with respect to ecliptic longitude is expected.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20070026139&hterms=environmental+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Denvironmental%2Banalysis','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070026139&hterms=environmental+analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Denvironmental%2Banalysis"><span id="translatedtitle">Planetary and <span class="hlt">Interplanetary</span> Environmental Models for Radiation Analysis</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>DeAngelis, G.; Cucinotta, F. A.</p> <p>2005-01-01</p> <p>The essence of environmental modeling is presented as suited for radiation analysis purposes. The variables of fundamental importance for radiation environmental assessment are discussed. The characterization is performed by dividing modeling into three areas, namely the <span class="hlt">interplanetary</span> medium, the circumplanetary environment, and the planetary or satellite surface. In the first area, the galactic cosmic rays (GCR) and their modulation by the heliospheric <span class="hlt">magnetic</span> field as well as and solar particle events (SPE) are considered, in the second area the magnetospheres are taken into account, and in the third area the effect of the planetary environment is also considered. Planetary surfaces and atmospheres are modeled based on results from the most recent targeted spacecraft. The results are coupled with suited visualization techniques and radiation transport models in support of trade studies of health risks for future exploration missions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760012956','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760012956"><span id="translatedtitle">On the acceleration of energetic particles in the <span class="hlt">interplanetary</span> medium</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fisk, L. A.</p> <p>1976-01-01</p> <p>Fermi scattering and transit time damping are two possible mechanisms for accelerating low energy protons (approximately 1 Mev) in co-rotating particle streams. Solutions to the equations which govern particle behavior in such streams are presented. It was found that acceleration by Fermi scattering requires a scattering mean-free path more than an order of magnitude smaller than the nominal value for low energy particles of 0.1 AU. Transit time damping of only the observed low level of magnitude fluctuations in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field appears to yield the required acceleration rate. Measurements of the direction of the anisotropy in the particle streams could help in deciding which mechanism is operative. In the case of Fermi scattering the anisotropy must be in the heliocentric radial direction, whereas for transit time damping a significant azimuthal anisotropy could be present.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740029875&hterms=kinetic+alfven+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dkinetic%2Balfven%2Bwaves','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740029875&hterms=kinetic+alfven+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dkinetic%2Balfven%2Bwaves"><span id="translatedtitle">Alfven waves in spiral <span class="hlt">interplanetary</span> field. [microscale MHD waves</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Whang, Y. C.</p> <p>1973-01-01</p> <p>This paper presents a theoretical study of the Alfven waves in the spiral <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. The Alfven waves under consideration are arbitrary large-amplitude nonmonochromatic microscale waves of any polarization. They superpose on a mesoscale background flow of thermally anisotropic plasma. When the WKB approximation is used, an analytical solution for the amplitude vectors is obtained as a function of the background flow properties: density, velocity, Alfven speed, thermal anisotropy, and the spiral angle. The relative intensity of fluctuations compared with the magnitude of the background field has its maximum in the region near 1 AU. Thus outside of this region the solar wind is less turbulent. Owing to attenuation of microscale Alfven waves, fluctuation energy is converted into the kinetic energy of the solar wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=EL-1994-00334&hterms=FAS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DFAS','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=EL-1994-00334&hterms=FAS&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DFAS"><span id="translatedtitle">LDEF (Prelaunch), AO201 : <span class="hlt">Interplanetary</span> Dust Experiment, Tray G10</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1984-01-01</p> <p>The prelaunch photograph shows the Inter planetary Dust Experiment (IDE) in a three (3) inch deep corner tray. The IDE is an active exper iment and is located on the earth facing end of the LDEF in the G10 location. AO201 - The <span class="hlt">Interplanetary</span> Dust Experiment (IDE) is an active experiment consisting of impact detectors, detector frames, a solar sensor and the necessary mounting hardware. The eighty (80) detectors, metal-oxide-silicon (MOS) capacitor-type impact sensors, bonded into anodized alumi num frames, are attached to the aluminum mounting plate with non-<span class="hlt">magnetic</span> stainless steel fas teners. A solar sensor, four (4) silicon solar cells in series mounted on an aluminum baseplate, is shown in the approximate center of the IDE mounting plate. The different colors seen on the detectors are the reflections of LDEF technicians and the surrounding clean room work area.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19810058178&hterms=electric+current&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2528electric%2Bcurrent%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810058178&hterms=electric+current&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2528electric%2Bcurrent%2529"><span id="translatedtitle">An electrodynamic model of electric currents and <span class="hlt">magnetic</span> fields in the dayside ionosphere of Venus</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cloutier, P. A.; Tascione, T. F.; Danieli, R. E., Jr.</p> <p>1981-01-01</p> <p>The electric current configuration induced in the ionosphere of Venus by the interaction of the solar wind has been calculated in previous papers (Cloutier and Daniell, 1973; Daniell and Cloutier, 1977; Cloutier and Daniell, 1979) for <span class="hlt">average</span> steady-state solar wind conditions and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. This model is generalized to include the effects of (1) plasma depletion and <span class="hlt">magnetic</span> field enhancement near the ionopause, (2) velocity-shear-induced MHD instabilities of the Kelvin-Helmholtz type within the ionosphere, and (3) variations in solar wind parameters and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. It is shown that the <span class="hlt">magnetic</span> field configuration resulting from the model varies in response to changes in solar wind and <span class="hlt">interplanetary</span> field conditions, and that these variations produce <span class="hlt">magnetic</span> field profiles in excellent agreement with those seen by the Pioneer-Venus Orbiter. The formation of flux-ropes by the Kelving-Helmholtz instability is shown to be a natural consequence of the model, with the spatial distribution and size of the flux-ropes determined by the <span class="hlt">magnetic</span> Reynolds number.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12804366','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12804366"><span id="translatedtitle">Fullerenes and <span class="hlt">interplanetary</span> dust at the Permian-Triassic boundary.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Poreda, Robert J; Becker, Luann</p> <p>2003-01-01</p> <p>We recently presented new evidence that an impact occurred approximately 250 million years ago at the Permian-Triassic boundary (PTB), triggering the most severe mass extinction in the history of life on Earth. We used a new extraterrestrial tracer, fullerene, a third carbon carrier of noble gases besides diamond and graphite. By exploiting the unique properties of this molecule to trap noble gases inside of its caged structure (helium, neon, argon), the origin of the fullerenes can be determined. Here, we present new evidence for fullerenes with extraterrestrial noble gases in the PTB at Graphite Peak, Antarctica, similar to PTB fullerenes from Meishan, China and Sasayama, Japan. In addition, we isolated a (3)He-rich <span class="hlt">magnetic</span> carrier phase in three fractions from the Graphite Peak section. The noble gases in this <span class="hlt">magnetic</span> fraction were similar to zero-age deep-sea <span class="hlt">interplanetary</span> dust particles (IDPs) and some <span class="hlt">magnetic</span> grains isolated from the Cretaceous-Tertiary boundary. The helium and neon isotopic compositions for both the bulk Graphite Peak sediments and an isolated <span class="hlt">magnetic</span> fraction from the bulk material are consistent with solar-type gases measured in zero-age deep-sea sediments and point to a common source, namely, the flux of IDPs to the Earth's surface. In this instance, the IDP noble gas signature for the bulk sediment can be uniquely decoupled from fullerene, demonstrating that two separate tracers are present (direct flux of IDPs for (3)He vs. giant impact for fullerene). PMID:12804366</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840053291&hterms=Power+Flow&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DPower%2BFlow','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840053291&hterms=Power+Flow&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DPower%2BFlow"><span id="translatedtitle">Power spectral signatures of <span class="hlt">interplanetary</span> corotating and transient flows</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldstein, M. L.; Burlaga, L. F.; Matthaeus, W. H.</p> <p>1984-01-01</p> <p>Studies of the time behavior of the galactic cosmic ray intensity have concluded that long term decreases in the intensity are generally associated with systems of <span class="hlt">interplanetary</span> flows that contain flare generated shock waves, <span class="hlt">magnetic</span> clouds and other transient phenomena. The <span class="hlt">magnetic</span> field power spectral signatures of such flow systems are compared to power spectra obtained during times when the solar wind is dominated by stable corotating streams that do not usually produce long-lived reduction in the cosmic ray intensity. The spectral signatures of these two types of regimes (transient and corotating) are distinct. However, the distinguishing features are not the same throughout the heliosphere. In data collected beyond 1 AU the primary differences are in the power spectra of the magnitude of the <span class="hlt">magnetic</span> field rather than in the power in the field components. Consequently, decreases in cosmic ray intensity are very likely due to <span class="hlt">magnetic</span> mirror forces and gradient drifts rather than to small angle scattering due to cyclotron wave-particle interactions. Previously announced in STAR as N84-18131</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/787785','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/787785"><span id="translatedtitle">Toroidal Plasma Thruster for <span class="hlt">Interplanetary</span> and Interstellar Space Flights</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>N.N. Gorelenkov; L.E. Zakharov; and M.V. Gorelenkova</p> <p>2001-07-11</p> <p>This work involves a conceptual assessment for using the toroidal fusion reactor for deep space <span class="hlt">interplanetary</span> and interstellar missions. Toroidal thermonuclear fusion reactors, such as tokamaks and stellarators, are unique for space propulsion, allowing for a design with the <span class="hlt">magnetic</span> configuration localized inside toroidal <span class="hlt">magnetic</span> field coils. Plasma energetic ions, including charged fusion products, can escape such a closed configuration at certain conditions, a result of the vertical drift in toroidal rippled <span class="hlt">magnetic</span> field. Escaping particles can be used for direct propulsion (since toroidal drift is directed one way vertically) or to create and heat externally confined plasma, so that the latter can be used for propulsion. Deuterium-tritium fusion neutrons with an energy of 14.1 MeV also can be used for direct propulsion. A special design allows neutrons to escape the shield and the blanket of the tokamak. This provides a direct (partial) conversion of the fusion energy into the directed motion of the propellant. In contrast to other fusion concepts proposed for space propulsion, this concept utilizes the natural drift motion of charged particles out of the closed <span class="hlt">magnetic</span> field configuration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH43A4175K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH43A4175K"><span id="translatedtitle">Multi-Spacecraft Observations of <span class="hlt">Interplanetary</span> Shocks Near Earth</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kajdic, P.; Blanco-Cano, X.; Lavraud, B.</p> <p>2014-12-01</p> <p>Space missions around Earth have been continuously monitoring solar wind and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field for many years now. They have detected a large number of <span class="hlt">interplanetary</span> (IP) shocks. These have been observed with multiple spacecraft at separations ranging from 103 km to several 105. Comparing observations of IP shocks at different locations in space can provide us with important insights on micro-physical processes that take place near or within the shock transitions. We have compiled a database of about 50 IP shocks detected between 2001 and 2014 with several missions. In the first part of our research we calculated local normals of IP shocks by using different one-spacecraft methods and also the 4-spacecraft method, when possible. In some cases we were able to compare the results of the latter method for different inter-spacecraft separations. This is the first time that comparison of IP shock profiles is also performed systematically on small inter-spacecraft separations of several 100 km (Cluster and Themis observations). Shock normals obtained by using different spacecraft configurations may differ. We find that spacecraft observe different shock profiles even when the their separations are only ~1000 km and the detection times differ by less than a second. The four-spacecraft method is less reliable when the detection times are small, since the changing shock profiles and uncertainties related to timing of the shock arrivals may distort the calculations. We also study regions upstream and downstream of IP shocks - we analyze the properties of suprathermal particles and <span class="hlt">magnetic</span> perturbations there.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015A%26A...582A..52A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015A%26A...582A..52A"><span id="translatedtitle">A tiny event producing an <span class="hlt">interplanetary</span> type III burst</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alissandrakis, C. E.; Nindos, A.; Patsourakos, S.; Kontogeorgos, A.; Tsitsipis, P.</p> <p>2015-10-01</p> <p>Aims: We investigate the conditions under which small-scale energy release events in the low corona gave rise to strong <span class="hlt">interplanetary</span> (IP) type III bursts. Methods: We analyzed observations of three tiny events, detected by the Nanay Radio Heliograph (NRH), two of which produced IP type III bursts. We took advantage of the NRH positioning information and of the high cadence of AIA/SDO data to identify the associated extreme-UV (EUV) emissions. We measured positions and time profiles of the metric and EUV sources. Results: We found that the EUV events that produced IP type III bursts were located near a coronal hole boundary, while the one that did not was located in a closed <span class="hlt">magnetic</span> field region. In all three cases tiny flaring loops were involved, without any associated mass eruption. In the best observed case, the radio emission at the highest frequency (435 MHz) was displaced by ~55'' with respect to the small flaring loop. The metric type III emission shows a complex structure in space and in time, indicative of multiple electron beams, despite the low intensity of the events. From the combined analysis of dynamic spectra and NRH images, we derived the electron beam velocity as well as the height, ambient plasma temperature, and density at the level of formation of the 160 MHz emission. From the analysis of the differential emission measure derived from the AIA images, we found that the first evidence of energy release was at the footpoints, and this was followed by the development of flaring loops and subsequent cooling. Conclusions: Even small energy release events can accelerate enough electrons to give rise to powerful IP type III bursts. The proximity of the electron acceleration site to open <span class="hlt">magnetic</span> field lines facilitates the escape of the electrons into the <span class="hlt">interplanetary</span> space. The offset between the site of energy release and the metric type III location warrants further investigation. The movie is available in electronic form at http://www.aanda.org</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987fuen.symp.....O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987fuen.symp.....O"><span id="translatedtitle">The VISTA spacecraft: Advantages of ICF (Inertial Confinement Fusion) for <span class="hlt">interplanetary</span> fusions propulsion applications</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Orth, Charles D.; Klein, Gail; Sercel, Joel; Hoffman, Nate; Murray, Kathy; Chang-Diaz, Franklin</p> <p>1987-10-01</p> <p>Inertial Confinement Fusion (ICF) is an attractive engine power source for <span class="hlt">interplanetary</span> manned spacecraft, especially for near-term missions requiring minimum flight duration, because ICF has inherent high power-to-mass ratios and high specific impulses. We have developed a new vehicle concept called VISTA that uses ICF and is capable of round-trip manned missions to Mars in 100 days using A.D. 2020 technology. We describe VISTA's engine operation, discuss associated plasma issues, and describe the advantages of DT fuel for near-term applications. Although ICF is potentially superior to non-fusion technologies for near-term <span class="hlt">interplanetary</span> transport, the performance capabilities of VISTA cannot be meaningfully compared with those of <span class="hlt">magnetic</span>-fusion systems because of the lack of a comparable study of the <span class="hlt">magnetic</span>-fusion systems. We urge that such a study be conducted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120015887','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120015887"><span id="translatedtitle">Coronal Mass Ejections Near the Sun and in the <span class="hlt">Interplanetary</span> Medium</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gopalswamy, Nat</p> <p>2012-01-01</p> <p>Coronal mass ejections (CMEs) are the most energetic phenomenon in the heliosphere. During solar eruptions, the released energy flows out from the Sun in the form of <span class="hlt">magnetized</span> plasma and electromagnetic radiation. The electromagnetic radiation suddenly increases the ionization content of the ionosphere, thus impacting communication and navigation systems. The plasma clouds can drive shocks that accelerate charged particles to very high energies in the <span class="hlt">interplanetary</span> space, which pose radiation hazard to astronauts and space systems. The plasma clouds also arrive at Earth in about two days and impact Earth's magnetosphere, producing geomagnetic storms. The <span class="hlt">magnetic</span> storms result in a number of effects including induced currents that can disrupt power grids, railroads, and underground pipelines. This lecture presents an overview of the origin, propagation, and geospace consequences of CMEs and their <span class="hlt">interplanetary</span> counterparts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930055986&hterms=Theory+everything&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D10%26Ntt%3DTheory%2Beverything','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930055986&hterms=Theory+everything&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D10%26Ntt%3DTheory%2Beverything"><span id="translatedtitle">Quasi-linear theory and transport theory. [particle acceleration in <span class="hlt">interplanetary</span> medium</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, Charles W.