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Sample records for average interplanetary magnetic

  1. Interplanetary magnetic holes: Theory

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Lemaire, J. F.

    1978-01-01

    Magnetic holes in the interplanetary medium are explained as stationary, non-propagating, equilibrium structures in which there are field-aligned enhancements of the plasma density and/or temperature. Magnetic anti-holes are considered to be associated with depressions in the plasma pressure. In this model, the observed changes in the magnetic field intensity and direction are due to diamagnetic currents that are carried by ions which drift in a sheath as the result of gradients in the magnetic field and in the plasma pressure within the sheath. The thickness of the sheaths considered is approximately a few ion Larmor radii. An electric field is normal to the magnetic field in the sheath. Solutions of Vlasov's equation and Maxwell's equations are presented which account for several types of magnetic holes, including null-sheets, that were observed.

  2. 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.

  3. The interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Davis, L., Jr.

    1972-01-01

    Large-scale properties of the interplanetary magnetic field as determined by the solar wind velocity structure are examined. The various ways in which magnetic fields affect phenomena in the solar wind are summarized. The dominant role of high and low velocity solar wind streams that persist, with fluctuations and evolution, for weeks or months is emphasized. It is suggested that for most purposes the sector structure is better identified with the stream structure than with the magnetic polarity and that the polarity does not necessarily change from one velocity sector to the next. Several mechanisms that might produce the stream structure are considered. The interaction of the high and low velocity streams is analyzed in a model that is steady state when viewed in a frame that corotates with the sun.

  4. On the angle between the average interplanetary magnetic field and the propagation direction of plane large amplitude Alfven waves

    NASA Technical Reports Server (NTRS)

    Lichtenstein, B. R.; Sonett, C. P.

    1979-01-01

    The paper shows that the experimentally observed close alignment of magnetic field minimum variance direction with the average magnetic field for Alfven waves in the solar wind is consistent with theoretically predicted properties of plane large amplitude Alfven waves in the MHD approximation. The theoretical properties of these Alfven waves constrain the time averaged magnetic field to cluster around the direction of minimum variance, which is aligned with the wave normal. Thus, spacecraft magnetometer observations in the solar wind of minimum variance directions strongly peaked about the average magnetic field direction are consistent with plane large amplitude Alfven waves which have wave normals aligned with the directions of minimum variance. This does not imply that geometrical hydromagnetic calculations for Alfven wave propagation direction in the solar wind are incorrect, but there is a discrepancy between geometrical hydromagnetics theory and observations that IMF minimum variance directions tend to be aligned with the ideal Parker spiral instead of the radial direction.

  5. Evolution of the interplanetary magnetic field

    NASA Astrophysics Data System (ADS)

    McComas, D. J.

    Remote observations of magnetic field topologies in the solar corona and in situ observations of the solar wind and interplanetary magnetic field (IMF) in interplanetary space are used to examine the temporal evolution of the spatial distribution of open and closed field regions emanating from the Sun. The simple 'open' configuration of inward and outward pointing sectors in the IMF is periodically disrupted by magnetically distinct coronal mass ejections (CME's) which erupt from previously closed magnetic field regions in the corona into interplanetary space. At 1 AU, CME's contain counterstreaming halo electrons which indicate their distinct magnetic topologies. This topology is generally thought to be one of the following: plasmoids that are completely disconnected from the Sun; magnetic 'bottles,' still tied to the corona at both ends; or flux ropes which are only partially disconnected. Fully disconnected plasmoids would have no long term effect on the amount of open flux; however, both in situ observations of details of the halo electron distributions and remote coronagraph observations of radial fields following CME's indicate that CME's generally do retain at least partial attached to the Sun. Both the magnetic-bottle and flux rope geometries require some mitigating process to close off previously open fields in order to avoid a flux catastrophe. In addition, the average amount of magnetic flux observed in interplanetary space varies over the solar cycle, also indicating that there must be ways in which new flux is opened and previously open flux is closed off. The most likely scenario for closing off open magnetic fields is for reconnection to occur above helmet streamers, where oppositely directed field regions are juxtaposed in the corona. These events would serve to return closed field arches to the Sun and release open, U-shaped structures into the solar wind.

  6. Evolution of the interplanetary magnetic field

    SciTech Connect

    McComas, D.J.

    1993-01-01

    Remote observations of magnetic field topologies in the solar corona and in situ observations of the solar wind and interplanetary magnetic field (IMF) in interplanetary space are used to examine the temporal evolution of the spatial distribution of open and closed field regions emanating from the Sun. The simple open'' configuration of inward and outward pointing sectors in the IMF is periodically disrupted by magnetically distinct coronal mass ejections (CMEs) which erupt from previously closed magnetic field regions in the corona into interplanetary space. At 1 AU, CMEs contain counterstreaming halo electrons which indicate their distinct magnetic topologies. This topology is generally thought to be: plasmoids that are completely disconnected from the Sun; magnetic bottles,'' still tied to the corona at both ends; or flux ropes which are only partially disconnected. Fully disconnected plasmoids would have no long term effect on the amount of open flux; however, both in situ observations of details of the halo electron distributions and remote coronagraph observations of radial fields following CMEs indicate that CMEs generally do retain at least partial attached to the Sun. Both the magnetic-bottle and flux rope geometries require some mitigating process to close off previously open fields in order to avoid a flux catastrophe. In addition, the average amount of magnetic flux observed in interplanetary space varies over the solar cycle, also indicating that there must be ways in which new flux is opened and previously open flux is closed off. The most likely scenario for closing off open magnetic fields is for reconnection to occurs above helmet streamers, where oppositely directed field regions are juxtaposed in the corona. These events would serve to return closed field arches to the Sun and release open, U-shaped structures into the solar wind.

  7. Evolution of the interplanetary magnetic field

    SciTech Connect

    McComas, D.J.

    1993-05-01

    Remote observations of magnetic field topologies in the solar corona and in situ observations of the solar wind and interplanetary magnetic field (IMF) in interplanetary space are used to examine the temporal evolution of the spatial distribution of open and closed field regions emanating from the Sun. The simple ``open`` configuration of inward and outward pointing sectors in the IMF is periodically disrupted by magnetically distinct coronal mass ejections (CMEs) which erupt from previously closed magnetic field regions in the corona into interplanetary space. At 1 AU, CMEs contain counterstreaming halo electrons which indicate their distinct magnetic topologies. This topology is generally thought to be: plasmoids that are completely disconnected from the Sun; magnetic ``bottles,`` still tied to the corona at both ends; or flux ropes which are only partially disconnected. Fully disconnected plasmoids would have no long term effect on the amount of open flux; however, both in situ observations of details of the halo electron distributions and remote coronagraph observations of radial fields following CMEs indicate that CMEs generally do retain at least partial attached to the Sun. Both the magnetic-bottle and flux rope geometries require some mitigating process to close off previously open fields in order to avoid a flux catastrophe. In addition, the average amount of magnetic flux observed in interplanetary space varies over the solar cycle, also indicating that there must be ways in which new flux is opened and previously open flux is closed off. The most likely scenario for closing off open magnetic fields is for reconnection to occurs above helmet streamers, where oppositely directed field regions are juxtaposed in the corona. These events would serve to return closed field arches to the Sun and release open, U-shaped structures into the solar wind.

  8. 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.

  9. 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.

  10. 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.

  11. Interplanetary magnetic clouds: Topology and driving mechanism

    NASA Astrophysics Data System (ADS)

    Chen, James; Garren, David A.

    1993-11-01

    A model is developed to study the origin and propagation of magnetic clouds. Starting with an equilibrium current loop embedded in an ambient plasma consistent with the solar corona, magnetic energy is injected by increasing the loop current. This causes the loop to rise, propelling plasma and magnetic field away from the Sun. Using a simple model of the interplanetary medium, the subsequent dynamics of the loop is calculated to 1 AU and beyond. The macroscopic properties of the resulting structures at 1 AU closely resemble those of observed magnetic clouds. Thermal effects indicate that clouds remain magnetically connected to the Sun in order to yield observed temperatures near 1 AU.

  12. Magnetic shielding for interplanetary spacecraft

    SciTech Connect

    Herring, J.S.; Merrill, B.J.

    1991-12-01

    The protection of spacecraft crews from the radiation produced by high energy electrons, protons and heavier ions in the space environment is a major health concern on long duration missions. Conventional approaches to radiation shielding in space have relied on thicker spacecraft walls to stop the high energy charged particles and to absorb the resulting gamma and bremsstrahlung photons. The shielding concept described here uses superconducting magnets to deflect charged particles before they collide with the spacecraft, thus avoiding the production of secondary particles. A number of spacecraft configurations and sizes have been analyzed, ranging from a small ``storm cellar`` for use during solar flares to continuous shielding for space stations having a crew of 15--25. The effectiveness of the magnetic shielding has been analyzed using a Monte Carlo program with incident proton energies from 0.5 to 1000 MeV. Typically the shield deflects 35--99 percent of the incident particles, depending, of course on particle energy and magnetic field strength. Further evaluation studies have been performed to assess weight comparisons between magnetic and conventional shielding; to determine magnet current distributions which minimize the magnetic field within the spacecraft itself; and to assess the potential role of ceramic superconductors. 2 figs., 8 tabs.