</p> <p>1992-01-01</p> <p>The theory of energetic particle scattering by magnetostatic fluctuations is reviewed in so far as it fails to produce the rigidity-independent mean-free-paths observed. Basic aspects of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field fluctuations are reviewed with emphasis placed on the existence of dissipation range spectra at high wavenumbers. These spectra are then incorporated into existing theories for resonant magnetostatic scattering and are shown to yield infinite mean-free-paths. Nonresonant scattering in the form of <span class="hlt">magnetic</span> mirroring is examined and offered as a partial solution to the magnetostatic problem. In the process, mean-free-paths are obtained in good agreement with observations in the <span class="hlt">interplanetary</span> medium at 1 AU and upstream of planetary bow shocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880003642','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880003642"><span id="translatedtitle">The VISTA spacecraft: Advantages of ICF (Inertial Confinement Fusion) for <span class="hlt">interplanetary</span> fusions propulsion applications</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Orth, Charles D.; Klein, Gail; Sercel, Joel; Hoffman, Nate; Murray, Kathy; Chang-Diaz, Franklin</p> <p>1987-01-01</p> <p>Inertial Confinement Fusion (ICF) is an attractive engine power source for <span class="hlt">interplanetary</span> manned spacecraft, especially for near-term missions requiring minimum flight duration, because ICF has inherent high power-to-mass ratios and high specific impulses. We have developed a new vehicle concept called VISTA that uses ICF and is capable of round-trip manned missions to Mars in 100 days using A.D. 2020 technology. We describe VISTA's engine operation, discuss associated plasma issues, and describe the advantages of DT fuel for near-term applications. Although ICF is potentially superior to non-fusion technologies for near-term <span class="hlt">interplanetary</span> transport, the performance capabilities of VISTA cannot be meaningfully compared with those of <span class="hlt">magnetic</span>-fusion systems because of the lack of a comparable study of the <span class="hlt">magnetic</span>-fusion systems. We urge that such a study be conducted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6112845','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6112845"><span id="translatedtitle">The VISTA spacecraft: Advantages of ICF (Inertial Confinement Fusion) for <span class="hlt">interplanetary</span> fusion propulsion applications</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Orth, C.D.; Klein, G.; Sercel, J.; Hoffman, N.; Murray, K.; Chang-Diaz, F.</p> <p>1987-10-02</p> <p>Inertial Confinement Fusion (ICF) is an attractive engine power source for <span class="hlt">interplanetary</span> manned spacecraft, especially for near-term missions requiring minimum flight duration, because ICF has inherent high power-to-mass ratios and high specific impulses. We have developed a new vehicle concept called VISTA that uses ICF and is capable of round-trip manned missions to Mars in 100 days using A.D. 2020 technology. We describe VISTA's engine operation, discuss associated plasma issues, and describe the advantages of DT fuel for near-term applications. Although ICF is potentially superior to non-fusion technologies for near-term <span class="hlt">interplanetary</span> transport, the performance capabilities of VISTA cannot be meaningfully compared with those of <span class="hlt">magnetic</span>-fusion systems because of the lack of a comparable study of the <span class="hlt">magnetic</span>-fusion systems. We urge that such a study be conducted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSM41A2008L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSM41A2008L"><span id="translatedtitle">Heating of Plasmas in the Near-Earth Magnetotail by the Impact of an <span class="hlt">Interplanetary</span> Shock</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, E.; Parks, G. K.; Wilber, M.; Lin, N.; Kim, K.; Lee, D.; SEON, J.; Jin, H.</p> <p>2011-12-01</p> <p>It has been reported that radiation belt particles are rapidly energized by the impact of an <span class="hlt">interplanetary</span> shock. In this study we report the observations by Cluster spacecraft that strong heating of plasmas occurs in the near-Earth magnetotail at ~-17 RE when an <span class="hlt">interplanetary</span> shock impacts Earth's magnetosphere. On 24 August 2005 an <span class="hlt">interplanetary</span> shock impacted Earth's magnetosphere and induced a storm sudden commencement (SSC) and <span class="hlt">magnetic</span> storm. After the SSC both the density and temperature of plasmas in the near-Earth magnetotail significantly increased. The increases are more clearly seen in electrons than ions. Also, the particle fluxes of ions and electrons with E > ~30 keV increased more than an order of magnitude after the SSC. For ions significant flux enhancement was observed up to ~92.2 keV. On the other hand, for electrons the enhancement was observed up to ~127.5 keV. These results suggest that the heating is more efficient on electrons than ions. We will discuss about the physical mechanism responsible for the heating of plasmas in the magnetotail due to the impact of an <span class="hlt">interplanetary</span> shock.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AN....336..749B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AN....336..749B"><span id="translatedtitle"><span class="hlt">Interplanetary</span> GPS using pulsar signals</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Becker, W.; Bernhardt, M. G.; Jessner, A.</p> <p>2015-11-01</p> <p>An external reference system suitable for deep space navigation can be defined by fast spinning and strongly <span class="hlt">magnetized</span> neutron stars, called pulsars. Their beamed periodic signals have timing stabilities comparable to atomic clocks and provide characteristic temporal signatures that can be used as natural navigation beacons, quite similar to the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location, the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. The unique properties of pulsars make clear already today that such a navigation system will have its application in future astronautics. In this paper we describe the basic principle of spacecraft navigation using pulsars and report on the current development status of this novel technology.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750022920','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750022920"><span id="translatedtitle">The <span class="hlt">interplanetary</span> acceleration of energetic nucleons</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mcdonald, F. B.; Teegarden, B. J.; Trainor, J. H.; Vonrosenvinge, T. T.; Webber, W. R.</p> <p>1975-01-01</p> <p>Co-rotating proton and electron streams are the dominant type of low-energy (0.1-10 MeV/nucleon) particle event observed at 1 A.U. The radial dependence of these events was studied between 1 and 4.6 A.U. using essentially identical low-energy detector systems on IMP 7, Pioneer 10 and Pioneer 11. It was expected that at a given energy, the intensity of these streams would decrease rapidly with heliocentric distance due to the effects of <span class="hlt">interplanetary</span> adiabatic deceleration. Instead it was found that from event to event the intensity either remains roughly constant or increases significantly (more than an order of magnitude) between 1 and 3 A.U. It appears that <span class="hlt">interplanetary</span> acceleration processes are the most plausible explanation. Several possible acceleration models are explored.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890056998&hterms=tin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dtin','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890056998&hterms=tin&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dtin"><span id="translatedtitle">Tin in a chondritic <span class="hlt">interplanetary</span> dust particle</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rietmeijer, Frans J. M.</p> <p>1989-01-01</p> <p>Submicron platey Sn-rich grains are present in chondritic porous <span class="hlt">interplanetary</span> dust particle (IDP) W7029 A and it is the second occurrence of a tin mineral in a stratospheric micrometeorite. Selected Area Electron Diffraction data for the Sn-rich grains match with Sn2O3 and Sn3O4. The oxide(s) may have formed in the solar nebula when tin metal catalytically supported reduction of CO or during flash heating on atmospheric entry of the IDP. The presence of tin is consistent with enrichments for other volatile trace elements in chondritic IDPs and may signal an emerging trend toward nonchondritic volatile element abundances in chondritic IDPs. The observation confirms small-scale mineralogical heterogeneity in fine-grained chondritic porous <span class="hlt">interplanetary</span> dust.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li class="active"><span>21</span></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_21 --> <div id="page_22" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="421"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740061138&hterms=streaming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dstreaming','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740061138&hterms=streaming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dstreaming"><span id="translatedtitle">Cosmic-ray streaming perpendicular to the mean <span class="hlt">magnetic</span> field</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Forman, M. A.; Jokipii, J. R.; Owens, A. J.</p> <p>1974-01-01</p> <p>Starting from a quasi-linear approximation for the ensemble-<span class="hlt">averaged</span> particle distribution function in a random <span class="hlt">magnetic</span> field, the complete diffusion tensor is derived. This is done by assuming a simple form for the ensemble-<span class="hlt">averaged</span> distribution function, explicitly retaining all components of the streaming flux. This derivation obtains the antisymmetric terms in a natural manner. The necessary dropping of higher-order terms gives a criterion for the lower-energy limit of validity of the perpendicular and antisymmetric diffusion coefficients. The limit for the assumed distribution function is about 0.8 GV rigidity in the <span class="hlt">interplanetary</span> field near 1 AU.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982mmis.proc.....B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982mmis.proc.....B"><span id="translatedtitle">Meteor matter in the <span class="hlt">interplanetary</span> space. ????????? ???????? ? ???????????? ????????????</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bel'kovich, O. I.; Babadzhanov, P. B.; Bronshten, V. A.; Sulejmanov, N. I.</p> <p>1982-05-01</p> <p>Proceedings of the All-USSR symposium "Meteor matter in the <span class="hlt">interplanetary</span> space" held in Kazan, USSR, Sept. 9-11, 1980. The 39 papers included cover the following topics: structure of the meteoroid complex in the vicinity of the Earth, observed structure of meteor showers, index of mass distribution in meteor showers, meteoroid streams and their evolution, densities and fragmentation of meteor bodies, meteor spectrums etc. The Proceedings are published in Russian, but includes the Contents and Abstracts in English.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36.1369G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36.1369G"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Proton Cumulated Fluence Model Update</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glover, A.; Hilgers, A.; Rosenqvist, L.; Evans, H.</p> <p></p> <p>Solar particle events constitute an important concern for space missions They may lead to effects seen in microelectronics or damage to solar cells and constitute a potential hazard for manned missions In order to estimate the risk related to mission integrated fluence a number of models have been developed which apply statistical analysis based on the collection of solar proton data from a variety of sources during the last few solar cycles Recent results have demonstrated the influence of assumptions and data caveats on these analyses This paper extends work done by Rosenqvist et al 2005 and Feynman et al 1990 1993 2002 to describe an updated engineering model for the proton <span class="hlt">interplanetary</span> fluence with energies 1 4 30 and 60 MeV This model is derived from a public list of solar proton fluences based on inter-calibrated data from a number of sources covering almost 3 solar cycles References J Feynman T P Armstrong L Dao-Gibner and S Silverman A New <span class="hlt">Interplanetary</span> Proton Fluence Model J Spacecraft and Rockets 27 403 1990 J Feynman G Spitale J Wang and S Gabriel <span class="hlt">Interplanetary</span> proton fluence model JPL 1991 J Geophys Res 98 13281-13294 1993 J Feynman A Ruznaikin and V Berdichevsky The JPL proton fluence model an update J Atmos Solar-Terr Phys 64 1679-1686 2002 Rosenqvist L A Hilgers H Evans E Daly M Hapgood R Stamper and R Zwickl S Bourdarie and D Bosher A toolkit for updating <span class="hlt">interplanetary</span> proton cumulated fluence models J Spacecraft and Rockets Vol 42</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E1986M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E1986M"><span id="translatedtitle">Dusty Plasma Effects in the <span class="hlt">Interplanetary</span> Medium?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Mann, Ingrid; Issautier, Karine; Meyer-Vernet, Nicole; Le Chat, Gaétan; Czechowski, Andrzej; Zaslavsky, Arnaud; Zouganelis, Yannis; Belheouane, Soraya</p> <p></p> <p>Cosmic dust particles exist in a variety of compositions and sizes in the <span class="hlt">interplanetary</span> medium. There is little direct information on the composition, but those <span class="hlt">interplanetary</span> dust particles that are collected in the upper Earth’s atmosphere and can be studied in the laboratory typically have an irregular, sometimes porous structure on scales <100 nm. They contain magnesium-rich silicates and silicon carbide, iron-nickel and iron-sulfur compounds, calcium- and aluminum oxides, and chemical compounds that contain a large mass fraction of carbon (e.g. carbonaceous species). A fraction of the dust originates from comets, but because of their bulk material temperature of about 280 K near 1 AU, most icy compounds have disappeared. The dust particles are embedded in the solar wind, a hot plasma with at 1 AU kinetic temperatures around 100 000 K and flow direction nearly radial outward from the Sun at supersonic bulk velocities around 400 km/s. Since the dust particles carry an electric surface charge they are subject to electromagnetic forces and the nanodust particles are efficiently accelerated to velocities of order of solar wind speed. The acceleration of the nanodust is similar, but not identical to the formation of pick-up ions. The S/WAVES radio wave instrument on STEREO measured a flux of nanodust at 1 AU [1]. The nanodust probably forms in the region inward of 1 AU and is accelerated by the solar wind as discussed. We also discuss the different paths of dust - plasma interactions in the <span class="hlt">interplanetary</span> medium and their observations with space experiments. Comparing these interactions we show that the <span class="hlt">interplanetary</span> medium near 1 AU can in many cases be described as “dust in plasma" rather than "dusty plasma”. [1] S. Belheouane, N. Meyer-Vernet, K. Issautier, G. Le Chat, A. Zaslavsky, Y. Zouganelis, I. Mann, A. Czechowski: Dynamics of nanoparticles detected at 1 AU by S/WAVES onboard STEREO spacecraft, in this session.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040171195','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040171195"><span id="translatedtitle">Identification of <span class="hlt">Interplanetary</span> Coronal Mass Ejections at 1 AU Using Multiple Solar Wind Plasma Composition Anomalies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richardson, I. G.; Cane, H. V.</p> <p>2004-01-01</p> <p>We investigate the use of multiple simultaneous solar wind plasma compositional anomalies, relative to the composition of the ambient solar wind, for identifying <span class="hlt">interplanetary</span> coronal mass ejection (ICME) plasma. We first summarize the characteristics of several solar wind plasma composition signatures (O(+7)/O(+6), Mg/O, Ne/O, Fe charge states, He/p) observed by the ACE and WIND spacecraft within the ICMEs during 1996 - 2002 identsed by Cane and Richardson. We then develop a set of simple criteria that may be used to identify such compositional anomalies, and hence potential ICMEs. To distinguish these anomalies from the normal variations seen in ambient solar wind composition, which depend on the wind speed, we compare observed compositional signatures with those 'expected' in ambient solar wind with the same solar wind speed. This method identifies anomalies more effectively than the use of fixed thresholds. The occurrence rates of individual composition anomalies within ICMEs range from approx. 70% for enhanced iron and oxygen charge states to approx. 30% for enhanced He/p (> 0.06) and Ne/O, and are generally higher in <span class="hlt">magnetic</span> clouds than other ICMEs. Intervals of multiple anomalies are usually associated with ICMEs, and provide a basis for the identification of the majority of ICMEs. We estimate that Cane and Richardson, who did not refer to composition data, probably identitied approx. 90% of the ICMEs present. However, around 10% of their ICMEs have weak compositional anomalies, suggesting that the presence of such signatures does not provide a necessary requirement for an ICME. We note a remarkably similar correlation between the Mg/O and O(7)/O(6) ratios in hourly-<span class="hlt">averaged</span> data both within ICMEs and the ambient solar wind. This 'universal' relationship suggests that a similar process (such as minor ion heating by waves inside coronal <span class="hlt">magnetic</span> field loops) produces the first-ionization potential bias and ion freezing-in temperatures in the source regions of both ICMEs and the ambient solar wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850007338&hterms=spent+grain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dspent%2Bgrain','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850007338&hterms=spent+grain&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dspent%2Bgrain"><span id="translatedtitle">Discovery of nuclear tracks in <span class="hlt">interplanetary</span> dust</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bradley, J. P.; Brownlee, D. E.</p> <p>1984-01-01</p> <p>Prior to capture by the Earth's atmosphere individual <span class="hlt">interplanetary</span> dust particles (IDP's) have allegedly spent up to 10 to the 5th power years as discrete bodies within the <span class="hlt">interplanetary</span> medium. Observation of tracks in IDP's in the form of solar flare tracks would provide hitherto unknown data about micrometeorites such as: (1) whether an IDP existed in space as an individual particle or as part of a larger meteroid; (2) the degree to which a particle was heated during the trauma of atmospheric entry; (3) residence time of an IDP within the <span class="hlt">interplanetary</span> medium; and (4) possible hints as to the pre-accretional exposure of component mineral grains to solar or galactic irradiation. Using transmission electron microscopy tracks in several micrometeorites have been successfully identified. All of the studied particles had been retrieved from the stratosphere by U-2 aircraft. Three pristine IDP's (between 5 and 15 micro m diameter) have so far been searched for solar flare tracks, and they have been found in the two smaller particles U2-20B11 (11 micro m) and U2-20B37 (8 micro m).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AcASn..56...44Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AcASn..56...44Q"><span id="translatedtitle">The Study of a Solar Storm and Its <span class="hlt">Interplanetary</span> and Geomagnetic Effects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qiu, B. H.; Li, C.</p> <p>2015-01-01</p> <p>We present a detailed study of a solar storm occurred on 2014 January 7. By using the remote-sensing solar observations from the Solar Dynamics Observatory (SDO) and the Solar and Heliospheric Observatory (SOHO), the eruptions of the solar flare and the coronal mass ejection (CME) are investigated. Based on the particle measurement from the Geostationary Operational Environmental Satellites (GOES) and the in-situ plasma measurement from the Advanced Composition Explorer (ACE), the solar energetic particle (SEP) event, the <span class="hlt">interplanetary</span> CME (ICME), and its driven shock are analyzed. The influence of the solar storm on the geomagnetic fields is also analyzed. The results show that: (1) The impulsive eruption of the solar flare and the lift of the CME are temporally in accordance with each other. (2) The solar protons are mainly accelerated by the CME-driven shock when the CME travels to 7.7 solar radius, rather than by the <span class="hlt">magnetic</span> reconnection in the flare. (3) The widths of the <span class="hlt">interplanetary</span> shock sheath and the ICME itself are derived to be 0.22 AU and 0.26 AU, respectively. (4) The <span class="hlt">interplanetary</span> shock and the ICME give rise to substorms and aurora, whereas no obvious geomagnetic storm is detected. The reason is that the ICME does not include a structure of the <span class="hlt">magnetic</span> cloud (MC) or southward <span class="hlt">magnetic</span> fields.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH43B4199Q','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH43B4199Q"><span id="translatedtitle">Simulations of Solar Energetic Particles Response to <span class="hlt">Interplanetary</span> Coronal Mass Ejections in the Gradual Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Qin, G.; Wang, Y.</p> <p>2014-12-01</p> <p>The gradual Solar Energetic Particle (SEP) events are usually associated with shock waves driven by <span class="hlt">Interplanetary</span> Coronal Mass Ejections (ICMEs). Multi-spacecraft observations show that low-energy (<20 MeV) proton intensities may decrease when the spacecraft enters into the ICMEs. Based on a numerical solution of a focused transport equation, we obtained the fluxes of solar energetic particles (SEPs) accelerated by an <span class="hlt">interplanetary</span> shock in a three-dimensional <span class="hlt">magnetic</span> field. The shock is treated as a moving source of energetic particles with an assumed particle distribution function, while the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field (IMF) disturbances generated by an ICME behind the shock are modeled by a Stokes' stream function with a spherical boundary. We computed the time profiles of particle flux and anisotropy as measured by multi-spacecraft. With perpendicular diffusion, energetic particles can cross <span class="hlt">magnetic</span> field lines, and they can still be detected after the spacecraft enters into the ICMEs. By comparing our simulations with observations, the particle perpendicular diffusion coefficients can be qualitatively determined, and the radial and latitudinal variations of SEPs response to ICMEs have been studied.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750016564','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750016564"><span id="translatedtitle">A New Look at Jupiter: Results at the Now Frontier. [Pioneer 10, <span class="hlt">interplanetary</span> space, and Jupiter atmosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1975-01-01</p> <p>Pioneer 10's encounter with Jupiter is discussed along with the <span class="hlt">interplanetary</span> space beyond the orbit of Mars. Other topics discussed include the size of Jupiter, the Galilean satellites, the <span class="hlt">magnetic</span> field of Jupiter, radiation belts, Jupiter's weather and interior, and future exploration possibilities. Educational projects are also included.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021482&hterms=halo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhalo','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021482&hterms=halo&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhalo"><span id="translatedtitle">Bi-directional streaming of halo electrons in <span class="hlt">interplanetary</span> plasma clouds observed between 0.3 and 1 AU</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ivory, K.; Schwenn, R.</p> <p>1995-01-01</p> <p>The solar wind data obtained from the two Helios solar probes in the years 1974 to 1986 were systematically searched for the occurrence of bi-directional electron events. Most often these events are found in conjunction with shock associated <span class="hlt">magnetic</span> clouds. The implications of these observations for the topology of <span class="hlt">interplanetary</span> plasma clouds are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950046657&hterms=solar+vortex&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Bvortex','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950046657&hterms=solar+vortex&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Bvortex"><span id="translatedtitle">Magnetospheric response to solar wind dynamic pressure variations: Interaction of <span class="hlt">interplanetary</span> tangential discontinuities with the bow shock</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wu, Bor-Han; Mandt, M. E.; Lee, L. C.; Chao, J. K.</p> <p>1993-01-01</p> <p>Some <span class="hlt">magnetic</span> impulse events observed in the polar region are related to vortices associated with plasma convection in the ionosphere. Recent analyses of satellite and ground data suggest that the interaction of solar wind dynamic pressure pulses and the magnetosphere may lead to the formation of velocity vortices in the magnetopause boundary layer region. This can in turn lead to the presence of vortices in the polar ionosphere. However, before reaching the Earth's magnetopause, these <span class="hlt">interplanetary</span> pressure pulses must interact with and pass through the bow shock. A variation of the solar wind dynamic pressure may be associated with shocks, <span class="hlt">magnetic</span> holes, or tangential discontinuities (TDs) in the <span class="hlt">interplanetary</span> medium. We study the interaction of <span class="hlt">interplanetary</span> TDs with the Earth's bow shock (BS) using both theoretical analysis and MHD computer simulations. It is found that as a result of the collision between a TD and the BS, the jump in the solar wind dynamic pressure associated with the TD is significantly modified, the bow shock moves, and a new fast shock or fast rarefaction wave, which propagates in the downstream direction, is excited. Our theoretical analysis shows that the change in the plasma density across the <span class="hlt">interplanetary</span> TD plays the most important role in the collision process. In the case with an enhanced dynamic pressure behind the <span class="hlt">interplanetary</span> TD, the bow shock is intensified in strength and moves in the earthward direction. The dynamic pressure jump associated with the transmitted TD is generally reduced from the value before the interaction. A fast compressional shock is excited ahead of the transmitted TD and propagates toward the Earth's magnetosphere. For the case in which the dynamic pressure is reduced behind the <span class="hlt">interplanetary</span> TD, the pressure jump across the transmitted TD is substantially weakened, the bow shock moves in the sunward direction, and a rarefaction wave which propagates downstream is excited. We also simulate and discuss the interaction of a pair of tangential discontinuities, which may correspond to a <span class="hlt">magnetic</span> hole, with the BS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740023172','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740023172"><span id="translatedtitle">Solar rotating <span class="hlt">magnetic</span> dipole?. [around axis perpendicular to rotation axis of the sun</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Antonucci, E.</p> <p>1974-01-01</p> <p>A <span class="hlt">magnetic</span> dipole rotating around an axis perpendicular to the rotation axis of the sun can account for the characteristics of the surface large-scale solar <span class="hlt">magnetic</span> fields through the solar cycle. The polarity patterns of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field, predictable from this model, agree with the observed <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> sector structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ChA%26A..39...78W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ChA%26A..39...78W"><span id="translatedtitle">Preliminary Analysis on the <span class="hlt">Interplanetary</span> Cause of Geomagnetically Induced Current and Its Effect on Power Systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, Kai-Rang; Liu, Lian-Guang; Li, Yan</p> <p>2015-01-01</p> <p>Using the detected events of geomagnetically induced current (GIC) in the Ling'ao nuclear power plant from 2004 to 2005, and focusing on the <span class="hlt">interplanetary</span> cause of GIC and its effect on power systems, we have analyzed the corresponding solar driving sources and <span class="hlt">interplanetary</span> solar wind structures, and performed spectral analysis on the most intense GIC event by means of wavelet transform. The results of this study show that: (1) Most GIC events were driven mainly by the halo coronal mass ejections, the <span class="hlt">interplanetary</span> cause of GIC events includes the shock sheath, <span class="hlt">magnetic</span> cloud, and multiplex <span class="hlt">interplanetary</span> solar wind structure. (2) Based on the strongest GIC event on 2001 November 9, we find that the fluctuation of GIC in the earlier stage was related to the <span class="hlt">magnetic</span> cloud boundary layer, and the variation of GIC intensity in the later stage was caused by <span class="hlt">magnetic</span> cloud itself. (3) Compared to the frequency of the power system (50 Hz), the GIC can be equivalent to a quasi direct current. The energy of the GIC is embodied in the two time intervals in the wavelet power spectrum: the first interval is shown as an impulsive type and with a weaker intensity, and the second one is stronger. Regarding to the cumulative time of the transformer temperature rise caused by GIC, the second interval has a longer duration than the first one. Hence, during the second interval, it is more harmful to the power systems and devices. (4) With a correlation analysis, the correlations of the SYM-H index and dBx/dt with the GIC are significantly stronger than those of other geomagnetic indices with the GIC.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AcASn..55..381W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AcASn..55..381W"><span id="translatedtitle">Primary Analysis on the <span class="hlt">Interplanetary</span> Cause of Geomagnetically Induced Current and Its Effects on Power System</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Wang, K. R.; Liu, L. G.; Li, Y.</p> <p>2014-09-01</p> <p>In this paper, we use the measured data of geomagnetically induced current (GIC) in Ling'ao nuclear power plant from 2004 to 2005 to analyze its solar driving source and <span class="hlt">interplanetary</span> solar wind structure, focus on the <span class="hlt">interplanetary</span> cause and its effects on power system, and apply the wavelet analysis to the greatest GIC event. We conclude that: (1) Most GIC events were driven by halo coronal mass ejections, and the sheath, the <span class="hlt">magnetic</span> cloud, and the multiple <span class="hlt">interplanetary</span> solar structure are the <span class="hlt">interplanetary</span> cause of GIC events. (2) Based on the strongest event on 2004 November 9, we find that the fluctuation of GIC in the earlier stage was related to the <span class="hlt">magnetic</span> cloud boundary layer, and the variation of GIC intensity in the later stage was caused by <span class="hlt">magnetic</span> cloud itself. (3) Compared to the frequency of the power system (50 Hz), the GIC can be equivalent to the quasi direct current. The energy of the GIC is embodied in the two time intervals within the wavelet power spectrum: the first interval is shown as the pulse type and with a weaker intensity, and the second one is stronger. Regarding to the cumulative time of the transformer temperature rise caused by GIC, the second interval has a longer duration than the first one. So during the second interval, it is more harmful to the power system and the equipments. (4) The correlations of SYM-H, and dBx/dt to GIC are significantly closer than those of other geomagnetic indices to GIC.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996JGR...10124393K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996JGR...10124393K"><span id="translatedtitle">A statistical survey of 5-MeV proton events at transient <span class="hlt">interplanetary</span> shocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kallenrode, May-Britt</p> <p>1996-11-01</p> <p>Between 1974 and 1985 the two Helios spacecraft observed 351 transient <span class="hlt">interplanetary</span> shocks. For 5-MeV protons the particle events associated with these shocks can be divided into three groups: (1) events without intensity increase above quiet time or increased background (47%), (2) solar and <span class="hlt">interplanetary</span> particle (SIP) events consisting of particles accelerated on or close to the Sun (solar or near-Sun component) as well as at the <span class="hlt">interplanetary</span> shock (24%), and (3) pure <span class="hlt">interplanetary</span> particle (PIP) events (29%) which consist of particles accelerated at the shock in <span class="hlt">interplanetary</span> space but do not show evidence for significant or even excess particle acceleration on the Sun. This classification shows that (1) only about half of the shocks accelerate MeV protons in <span class="hlt">interplanetary</span> space and (2) MeV protons accelerated on the Sun are neither a necessary nor a sufficient condition for the acceleration of MeV protons in <span class="hlt">interplanetary</span> space. Shock parameters such as speed or shock strength alone do not give an indication for the class of the associated particle event, because in the parameter range which covers most of the shocks, all three classes are distributed rather evenly. However, the shocks strongest in these parameters tend to accelerate particles. The intensity at the time of shock-passage, which can be used as a crude measure for the local acceleration efficiency, is correlated with the local shock speed and the <span class="hlt">magnetic</span> compression. The correlation coefficients are small but statistically significant, indicating that (1) the correlations are real and (2) the intensity is influenced by additional parameters, which are not necessarily shock inherent. As an example I will show that the local acceleration at the shock decreases roughly symmetrically with increasing distance from the nose of the shock with a median e-folding angle of 10. Occasionally, larger e-folding angles are observed close to the nose of the shock. The question of how the shock accelerates protons in the MeV range could not be answered here, but I will suggest future studies that could shed a new light on this problem.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008GeoRL..35.6S05T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008GeoRL..35.6S05T"><span id="translatedtitle">CAWSES November 7-8, 2004, superstorm: Complex solar and <span class="hlt">interplanetary</span> features in the post-solar maximum phase</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tsurutani, Bruce T.; Echer, Ezequiel; Guarnieri, Fernando L.; Kozyra, J. U.</p> <p>2008-02-01</p> <p>The complex <span class="hlt">interplanetary</span> structures during 7 to 8 Nov 2004 are analyzed to identify their properties as well as resultant geomagnetic effects and the solar origins. Three fast forward shocks, three directional discontinuities and two reverse waves were detected and analyzed in detail. The three fast forward shocks ``pump'' up the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field from a value of ~4 nT to ~44 nT. However, the fields after the shocks were northward, and <span class="hlt">magnetic</span> storms did not result. The three ram pressure increases were associated with major sudden impulses (SI + s) at Earth. A <span class="hlt">magnetic</span> cloud followed the third forward shock and the southward Bz associated with the latter was responsible for the superstorm. Two reverse waves were detected, one at the edge and one near the center of the <span class="hlt">magnetic</span> cloud (MC). It is suspected that these ``waves'' were once reverse shocks which were becoming evanescent when they propagated into the low plasma beta MC. The second reverse wave caused a decrease in the southward component of the IMF and initiated the storm recovery phase. It is determined that flares located at large longitudinal distances from the subsolar point were the most likely causes of the first two shocks without associated <span class="hlt">magnetic</span> clouds. It is thus unlikely that the shocks were ``blast waves'' or that <span class="hlt">magnetic</span> reconnection eroded away the two associated MCs. This <span class="hlt">interplanetary</span>/solar event is an example of the extremely complex <span class="hlt">magnetic</span> storms which can occur in the post-solar maximum phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080036103&hterms=mcs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmcs','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080036103&hterms=mcs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmcs"><span id="translatedtitle">CAWSES November 7-8, 2004, Superstorm: Complex Solar and <span class="hlt">Interplanetary</span> Features in the Post-Solar Maximum Phase</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tsurutani, Bruce T.; Echer, Ezequiel; Guarnieri, Fernando L.; Kozyra, J. U.</p> <p>2008-01-01</p> <p>The complex <span class="hlt">interplanetary</span> structures during 7 to 8 Nov 2004 are analyzed to identify their properties as well as resultant geomagnetic effects and the solar origins. Three fast forward shocks, three directional discontinuities and two reverse waves were detected and analyzed in detail. The three fast forward shocks 'pump' up the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field from a value of approx.4 nT to 44 nT. However, the fields after the shocks were northward, and <span class="hlt">magnetic</span> storms did not result. The three ram pressure increases were associated with major sudden impulses (SI + s) at Earth. A <span class="hlt">magnetic</span> cloud followed the third forward shock and the southward Bz associated with the latter was responsible for the superstorm. Two reverse waves were detected, one at the edge and one near the center of the <span class="hlt">magnetic</span> cloud (MC). It is suspected that these 'waves' were once reverse shocks which were becoming evanescent when they propagated into the low plasma beta MC. The second reverse wave caused a decrease in the southward component of the IMF and initiated the storm recovery phase. It is determined that flares located at large longitudinal distances from the subsolar point were the most likely causes of the first two shocks without associated <span class="hlt">magnetic</span> clouds. It is thus unlikely that the shocks were 'blast waves' or that <span class="hlt">magnetic</span> reconnection eroded away the two associated MCs. This <span class="hlt">interplanetary</span>/solar event is an example of the extremely complex <span class="hlt">magnetic</span> storms which can occur in the post-solar maximum phase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JASTP.114...19A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JASTP.114...19A"><span id="translatedtitle">Correlations between sunspot numbers, <span class="hlt">interplanetary</span> parameters and geomagnetic trends over solar cycles 21-23</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Arora, Kusumita; Chandrasekhar, N. Phani; Nagarajan, Nandini; Singh, Ankit</p> <p>2014-07-01</p> <p>We have analysed correlations between sunspot numbers, solar wind, ion density, <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field vis-à-vis <span class="hlt">magnetic</span> activity. Planetary geomagnetic index (Ap) and local residual measure of <span class="hlt">magnetic</span> activity (IΔH) from low-latitude <span class="hlt">Magnetic</span> Observatory, CSIR-NGRI, Hyderabad (IMO-HYB) spanning solar cycles 21-23 are used for this study. Using correlation coefficients between and wavelet decomposition of sunspot numbers, <span class="hlt">interplanetary</span> parameters and measures of <span class="hlt">magnetic</span> activity, the complex and time varying nature of these inter-relationships are brought out. The overall influence of sunspot number could be separated and combined episodic effects of other solar parameters could be distinguished. The demonstrated correlation or lack of it, between measures of <span class="hlt">magnetic</span> activity (Ap and IΔH), and all the parameters of solar activity, presented here corroborate established mechanisms as well as delineated clearly the relative impact of different solar mechanisms over phases of three solar cycles. The possible role of non-sunspot related activity from high latitude regions of the sun is indicated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43..978A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43..978A"><span id="translatedtitle">Outer radiation belt dropout dynamics following the arrival of two <span class="hlt">interplanetary</span> coronal mass ejections</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Alves, L. R.; Da Silva, L. A.; Souza, V. M.; Sibeck, D. G.; Jauer, P. R.; Vieira, L. E. A.; Walsh, B. M.; Silveira, M. V. D.; Marchezi, J. P.; Rockenbach, M.; Lago, A. Dal; Mendes, O.; Tsurutani, B. T.; Koga, D.; Kanekal, S. G.; Baker, D. N.; Wygant, J. R.; Kletzing, C. A.