  13. Magnetic shielding for interplanetary spacecraft

    SciTech Connect

    Herring, J.S.; Merrill, B.J.

    1991-01-01

    The protection of spacecraft crews from the radiation produced by high energy electrons, protons and heavier ions in the space environment is a major health concern on long duration missions. Conventional approaches to radiation shielding in space have relied on thicker spacecraft walls to stop the high energy charged particles and to absorb the resulting gamma and bremsstrahlung photons. The shielding concept described here uses superconducting magnets to deflect charged particles before they collide with the spacecraft, thus avoiding the production of secondary particles. A number of spacecraft configurations and sizes have been analyzed, ranging from a small storm cellar'' for use during solar flares to continuous shielding for space stations having a crew of 15--25. The effectiveness of the magnetic shielding has been analyzed using a Monte Carlo program with incident proton energies from 0.5 to 1000 MeV. Typically the shield deflects 35--99 percent of the incident particles, depending, of course on particle energy and magnetic field strength. Further evaluation studies have been performed to assess weight comparisons between magnetic and conventional shielding; to determine magnet current distributions which minimize the magnetic field within the spacecraft itself; and to assess the potential role of ceramic superconductors. 2 figs., 8 tabs.

  14. Magnetic Reconnection in Interplanetary Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Fermo, R. L.; Opher, M.; Drake, J. F.

    2014-12-01

    Magnetic reconnection is a ubiquitous phenomenon in many varied space and astrophysical plasmas, and as such plays an important role in the dynamics of interplanetary coronal mass ejections (ICMEs). It is widely regarded that reconnection is instrumental in the formation and ejection of the initial CME flux rope, but reconnection also continues to affect the dynamics as it propagates through the interplanetary medium. For example, reconnection on the leading edge of the ICME, by which it interacts with the interplanetary medium, leads to flux erosion. However, recent in situ observations by Gosling et al. found signatures of reconnection exhausts in the interior. In light of this data, we consider the stability properties of systems with this flux rope geometry with regard to their minimum energy Taylor state. Variations from this state will result in the magnetic field relaxing back towards the minimum energy state, subject to the constraints that the toroidal flux and magnetic helicity remain invariant. In reversed field pinches, this relaxation is mediated by reconnection in the interior of the system, as has been shown theoretically and experimentally. By treating the ICME flux rope in a similar fashion, we show analytically that the the elongation of the flux tube cross section in the latitudinal direction will result in a departure from the Taylor state. The resulting relaxation of the magnetic field causes reconnection to commence in the interior of the ICME, in agreement with the observations of Gosling et al. We present MHD simulations in which reconnection initiates at a number of rational surfaces, and ultimately produces a stochastic magnetic field. If the time scales for this process are shorter than the propagation time to 1 AU, this result explains why many ICME flux ropes no longer exhibit the smooth, helical flux structure characteristic of a magnetic cloud.

  15. Regulation of the interplanetary magnetic flux

    SciTech Connect

    McComas, D.J.; Gosling, J.T.; Phillips, J.L.

    1991-01-01

    In this study we use a recently developed technique for measuring the 2-D magnetic flux in the ecliptic plane to examine (1) the long term variation of the magnetic flux in interplanetary space and (2) the apparent rate at which coronal mass ejections (CMEs) may be opening new flux from the Sun. Since there is a substantial variation ({approximately}50%) of the flux in the ecliptic plane over the solar cycle, we conclude that there must be some means whereby new flux can be opened from the Sun and previously open magnetic flux can be closed off. We briefly describe recently discovered coronal disconnections events which could serve to close off previously open magnetic flux. CMEs appear to retain at least partial magnetic connection to the Sun and hence open new flux, while disconnections appear to be likely signatures of the process that returns closed flux to the Sun; the combination of these processes could regulate the amount of open magnetic flux in interplanetary space. 6 refs., 3 figs.

  16. 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.

  17. 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.

  18. Interplanetary magnetic flux - Measurement and balance

    NASA Technical Reports Server (NTRS)

    Mccomas, D. J.; Gosling, J. T.; Phillips, J. L.

    1992-01-01

    A new method for determining the approximate amount of magnetic flux in various solar wind structures in the ecliptic (and solar rotation) plane is developed using single-spacecraft measurements in interplanetary space and making certain simplifying assumptions. The method removes the effect of solar wind velocity variations and can be applied to specific, limited-extent solar wind structures as well as to long-term variations. Over the 18-month interval studied, the ecliptic plane flux of coronal mass ejections was determined to be about 4 times greater than that of HFDs.

  19. 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.

  20. Solar cycle variations in the interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Slavin, J. A.; Smith, E. J.

    1983-01-01

    ISEE 3 interplanetary magnetic field measurements have been used to extend the NSSDC hourly averaged IMF composite data set through mid-1982. Most of sunspot cycle 20 (start:1964) and the first half of cycle 21 (start:1976) are now covered. The average magnitude of the field was relatively constant over cycle 20 with approx. 5-10% decreases in 1969 and 1971, when the Sun's polar regions changed polarity, and a 20% decrease in 1975-6 around solar minimum. Since the start of the new cycle, the total field strength has risen with the mean for the first third of 1982 being about 40% greater than the cycle 20 average. As during the previous cycle, an approx. 10% drop in IMF magnitude accompanied the 1980 reversal of the solar magnetic field. While the interplanetary magnetic field is clearly stronger during the present solar cycle, another 5-7 years of observations will be needed to determine if cycle 21 exhibits the same modest variations as the last cycle. Accordingly, it appears at this time that intercycle changes in IMF magnitude may be much larger than the intracycle variations.

  1. EULERIAN DECORRELATION OF FLUCTUATIONS IN THE INTERPLANETARY MAGNETIC FIELD

    SciTech Connect

    Matthaeus, W. H.; Osman, K. T.; Dasso, S.; Weygand, J. M.; Kivelson, M. G.

    2010-09-20

    A method is devised for estimating the two-time correlation function and the associated Eulerian decorrelation timescale in turbulence. With the assumptions of a single decorrelation time and a frozen-in flow approximation for the single-point analysis, the method compares two-point correlation measurements with single-point correlation measurements at the corresponding spatial lag. This method is applied to interplanetary magnetic field measurements from the Advanced Composition Explorer and Wind spacecraft. An average Eulerian decorrelation time of 2.9 hr is found. This measures the total rate of distortion of turbulent fluid elements-including sweeping, nonlinear distortion, and wave propagation.

  2. 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.

  3. Interplanetary magnetic sector polarity inferred from polar geomagnetic field observations

    NASA Technical Reports Server (NTRS)

    Friis-Christensen, E.; Lassen, K.; Wilcox, J. M.; Gonzalez, W.; Colburn, D. S.

    1971-01-01

    In order to infer the interplanetary sector polarity from polar geomagnetic field diurnal variations, measurements were carried out at Godhavn and Thule (Denmark) Geomagnetic Observatories. The inferred interplanetary sector polarity was compared with the polarity observed at the same time by Explorer 33 and 35 magnetometers. It is shown that the polarity (toward or away from the sun) of the interplanetary magnetic field can be reliably inferred from observations of the polar cap geomagnetic fields.

  4. Correlation length for interplanetary magnetic field fluctuations.

    NASA Technical Reports Server (NTRS)

    Fisk, L. A.; Sari, J. W.

    1973-01-01

    It is argued that it is necessary to consider two correlation lengths for interplanetary magnetic field fluctuations. For particles with gyroradii large enough to encounter and be scattered by large-scale tangential discontinuities in the field (particles with energies of above several GeV/nucleon) the appropriate correlation length is simply the mean spatial separation between the discontinuities. Particles with gyroradii much less than this mean separation appear to be unaffected by the discontinuities and respond only to smaller-scale field fluctuations. With this system of two correlation lengths the cosmic ray diffusion tensor may be altered from what was predicted by, for example, Jokipii and Coleman, and the objections raised recently by Klimas and Sandri to the diffusion analysis of Jokipii may apply only at relatively low energies (about 50 MeV/nucleon).

  5. 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.

  6. Interplanetary magnetic sector polarity inferred from polar geomagnetic field observations

    NASA Technical Reports Server (NTRS)

    Eriss-Christensen, E.; Lassen, K.; Wilcox, J. M.; Gonzalez, W.; Colburn, D. S.