</p> <p>2016-02-01</p> <p>Magnetopause shadowing and wave-particle interactions are recognized as the two primary mechanisms for losses of electrons from the outer radiation belt. We investigate these mechanisms, using satellite observations both in <span class="hlt">interplanetary</span> space and within the magnetosphere and particle drift modeling. Two <span class="hlt">interplanetary</span> shocks/sheaths impinged upon the magnetopause causing a relativistic electron flux dropout. The <span class="hlt">magnetic</span> cloud (MC) and <span class="hlt">interplanetary</span> structure sunward of the MC had primarily northward <span class="hlt">magnetic</span> field, perhaps leading to a concomitant lack of substorm activity and a 10 daylong quiescent period. The arrival of two shocks caused an unusual electron flux dropout. Test-particle simulations have shown ˜ 2 to 5 MeV energy, equatorially mirroring electrons with initial values of L≥5.5 can be lost to the magnetosheath via magnetopause shadowing alone. For electron losses at lower L-shells, coherent chorus wave-driven pitch angle scattering and ULF wave-driven radial transport have been shown to be viable mechanisms.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992ESASP.346..207H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992ESASP.346..207H"><span id="translatedtitle">Detecting and tracking changes in solar wind conditions using <span class="hlt">interplanetary</span> scintillation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Harrison, Richard A.; Hapgood, M. A.; Sime, D. G.</p> <p>1992-09-01</p> <p>A scintillation activity index which provides an objective method for the identification of <span class="hlt">interplanetary</span> features such as discrete ejecta and corotating streams was developed. Its effectiveness in predicting several sudden impulse events and correlating with geomagnetic activity is demonstrated. Using the <span class="hlt">Interplanetary</span> Scintillation (IPS) activity index, I35, a data set during Feb. to Apr. 1992 was examined. A good correlation between the activity seen in <span class="hlt">interplanetary</span> space and geomagnetic activity was found. Apparently, the onset of the most significant event in the geomagnetic index, Ap, is observed several days earlier using the IPS technique. Also, using a prediction technique developed for the IPS index, an 'event approaching' was predicted on six days, all of which occur on either the day of a sudden impulse or within the three days prior to a sudden impulse. One IPS event apparently unrelated to Ap or sudden impulse activity was found. This is proposed to be due to an event missing the Earth or to an event with a northward directed <span class="hlt">magnetic</span> field which is unlikely to cause a significant impulse to the Earth's <span class="hlt">magnetic</span> field.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li class="active"><span>22</span></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_22 --> <div id="page_23" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="441"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770044461&hterms=1086&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231086','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770044461&hterms=1086&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231086"><span id="translatedtitle">August 1972 solar-terrestrial events - Observations of <span class="hlt">interplanetary</span> shocks at 2.2 AU</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Smith, E. J.; Davis, L., Jr.; Coleman, P. J., Jr.; Colburn, D. S.; Dyal, P.; Jones, D. E.</p> <p>1977-01-01</p> <p>Simultaneous <span class="hlt">magnetic</span> field and plasma observations on Pioneer 10 were used to identify three shocks and a plasma driver (possible flare ejecta) at 2.2 AU caused by the four large solar flares of August 2-7, 1972. Two shocks, the first and third, were forward shocks, while the second was a reverse shock. The local inertial velocities of all three shocks were estimated under the assumption of quasi-perpendicularity, i.e., the shocks were assumed to be propagating principally across, rather than along, the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850035588&hterms=Monsanto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DMonsanto','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850035588&hterms=Monsanto&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DMonsanto"><span id="translatedtitle">Discovery of nuclear tracks in <span class="hlt">interplanetary</span> dust</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bradley, J. P.; Brownlee, D. E.; Fraundorf, P.</p> <p>1984-01-01</p> <p>Nuclear tracks have been identified in <span class="hlt">interplanetary</span> dust particles (IDP's) collected from the stratosphere. The presence of tracks unambiguously confirms the extraterrestrial nature of IDP's, and the high track densities (10 to the 10th to 10 to the 11th per square centimeter) suggest an exposure age of approximately 10,000 years within the inner solar system. Tracks also provide an upper temperature limit for the heating of IDP's during atmospheric entry, thereby making it possible to distinguish between pristine and thermally modified micrometeorites.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880001349','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880001349"><span id="translatedtitle">Coronal and <span class="hlt">interplanetary</span> Type 2 radio emission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Cane, H. V.</p> <p>1987-01-01</p> <p>Several observations suggest that the disturbances which generate coronal (meter wavelength) type II radio bursts are not driven by coronal mass ejections (CMEs). A new analysis using a large sample of metric radio bursts and associated soft X-ray events provides further support for the original hypothesis that type II-producing disturbances are blast waves generated at the time of impulsive energy release in flares. <span class="hlt">Interplanetary</span> (IP) shocks, however, are closely associated with CMEs. The shocks responsible for IP type II events (observed at kilometer wavelengths) are associated with the most energetic CMEs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AstPo...6...95H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AstPo...6...95H"><span id="translatedtitle">Problems of <span class="hlt">Interplanetary</span> and Interstellar Trade</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hickman, John</p> <p>2008-01-01</p> <p>If and when <span class="hlt">interplanetary</span> and interstellar trade develops, it will be novel in two respects. First, the distances and time spans involved will reduce all or nearly all trade to the exchange of intangible goods. That threatens the possibility of conducting business in a genuinely common currency and of enforcing debt agreements, especially those involving sovereign debt. Second, interstellar trade suggests trade between humans and aliens. Cultural distance is a probable obstacle to initiating and sustaining such trade. Such exchange also threatens the release of new and potentially toxic memes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950037085&hterms=western+media&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dwestern%2Bmedia','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950037085&hterms=western+media&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dwestern%2Bmedia"><span id="translatedtitle">Galactic cosmic ray modulation and <span class="hlt">interplanetary</span> medium perturbations due to a long-living active region during October 1989</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bavassano, B.; Iucci, N.; Lepping, R. P.; Signorini, C.; Smith, E. J.; Villoresi, G.</p> <p>1994-01-01</p> <p>During October 1989, three very energetic flares were ejected by the same active region at longitudes 9 deg E, 32 deg W, and 57 deg W, respectively. The shape of the galactic cosmic ray variations suggests the presence of large <span class="hlt">magnetic</span> cloud structures (Nagashima et al., 1990) following the shock-associated perturbations. In spite of long data gaps the <span class="hlt">interplanetary</span> observations at <span class="hlt">Interplanetary</span> Monitoring Platform (IMP) 8 (near the Earth) and International Cometary Explorer (ICE)(approximately 1 AU, approximately 65 deg W) confirm this possibility for the event related to the 9 deg E flare; the principal axes analysis shows that the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field variations at both spacecraft locations are mainly confined on a meridian plane. This result suggests that the western longitudinal extension of this cloud is indeed very large (greater than or equal to 5 deg). The nonnegligible depression in the cosmic ray intensity observed inside the possible cloud related to the 57 deg W flare indicates that also the eastern extension could be very wide. The analysis of neutron monitor data shows clearly the cosmic ray trapping effect of <span class="hlt">magnetic</span> clouds; this mechanism seems to be responsible for the enhanced diurnal effect often observed during the recovery phase of Forbush decreases. We give an interpretation for the anisotropic cosmic ray peak occurring in the third event, and, related to that, we suggest that the Forbush decrease modulated region at the Earth's orbit could be somewhat wider than the <span class="hlt">magnetic</span> cloud, as already anticipated by Nagashima et al. (1990). By this analysis, based mainly on cosmic ray data, we show that it is possible to do reasonable inferences on the large-scale structure of flare-related <span class="hlt">interplanetary</span> perturbations when <span class="hlt">interplanetary</span> medium data are not completely present.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20120011758','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120011758"><span id="translatedtitle">Observations of Electromagnetic Whistler Precursors at Supercritical <span class="hlt">Interplanetary</span> Shocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, L. B., III; Koval, A.; Szabo, Adam; Breneman, A.; Cattell, C. A.; Goetz, K.; Kellogg, P. J.; Kersten, K.; Kasper, J. C.; Maruca, B. A.; Pulupa, M.</p> <p>2012-01-01</p> <p>We present observations of electromagnetic precursor waves, identified as whistler mode waves, at supercritical <span class="hlt">interplanetary</span> shocks using the Wind search coil magnetometer. The precursors propagate obliquely with respect to the local <span class="hlt">magnetic</span> field, shock normal vector, solar wind velocity, and they are not phase standing structures. All are right-hand polarized with respect to the <span class="hlt">magnetic</span> field (spacecraft frame), and all but one are right-hand polarized with respect to the shock normal vector in the normal incidence frame. They have rest frame frequencies f(sub ci) < f much < f(sub ce) and wave numbers 0.02 approx < k rho (sub ce) approx <. 5.0. Particle distributions show signatures of specularly reflected gyrating ions, which may be a source of free energy for the observed modes. In one event, we simultaneously observe perpendicular ion heating and parallel electron acceleration, consistent with wave heating/acceleration due to these waves. Al though the precursors can have delta B/B(sub o) as large as 2, fluxgate magnetometer measurements show relatively laminar shock transitions in three of the four events.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820054343&hterms=anisotropy+earth&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Danisotropy%2Bearth','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820054343&hterms=anisotropy+earth&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Danisotropy%2Bearth"><span id="translatedtitle">Energetic <span class="hlt">interplanetary</span> nucleon flux anisotropies - The effect of earth's bow shock and magnetosheath on sunward flow</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Christon, S. P.</p> <p>1982-01-01</p> <p>Attention is given to the combined, <span class="hlt">average</span> effects of the bow shock and magnetosheath on the diffusive flow of <span class="hlt">interplanetary</span> nuclei. The observations presented show that differences between 'connected' and 'unconnected' data subsets are apparent from the beginning of the analysis. Through an investigation of the mean unconnected diffusive anisotropy (those fluxes least affected by the earth's bow shock and magnetosheath) it is confirmed that the cross-field transport of MeV energy nuclei in <span class="hlt">interplanetary</span> space is statistically significant and in the direction expected from the large-scale particle flux gradients. The direction of particle flow relative to the IMF is then used to show that nucleon flow characteristics on connected IMF differ from those on unconnected IMF. A scenario for producing this difference is then presented. It is concluded that the inclusion of the bow shock connected information biases measurements of the flux anisotropies of MeV energy H.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880057190&hterms=energetic+materials&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Denergetic%2Bmaterials','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880057190&hterms=energetic+materials&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Denergetic%2Bmaterials"><span id="translatedtitle">Bimodal abundances in the energetic particles of solar and <span class="hlt">interplanetary</span> origin</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Reames, Donald V.</p> <p>1988-01-01</p> <p>This letter reports the first results from an examination of the daily-<span class="hlt">averaged</span> abundances of the elements from H through Fe as well as electrons and isotopes of He in energetic particles observed in <span class="hlt">interplanetary</span> space by the ISEE 3 spacecraft over an 8.5 yr period. The abundances of heavy elements such as Fe/O show, for the first time, clear evidence of the presence of two distinct populations of particles. Earlier observations could be interpreted as extreme variations within a single population. The population with enhanced Fe/O shows correlated enhancements in He-3/He-4, p/e, and He/H. This population is consistent with material that has been processed to high temperatures in the impulsively heated regions of solar flares. The second population, with more normal abundances, is probably accelerated from ambient material by coronal and <span class="hlt">interplanetary</span> shocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010P%26SS...58.1180P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010P%26SS...58.1180P"><span id="translatedtitle">Laboratory simulation of <span class="hlt">interplanetary</span> ultraviolet radiation (broad spectrum) and its effects on Deinococcus radiodurans</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Paulino-Lima, Ivan Glucio; Pilling, Srgio; Janot-Pacheco, Eduardo; de Brito, Arnaldo Naves; Barbosa, Joo Alexandre Ribeiro Gonalves; Leito, Alvaro Costa; Lage, Claudia de Alencar Santos</p> <p>2010-08-01</p> <p>The radiation-resistant bacterium Deinococcus radiodurans was exposed to a simulated <span class="hlt">interplanetary</span> UV radiation at the Brazilian Synchrotron Light Laboratory (LNLS). Bacterial samples were irradiated on different substrates to investigate the influence of surface relief on cell survival. The effects of cell multi-layers were also investigated. The ratio of viable microorganisms remained virtually the same (<span class="hlt">average</span> 2%) for integrated doses from 1.2 to 12 kJ m -2, corresponding to 16 h of irradiation at most. The asymptotic profiles of the curves, clearly connected to a shielding effect provided by multi-layering cells on a cavitary substrate (carbon tape), means that the inactivation rate may not change significantly along extended periods of exposure to radiation. Such high survival rates reinforce the possibility of an <span class="hlt">interplanetary</span> transfer of viable microbes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930020188','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930020188"><span id="translatedtitle">Long Duration Exposure Facility (LDEF) attitude measurements of the <span class="hlt">Interplanetary</span> Dust Experiment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kassel, Philip C., Jr.; Motley, William R., III; Singer, S. Fred; Mulholland, J. Derral; Oliver, John P.; Weinberg, Jerry L.; Cooke, William J.; Wortman, Jim J.</p> <p>1993-01-01</p> <p>Analysis of the data from the Long Duration Exposure Facility (LDEF) <span class="hlt">Interplanetary</span> Dust Experiment (IDE) sun sensors has allowed a confirmation of the attitude of LDEF during its first year in orbit. Eight observations of the yaw angle at specific times were made and are tabulated in this paper. These values range from 4.3 to 12.4 deg with maximum uncertainty of plus or minus 2.0 deg and an <span class="hlt">average</span> of 7.9 deg. No specific measurements of pitch or roll were made but the data indicates that LDEF had an <span class="hlt">average</span> pitch down attitude of less than 0.7 deg.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015GeoRL..42.6155K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015GeoRL..42.6155K"><span id="translatedtitle">Revisit of relationship between geosynchronous relativistic electron enhancements and <span class="hlt">magnetic</span> storms</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Hee-Jeong; Lyons, Larry; Pinto, Victor; Wang, Chih-Ping; Kim, Kyung-Chan</p> <p>2015-08-01</p> <p>We find evidence that <span class="hlt">magnetic</span> storms are not only unnecessary for geosynchronous relativistic electron enhancements but also not directly relevant to the electron enhancements even if the enhancements are accompanied by <span class="hlt">magnetic</span> storms. What is crucial for electron enhancements at geosynchronous orbit are sustained south-oriented or north-south fluctuating <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) Bz that drives sufficiently large substorm activity and small solar wind density Nsw that likely leads to low loss rate of relativistic electrons to the ionosphere and/or to the magnetopause for an extended time period. Specifically, almost all the abrupt, large electron increases in our data set took place under the condition of <span class="hlt">average</span> AE > 235 nT and <span class="hlt">average</span> Nsw ? 5 cm-3. Examination of detailed time profiles clearly shows that electron flux starts to increase quite immediately with arrival of the right IMF and solar wind conditions, regardless of a <span class="hlt">magnetic</span> storm, leaving the accompanied <span class="hlt">magnetic</span> storms merely coincident.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080048006','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080048006"><span id="translatedtitle">The <span class="hlt">Interplanetary</span> Overlay Networking Protocol Accelerator</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pang, Jackson; Torgerson, Jordan L.; Clare, Loren P.</p> <p>2008-01-01</p> <p>A document describes the <span class="hlt">Interplanetary</span> Overlay Networking Protocol Accelerator (IONAC) an electronic apparatus, now under development, for relaying data at high rates in spacecraft and <span class="hlt">interplanetary</span> radio-communication systems utilizing a delay-tolerant networking protocol. The protocol includes provisions for transmission and reception of data in bundles (essentially, messages), transfer of custody of a bundle to a recipient relay station at each step of a relay, and return receipts. Because of limitations on energy resources available for such relays, data rates attainable in a conventional software implementation of the protocol are lower than those needed, at any given reasonable energy-consumption rate. Therefore, a main goal in developing the IONAC is to reduce the energy consumption by an order of magnitude and the data-throughput capability by two orders of magnitude. The IONAC prototype is a field-programmable gate array that serves as a reconfigurable hybrid (hardware/ firmware) system for implementation of the protocol. The prototype can decode 108,000 bundles per second and encode 100,000 bundles per second. It includes a bundle-cache static randomaccess memory that enables maintenance of a throughput of 2.7Gb/s, and an Ethernet convergence layer that supports a duplex throughput of 1Gb/s.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AdSpR..42.1564G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AdSpR..42.1564G"><span id="translatedtitle"><span class="hlt">Interplanetary</span> proton cumulated fluence model update</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Glover, A.; Hilgers, A.; Rosenqvist, L.; Bourdarie, S.</p> <p>2008-11-01</p> <p>Solar particle events leading to important increase of particle fluxes at energies of order of magnitude ranging from MeV to GeV constitute an important hazard for space missions. They may lead to effects seen in microelectronics or damage to solar cells and constitute a potential hazard for manned missions. Cumulative damage is commonly expressed as a function of fluence which is defined as the integral of the flux over time. A priori deterministic estimates of the expected fluence cannot be made because over the time scale of a space mission, the fluence can be dominated by the contribution of a few rare and unpredictable high intensity events. Therefore, statistical approaches are required in order to estimate fluences likely to be encountered by a space mission in advance. This paper extends work done by Rosenqvist et al. [Rosenqvist, L., Hilgers, A., Evans, H., Daly, E., Hapgood, M., Stamper, R., Zwickl, R., Bourdarie, S., Boscher, D. Toolkit for updating <span class="hlt">interplanetary</span> proton-cumulated fluence models. J. Spacecraft Rockets, 42(6), 1077 1090, 2005] to describe an updated predictive engineering model for the proton <span class="hlt">interplanetary</span> fluence with energies >30 MeV. This model is derived from a complete list of solar proton fluences based on data from a number of calibrated sources covering almost three solar cycles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002cosp...34E1276C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002cosp...34E1276C"><span id="translatedtitle">The <span class="hlt">interplanetary</span> gamma ray burst network</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cline, T.</p> <p></p> <p>The <span class="hlt">Interplanetary</span> Gamma-Ray Burst Network (IPN) is providing gamma-ray burst (GRB) alerts and localizations at the maximum rate anticipated before the launch of the Swift mission. The arc-minute source precision of the IPN is again permitting searches for GRB afterglows in the radio and optical regimes with delays of only hours up to 2 days. The successful addition of the Mars Odyssey mission has compensated for the loss of the asteroid mission NEAR, to reconstitute a fully long- baseline <span class="hlt">interplanetary</span> network, with Ulysses at > 5 AU and Konus-Wind and HETE-2 near the Earth. In addition to making unassisted GRB localizations that enable a renewed supply of counterpart observations, the Mars/Ulysses/Wind IPN is confirming and reinforcing GRB source localizations with HETE-2. It has also confirmed and reinforced localizations with the BeppoSAX mission before the BeppoSAX termination in May and has detected and localized both SGRs and an unusual hard x-ray transient that is neither an SGR nor a GRB. This IPN is expected to operate until at least 2004.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110011249','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110011249"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Propagation of Coronal Mass Ejections</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gopalswamy, Nat</p> <p>2011-01-01</p> <p>Although more than ten thousand coronal mass ejections (CMEs) are produced during each solar cycle at the Sun, only a small fraction hits the Earth. Only a small fraction of the Earth-directed CMEs ultimately arrive at Earth depending on their interaction with the solar wind and other large-scale structures such as coronal holes and CMEs. The <span class="hlt">interplanetary</span> propagation is essentially controlled by the drag force because the propelling force and the solar gravity are significant only near the Sun. Combined remote-sensing and in situ observations have helped us estimate the influence of the solar wind on the propagation of CMEs. However, these measurements have severe limitations because the remote-sensed and in-situ observations correspond to different portions of the CME. Attempts to overcome this problem are made in two ways: the first is to model the CME and get the space speed of the CME, which can be compared with the in situ speed. The second method is to use stereoscopic observation so that the remote-sensed and in-situ observations make measurements on the Earth-arriving part of CMEs. The Solar Terrestrial Relations Observatory (STEREO) mission observed several such CMEs, which helped understand the <span class="hlt">interplanetary</span> evolution of these CMEs and to test earlier model results. This paper discusses some of these issues and updates the CME/shock travel time estimates for a number of CMEs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17801776','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17801776"><span id="translatedtitle">Magnesium isotopic composition of <span class="hlt">interplanetary</span> dust particles.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Esat, T M; Brownlee, D E; Papanastassiou, D A; Wasserburg, G J</p> <p>1979-10-12</p> <p>The magnesium isotopic composition of some extraterrestrial dust particles has been measured. The particles are believed to be samples of <span class="hlt">interplanetary</span> dust, a significant fraction of which originated from the disaggregation of comets and may contain preserved isotopic anomalies. Improvements in mass spectrometric and sample preparation techniques have made it possible to measure the magnesium isotopic composition of the dust particles, which are typically 10 micrometers in size and contain on the order of 10(-10) gram of magnesium. Of the 13 samples analyzed, nine have the terrestrial magnesium isotopic composition within 2 parts per thousand, and one shows isotopic mass fractionation of 1.1 percent per mass unit. A subset of the particles, described as chondritic aggregates, are very close to normal isotopic composition, but their normalized isotopic ratios appear to show nonlinear effects of 3 to 4 parts per thousand, which is near the present limit of detection for samples of this size. The isotopic composition of calcium was also determined in one particle and found to be normal within 2 percent. It is clear that the isotopic composition of <span class="hlt">interplanetary</span> dust particles can be determined with good precision. Collection of dust particles during the earth's passage through a comet tail or an intense meteor stream may permit laboratory analysis of material from a known comet. PMID:17801776</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ARep...59..888P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ARep...59..888P"><span id="translatedtitle">Acceleration of solar cosmic rays in a flare current sheet and their propagation in <span class="hlt">interplanetary</span> space</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Podgorny, A. I.; Podgorny, I. M.</p> <p>2015-09-01</p> <p>Analyses of GOES spacecraft data show that the prompt component of high-energy protons arrive at the Earth after a time corresponding to their generation in flares in the western part of the solar disk, while the delayed component is detected several hours later. All protons in flares are accelerated by a single mechanism. The particles of the prompt component propagate along <span class="hlt">magnetic</span> lines of the Archimedean spiral connectng the flare with the Earth. The prompt component generated by flares in the eastern part of the solar disk is not observed at the Earth, since particles accelerated by these flares do not intersect <span class="hlt">magnetic</span>-field lines connecting the flare with the Earth. These particles arrive at the Earth via their motion across the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. These particles are trapped by the <span class="hlt">magnetic</span> field and transported by the solar wind, since the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is frozen in the wind plasma, and these particles also diffuse across the field. The duration of the delay reaches several days.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1616847T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1616847T"><span id="translatedtitle">Solar Protons above 500 MeV in the Sun's Atmosphere and in <span class="hlt">Interplanetary</span> Space</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tylka, Allan J.; Share, Gerald H.; Dietrich, William F.; Murphy, Ronald J.; Keong Ng, Chee; Shea, Margaret A.; Smart, Don F.</p> <p>2014-05-01</p> <p>At least two distinct acceleration mechanisms produce energetic particles at or near the Sun: (1) acceleration at coronal sites of <span class="hlt">magnetic</span> reconnection, generally associated with flares and (2) acceleration at shocks driven by fast coronal mass ejections (CMEs). Both mechanisms can accelerate protons to well beyond 500 MeV. Moreover, when a very large solar energetic particle (SEP) event is observed in <span class="hlt">interplanetary</span> space, both a large flare and the launch of a fast CME are observed nearly simultaneously (unless the flare occurs behind a limb). Numerous studies have tried to sort out how these two phenomena contribute to the energetic particle population. To date, there is no consensus on this issue, particularly at the highest energies, where the release of particles from the neighborhood of the Sun generally persists for only a short period of time. Although the maximum of Cycle 24 has been notably deficient in producing high-energy SEPs, new instrumentation has provided powerful new insights into these questions. Fermi provides routine measurements of solar gamma-rays above 100 MeV, from which the number of >500 MeV protons interacting in the solar-atmosphere can be deduced, separately in the impulsive phase of the flare (lasting minutes and coincident with hard x-ray emission) and in the frequently observed extended phase (which can persist for many hours and whose origin is under debate). Simultaneously, other satellites and ground-based neutron monitors provide measurements of these high-energy protons in <span class="hlt">interplanetary</span> space, the modeling of which is greatly strengthened by the STEREO's observations of the large-scale heliospheric distribution of SEPs. We report results for seven events in which the time-integrated number of >500 MeV protons at the Sun and in <span class="hlt">interplanetary</span> space have been independently extracted. We find that >500 MeV protons in the impulsive phase of the flare typically constitute a percent or less of the protons in IP space, without any clear correlation to the number of >500 MeV protons in <span class="hlt">interplanetary</span> space. By contrast, the number of >500 MeV protons in the extended phase of the flare is typically ~5-10% of the number in <span class="hlt">interplanetary</span> space and is well correlated with it. These results suggest that (1) the impulsive phase of the flare does not make a significant contribution to the <span class="hlt">interplanetary</span> population at these very high energies and (2) the extended-phase gamma-ray emissions are likely due to shock-accelerated protons precipitating down onto the solar atmosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=EL-1994-00329&hterms=B12&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DB12','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=EL-1994-00329&hterms=B12&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DB12"><span id="translatedtitle">LDEF (Prelaunch), AO201 : <span class="hlt">Interplanetary</span> Dust Experiment, Tray B12</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1984-01-01</p> <p>LDEF (Prelaunch), AO201 : <span class="hlt">Interplanetary</span> Dust Experiment, Tray B12 The prelaunch photograph shows the six (6) inch deep <span class="hlt">Interplanetary</span> Dust Experiment (IDE) master control tray. The tray has three (3) mounting/cover plates elevated on fiberglass stand-offs to provide clearance and protection for hardware and electronics located underneath. The stand-offs also raise the plates to a level that minimizes shading of detectors by the tray sidewalls. The mounting plate located at the left hand end of the tray is populated with eighty (80) metaloxide-silicon (MOS) capacitor-type impact sensors and one (1) solar sensor that is located approximately in the center of the mounting plate. The IDE sensors are two (2) inch diameter MOS capacitor structures approximately 250 um thick. The detectors are formed by growing either 0.4um or 1.0um thick silicon oxide, SiO2, layer on the 250um thick, B-doped polished silicon wafer. The top metal contact, the visible surface, was formed by vapor deposition of 1000A of aluminum on the SiO2 surface. Aluminum was also vapor deposited on the backside to form the contact with the silicon substrate. Gold wires are bonded to the front and back aluminum layers for use in connecting the detectors to the circuits. The complete wafers, IDE detectors, are mounted on chromic anodized aluminum frames by bonding the detector backside to the aluminum frame with a space qualified RTV silicon adhesive, de-volatized RTV-511. The difference in colors of the detectors is caused by reflections in the metallized surfaces. A reflection of one of the technicians is visible in the three (3) rows of detector on the left hand side of the mounting plate. The solar sensor, located at the mounting plate center, consist of four (4) silicon solar cells connected in series and associated circuity bonded to an aluminum baseplate. The solar sensor registered each orbital sunrise independant of LDEF orientation at the time of sunrise. When IDE solar sensor data from the six (6) orthogonal faces of the LDEF was correlated, the <span class="hlt">Interplanetary</span> Dust Experiment clock could be precisely calibrated. The center 1/3rd tray cover is a chromic anodized aluminum plate that protects the IDE data conditioning and control electronics mounted underneath. The cover plate also serves as a mounting platform for ten (10) individual specimen holders provided by one of the IDE investigators.The material specimen, consisting of germanium, sapphire and zinc sulfide of different sizes, shapes and colors, are bonded to the specimen holders with an RTV adhesive. The specimen holders are attached to the cover plate with stainless steel non-<span class="hlt">magnetic</span> fasteners. The 1/3rd tray cover plate in the right hand end of the experiment tray is an aluminum plate painted white with Chemglaze II A-276 paint and used as a thermal cover for the Experiment Power and Data System (EPDS). The EPDS is a system provided by the LDEF Project Office that processes and stores, on <span class="hlt">magnetic</span> tape, the orbital experiment and housekeeping data from six (6) experiment locations on the LDEF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ChA%26A..39..487B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ChA%26A..39..487B"><span id="translatedtitle">The Study on a Solar Storm and Its <span class="hlt">Interplanetary</span> and Geomagnetic Effects</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bai-han, Qiu; Chuan, LI</p> <p>2015-10-01</p> <p>We present a detailed study on a solar storm occurred on 2014 January 7. By using the remote-sensing observations of solar activities at multiple wavelengths from the Solar Dynamics Observatory (SDO) and the Solar and Heliospheric Observatory (SOHO), the eruptions of the solar flare and coronal mass ejection (CME) are investigated. Based on the measurement of energetic protons from the Geostationary Operational Environmental Satellite (GOES) and the in-situ plasma measurement from the Advanced Composition Explorer (ACE) at the solar-terrestrial L1 point, the solar energetic particle (SEP) event and <span class="hlt">interplanetary</span> CME (ICME) accompanied by the solar storm, and the shock driven by the ICME are analyzed. The influence of the solar storm on the geomagnetic fields is also analyzed with the ground-based <span class="hlt">magnetic</span> data. The results in this study show that: (1) The initial time of impulsive phase of the solar flare and the ejection time of the CME are temporally in accordance with each other. (2) The solar protons are mainly accelerated by the CME-driven shock, rather than by the <span class="hlt">magnetic</span> reconnection in the flare, and the protons are released when the CME travels to 7.7 solar radius. (3) The widths of the <span class="hlt">interplanetary</span> shock sheath and the ICME itself are derived to be 0.22 AU and 0.26 AU, respectively. (4) The <span class="hlt">interplanetary</span> shock and the ICME give rise to substorms and aurora, whereas no obvious geomagnetic storm is detected. The reason is that the ICME does not contain a regular structure of <span class="hlt">magnetic</span> cloud (MC) or evident southward component of <span class="hlt">magnetic</span> field.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li class="active"><span>23</span></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_23 --> <div id="page_24" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="461"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920018015&hterms=Rare+earth+metals&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528%2528Rare%2Bearth%2529%2Bmetals%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920018015&hterms=Rare+earth+metals&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3D%2528%2528Rare%2Bearth%2529%2Bmetals%2529"><span id="translatedtitle"><span class="hlt">Interplanetary</span> meteoroid debris in LDEF metal craters</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Brownlee, D. E.; Horz, F.; Bradley, J.