    1971-01-01

    With the use of a prediction technique it is shown that the polarity (toward or away from the sun) of the interplanetary magnetic field can be reliably inferred from observations of the polar geomagnetic field.

  7. The interplanetary and solar magnetic field sector structures, 1962 - 1968

    NASA Technical Reports Server (NTRS)

    Jones, D. E.

    1972-01-01

    The interplanetary magnetic field sector structure was observed from late 1962 through 1968. During this time it has been possible to study the manner in which the sector pattern and its relation to the photospheric magnetic field configuration changes from solar minimum to solar maximum. Observations were also made relating sector boundaries to specific regions on the solar disk. These and other observations related to the solar origin of the interplanetary field are briefly reviewed.

  8. 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.

  9. Magnetic field line lengths inside interplanetary magnetic flux ropes

    NASA Astrophysics Data System (ADS)

    Hu, Qiang; Qiu, Jiong; Krucker, Sam

    2015-07-01

    We report on the detailed and systematic study of field line twist and length distributions within magnetic flux ropes embedded in interplanetary coronal mass ejections (ICMEs). The Grad-Shafranov reconstruction method is utilized together with a constant-twist nonlinear force-free (Gold-Hoyle) flux rope model to reveal the close relation between the field line twist and length in cylindrical flux ropes, based on in situ Wind spacecraft measurements. We show that the field line twist distributions within interplanetary flux ropes are inconsistent with the Lundquist model. In particular, we utilize the unique measurements of magnetic field line lengths within selected ICME events as provided by Kahler et al. () based on energetic electron burst observations at 1 AU and the associated type III radio emissions detected by the Wind spacecraft. These direct measurements are compared with our model calculations to help assess the flux rope interpretation of the embedded magnetic structures. By using the different flux rope models, we show that the in situ direct measurements of field line lengths are consistent with a flux rope structure with spiral field lines of constant and low twist, largely different from that of the Lundquist model, especially for relatively large-scale flux ropes.

  10. A survey of long term interplanetary magnetic field variations

    NASA Technical Reports Server (NTRS)

    King, J. H.

    1975-01-01

    Interplanetary magnetic field data from 10 IMP, AIMP, and HEOS spacecraft were merged into a composite data set spanning 1963 to 1974. A consideration of the mutual consistency of the individual data sets reveals agreement typically to within 0.2 gamma. Composite data set analysis reveals: (1) whereas the yearly averaged magnitudes of all field vectors show virtually no solar cycle variation, the yearly averaged magnitudes of positive- and negative-polarity field vectors show separate solar cycle variations, consistent with variations in the average azimuthal angles of positive- and negative-polarity field vectors, (2) there is no heliolatitude dependence of long time average field magnitudes, (3) field vectors parallel to the earth-sun line are on the average 1 gamma less in magnitude than field vectors perpendicular to this line, and (4) the heliolatitude-dependent dominant polarity effect exhibits a complex sign reversal in the 1968 to 1971 period and a measure of symmetry in 1972 to 1974 not found in earlier data.

  11. A survey of long-term interplanetary magnetic field variations

    NASA Technical Reports Server (NTRS)

    King, J. H.

    1976-01-01

    Interplanetary-magnetic-field data from the IMP-10, IMP-A, and Heos spacecraft have been merged into a composite data set spanning the period from 1963 to 1974. Consideration of the mutual consistency of the individual data sets reveals agrement typically to within 0.2 gamma. Analysis of the composite data set reveals the following: (1) although the yearly averaged magnitudes of all field vectors show virtually no solar-cycle variation, the yearly averaged magnitudes of positive- and negative-polarity field vectors show separate solar-cycle variations consistent with variations in the average azimuthal angles of positive- and negative-polarity field vectors; (2) there is no solar latitude dependence of long-time average field magnitudes; (3) field vectors parallel to the earth-sun line are on the average 1 gamma less in magnitude than field vectors perpendicular to this line; and (4) the solar latitude-dependent dominant polarity effect exhibits a complex sign reversal in the period from 1968 to 1971 and a measure of symmetry in 1972 through 1974 not found in earlier data.

  12. 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.

  13. The spiral interplanetary magnetic field: A polarity and sunspot cycle variation

    NASA Technical Reports Server (NTRS)

    Svalgaard, L.; Wilcox, J. M.

    1974-01-01

    Spacecraft observations near the earth of the yearly average direction of the interplanetary magnetic field during the sunspot maximum year 1968 showed a deviation from the spiral field. The angle between the average field direction when the field polarity was away from the sun and the average direction for toward polarity was 168 deg, rather than 180 deg. This effect appears to have a sunspot cycle variation.

  14. The spiral interplanetary magnetic field - A polarity and sunspot cycle variation

    NASA Technical Reports Server (NTRS)

    Svalgaard, L.; Wilcox, J. M.

    1974-01-01

    Spacecraft observations near the earth of the average direction of the interplanetary magnetic field during the sunspot maximum year 1968 showed a deviation from the spiral field of Parker's classical description. The included angle between the average field direction when the field polarity was away from the sun and the average direction when the field polarity was toward the sun was 168 deg, rather than 180 deg as predicted by Parker. This effect appears to have a sunspot cycle variation.

  15. Interplanetary magnetic field effects on high latitude ionospheric convection

    NASA Technical Reports Server (NTRS)

    Heelis, R. A.

    1985-01-01

    Relations between the electric field and the electric current in the ionosphere can be established on the basis of a system of mathematical and physical equations provided by the equations of current continuity and Ohm's law. For this reason, much of the synthesis of electric field and plasma velocity data in the F-region is made with the aid of similar data sets derived from field-aligned current and horizontal current measurements. During the past decade, the development of a self-consistent picture of the distribution and behavior of these measurements has proceeded almost in parallel. The present paper is concerned with the picture as it applies to the electric field and plasma drift velocity and its dependence on the interplanetary magnetic field. Attention is given to the southward interplanetary magnetic field and the northward interplanetary magnetic field.

  16. Interplanetary magnetic fields, their fluctuations, and cosmic ray variations

    NASA Technical Reports Server (NTRS)

    Barouch, E.; Sari, J. W.

    1975-01-01

    The cause of Forbush decreases is examined using neutron monitor data and measurements of the interplanetary magnetic field. It is found that for the period examined (Dec. 15, 1965 to April 23, 1966) large enhancements of the interplanetary magnetic field correlate well with decreases in cosmic ray intensity, while various parameters connected with the fluctuations in the field do not display such good correlation. The inference is drawn that Forbush decreases are not related to the turbulence or random motions in the field but to the large scale features of the field.

  17. Average Spatial Distribution of Cosmic Rays behind the Interplanetary Shock—Global Muon Detector Network Observations

    NASA Astrophysics Data System (ADS)

    Kozai, M.; Munakata, K.; Kato, C.; Kuwabara, T.; Rockenbach, M.; Dal Lago, A.; Schuch, N. J.; Braga, C. R.; Mendonça, R. R. S.; Jassar, H. K. Al; Sharma, M. M.; Duldig, M. L.; Humble, J. E.; Evenson, P.; Sabbah, I.; Tokumaru, M.

    2016-07-01

    We analyze the galactic cosmic ray (GCR) density and its spatial gradient in Forbush Decreases (FDs) observed with the Global Muon Detector Network (GMDN) and neutron monitors (NMs). By superposing the GCR density and density gradient observed in FDs following 45 interplanetary shocks (IP-shocks), each associated with an identified eruption on the Sun, we infer the average spatial distribution of GCRs behind IP-shocks. We find two distinct modulations of GCR density in FDs, one in the magnetic sheath and the other in the coronal mass ejection (CME) behind the sheath. The density modulation in the sheath is dominant in the western flank of the shock, while the modulation in the CME ejecta stands out in the eastern flank. This east–west asymmetry is more prominent in GMDN data responding to ∼60 GV GCRs than in NM data responding to ∼10 GV GCRs, because of the softer rigidity spectrum of the modulation in the CME ejecta than in the sheath. The geocentric solar ecliptic-y component of the density gradient, G y , shows a negative (positive) enhancement in FDs caused by the eastern (western) eruptions, while G z shows a negative (positive) enhancement in FDs caused by the northern (southern) eruptions. This implies that the GCR density minimum is located behind the central flank of IP-shocks and propagating radially outward from the location of the solar eruption. We also confirmed that the average G z changes its sign above and below the heliospheric current sheet, in accord with the prediction of the drift model for the large-scale GCR transport in the heliosphere.

  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. 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.

  20. The extension of solar magnetic fields into interplanetary space

    NASA Astrophysics Data System (ADS)

    McComas, D. J.; Phillips, J. L.