</p> <p>1992-01-01</p> <p>The extraterrestrial meteoroid residue found lining craters in the Long Duration Exposure Facility (LDEF) aluminum and gold targets is highly variable in both quantity and type. In typical craters only a minor amount of residue is found and for these craters it is evident that most of the impacting projectile was ejected during crater formation. Less than 10 percent of the craters greater than 100 microns contain abundant residue consistent with survival of a major fraction of the projectile. In these cases the residue can be seen optically as a dark liner and it can easily be analyzed by SEM-EDX techniques. Because they are rare, the craters with abundant residue must be a biased sampling of the meteoroids reaching the earth. Factors that favor residue retention are low impact velocity and material properties such as high melting point. In general, the SEM-EDX observations of crater residues are consistent with the properties of chondritic meteorites and <span class="hlt">interplanetary</span> dust particles collected in the stratosphere. Except for impacts by particles dominated by single minerals such as FeS and olivine, most of the residue compositions are in broad agreement with the major element compositions of chondrites. In most cases the residue is a thin liner on the crater floor and these craters are difficult to quantitatively analyze by EDX techniques because the electron beam excites both residue and underlying metal substrate. In favorable cases, the liner is thick and composed of vesicular glass with imbedded FeNi, sulfide and silicate grains. In the best cases of meteoroid preservation, the crater is lined with large numbers of unmelted mineral grains. The projectiles fragmented into micron sized pieces but the fragments survived without melting. In one case, the grains contain linear defects that appear to be solar flare tracks. Solar flare tracks are common properties of small <span class="hlt">interplanetary</span> particles and their preservation during impact implies that the fragments were not heated above 600 C. We are investigating the meteoroid fragments in LDEF metal craters to determine the properties of <span class="hlt">interplanetary</span> dust and to determine if there are meteoroid types that are overlooked or otherwise undetected in cosmic dust collections obtained from the stratosphere and polar ice.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSH41A1626N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSH41A1626N"><span id="translatedtitle">PROPAGATION AND EVOLUTION OF THE JUNE 1st 2008 CME IN THE <span class="hlt">INTERPLANETARY</span> MEDIUM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nieves-Chinchilla, T.; Lamb, D. A.; Davila, J. M.; Vinas, A. F.; Moestl, C.; Hidalgo, M. A.; Farrugia, C. J.; Malandraki, O.; Dresing, N.; Gómez-Herrero, R.</p> <p>2009-12-01</p> <p>In this work we present a study of the coronal mass ejection (CME) of June 1st of 2008 in the <span class="hlt">interplanetary</span> medium. This event has been extensively studied by others because of its favorable geometry and the possible consequences of its peculiar initiation for space weather forecasting. We show an analysis of the evolution of the CME in the <span class="hlt">interplanetary</span> medium in order to shed some light on the propagation mechanism of the ICME. We have determined the typical shock associated characteristics of the ICME in order to understand the propagation properties. Using two different non force-free models of the <span class="hlt">magnetic</span> cloud allows us to incorporate expansion of the cloud. We use in-situ measurements from STEREO B/IMPACT to characterize the ICME. In addition, we use images from STEREO A/SECCHI-HI to analyze the propagation and visual evolution of the associated flux rope in the <span class="hlt">interplanetary</span> medium. We compare and contrast these observations with the results of the analytical models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850035908&hterms=electric+current&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2528electric%2Bcurrent%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850035908&hterms=electric+current&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3D%2528electric%2Bcurrent%2529"><span id="translatedtitle">The <span class="hlt">interplanetary</span> electric field, cleft currents and plasma convection in the polar caps</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Banks, P. M.; Clauer, C. R.; Araki, T.; St. Maurice, J. P.; Foster, J. C.</p> <p>1984-01-01</p> <p>The relationship between the pattern of plasma convection in the polar cleft and the dynamics of the <span class="hlt">interplanetary</span> electric field (IEF) is examined theoretically. It is shown that owing to the geometrical properties of the magnetosphere, the East-West component of the IEF will drive field-aligned currents which connect to the ionosphere at points lying on either side of noon, while currents associated with the North-South component of the IEF will connect the two polar caps as sheet currents, also centered at 12 MLT. In order to describe the consequences of the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field (IMF) effects upon high-latitude electric fields and convection patterns, a series of numerical simulations was carried out. The simulations were based on a solution to the steady-state equation of current continuity in a height-integrated ionospheric current. The simulations demonstrate that a simple hydrodynamical model can account for the narrow 'throats' of strong dayside antisunward convection observed during periods of southward <span class="hlt">interplanetary</span> IMF drift, as well as the sunward convection observed during periods of strongly northward IMF drift.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19810012467','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810012467"><span id="translatedtitle">On the complex state of the <span class="hlt">interplanetary</span> medium of 28-29 July 1977</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>King, J. H.; Lepping, R. P.; Sullivan, J. D.</p> <p>1981-01-01</p> <p>Observations of plasma and <span class="hlt">magnetic</span> field variations in the near-Earth solar wind are discussed. Both a corotating stream and a driven shock are present. The driver gas seems to be enveloped in the rising speed phase of this stream; this appearance is attributed to a convoluted surface separating the two plasma domains. The <span class="hlt">magnetic</span> field in the post shock flow (0030-1230 UT of July 29) has a large and geoeffective southward component at times; the energy coupling coefficient reaches approximately 5.4 x 10 to the 19th power ergs/s. In the driver gas (1230 UT of July 29 to 0110 of July 30) the <span class="hlt">magnetic</span> field is dominantly northward. The density and dynamic pressure decrease by almost two orders of magnitude (100 to 2 cm/3) from just behind the <span class="hlt">interplanetary</span> shock to approximately 3 hours into the driver gas flow. The dominant <span class="hlt">magnetic</span> field variation in the driver gas is modeled by a cloud-like structure. Significant plasma parameter variations within the driver gas are attributed to structure in the parent solar mass ejection event and to <span class="hlt">interplanetary</span> kinematics.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/117680','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/117680"><span id="translatedtitle">Coherent radar estimates of <span class="hlt">average</span> high-latitude ionospheric Joule heating</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kosch, M.J.; Nielsen, E.</p> <p>1995-07-01</p> <p>The Scandinavian Twin Auroral Radar Experiment (STARE) and Sweden and Britain Radar Experiment (SABRE) bistatic coherent radar systems have been employed to estimate the spatial and temporal variation of the ionospheric Joule heating in the combined geographic latitude range 63.8 deg - 72.6 deg (corrected geomagnetic latitude 61.5 deg - 69.3 deg) over Scandinavia. The 173 days of good observations with all four radars have been analyzed during the period 1982 to 1986 to estimate the <span class="hlt">average</span> ionospheric electric field versus time and latitude. The AE dependent empirical model of ionospheric Pedersen conductivity of Spiro et al. (1982) has been used to calculate the Joule heating. The latitudinal and diurnal variation of Joule heating as well as the estimated mean hemispherical heating of 1.7 x 10(exp 11) W are in good agreement with earlier results. <span class="hlt">Average</span> Joule heating was found to vary linearly with the AE, AU, and AL indices and as a second-order power law with Kp. The <span class="hlt">average</span> Joule heating was also examined as a function of the direction and magnitude of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. It has been shown for the first time that the ionospheric electric field magnitude as well as the Joule heating increase with increasingly negative (southward) Bz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740026037','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740026037"><span id="translatedtitle"><span class="hlt">Interplanetary</span> navigation using pulsating radio sources</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Downs, G. S.</p> <p>1974-01-01</p> <p>Radio beacons with distinguishing signatures exist in nature as pulsating radio sources (pulsars). These objects radiate well determined pulse trains over hundreds of megahertz of bandwidth at radio frequencies. Since they are at known positions, they can also be used as navigation beacons in <span class="hlt">interplanetary</span> space. Pulsar signals are weak and dispersive when viewed from earth. If an omnidirectional antenna is connected to a wideband receiver (200 MHz bandwidth centered at 200 MHz) in which dispersion effects are removed, nominal spacecraft position errors of 1500 km can be obtained after 24 h of signal integration. An antenna gain of 10 db would produce errors as low as 150 km. Since the spacecraft position is determined from the measurement of the phase of a periodic signal, ambiguities occur in the position measurement. Simultaneous use of current spacecraft navigation schemes eliminates these ambiguities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014mcp..book..287B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014mcp..book..287B"><span id="translatedtitle">Early Solar Nebula Grains - <span class="hlt">Interplanetary</span> Dust Particles</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bradley, J. P.</p> <p></p> <p>This chapter examines the compositions, mineralogy, sources, and geochemical significance of <span class="hlt">interplanetary</span> dust particles (IDPs). Despite their micrometer-scale dimensions and nanogram masses, it is now possible, primarily as a result of advances in small particle handling techniques and analytical instrumentation, to examine IDPs at close to atomic-scale resolution. The most widely used instruments for IDP studies are presently the analytical electron microscope, synchrotron facilities, and the ion microprobe. These laboratory analytical techniques are providing fundamental insights about IDP origins, mechanisms of formation, and grain processing phenomena that were important in the early solar system and presolar environments. At the same time, laboratory data from IDPs are being compared with astronomical data from dust in comets, circumstellar disks, and the interstellar medium. The direct comparison of grains in the laboratory with grains in astronomical environments is known as "astromineralogy."</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19760060793&hterms=windmill&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwindmill','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760060793&hterms=windmill&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwindmill"><span id="translatedtitle">Rotational bursting of <span class="hlt">interplanetary</span> dust particles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Paddack, S. J.; Rhee, J. W.</p> <p>1976-01-01</p> <p>Rotationally induced bursting of <span class="hlt">interplanetary</span> dust particles by a windmill effect stemming from solar radiation pressure, and eventual elimination of the particles from the solar system, is discussed. A life span on the order of 100,000 years for stony meteoritic material or tektite glass with radii of about 1 cm is arrived at for this process. A life span of a million years is computed for particles containing Fe, Ni, or Al with spin damping effects taken into cognizance. This depletion mechanism operates at a rate two orders of magnitude greater than that of the Poynting-Robertson effect in the case of nonmetallic particles and one order of magnitude greater in the case of metallic particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840058817&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtechnologie','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840058817&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtechnologie"><span id="translatedtitle">Suprathermal ions upstream from <span class="hlt">interplanetary</span> shocks</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gosling, J. T.; Bame, S. J.; Feldman, W. C.; Paschmann, G.; Sckopke, N.; Russell, C. T.</p> <p>1984-01-01</p> <p>Low energy (10 eV-30 keV) observations of suprathermal ions ahead of outward propagating <span class="hlt">interplanetary</span> shock waves (ISQ) are reported. The data were taken with the fast plasma experiment on ISEE 1 and 2 during 17 events. Structure was more evident in the suprathermal ion distribution in the earth bow shock region than in the upstream region. Isotropic distributions were only observed ahead of ISW, although field alignment, kidney-bean distributions, ion shells in velocity space and bunches of gyrating ions were not. The data suggest that the solar wind ions are accelerated to suprathermal energies in the vicinity of the shocks, which feature low and subcritical Mach numbers at 1 AU.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/324289','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/324289"><span id="translatedtitle"><span class="hlt">Interplanetary</span> space transport using inertial fusion propulsion</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Orth, C.D.</p> <p>1998-04-20</p> <p>In this paper, we indicate how the great advantages that ICF offers for <span class="hlt">interplanetary</span> propulsion can be accomplished with the VISTA spacecraft concept. The performance of VISTA is expected to surpass that from other realistic technologies for Mars missions if the energy gain achievable for ICF targets is above several hundred. Based on the good performance expected from the U. S. National Ignition Facility (NIF), the requirements for VISTA should be well within the realm of possibility if creative target concepts such as the fast ignitor can be developed. We also indicate that a 6000-ton VISTA can visit any planet in the solar system and return to Earth in about 7 years or less without any significant physiological hazards to astronauts. In concept, VISTA provides such short-duration missions, especially to Mars, that the hazards from cosmic radiation and zero gravity can be reduced to insignificant levels. VISTA therefore represents a significant step forward for space-propulsion concepts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19780019213','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19780019213"><span id="translatedtitle"><span class="hlt">Interplanetary</span> approach optical navigation with applications</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jerath, N.</p> <p>1978-01-01</p> <p>The use of optical data from onboard television cameras for the navigation of <span class="hlt">interplanetary</span> spacecraft during the planet approach phase is investigated. Three optical data types were studied: the planet limb with auxiliary celestial references, the satellite-star, and the planet-star two-camera methods. Analysis and modelling issues related to the nature and information content of the optical methods were examined. Dynamic and measurement system modelling, data sequence design, measurement extraction, model estimation and orbit determination, as relating optical navigation, are discussed, and the various error sources were analyzed. The methodology developed was applied to the Mariner 9 and the Viking Mars missions. Navigation accuracies were evaluated at the control and knowledge points, with particular emphasis devoted to the combined use of radio and optical data. A parametric probability analysis technique was developed to evaluate navigation performance as a function of system reliabilities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19800021898&hterms=equipment+oxygen&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dequipment%2Boxygen','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19800021898&hterms=equipment+oxygen&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dequipment%2Boxygen"><span id="translatedtitle">Oxygen production for <span class="hlt">interplanetary</span> return missions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richter, R.; Ash, R.; Dowler, W.</p> <p>1980-01-01</p> <p><span class="hlt">Interplanetary</span> missions with extraterrestrial returns are limited by large propulsion mass requirements. The injected mass landed on an extraterrestrial body can be reduced substantially by utilizing indigenous materials for the production of propellant on the extraterrestrial body. Analyses reported show that for Mars return missions, in situ production of oxygen during the wait between landing and the next low-energy return opportunity reduces the Earth-launch mass requirements to the allowable limit for direct entry and direct return missions. A small chemical processor using radioisotope thermal energy can extract oxygen several times its own mass from carbon dioxide, during the several-hundred-days wait on Mars. The fundamental element of the concept is the electrolytic process. Solid electrolyte cells for extracting oxygen from gaseous feedstock are identified. The basic physical principles underlying the extraction process are analyzed, and the relations between the major parameters established. The laboratory equipment for experimental investigation of the process is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19890019083','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19890019083"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Particle Environment. Proceedings of a Conference</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Feynman, Joan (Editor); Gabriel, Stephen (Editor)</p> <p>1988-01-01</p> <p>A workshop entitled the <span class="hlt">Interplanetary</span> Charged Particle Environment was held at the Jet Propulsion Laboratory (JPL) on March 16 and 17, 1987. The purpose of the Workshop was to define the environment that will be seen by spacecraft operating in the 1990s. It focused on those particles that are involved in single event upset, latch-up, total dose and displacement damage in spacecraft microelectronic parts. Several problems specific to Magellan were also discussed because of the sensitivity of some electronic parts to single-event phenomena. Scientists and engineers representing over a dozen institutions took part in the meeting. The workshop consisted of two major activities, reviews of the current state of knowledge and the formation of working groups and the drafting of their reports.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005EAS....16..129T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005EAS....16..129T"><span id="translatedtitle">The Spanish Fireball Network: Popularizing <span class="hlt">Interplanetary</span> Matter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Trigo-Rodrguez, J. M.; Castro-Tirado, A.; Llorca, J.; Fabregat, J.</p> <p></p> <p>In order to increase in Spain the social interest in the study of <span class="hlt">interplanetary</span> matter (asteroids, comets and meteoroids) we created the Spanish Photographic Meteor Network (SPMN) in 1997. This network has been dedicated to studying <span class="hlt">interplanetary</span> matter with participation of researchers from three universities (Universitat Jaume I, Universitat de Barcelona and Universitat de Valncia), the Institut d'Estudis Espacials de Catalunya (IEEC) and the Instituto de Astrofsica de Andaluca and it is also supported by the Atmospheric Sounding Station at El Arenosillo (INTA-CEDEA) and by the Experimental Station La Mayora (EELM-CSIC). In order to promote the participation of amateurs, our homepage (www.spmn.uji.es) presents public information about our research explains how amateur astronomers can participate in our network. In this paper we give some examples of the social role of a Fireball Network in order to give a coherent explanation to bright fireball events. Moreover, we also discuss the role of this kind of research project as a promoter of amateur participation and contribution to science. In fact, meteor astronomy can become an excellent area to form young researchers because systematic observation of meteors using photographic, video and CCD techniques has become one of the rare fields in astronomy in which amateurs can work together with professionals to make important contributions. We present here some results of the campaigns realized from the formation of the network. Finally, in a new step of development of our network, the all-sky CCD automatic cameras will be continuously detecting meteors and fireballs from four stations located in the Andalusia and Valencian communities by the end of 2005. Additionally, during important meteor showers we plan to develop fireball spectroscopy using medium field lenses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820025436','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820025436"><span id="translatedtitle">Jovian modulation of <span class="hlt">interplanetary</span> electrons as observed with Voyagers 1 and 2</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Schardt, A. W.; Mcdonald, F. B.; Trainor, J. H.</p> <p>1982-01-01</p> <p>The release of magnetospheric electrons from Jupiter into <span class="hlt">interplanetary</span> space is modulated by the Jovian rotation period. The Voyager 1 and 2 observations showed that the modulation period agrees on the <span class="hlt">average</span> with the synodic period of Jupiter (9h 55m 33.12s), but over intervals of weeks it can differ from the synodic period by several minutes. The lack of exact synchronization is attributed to changes of the plasma population in the Jovian magnetosphere. The Jovian modulation appears to be a persistent feature of the interaction between the solar wind and the magnetosphere and the disappearance of the modulation away from Jupiter is attributed to <span class="hlt">interplanetary</span> propagation conditions. This leads to the following limits on the diffuse coefficient for <span class="hlt">interplanetary</span> electrons: kappa perpendicular is or = 8 x 10 to the 19th power sq cm/s and kappa parallel is or = 10 to the 21st power sq cm/s. Modulation was still detectable at 3.8 A.U. behind Jupiter in the far magnetotail. This requires a mean free path in the tail 0.75 A.U. and good field connection along the tail to Jupiter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950007245','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950007245"><span id="translatedtitle"><span class="hlt">Interplanetary</span> medium data book, supplement 5, 1988-1993</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>King, Joseph H.; Papitashvili, Natalia E.</p> <p>1994-01-01</p> <p>This publication represents an extension of the series of <span class="hlt">Interplanetary</span> Medium Data Books and supplements that have been issued by the National Space Science Data Center since 1977. This volume contains solar wind <span class="hlt">magnetic</span> field and plasma data from the IMP 8 spacecraft for 1988 through the end of 1993. The normalization of the MIT plasma density and temperature, which has been discussed at length in previous volumes, is implemented as before, using the same normalization constants for 1988-1993 data as for the earlier data. Owing to a combination of non-continuity of IMP 8 telemetry acquisition and IMP's being out of the solar wind for about 40 percent of its orbit, the annual solar wind coverage for 1988-1993 is 40 plus or minus 5 percent. The plots and listings of this supplement are in essentially the same format as in previous supplements. Days for which neither IMF nor plasma data were available for any hours are omitted from the listings.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20070008416&hterms=Decker&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DDecker%252C%2BJ.','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070008416&hterms=Decker&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DDecker%252C%2BJ."><span id="translatedtitle">Multi-Spacecraft Observations of <span class="hlt">Interplanetary</span> Shock Accelerated Particle Events</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ho, G. C.; Lario, D.; Decker, R. B.; Desai, M. I.; Hu, Q.; Kasper, J.</p> <p>2006-01-01</p> <p>We use simultaneous measurements from the Wind and ACE spacecraft to determine the spatial properties of both <span class="hlt">interplanetary</span> (IP) shocks and the shock-associated energetic particle events. We combine plasma, <span class="hlt">magnetic</span> field and energetic particle data from ACE and Wind for 124 energetic storm particle (ESP) events from 1998 to 2003 and examine the spatial and temporal variations of these events in the Earth's vicinity. We find that even though the two spacecraft were occasionally separated by more than 400 RE, the plasma, field, and energetic particle time-intensity profiles during the events were very similar. In addition, we find that the ion composition and energy spectra in individual IP shock events are identical at the two spacecraft locations. We also use the fitted shock velocity along the normal from ACE and estimate the shock transit time to Wind location. In general, there is poor agreement between the estimated transit time and the actual measured transit time. Hence, our assumptions that a) the IP shock at 1 AU propagates radially, and/or b) the IP shock is spherically symmetric at 1 AU are not valid. In this paper, we will also study, for the first time, the anisotropy measurements of low-energy IP shock-associated ions at both ACE and Wind. We will then compare these new anisotropy analyses with locally measured shock parameters and identify possible signatures of different shock acceleration processes as predicted by the first-order Fermi and shock-drift models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140006922','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140006922"><span id="translatedtitle">The Radiation, <span class="hlt">Interplanetary</span> Shocks, and Coronal Sources (RISCS) Toolset</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zank, G. P.; Spann, J.</p> <p>2014-01-01</p> <p>We outline a plan to develop a physics based predictive toolset RISCS to describe the <span class="hlt">interplanetary</span> energetic particle and radiation environment throughout the inner heliosphere, including at the Earth. To forecast and "nowcast" the radiation environment requires the fusing of three components: 1) the ability to provide probabilities for incipient solar activity; 2) the use of these probabilities and daily coronal and solar wind observations to model the 3D spatial and temporal heliosphere, including <span class="hlt">magnetic</span> field structure and transients, within 10 AU; and 3) the ability to model the acceleration and transport of energetic particles based on current and anticipated coronal and heliospheric conditions. We describe how to address 1) - 3) based on our existing, well developed, and validated codes and models. The goal of RISCS toolset is to provide an operational forecast and "nowcast" capability that will a) predict solar energetic particle (SEP) intensities; b) spectra for protons and heavy ions; c) predict maximum energies and their duration; d) SEP composition; e) cosmic ray intensities, and f) plasma parameters, including shock arrival times, strength and obliquity at any given heliospheric location and time. The toolset would have a 72 hour predicative capability, with associated probabilistic bounds, that would be updated hourly thereafter to improve the predicted event(s) and reduce the associated probability bounds. The RISCS toolset would be highly adaptable and portable, capable of running on a variety of platforms to accommodate various operational needs and requirements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.4313O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.4313O"><span id="translatedtitle">Impact angle control of <span class="hlt">interplanetary</span> shock geoeffectiveness: A statistical study</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oliveira, Denny M.; Raeder, Joachim</p> <p>2015-06-01</p> <p>We present a survey of <span class="hlt">interplanetary</span> (IP) shocks using Wind and ACE satellite data from January 1995 to December 2013 to study how IP shock geoeffectiveness is controlled by IP shock impact angles. A shock list covering one and a half solar cycle is compiled. The yearly number of IP shocks is found to correlate well with the monthly sunspot number. We use data from SuperMAG, a large chain with more than 300 geomagnetic stations, to study geoeffectiveness triggered by IP shocks. The SuperMAG SML index, an enhanced version of the familiar AL index, is used in our statistical analysis. The jumps of the SML index triggered by IP shock impacts on the Earth's magnetosphere are investigated in terms of IP shock orientation and speed. We find that, in general, strong (high speed) and almost frontal (small impact angle) shocks are more geoeffective than inclined shocks with low speed. The strongest correlation (correlation coefficient R = 0.78) occurs for fixed IP shock speed and for varied IP shock impact angle. We attribute this result, predicted previously with simulations, to the fact that frontal shocks compress the magnetosphere symmetrically from all sides, which is a favorable condition for the release of <span class="hlt">magnetic</span> energy stored in the magnetotail, which in turn can produce moderate to strong auroral substorms, which are then observed by ground-based magnetometers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22092237','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22092237"><span id="translatedtitle">PARTICLE ENERGY SPECTRA AT TRAVELING <span class="hlt">INTERPLANETARY</span> SHOCK WAVES</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Reames, Donald V.</p> <p>2012-09-20</p> <p>We have searched for evidence of significant shock acceleration of He ions of {approx}1-10 MeV amu{sup -1} in situ at 258 <span class="hlt">interplanetary</span> traveling shock waves observed by the Wind spacecraft. We find that the probability of observing significant acceleration, and the particle intensity observed, depends strongly upon the shock speed and less strongly upon the shock compression ratio. For most of the 39 fast shocks with significant acceleration, the observed spectral index agrees with either that calculated from the shock compression ratio or with the spectral index of the upstream background, when the latter spectrum is harder, as expected from diffusive shock theory. In many events the spectra are observed to roll downward at higher energies, as expected from Ellison-Ramaty and from Lee shock-acceleration theories. The dearth of acceleration at {approx}85% of the shocks is explained by (1) a low shock speed, (2) a low shock compression ratio, and (3) a low value of the shock-normal angle with the <span class="hlt">magnetic</span> field, which may cause the energy spectra that roll downward at energies below our observational threshold. Quasi-parallel shock waves are rarely able to produce measurable acceleration at 1 AU. The dependence of intensity on shock speed, seen here at local shocks, mirrors the dependence found previously for the peak intensities in large solar energetic-particle events upon speeds of the associated coronal mass ejections which drive the shocks.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740035868&hterms=Hume&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DHume','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740035868&hterms=Hume&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DHume"><span id="translatedtitle"><span class="hlt">Interplanetary</span> and near-Jupiter meteoroid environments - Preliminary results from the meteoroid detection experiment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kinard, W. H.; O'Neal, R. L.; Alvarez, J. M.; Humes, D. H.</p> <p>1974-01-01</p> <p>Data on <span class="hlt">interplanetary</span> and near-Jupiter micrometer-sized particle encounters from the meteoroid-detection experiment on Pioneer 10 indicate that Jupiter is much 'dustier' than <span class="hlt">interplanetary</span> space. Whereas the near-earth particulate flux showed very little increase over the <span class="hlt">interplanetary</span> flux, the near-Jupiter penetration flux was over two orders of magnitude higher than the <span class="hlt">interplanetary</span> flux.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22420353','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22420353"><span id="translatedtitle">Comprehensive Population-<span class="hlt">Averaged</span> Arterial Input Function for Dynamic Contrast–Enhanced v<span class="hlt">Magnetic</span> Resonance Imaging of Head and Neck Cancer</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Onxley, Jennifer D.; Yoo, David S.; Muradyan, Naira; MacFall, James R.; Brizel, David M.; Craciunescu, Oana I.</p> <p>2014-07-01</p> <p>Purpose: To generate a population-<span class="hlt">averaged</span> arterial input function (PA-AIF) for quantitative analysis of dynamic contrast-enhanced MRI data in head and neck cancer patients. Methods and Materials: Twenty patients underwent dynamic contrast-enhanced MRI during concurrent chemoradiation therapy. Imaging consisted of 2 baseline scans 1 week apart (B1/B2) and 1 scan after 1 week of chemoradiation therapy (Wk1). Regions of interest (ROIs) in the right and left carotid arteries were drawn on coronal images. Plasma concentration curves of all ROIs were <span class="hlt">averaged</span> and fit to a biexponential decay function to obtain the final PA-AIF (AvgAll). Right-sided and left-sided ROI plasma concentration curves were <span class="hlt">averaged</span> separately to obtain side-specific AIFs (AvgRight/AvgLeft). Regions of interest were divided by time point to obtain time-point-specific AIFs (AvgB1/AvgB2/AvgWk1). The vascular transfer constant (K{sub trans}) and the fractional extravascular, extracellular space volume (V{sub e}) for primaries and nodes were calculated using the AvgAll AIF, the appropriate side-specific AIF, and the appropriate time-point-specific AIF. Median K{sub trans} and V{sub e} values derived from AvgAll were compared with those obtained from the side-specific and time-point-specific AIFs. The effect of using individual AIFs was also investigated. Results: The plasma parameters for AvgAll were a{sub 1,2} = 27.11/17.65 kg/L, m{sub 1,2} = 11.75/0.21 min{sup −1}. The coefficients of repeatability (CRs) for AvgAll versus AvgLeft were 0.04 min{sup −1} for K{sub trans} and 0.02 for V{sub e}. For AvgAll versus AvgRight, the CRs were 0.08 min{sup −1} for K{sub trans} and 0.02 for V{sub e}. When AvgAll was compared with AvgB1/AvgB2/AvgWk1, the CRs were slightly higher: 0.32/0.19/0.78 min{sup −1}, respectively, for K{sub trans}; and 0.07/0.08/0.09 for V{sub e}. Use of a PA-AIF was not significantly different from use of individual AIFs. Conclusion: A PA-AIF for head and neck cancer was generated that accounts for differences in right carotid artery versus left carotid artery, day-to-day fluctuations, and early treatment-induced changes. The small CRs obtained for K{sub trans} and V{sub e} indicate that side-specific AIFs are not necessary. However, a time-point-specific AIF may improve pharmacokinetic accuracy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750004795','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750004795"><span id="translatedtitle">On the use of Godhavn H-component as an indicator of the <span class="hlt">interplanetary</span> sector polarity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Svalgaard, L.</p> <p>1974-01-01</p> <p>An objective method of inferring the polarity of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field using the H-component at Godhavn is presented. The objectively inferred polarities are compared with a subjective index inferred earlier. It is concluded that no significant difference exists between the two methods. The inferred polarities derived from Godhavn H is biased by the (slp) sub q signature in the sense that during summer prolonged intervals of geomagnetic calm will result in inferred Away polarity regardless of the actual sector polarity. This bias does not significantly alter the large scale structure of the inferred sector structure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5135325','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5135325"><span id="translatedtitle">Overview of cosmic rays, solar and <span class="hlt">interplanetary</span> physics research (1987-1990)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jokipii, J.R. )</p> <p>1991-01-01</p> <p>A brief survey of recent U.S. investigations in the field of heliospheric plasmas and their manifestations is presented, introducing the following collection of detailed reviews (accessions A91-46959 to A91-46964). Topics examined include the large-scale structure of <span class="hlt">interplanetary</span> plasmas, models of Galactic cosmic-ray production and propagation, solar-wind turbulence, long-period solar-terrestrial variability, the possible relation between solar-neutrino counts and the sunspot cycle, X-ray studies of solar flares and their implications for solar processes, and the near-sun <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19730056702&hterms=energy+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Denergy%2Bwaves','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19730056702&hterms=energy+waves&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Denergy%2Bwaves"><span id="translatedtitle">Evidence for confinement of low-energy cosmic rays ahead of <span class="hlt">interplanetary</span> shock waves.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Palmeira, R. A. R.; Allum, F. R.</p> <p>1973-01-01</p> <p>Short-lived (about 15 min), low-energy proton increases associated with the passage of <span class="hlt">interplanetary</span> shock waves have been previously reported. In the present paper, we have examined in a fine time scale (about 1 min) the concurrent particle and <span class="hlt">magnetic</span> field data, taken by detectors on Explorer 34, for four of these events. Our results further support the view that these impulsive events are due to confinement of the solar cosmic-ray particles in the region just ahead (about 1,000,000 km) of the advancing shock front.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007248','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007248"><span id="translatedtitle">CME Interaction with Coronal Holes and Their <span class="hlt">Interplanetary</span> Consequences</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gopalswamy, N.; Makela, P.; Xie, H.; Akiyama, S.; Yashiro, S.</p> <p>2008-01-01</p> <p>A significant number of <span class="hlt">interplanetary</span> (IP) shocks (-17%) during cycle 23 were not followed by drivers. The number of such "driverless" shocks steadily increased with the solar cycle with 15%, 33%, and 52% occurring in the rise, maximum, and declining phase of the solar cycle. The solar sources of 15% of the driverless shocks were very close the central meridian of the Sun (within approx.15deg), which is quite unexpected. More interestingly, all the driverless shocks with their solar sources near the solar disk center occurred during the declining phase of solar cycle 23. When we investigated the coronal environment of the source regions of driverless shocks, we found that in each case there was at least one coronal hole nearby suggesting that the coronal holes might have deflected the associated coronal mass ejections (CMEs) away from the Sun-Earth line. The presence of abundant low-latitude coronal holes during the declining phase further explains why CMEs originating close to the disk center mimic the limb CMEs, which normally lead to driverless shocks due to purely geometrical reasons. We also examined the solar source regions of shocks with drivers. For these, the coronal holes were located such that they either had no influence on the CME trajectories. or they deflected the CMEs towards the Sun-Earth line. We also obtained the open <span class="hlt">magnetic</span> field distribution on the Sun by performing a potential field source surface extrapolation to the corona. It was found that the CMEs generally move away from the open <span class="hlt">magnetic</span> field regions. The CME-coronal hole interaction must be widespread in the declining phase, and may have a significant impact on the geoeffectiveness of CMEs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SoPh..291..239G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SoPh..291..239G"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Coronal Mass Ejections Observed by MESSENGER and Venus Express</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Good, S. W.; Forsyth, R. J.