    The flow of coronal plasma into interplanetary space results in outward transport of the solar magnetic field. The prevailing open interplanetary magnetic field is rooted in the corona and wraps up into a spiral due to the rotation of the Sun. This simple configuration, however, is disrupted by magnetically distinct coronal mass ejections (CME's) which erupt from the solar corona into interplanetary space. Observations of CME's at 1 AU reveal electron signatures indicating a closed magnetic topology, postulated to be: (1) magnetic bottles tied to the corona at both ends; (2) plasmoids that are completely disconnected from the Sun; or (3) flux ropes which have topologies intermediate between (1) and (2). With either the magnetic-bottle or flux rope hypothesis, the inward and outward flux at 1 AU should increase indefinitely as CME's continue to erupt. Using a new technique to calculate the 2-D flux through 1 AU from single spacecraft measurements, we show that while there is a solar cycle variation to the magnetic flux, it clearly does not grow without bound. This suggests that either CME's are closed plasmoids which add to no new flux to the interplanetary medium, or that the opening of new flux by CME's is balanced via reconnection elsewhere in the corona. We suggest that the latter process may be dominant and describe observation from the Solar Maximum Mission coronagraph which are consistent with reconnection above helmet streamers in the corona. Such disconnections would serve to return closed field arches to the Sun and release open, U-shaped structures into the solar wind. Coronal disconnections appear in some cases to be triggered by pressure pulses caused by CME eruption elsewhere, suggesting a dynamic flux-balance process. We describe a class of solar wind structures, called heat flux dropouts, in which the solar wind electron heat flux, driven by magnetic connection to the hot corona, is absent or greatly reduced.

  1. Polytropic relationship in interplanetary magnetic clouds

    NASA Technical Reports Server (NTRS)

    Osherovich, V. A.; Farrugia, C. J.; Burlaga, L. F.; Lepping, R. P.; Fainberg, J.; Stone, R. G.

    1993-01-01

    High time-resolution data from the ISEE 3 and IMP 8 spacecraft are presented for the magnetic field and the proton and electron populations of a number of magnetic clouds, in order to investigate such clouds' thermodynamics and the relationship between their magnetic and thermodynamic structures. It is judged on the basis of these data that while the magnetic flield of the cloud expands, the ions are cooled. Hot electrons are trapped by the magnetic field in the magnetic cloud's core. These conditions are favorable for the generation of ion-acoustic waves.

  2. On the limitations of geomagnetic measures of interplanetary magnetic polarity

    NASA Technical Reports Server (NTRS)

    Russell, C. T.; Rosenberg, R. L.

    1974-01-01

    The maximum attainable accuracy in inferring the interplanetary magnetic polarity from polar cap magnetograms is about 88%. This is achieved in practice, when high-latitude polar cap stations are used during local summer months, and the signature in the ground records is strong. An attempt by Svalgaard (1972) to use this effect to infer an index of interplanetary magnetic polarity back to 1926 has not been so successful. Furthermore, some of the properties of the index have changed with time. Prior to 1963, the inferred polarities are strongly dependent on geomagnetic activity, while after this time they are not. Thus, this index should not be used to separate solar-magnetic from solar-activity effects prior to 1963.

  3. Interplanetary Magnetic Field Strength 1902-1906

    NASA Astrophysics Data System (ADS)

    Svalgaard, L.; Cliver, E. W.

    2006-05-01

    Using geomagnetic measurements made by Robert F. Scott at Discovery Hut in the Antarctic polar cap 1902- 1903 and by Roald Amundsen at Gjøahavn in the Arctic polar cap 1903-1906 we determine the strength of the cross polar cap equivalent current. This quantity is controlled by the interplanetary electric field, E, (essentially the product VB of solar wind speed V and IMF strength B). Comparison with modern data from contemporary polar cap stations at similar latitudes and locations and from spacecraft yields the conversion factor from the variation measured on the ground to the electric field E. Our geomagnetic activity indices IDV and IHV measure B and BV22, respectively, thus allowing both B and V to be determined since at least 1882. Their product VB agrees well with VB determined from the early polar cap data, providing an important independent confirmation of the validity of all three methods. We find that B during 1902-1906 was ~6 nT, comparable to present day values ~100 years later.

  4. Studies of the interplanetary magnetic field: IMP's to Voyager

    NASA Technical Reports Server (NTRS)

    Ness, Norman F.

    1987-01-01

    During the last two decades, spacecraft projects and individual experiments for which Frank McDonald was a leader have contributed very significantly to the current understanding of the structure of interplanetary space and the correlation between solar and interplanetary disturbances. Studies on the IMP, HELIOS, and Pioneer spin-stabilized spacecraft and the larger attitude-stabilized Voyager spacecraft have provided data sets from which the modern view of the heliosphere has evolved. That concept in which the inner solar system is shown to be dominated by individual streams associated with specific source regions on the Sun is illustrated. As these high-speed streams overtake the preexisting solar plasma, they coalesce and modify the characteristics so that at larger heliocentric distances, these disturbances appear as radially propagating concentric shells of compressed magnetic fields and enhanced fluctuations

  5. 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.

  6. Magnetic Reconnection in the Interior of Interplanetary Coronal Mass Ejections

    NASA Astrophysics Data System (ADS)

    Fermo, R. L.; Opher, M.; Drake, J. F.

    2014-07-01

    Recent in situ observations of interplanetary coronal mass ejections (ICMEs) found signatures of reconnection exhausts in their interior or trailing edge. Whereas reconnection on the leading edge of an ICME would indicate an interaction with the coronal or interplanetary environment, this result suggests that the internal magnetic field reconnects with itself. In light of this data, we consider the stability properties of flux ropes first developed in the context of astrophysics, then further elaborated upon in the context of reversed field pinches (RFPs). It was shown that the lowest energy state of a flux rope corresponds to ∇×B=λB with λ a constant, the so-called Taylor state. Variations from this state will result in the magnetic field trying to reorient itself into the Taylor state solution, subject to the constraints that the toroidal flux and magnetic helicity are invariant. In reversed field pinches, this relaxation is mediated by the reconnection of the magnetic field, resulting in a sawtooth crash. If we likewise treat the ICME as a flux rope, any deviation from the Taylor state will result in reconnection within the interior of the flux tube, in agreement with the observations by Gosling et al. Such a departure from the Taylor state takes place as the flux tube cross section expands in the latitudinal direction, as seen in magnetohydrodynamic (MHD) simulations of flux tubes propagating through the interplanetary medium. We show analytically that this elongation results in a state which is no longer in the minimum energy Taylor state. We then present magnetohydrodynamic simulations of an elongated flux tube which has evolved away from the Taylor state and show that reconnection at many surfaces produces a complex stochastic magnetic field as the system evolves back to a minimum energy state configuration.

  7. Interplanetary gas. XXV - A solar wind and interplanetary magnetic field interpretation of cometary light outbursts

    NASA Technical Reports Server (NTRS)

    Niedner, M. B., Jr.

    1980-01-01

    Possible relationships of cometary brightness outbursts with the solar wind and interplanetary magnetic field are examined. Two types of outburst are distinguished: those which involve a significant brightening of both the head and the tail in a comet with a conspicuous plasma tail (Class I), and those involving the brightening of the central condensation of a previously faint comet with no detectable plasma tail (Class II). Class I bursts, as exemplified by Comet Morehouse 1908c, are attributed to the generation in the head of enhanced amounts of ions and their injection into the tail shortly before it disconnects, with ionization provided by sector boundary crossings. Class II events, as exhibited by Comet P/Tuttle-Giacobini-Kresak 1973b, are interpreted as the result of the bombardment of the nucleus by disturbed solar wind near corotated high-speed streams and sector boundaries, leading to highly exothermic chemical reactions.

  8. 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

  9. 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

  10. 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.

  11. The topology of intrasector reversals of the interplanetary magnetic field

    NASA Astrophysics Data System (ADS)

    Kahler, S. W.; Crooker, N. U.; Gosling, J. T.

    1996-11-01

    A technique has been developed recently to determine the polarities of interplanetary magnetic fields relative to their origins at the Sun by comparing energetic electron flow directions with local magnetic field directions. Here we use heat flux electrons from the Los Alamos National Laboratory (LANL) plasma detector on the ISEE 3 spacecraft to determine the field polarities. We examine periods within well-defined magnetic sectors when the field directions appear to be reversed from the normal spiral direction of the sector. About half of these intrasector field reversals (IFRs) are cases in which the polarities match those of the surrounding sectors, indicating that those fields have been folded back toward the Sun. The more interesting cases are those with polarity reversals. We find no clear cases of isolated reverse polarity fields, which suggests that islands of reverse polarity in the solar source dipole field probably do not exist. The IFRs with polarity reversals are strongly associated with periods of bidirectional electron flows, suggesting that those fields occur only in conjunction with closed fields. We propose that both those IFRs and the bidirectional flows are signatures of coronal mass ejections (CMEs). In that case, many interplanetary CMEs are larger and more complex than previously thought, consisting of both open and closed field components.

  12. Ground state alignment as a tracer of interplanetary magnetic field

    NASA Astrophysics Data System (ADS)

    Yan, H.

    2012-12-01

    We demonstrate a new way of studying interplanetary magnetic field -- spectropolarimetry based on ground state alignment. Ground state alignment is a new promising way of sub-gausian magnetic fields in radiation-dominated environment. The polarization of spectral lines that are pumped by the anisotropic radiation from the sun is influenced by the magnetic alignment, which happens for sub-gausian magnetic field. As a result, the linear polarization becomes an excellent tracer of the embedded magnetic field. The method is illustrated by our synthetic obser- vation of the Jupiter's Io and comet Halley. A uniform density distribution of Na was considered and polar- ization at each point was then constructed. Both spa- tial and temporal variations of turbulent magnetic field can be traced with this technique as well. Instead of sending thousands of space probes, ground state alignment allows magnetic mapping with any ground telescope facilities equipped with spectrometer and polarimeter. For remote regions like the the boundary of interstellar medium, ground state alignment provides a unique diagnostics of magnetic field, which is crucial for understanding the physical processes such as the IBEX ribbons.

  13. 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.

  14. Interplanetary magnetic field variations and the electromagnetic state of the equatorial ionosphere

    NASA Technical Reports Server (NTRS)

    Patel, V. L.

    1978-01-01

    The Esq phenomena were selected in order to examine the effect of the interplanetary magnetic field (IMF) on the ionospheric plasma and to obtain insight into the interplanetary ionospheric coupling processes. January-March 1973 interplanetary magnetic field data of Explorer 43, Huancayo ionograms, and surface equatorial magnetograms were used. The IMF observations from Explorer 43 in the form of 15-sec averages were examined around the time of disappearance of the Esq. The IMF z-component was observed to change from a negative to a positive value before the disappearance of the Esq in four events where simultaneous data were available. The general explanation is that the induced electric field becomes westward from a previous eastward direction, coinciding with the IMF z-component reversal. Thus, just before the Esq disappears, the magnetosphere is subjected to the westward electric field. If this field is impressed to the low-latitude ionosphere, the resultant electric field in the equatorial ionosphere changes from eastward (westward) to westward (eastward) in the daytime (nighttime).

  15. 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.

  16. 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.

  17. Interplanetary magnetic field enhancements in the solar wind Statistical properties at 1 AU

    NASA Technical Reports Server (NTRS)

    Arghavani, M. R.; Russell, C. T.; Luhmann, J. G.; Elphic, R. C.

    1985-01-01

    The present investigation is concerned with interplanetary magnetic field (IMF) enhancements which do not resemble any of the previously reported amplifications in the IMF. The magnetic field enhacements observed increase slowly at first and then more rapidly to a peak followed by a symmetrical decay. Interplanetary magnetic field enhacement observed by ISEE-3 on various dates are considered, giving attention to observations on June 5, 1979; September 8-9, 1980; February 5, 1981; and June 14-15, 1981. Interplanetary magnetic field enhancement observed with the aid of IMP-8 are also considered. A total of 45 events is found in surveying a 9-year period of magnetic field data.

  18. Charged Dust Grain Dynamics Subject to Solar Wind, Poynting–Robertson Drag, and the Interplanetary Magnetic Field

    NASA Astrophysics Data System (ADS)

    Lhotka, Christoph; Bourdin, Philippe; Narita, Yasuhito

    2016-09-01

    We investigate the combined effect of solar wind, Poynting–Robertson drag, and the frozen-in interplanetary magnetic field on the motion of charged dust grains in our solar system. For this reason, we derive a secular theory of motion by the means of an averaging method and validate it with numerical simulations of the unaveraged equations of motions. The theory predicts that the secular motion of charged particles is mainly affected by the z-component of the solar magnetic axis, or the normal component of the interplanetary magnetic field. The normal component of the interplanetary magnetic field leads to an increase or decrease of semimajor axis depending on its functional form and sign of charge of the dust grain. It is generally accepted that the combined effects of solar wind and photon absorption and re-emmision (Poynting–Robertson drag) lead to a decrease in semimajor axis on secular timescales. On the contrary, we demonstrate that the interplanetary magnetic field may counteract these drag forces under certain circumstances. We derive a simple relation between the parameters of the magnetic field, the physical properties of the dust grain, as well as the shape and orientation of the orbital ellipse of the particle, which is a necessary conditions for the stabilization in semimajor axis.

  19. Helioseismology with Seismometers: II Coherence with the Interplanetary Magnetic Field

    NASA Astrophysics Data System (ADS)

    Thomson, David J.; Vernon, Frank L.

    2015-04-01

    Since the discovery of seismic "hum'' in 1998 unexpected lines have been observed in terrestrial seismology.In this talk we give further evidence that these lines originate as normal modes of the Sun. Frequencies observed in terrestrial seismic and geomagnetic data are often split by multiples of a cycle/day and, unexpectedly, by multiples of one-half cycle per sidereal day.There is coherence between the interplanetary magnetic field (IMF) at ACE (located at L_1) and terrestrial geomagnetic and seismic data. There are slight frequency offsets between colocated geomagnetic and seismic data similar to those observed in normal modes excited by earthquakes. These have been attributed to dispersion from large-scale structure in the Earth.Both the splitting and coherence with the IMF give further confirmation that solar modes propagatethrough interplanetary space and are sufficiently strong to literally shake the Earth. This gives another method to detect and possibly identify solar gravity and low--frequency P-modes.

  20. 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.

  1. Time delay of interplanetary magnetic field penetration into Earth's magnetotail

    NASA Astrophysics Data System (ADS)

    Rong, Z. J.; Lui, A. T. Y.; Wan, W. X.; Yang, Y. Y.; Shen, C.; Petrukovich, A. A.; Zhang, Y. C.; Zhang, T. L.; Wei, Y.

    2015-05-01

    Many previous studies have demonstrated that the interplanetary magnetic field (IMF) can control the magnetospheric dynamics. Immediate magnetospheric responses to the external IMF have been assumed for a long time. The specific processes by which IMF penetrates into magnetosphere, however, are actually unclear. Solving this issue will help to accurately interpret the time sequence of magnetospheric activities (e.g., substorm and tail plasmoids) exerted by IMF. With two carefully selected cases, we found that the penetration of IMF into magnetotail is actually delayed by 1-1.5 h, which significantly lags behind the magnetotail response to the solar wind dynamic pressure. The delayed time appears to vary with different auroral convection intensity, which may suggest that IMF penetration in the magnetotail is controlled considerably by the dayside reconnection. Several unfavorable cases demonstrate that the penetration lag time is more clearly identified when storm/substorm activities are not involved.

  2. Inferring interplanetary magnetic field polarities from geomagnetic variations

    NASA Astrophysics Data System (ADS)

    Vokhmyanin, M. V.; Ponyavin, D. I.

    2012-06-01

    In this paper, we propose a modified procedure to infer the interplanetary magnetic field (IMF) polarities from geomagnetic observations. It allows to identify the polarity back to 1905. As previous techniques it is based on the well-known Svalgaard-Mansurov effect. We have improved the quality and accuracy of polarity inference compared with the previous results of Svalgaard (1975) and Vennerstroem et al. (2001) by adding new geomagnetic stations and extracting carefully diurnal curve. The data demonstrates an excess of one of the two IMF sectors within equinoxes (Rosenberg-Coleman rule) evidencing polar field reversals at least for the last eight solar cycles. We also found a predominance of the two-sector structure in late of descending phase of solar cycle 16.

  3. 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.

  4. Evidence linking coronal mass ejections with interplanetary magnetic clouds

    NASA Technical Reports Server (NTRS)

    Wilson, R. M.; Hildner, E.

    1983-01-01

    Using proxy data for the occurrence of those mass ejections from the solar corona which are directed earthward, we investigate the association between the post-1970 interplanetary magnetic clouds of Klein and Burlaga and coronal mass ejections. The evidence linking magnetic clouds following shocks with coronal mass ejections is striking; six of nine clouds observed at Earth were preceded an appropriate time earlier by meter-wave type II radio bursts indicative of coronal shock waves and coronal mass ejections occurring near central meridian. During the selected periods when no clouds were detected near Earth, the only type II bursts reported were associated with solar activity near the limbs. Where the proxy solar data to be sought are not so clearly suggested, that is, for clouds preceding interaction regions and clouds within cold magnetic enhancements, the evidence linking the clouds and coronal mass ejections is not as clear; proxy data usually suggest many candidate mass-ejection events for each cloud. Overall, the data are consistent with and support the hypothesis suggested by Klein and Burlaga that magnetic clouds observed with spacecraft at 1 AU are manifestations of solar coronal mass ejection transients.

  5. Magnetic field directional discontinuities. I - Minimum variance errors. [of interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Lepping, R. P.; Behannon, K. W.