</p> <p>2016-01-01</p> <p><span class="hlt">Interplanetary</span> coronal mass ejections (ICMEs) observed by the MESSENGER and Venus Express spacecraft have been catalogued and analysed. The ICMEs were identified by a relatively smooth rotation of the <span class="hlt">magnetic</span> field direction consistent with a flux rope structure, coinciding with a relatively enhanced <span class="hlt">magnetic</span> field strength. A total of 35 ICMEs were found in the surveyed MESSENGER data (primarily from March 2007 to April 2012), and 84 ICMEs in the surveyed Venus Express data (from May 2006 to December 2013). The ICME flux rope configurations have been determined. Ropes with northward leading edges were about four times more common than ropes with southward leading edges, in agreement with a previously established solar cycle dependence. Ropes with low inclinations to the solar equatorial plane were about four times more common than ropes with high inclinations, possibly an observational effect. Left- and right-handed ropes were observed in almost equal numbers. In addition, data from MESSENGER, Venus Express, STEREO-A, STEREO-B and ACE were examined for multipoint signatures of the catalogued ICMEs. For spacecraft separations below 15° in heliocentric longitude, the second spacecraft observed the ICME flux rope in 82 % of cases; this percentage dropped to 49 % for separations between 15 and 30°, to 18 % for separations between 30 and 45°, and to 12 % for separations between 45 and 60°. As the spacecraft separation increased, it became increasingly likely that only the sheath and not the flux rope of the ICME was observed, in agreement with the notion that ICME flux ropes are smaller in longitudinal extent than the shocks or discontinuities that they often drive. Furthermore, this study has identified 23 ICMEs observed by pairs of spacecraft close to radial alignment. A detailed analysis of these events could lead to a better understanding of how ICMEs evolve during propagation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SoPh..tmp..181G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SoPh..tmp..181G"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Coronal Mass Ejections Observed by MESSENGER and Venus Express</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Good, S. W.; Forsyth, R. J.</p> <p>2015-12-01</p> <p><span class="hlt">Interplanetary</span> coronal mass ejections (ICMEs) observed by the MESSENGER and Venus Express spacecraft have been catalogued and analysed. The ICMEs were identified by a relatively smooth rotation of the <span class="hlt">magnetic</span> field direction consistent with a flux rope structure, coinciding with a relatively enhanced <span class="hlt">magnetic</span> field strength. A total of 35 ICMEs were found in the surveyed MESSENGER data (primarily from March 2007 to April 2012), and 84 ICMEs in the surveyed Venus Express data (from May 2006 to December 2013). The ICME flux rope configurations have been determined. Ropes with northward leading edges were about four times more common than ropes with southward leading edges, in agreement with a previously established solar cycle dependence. Ropes with low inclinations to the solar equatorial plane were about four times more common than ropes with high inclinations, possibly an observational effect. Left- and right-handed ropes were observed in almost equal numbers. In addition, data from MESSENGER, Venus Express, STEREO-A, STEREO-B and ACE were examined for multipoint signatures of the catalogued ICMEs. For spacecraft separations below 15 in heliocentric longitude, the second spacecraft observed the ICME flux rope in 82 % of cases; this percentage dropped to 49 % for separations between 15 and 30, to 18 % for separations between 30 and 45, and to 12 % for separations between 45 and 60. As the spacecraft separation increased, it became increasingly likely that only the sheath and not the flux rope of the ICME was observed, in agreement with the notion that ICME flux ropes are smaller in longitudinal extent than the shocks or discontinuities that they often drive. Furthermore, this study has identified 23 ICMEs observed by pairs of spacecraft close to radial alignment. A detailed analysis of these events could lead to a better understanding of how ICMEs evolve during propagation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSM11D2326L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSM11D2326L"><span id="translatedtitle">Variation of the Plasma Sheet in the Near-Earth Magnetotail by the Impact of an <span class="hlt">Interplanetary</span> Shock</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lee, E.; Parks, G. K.; Lin, N.; Kim, K.; Lee, D.; SEON, J.; Jin, H.</p> <p>2012-12-01</p> <p>It has been reported that Earth's magnetosphere is compressed by the impact of an <span class="hlt">interplanetary</span> shock. ULF waves or pulses of electric fields are induced in the inner magnetosphere by the impact, which can energize radiation belt particles. In this study we report the observations of the plasma sheet in the near-Earth magnetotail around ~-17 RE by the Cluster spacecraft when an <span class="hlt">interplanetary</span> shock impacts Earth's magnetosphere. On 24 August 2005 an <span class="hlt">interplanetary</span> shock impacted Earth's magnetosphere and induced a storm sudden commencement (SSC) and a <span class="hlt">magnetic</span> storm. After the SSC both the density and temperature of plasmas in the near-Earth magnetotail significantly increased. The current density in the plasma sheet also increased, which implies that the plasma sheet was compressed. The increase of the particle fluxes of ions and electrons was measured predominantly for E > ~30 keV up to ~100 keV, which is much lower than the energies of the particles observed in the radiation belt. The flux enhancement was more prominent for electrons than ions, which suggests that the energization is more efficient for electrons than ions. These observations show that the plasma sheet in the near-Earth magnetotail is affected by the impact of an <span class="hlt">interplanetary</span> shock, but some aspects are different from those observed in the inner magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1987PhDT.........7K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1987PhDT.........7K"><span id="translatedtitle">Gone with the solar wind: A study of protons accelerated by <span class="hlt">interplanetary</span> shocks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kessel, Ramona Louise</p> <p></p> <p>The availability of high time resolution spacecraft data has made possible in-situ and detailed study of plasma processes in the <span class="hlt">interplanetary</span> medium. One important process that has received a lot of attention is the energization of charged particles due to the interaction with traveling <span class="hlt">interplanetary</span> shock waves. The specific goal is to make use of observed <span class="hlt">magnetic</span> fields, plasma density and velocity, and initial particle trajectories calculated from real spacecraft orientations in a time-reversed computer simulation which follows particles through a single complete interaction with a shock in order to predict the angular distribution of energetic protons. The shock is considered to be a planar surface. Shock parameters used in the simulation are determined from plasma and <span class="hlt">magnetic</span> field observations fit to the Rankine-Hugoniot equations which conserve mass, momentum, and energy across the shock surface. Shock normals are determined from the single spacecraft method of Lepping and Argentiero (1971) and from the method of Vinas and Scudder (1986) using the Imp 8 <span class="hlt">magnetic</span> field data and OMNI plasma data. Energy gains and losses are used to predict the amount of enhancement in each sector, assuming an isotropic ambient medium and a relationship between energy and particle number that is based on a power law.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20010044987&hterms=nano+particles&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dnano%2Bparticles','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20010044987&hterms=nano+particles&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dnano%2Bparticles"><span id="translatedtitle">Nano-Diamonds in Chondritic <span class="hlt">Interplanetary</span> Dust Particles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dai, Z. R.; Joswiak, D. J.; Bradley, J. P.; Brownlee, D. E.; Hill, H. G. M.</p> <p>2001-01-01</p> <p>In-situ acid etching of ultramicrotomed thin sections has lead to the identification of nano-diamonds in <span class="hlt">interplanetary</span> dust particles. Additional information is contained in the original extended abstract.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013LPICo1766.1032H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013LPICo1766.1032H"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Migration of Eucaryotic Cell, Spore of Schizosaccharomyces Pombe</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hayashi, N.; Nosaka, J.; Ando, R.; Hashimoto, H.; Yokobori, S.; Narumi, I.; Nakagawa, K.; Yamagishi, A.; Tohda, H.</p> <p>2013-11-01</p> <p>The Tanpopo mission to examine possible <span class="hlt">interplanetary</span> migration of microbes is progressing. Spore of Schizosaccharomyces pombe are considered as the exposed samples. In this paper, results of preliminary experiments for the exposure are shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012P%26SS...71...55D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012P%26SS...71...55D"><span id="translatedtitle">Comments on <span class="hlt">Interplanetary</span> and geomagnetic parameters during January 16-26, 2005 by R.P. Kane</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Du, A. M.; Tsurutani, B. T.; Sun, W.</p> <p>2012-10-01</p> <p>We write this note of clarification to show that Kane (2012) has incorrectly interpreted the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field during the event by using low time-resolution data, and has thus misinterpreted the concluding comments of Du et al. (2008). Our recent paper (Du et al., 2011b) has shown that the solar wind energy input during northward IMF events is very low. Thus the interpretation of the Du et al. (2008) article given by the authors stand as was stated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930029962&hterms=ancient+history&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dancient%2Bhistory','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930029962&hterms=ancient+history&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dancient%2Bhistory"><span id="translatedtitle">On the origin of <span class="hlt">interplanetary</span> dust within recorded history</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Reach, William T.</p> <p>1992-01-01</p> <p>The possibility of an abrupt origin of <span class="hlt">interplanetary</span> dust as a result of a collision between asteroids or an extraordinary comet is considered. If all <span class="hlt">interplanetary</span> dust were produced in one event within recorded history, it would have been visible from the Earth with the unaided eye. The rate, surface area, and brightness of asteroid collision remnants are derived. Ancient Chinese records are searched for extraordinary comets aand bright pointlike objects with small angular motion and concentration to the ecliptic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://eric.ed.gov/?q=probability+AND+paradox&pg=2&id=EJ392658','ERIC'); return false;" href="http://eric.ed.gov/?q=probability+AND+paradox&pg=2&id=EJ392658"><span id="translatedtitle">Paradoxes in <span class="hlt">Averages</span>.</span></a></p> <p><a target="_blank" href="http://www.eric.ed.gov/ERICWebPortal/search/extended.jsp?_pageLabel=advanced">ERIC Educational Resources Information Center</a></p> <p>Mitchem, John</p> <p>1989-01-01</p> <p>Examples used to illustrate Simpson's paradox for secondary students include probabilities, university admissions, batting <span class="hlt">averages</span>, student-faculty ratios, and <span class="hlt">average</span> and expected class sizes. Each result is explained. (DC)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110022647','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110022647"><span id="translatedtitle">Global Magnetospheric Response to an <span class="hlt">Interplanetary</span> Shock: THEMIS Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zhang, Hui; Sibeck, David G.; Zong, Q.-G.; McFadden, James P.; Larson, Davin; Glassmeier, K.-H.; Angelopoulos, V.</p> <p>2011-01-01</p> <p>We investigate the global response of geospace plasma environment to an <span class="hlt">interplanetary</span> shock at approx. 0224 UT on May 28, 2008 from multiple THEMIS spacecraft observations in the magnetosheath (THEMIS B and C) and the mid-afternoon (THEMIS A) and dusk magnetosphere (THEMIS D and E). The interaction of the transmitted <span class="hlt">interplanetary</span> shock with the magnetosphere has global effects. Consequently, it can affect geospace plasma significantly. After interacting with the bow shock, the <span class="hlt">interplanetary</span> shock transmitted a fast shock and a discontinuity which propagated through the magnetosheath toward the Earth at speeds of 300 km/s and 137 km/s respectively. THEMIS A observations indicate that the plasmaspheric plume changed significantly by the <span class="hlt">interplanetary</span> shock impact. The plasmaspheric plume density increased rapidly from 10 to 100/ cubic cm in 4 min and the ion distribution changed from isotropic to strongly anisotropic distribution. Electromagnetic ion cyclotron (EMIC) waves observed by THEMIS A are most likely excited by the anisotropic ion distributions caused by the <span class="hlt">interplanetary</span> shock impact. To our best knowledge, this is the first direct observation of the plasmaspheric plume response to an <span class="hlt">interplanetary</span> shock's impact. THEMIS A, but not D or E, observed a plasmaspheric plume in the dayside magnetosphere. Multiple spacecraft observations indicate that the dawn-side edge of the plasmaspheric plume was located between THEMIS A and D (or E).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSM33B..02Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSM33B..02Z"><span id="translatedtitle">Global Magnetospheric Response to an <span class="hlt">Interplanetary</span> Shock: THEMIS Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhang, H.; Sibeck, D. G.; Zong, Q.; McFadden, J. P.; Larson, D. E.; Glassmeier, K.; Angelopoulos, V.</p> <p>2011-12-01</p> <p>We investigate the global response of the geospace plasma environment to an <span class="hlt">interplanetary</span> shock at ~0224 UT on May 28, 2008 from multiple THEMIS spacecraft observations in the magnetosheath (THEMIS B and C), the mid-afternoon (THEMIS A), and the dusk magnetosphere (THEMIS D and E). The interaction of the transmitted <span class="hlt">interplanetary</span> shock with the magnetosphere has global effects. Consequently, it can affect geospace plasma significantly. After interacting with the bow shock, the <span class="hlt">interplanetary</span> shock transmitted a fast shock and a discontinuity which propagated through the magnetosheath toward the Earth at speeds of 300 km/s and 137 km/s respectively. THEMIS A observations indicate that the <span class="hlt">interplanetary</span> shock changed the properties of the plasmaspheric plume significantly. The plasmaspheric plume density increased rapidly from 10 to 100 cm-3 in 4 min and the ion distribution changed from an isotropic to a strongly anisotropic distribution. Electromagnetic ion cyclotron (EMIC) waves observed by THEMIS A are most likely excited by the anisotropic ion distributions caused by the <span class="hlt">interplanetary</span> shock impact. We show that the arrival of the <span class="hlt">interplanetary</span> shock energize the plue population, resulting in strongly anisotropic particle distributions. THEMIS A, but not D or E, observed a plasmaspheric plume in the dayside magnetosphere. Multiple spacecraft observations indicate that the dawn-side edge of the plasmaspheric plume was located between THEMIS A and D (or E).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840058818&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtechnologie','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840058818&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dtechnologie"><span id="translatedtitle">Plasma and energetic particle structure upstream of a quasi-parallel <span class="hlt">interplanetary</span> shock</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kennel, C. F.; Scarf, F. L.; Coroniti, F. V.; Russell, C. T.; Wenzel, K.-P.; Sanderson, T. R.; Van Nes, P.; Smith, E. J.; Tsurutani, B. T.; Scudder, J. D.</p> <p>1984-01-01</p> <p>ISEE 1, 2 and 3 data from 1978 on <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> fields, shock waves and particle energetics are examined to characterize a quasi-parallel shock. The intense shock studied exhibited a 640 km/sec velocity. The data covered 1-147 keV protons and electrons and ions with energies exceeding 30 keV in regions both upstream and downstream of the shock, and also the magnitudes of ion-acoustic and MHD waves. The energetic particles and MHD waves began being detected 5 hr before the shock. Intense halo electron fluxes appeared ahead of the shock. A closed <span class="hlt">magnetic</span> field structure was produced with a front end 700 earth radii from the shock. The energetic protons were cut off from the interior of the <span class="hlt">magnetic</span> bubble, which contained a markedly increased density of 2-6 keV protons as well as the shock itself.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840010082','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840010082"><span id="translatedtitle">Rapporteur paper for sessions MG1, MG3 and MG4: Modulation theory, <span class="hlt">interplanetary</span> propagation and <span class="hlt">interplanetary</span> acceleration</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Jones, F. C.</p> <p>1983-01-01</p> <p>Theories and reported results from investigations of cosmic ray modulation and acceleration are summarized. Aspects considered include microscopic or fundamental theory; gradient and curvature drifts in modulation; and <span class="hlt">interplanetary</span> acceleration of shocks and particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19930015288','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19930015288"><span id="translatedtitle">Inward electrostatic precipitation of <span class="hlt">interplanetary</span> particles</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rulison, Aaron J.; Flagan, Richard C.; Ahrens, Thomas J.</p> <p>1993-01-01</p> <p>An inward precipitator collects particles initially dispersed in a gas throughout either a cylindrical or spherical chamber onto a small central planchet. The instrument is effective for particle diameters greater than about 1 micron. One use is the collection of <span class="hlt">interplanetary</span> dust particles (IDPs) which are stopped in a noble gas (xenon) by drag and ablation after perforating the wall of a thin-walled spacecraft-mounted chamber. First, the particles are positively charged for several seconds by the corona production of positive xenon ions from inward facing needles placed on the chamber wall. Then an electric field causes the particles to migrate toward the center of the instrument and onto the planchet. The collection time (on the order of hours for a 1 m radius spherical chamber) is greatly reduced by the use of optimally located screens which reapportion the electric field. Some of the electric field lines terminate on the wires of the screens so a fraction of the total number of particles in the chamber is lost. The operation of the instrument is demonstrated by experiments which show the migration of carbon soot particles with radius of approximately 1 micron in a 5 cm diameter cylindrical chamber with a single field enhancing screen toward a 3.2 mm central collection rod.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_25 --> <center> <div class="footer-extlink text-muted"><small>Some links on this page may take you to non-federal websites. 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