    1980-01-01

    The paper deals with a statistical analysis of the errors associated with a minimum variance analysis of directional discontinuities by use of an idealized model of these discontinuities and various simulations, and also by an examination of actual Mariner 10 interplanetary magnetic field data. An empirical expression is derived for the magnitude of the error in an estimated discontinuity normal component, relative to the total field across the directional discontinuity. The analysis was performed primarily to aid in differentiating between interplanetary tangential and rotational discontinuities observed by Mariner 10.

  6. 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.

  7. 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.

  8. The local dayside reconnection rate for oblique interplanetary magnetic fields

    NASA Astrophysics Data System (ADS)

    Komar, C. M.; Cassak, P. A.

    2016-06-01

    We present an analysis of local properties of magnetic reconnection at the dayside magnetopause for various interplanetary magnetic field (IMF) orientations in global magnetospheric simulations. This has heretofore not been practical because it is difficult to locate where reconnection occurs for oblique IMF, but new techniques make this possible. The approach is to identify magnetic separators, the curves separating four regions of differing magnetic topology, which map the reconnection X line. The electric field parallel to the X line is the local reconnection rate. We compare results to a simple model of local two-dimensional asymmetric reconnection. To do so, we find the plasma parameters that locally drive reconnection in the magnetosheath and magnetosphere in planes perpendicular to the X line at a large number of points along the X line. The global magnetohydrodynamic simulations are from the three-dimensional Block-Adaptive, Tree Solarwind Roe-type Upwind Scheme (BATS-R-US) code with a uniform resistivity, although the techniques described here are extensible to any global magnetospheric simulation model. We find that the predicted local reconnection rates scale well with the measured values for all simulations, being nearly exact for due southward IMF. However, the absolute predictions differ by an undetermined constant of proportionality, whose magnitude increases as the IMF clock angle changes from southward to northward. We also show similar scaling agreement in a simulation with oblique southward IMF and a dipole tilt. The present results will be an important component of a full understanding of the local and global properties of dayside reconnection.

  9. 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.

  10. Correlation of the 27-day variation of cosmic rays to the interplanetary magnetic field strength

    NASA Astrophysics Data System (ADS)

    Sabbah, I.

    2001-08-01

    We analyze cosmic ray data as well as interplanetary magnetic field (IMF) data, to examine the relation and correlation between their 27-day variations during the time interval 1965-1995. The amplitude of the 27day variation of galactic cosmic rays is linearly correlated with: the IMF strength (B), the z-component (Bz) of the IMF vector and the product of the solar wind speed (V) times B (VB). It is well correlated with the heliospheric current sheet tiltangle.Thecross-correlationfunctionofthe27-daycosmic ray variation versus the solar wind speed shows a negative correlation. The solar wind speed leads the cosmic ray variation by 2 years. The 27-day variation of cosmic rays is correlated with the variation in both the xand y-components of the IMF, it lags with 3-5 years. 1. Introduction Galactic cosmic rays are modulated (modified) through their propagation in the heliosphere by the effect of the large scale structure of the interplanetary medium. A wavy structured neutralcurrentsheet(NCS) separatesthe heliosphereintotwo regions of opposite magnetic polarity. During positive magnetic phase, the interplanetary magnetic field (IMF) is directed away from the Sun above the NCS and toward the Sun south of it. During negative magnetic phase the IMF direction is reversed. The angle between the Sun's equatorial plane and the NCS is referred as the tilt angle R, of the neutral sheet. It exhibits a solar activity dependence, R is small near sunspot minimum and large near solar maximum. The 27-day variations of galactic cosmic rays have been related to the changing position of the interplanetary NCS (Swinson and Yasue, 1992; Valdes-Galicia and Dorman, 1997). Here we examine the effect of the interplanetary parameters upon the 27-day variation of galactic cosmic rays during the last three solar cycles. 2. Solar Cycle Dependance We used hourly averaged cosmic ray counts observed with neutron monitors at Deep River (DR) and Huancayo (HU) and muon surface telescope at Nagoya (NA

  11. 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

  12. 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+τ)-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

  13. The large-scale magnetic field in the solar wind. [astronomical models of interplanetary magnetics and the solar magnetic field

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; Ness, N. F.

    1976-01-01

    A literature review is presented of theoretical models of the interaction of the solar wind and interplanetary magnetic fields. Observations of interplanetary magnetic fields by the IMP and OSO spacecraft are discussed. The causes for cosmic ray variations (Forbush decreases) by the solar wind are examined. The model of Parker is emphasized. This model shows the three dimensional magnetic field lines of the solar wind to have the form of spirals wrapped on cones. It is concluded that an out-of-the-ecliptic solar probe mission would allow the testing and verification of the various theoretical models examined. Diagrams of the various models are shown.

  14. Magnetopause shape under a radial interplanetary magnetic field

    NASA Astrophysics Data System (ADS)

    Grygorov, Kostiantyn; Nemecek, Zdenek; Safrankova, Jana; Shue, Jih-Hong; Pi, Gilbert

    2016-07-01

    The orientation of the interplanetary magnetic field (IMF) is the most important factor influencing the magnetopause processes and, consequently, a transfer of solar wind mass and momentum into the magnetosphere. A role of the north-south IMF component is more or less well understood in terms of changes of a location of the reconnection site(s) on the magnetopause surface that leads to the changes of the magnetopause location and flaring angle. A very rarely observed radial IMF results in a shift of magnetopause locations up to several radii farther from the Earth and probably leads to a specific magnetopause shape. We present several case studies of magnetopause crossings observed by the fleet of THEMIS spacecraft under a long lasting radial IMF and analyze the difference between observed magnetopause positions and those which are predicted by empirical magnetopause models. We use the data propagated from the L1 point as well as observations of near-Earth solar wind monitors (if available) as a model input. We discuss possible processes that can lead to the magnetopause displacement and to changes of its shape.

  15. The correlation length for interplanetary magnetic field fluctuations

    NASA Technical Reports Server (NTRS)

    Fisk, L. A.; Sari, J. W.

    1972-01-01

    It is argued that it is appropriate to consider two correlation lengths for interplanetary magnetic field fluctuations. For particles with gyro-radii large enough to encounter and be scattered by large-scale tangential discontinuities in the field (particles with energies greater than or approximately equal to several GeV/nucleon) the appropriate correlation length is simply the mean spatial separation between the discontinuities, L approximately 2 x 10 to the 11th power. Particles with gyro-radii much less than this mean separation (energies less than or approximately equal to 100 MeV/nucleon) appear to be unaffected by the discontinuities and respond only to smaller-scale field fluctuations. For these particles the correlation length is shown to be L approximately 10 to the 10th power cm. With this system of two correlation lengths the cosmic-ray diffusion tensor may be altered from what was predicted by, for example, Jokipii and Coleman, and the objections raised recently by Klimas and Sandri to the diffusion analysis of Jokipii may apply only at relatively low energies (approximately 50 MeV/nucleon).

  16. Intense interplanetary magnetic fields observed by geocentric spacecraft during 1963-1975

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.; King, J. H.

    1979-01-01

    In the present paper, interplanetary magnetic field and plasma data are reviewed over a period exceeding one full solar cycle for intervals in which the magnetic intensity was greater than 13 gammas. One hundred forty nine intervals of this type, with almost complete plasma and magnetic field data, are identified. Most (79%) of these enhancements could be associated either with interplanetary shocks or with high-speed stream interfaces. Half of the remaining 21% of the enhancements could be identified as cold magnetic enhancements, while the other half could not be associated with a single shock, interface, or cold magnetic enhancement.

  17. 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.

  18. Interplanetary magnetic field as a detector of turbulence in the inner heliosphere

    NASA Astrophysics Data System (ADS)

    Khabarova, O.

    2013-12-01

    Analysis of the interplanetary magnetic field (IMF) behavior at different scales may give a key for understanding of turbulence spatial evolution in the heliosphere. It has been known that the solar wind plasma becomes more and more turbulent with heliocentric distance. Recent multi-spacecraft investigations of the large-scale IMF [1] show unexpectedly fast lost of the regular sector structure of the solar wind in the inner heliosphere. In the ecliptic plane, it seems to be broken at 3-4 AU, much closer to the Sun than the Parker spiral gets perpendicular to the sunward direction. At the same time, the high-latitude solar wind remains more structured at the same heliocentric distances [2]. This fact may bear evidence of radial increase of turbulence and intermittency in the solar wind due to magnetic reconnection. The magnetic reconnection recurrently occurs at the large-scale heliospheric current sheet (HCS) as well as at smaller-scale current sheets during the solar wind expansion [3]. As a result, a significant part of the heliosphere is filled with secondary current sheets as well as with waves and accelerated particles in some vicinity of the HCS. Under averaging, it looks as a radial increase of turbulence, especially in low latitudes. It also can be considered as one of the main causes of the break of the expected IMF radial dependence law [1, 2]. Results of the consequent multi-spacecraft analysis of plasma and magnetic filed turbulence characteristics at different heliocentric distances and heliolatitudes will be discussed. 1. O. Khabarova, V. Obridko, Puzzles of the Interplanetary Magnetic 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 2. O.V. Khabarova, The interplanetary magnetic field: radial and latitudinal dependences, Astronomy Reports, 2013, 57, 11, http://arxiv.org/ftp/arxiv/papers/1305/1305.1204.pdf 3. V. Zharkova, O. Khabarova, Particle Acceleration in

  19. 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.

  20. 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.

  1. 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.

  2. Geologic analysis of averaged magnetic satellite anomalies

    NASA Technical Reports Server (NTRS)

    Goyal, H. K.; Vonfrese, R. R. B.; Ridgway, J. R.; Hinze, W. J.

    1985-01-01

    To investigate relative advantages and limitations for quantitative geologic analysis of magnetic satellite scalar anomalies derived from arithmetic averaging of orbital profiles within equal-angle or equal-area parallelograms, the anomaly averaging process was simulated by orbital profiles computed from spherical-earth crustal magnetic anomaly modeling experiments using Gauss-Legendre quadrature integration. The results indicate that averaging can provide reasonable values at satellite elevations, where contributing error factors within a given parallelogram include the elevation distribution of the data, and orbital noise and geomagnetic field attributes. Various inversion schemes including the use of equivalent point dipoles are also investigated as an alternative to arithmetic averaging. Although inversion can provide improved spherical grid anomaly estimates, these procedures are problematic in practice where computer scaling difficulties frequently arise due to a combination of factors including large source-to-observation distances ( 400 km), high geographic latitudes, and low geomagnetic field inclinations.

  3. 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://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://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://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://ntrs.nasa.gov/search.jsp?R=19910060875&hterms=magnetic+fields+interactions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bfields%2Binteractions','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910060875&hterms=magnetic+fields+interactions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bfields%2Binteractions"><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://adsabs.harvard.edu/abs/1995SoPh..157..367A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995SoPh..157..367A"><span id="translatedtitle">The solar wind angular momentum and energy carried by 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>Alexander, P.; de La Torre, A.</p> <p>1995-03-01</p> <p>Solutions already found by one of the authors with a two-region model of the solar coronal expansion are used to analyze the transport of angular momentum and energy by the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. In agreement with observations, it is predicted that the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field plays an insignificant role for the flux of energy, but carries a large amount of angular momentum. The appropriate description might be related to the replacement of classical transport coefficients by a collisionless heat flux equation in the outer region of the model. The Sun's loss of angular momentum may affect the strength of the solar rotation in the long term.</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> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770038810&hterms=magnetic+separation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmagnetic%2Bseparation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770038810&hterms=magnetic+separation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmagnetic%2Bseparation"><span id="translatedtitle">The August 1972 solar-terrestrial events - <span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field observations</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.</p> <p>1976-01-01</p> <p><span class="hlt">Interplanetary-magnetic</span>-field measurements made by Pioneers 9 and 10, HEOS 2, and Explorer 41 during early August 1972 are reviewed. It is noted that the two Pioneers were nearly radially aligned during the flare events, with Pioneer 9 at a distance of 0.78 AU from the sun and Pioneer 10 at a distance of 2.2 AU. The data obtained by Pioneer 9, Pioneer 10, and the two near-earth satellites are analyzed separately, and the major flare-associated shocks are identified. An attempt is made to identify corresponding shocks at the different locations and to determine their propagation velocities in the region between 0.8 and 2.2 AU. It is found that there was an obvious tendency for the <span class="hlt">average</span> shock velocities to decrease with increasing radial distance from the sun and that the local velocities at the Pioneer locations were significantly smaller than the appropriate <span class="hlt">average</span> values. A comparison of these local velocities indicates that there was a large deceleration of the shocks between the sun and some distance within 0.8 AU but little, if any, deceleration beyond that distance. A plot of <span class="hlt">average</span> shock velocities from the sun to 1.0 AU as a function of longitude separation between the flares and Pioneer 9 is shown to suggest a pronounced deviation of the shock fronts from spherical symmetry.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMSH31A1178W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMSH31A1178W"><span id="translatedtitle">Orientation Of <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Clouds Associated With Filament Eruptions And Major 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>Wang, Y.; Ye, P.; Zhou, G.; Wang, S.; Wang, J.</p> <p>2004-12-01</p> <p>As a major source of non-recurrent geomagnetic storms, more than half of <span class="hlt">magnetic</span> clouds in the <span class="hlt">interplanetary</span> medium are associated with filament eruptions [Subramanian and Dere, 2001]. The strength of south component of the <span class="hlt">magnetic</span> field inside <span class="hlt">magnetic</span> cloud and its duration are consider the very important factors in causing geomagnetic storm. Obviously, these factors are related to the orientation of <span class="hlt">magnetic</span> cloud in terms of flux rope model. By investigating the observations of SOHO and ACE spacecraft from 2000 to 2003, the relationship between the orientation of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds which were associated with filament eruptions and major geomagnetic storms are studied. Two issues are discussed: (1) the effect of <span class="hlt">magnetic</span> cloud's orientation on the intensity of geomagnetic storm, and (2) the possible factors in influencing the cloud's orientation. The results will be worked out.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1981ICRC....3..113Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981ICRC....3..113Z"><span id="translatedtitle">Low-energy particles in <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field near the sectorial boundary on September 26, 1977</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zeldovich, M. A.; Kuzhevskii, B. M.</p> <p></p> <p>Prognoz-6 data are used to examine effects of the sign reversal in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field of September 26, 1977 on the 70-keV to 40 MeV proton fluxes, and the 10-30 keV and 40-500 keV electron fluxes. The sectorial boundary of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field traversed the earth at 2300 UT, and in that period the <span class="hlt">interplanetary</span> space was filled with the solar cosmic ray particles generated in the flare of September 24, 1977, whose intensity decreased in time. Results indicate that the event of September 26, 1977 was the first observation where effects of the sectorial boundary were traced up to proton energies of 40-50 MeV.</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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E1678S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E1678S&link_type=ABSTRACT"><span id="translatedtitle">Structure of magnetopause layers formed by a radial <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>Safrankova, Jana; Simunek, Jiri; Nemecek, Zdenek; Prech, Lubomir; Grygorov, Kostiantyn; Shue, Jih-Hong; Samsonov, Andrey; Pi, Gilbert</p> <p>2016-07-01</p> <p>The magnetopause location is generally believed to be determined by the solar wind dynamic pressure and by the sign and value of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) vertical (Bz) component. A contribution of other parameters is usually assumed to be minor or negligible near the equatorial plane. However, recent papers have shown a magnetopause expansion during intervals of a nearly radial IMF (large IMF Bx component). Under such conditions, the total pressure exerted on the subsolar magnetopause is significantly lower than the solar wind dynamic pressure as demonstrate both MHD simulations and statistical investigations. During a long-duration radial IMF, all parameters - the IMF magnitude, solar wind speed, density, and especially the temperature are depressed in comparison with their yearly <span class="hlt">averages</span>. Moreover, in this case, the structures of the LLBL change; the LLBL shows different profiles at both hemispheres for negative and positive IMF Bx polarities. This asymmetry changes over time and influences the LLBL structures due to <span class="hlt">magnetic</span> reconnection. We present an overview of important physical quantities controlling the magnetopause compression and new results that deal with the structure of the magnetopause and adjacent layers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010JGRA..11510320W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010JGRA..11510320W"><span id="translatedtitle">Statistical maps of geomagnetic perturbations as a function 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>Weimer, D. R.; Clauer, C. R.; Engebretson, M. J.; Hansen, T. L.; Gleisner, H.; Mann, I.; Yumoto, K.</p> <p>2010-10-01</p> <p>Mappings of geomagnetic perturbations are shown for different combinations of the solar wind velocity, <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF), and dipole tilt angle (season). <span class="hlt">Average</span> maps were derived separately for the northward, eastward, and vertical (downward) components of the geomagnetic disturbances, using spherical cap harmonics in least error fits of sorted measurements. The source data are obtained from 104 ground-based magnetometer stations in the Northern Hemisphere at geomagnetic latitudes over 40° during the years 1998 through 2001. Contour maps of statistical fits are shown along-side scatter plots of individual measurements in corrected geomagnetic apex coordinates. The patterns are consistent with previous mappings of ionospheric electric potential. Interestingly, the vertical component of the <span class="hlt">magnetic</span> perturbations closely resembles maps of the overhead, field-aligned currents, including the Northward IMF configuration. The maximum and minimum values from the statistical mappings are graphed to show their changes as a function of southward IMF magnitude, solar wind velocity, and seasons. It is expected that this work will lead to better advance predictions of the geomagnetic perturbations that are based on real-time IMF measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19730037253&hterms=kawasaki&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dkawasaki','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19730037253&hterms=kawasaki&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dkawasaki"><span id="translatedtitle">Cross-correlation analysis of the AE index and the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field Bz component.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Meng, C.-I.; Tsurutani, B.; Kawasaki, K.; Akasofu, S.-I.</p> <p>1973-01-01</p> <p>A cross-correlation study between magnetospheric activity (the AE index) and the southward-directed component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) is made for a total of 792 hours (33 days) with a time resolution of about 5.5 min. The peak correlation tends to occur when the <span class="hlt">interplanetary</span> data are shifted approximately 40 min later with respect to the AE index data. Cross-correlation analysis is conducted on some idealized wave forms to illustrate that this delay between southward turning of the IMF and the AE index should not be interpreted as being the duration of the growth phase.</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; Lühr, 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 μA/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/2060/19770027121','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/2060/19730002064','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002064"><span id="translatedtitle">Comments on the measurement of power spectra of 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>Russell, C. T.</p> <p>1972-01-01</p> <p>Examination of possible noise sources in the measurement of the power spectrum of fluctuations in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field shows that most measurements by fluxgate magnetometers are limited by digitization noise whereas the search coil magnetometer is limited by instrument noise. The folding of power about the Nyquist frequency or aliasing can be a serious problem at times for many magnetometers, but it is not serious during typical solar wind conditions except near the Nyquist frequency. Waves in the solar wind associated with the presence of the earth's bow shock can contaminate the <span class="hlt">interplanetary</span> spectrum in the vicinity of the earth. However, at times the spectrum in this region is the same as far from the earth. Doppler shifting caused by the convection of waves by the solar wind makes the interpretation of <span class="hlt">interplanetary</span> spectra difficult.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.1263W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.1263W"><span id="translatedtitle">Response of ionosphere and thermosphere during radial <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>Wang, Hui; Luehr, Hermann; Shue, Jihong</p> <p>2014-05-01</p> <p>The configurations of ionosphere and thermosphere have been investigated by using high-resolution measurements of CHAMP satellite. During the period IMF By and Bz components are weak and Bx keeps pointing to the Earth for almost 10 hours. The geomagnetic indices Dst is about -40 nT and AE about 100 nT on <span class="hlt">average</span> during the interest period. The CPCP (cross polar cap potential) output by AMIE and calculated from DMSP observations have <span class="hlt">average</span> values of 15-20 kV. Obvious hemispheric differences are shown in the configurations of FACs on the dayside and nightside. In the south pole FACs diminish in intensity with magnitudes below 0.25 µA/m2, the plasma convection retains its quiet time two cell flow pattern, and the air density is quiet low. However, there are obvious activities in the north cusp FACs. One pair of FACs emerges in the north cusp region, which shows opposite polarities to DPY FACs. The new type of currents is accompanied by sunward plasma flow channels. These ionospheric features might be manifestations of the <span class="hlt">magnetic</span> reconnection processes occurring in the north magnetospheric flanks. The enhanced ionospheric current systems have deposited large amount of energies into the thermosphere, causing enhanced air densities in the cusp region, which subsequently propagate equatorward both on the dayside and nightside. Although the radial IMF is considered as geomagnetic quiet condition, the present study has demonstrated for the first time there are prevailing energy inputs from the magnetosphere to both the ionosphere and thermosphere in the polar cusp region.</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://hdl.handle.net/2060/19730002088','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002088"><span id="translatedtitle">Effects of interstellar particles upon 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>Coleman, P. J., Jr.; Winter, E. M.</p> <p>1972-01-01</p> <p>The flow of interstellar neutral particles into the <span class="hlt">interplanetary</span> medium and their subsequent ionization in the presence of the electromagnetic field of the solar wind can cause a loss of field angular momentum by the solar wind. One effect of this loss of field angular momentum is a significant unwinding of the spiral field. This effect is evaluated using simple models for neutral density and ion production. For a free-stream interstellar medium with a neutral hydrogen density of 1 per cubic centimeter and a velocity relative to the sun of 10 to 20 km per second, the spiral angle at the orbit of Jupiter will be less than its nominal value of 45 deg at the orbit of the earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19760040203&hterms=E-LAYER&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DE-LAYER','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760040203&hterms=E-LAYER&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DE-LAYER"><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://ntrs.nasa.gov/search.jsp?R=19760033553&hterms=Statistical+Energy+Analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DStatistical%2BEnergy%2BAnalysis','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760033553&hterms=Statistical+Energy+Analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DStatistical%2BEnergy%2BAnalysis"><span id="translatedtitle">Statistical properties of the <span class="hlt">interplanetary</span> microscale fluctuations. [in 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>Belcher, J. W.</p> <p>1975-01-01</p> <p>Results are reported for a statistical study of short-period fluctuations in the <span class="hlt">interplanetary</span> plasma velocity and <span class="hlt">magnetic</span> field. The data base used consists of measurements of the <span class="hlt">interplanetary</span> plasma and <span class="hlt">magnetic</span> field by Pioneer 6 with a time resolution of 72 sec and by Mariner 5 with a resolution of 5 min. The analysis is conducted to characterize the parent population from which all individual microscale events on these time scales are drawn. The microscale changes are grouped according to their energy densities relative to the energy density of the background <span class="hlt">magnetic</span> field, and it is found that each grouping exhibits certain statistical properties within the limits of observational uncertainty. It is noted that these statistical properties are purely observational and independent of any physical model which may be used to interpret them. The results are discussed in the context of MHD discontinuity theory for a thermally anisotropic plasma.</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://ntrs.nasa.gov/search.jsp?R=19720046848&hterms=magnetic+fields+interactions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmagnetic%2Bfields%2Binteractions','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19720046848&hterms=magnetic+fields+interactions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmagnetic%2Bfields%2Binteractions"><span id="translatedtitle">The effects of boundary condition asymmetries on the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field-moon interaction.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Reisz, A. C.; Paul, D. L.; Madden, T. R.</p> <p>1972-01-01</p> <p>Boundary condition asymmetries inherent in the solar wind flow past the moon are included in a cylindrical model of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field-moon interaction. Numerical examinations of the sunward side response of this model are compared in the frequency domain with those of symmetrically excited spherical and cylindrical models and two characteristic differences are observed: the response of the asymmetric model is depressed at low frequencies due to <span class="hlt">magnetic</span> diffusion around a conducting core, and is flattened at high frequencies because of the finite application time of the incident <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. The diffusion of field lines around the core is also evident in the time response of the model in the antisolar cavity. The above features of the lunar response resulting from boundary condition asymmetries are shown to be evident in observational measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930046797&hterms=cosmic+geometry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcosmic%2Bgeometry','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930046797&hterms=cosmic+geometry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcosmic%2Bgeometry"><span id="translatedtitle">Long-term variations of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field spectra with implications for cosmic ray modulation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bieber, John W.; Chen, Jiasheng; Matthaeus, William H.; Smith, Charles W.; Pomerantz, Martin A.</p> <p>1993-01-01</p> <p>The paper calculates yearly <span class="hlt">averaged</span> power spectra of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field turbulence at 1 AU over the period 1965-1988 for fluctuations in the frequency range 5.8 x 10 exp -6 to 4.6 x 10 exp -5 Hz, corresponding to periods of 6-48 hr. The amplitudes of the spectra vary with the sunspot cycle and are inversely correlated with the intensity of about 10-GeV cosmic rays. The observed spectra are used to calculate a lower limit to the cosmic ray scattering mean free path employing resonant magnetostatic quasi-linear theory for both 'slab' and isotropic geometries of the turbulence. The mean free paths thus obtained are typically about 0.1 AU in the slab model and about 0.3 AU in the isotropic model, but they are not significantly correlated with the modulated galactic cosmic ray intensity recorded by neutron monitors. It is inferred that the scattering processes described by resonant magnetostatic theory play, at best, a very minor role in the solar modulation of about 10-GeV cosmic rays.</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=19780068596&hterms=1607&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2526%25231607','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19780068596&hterms=1607&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2526%25231607"><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>1978-01-01</p> <p>The paper examines sources of <span class="hlt">magnetic</span> fields in recurrent streams observed by the Imp 8 and Heos spacecraft at 1 AU and by Mariner 10 en route to Mercury between October 31, 1973 and February 9, 1974, during Carrington rotations 1607-1610. Although 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 at 1 AU were related to open field line regions on the sun which were not associated with known coronal holes, indicating that open field lines may be more basic than coronal holes as sources of the solar wind. <span class="hlt">Magnetic</span> field intensities in five equatorial coronal holes, certain photospheric <span class="hlt">magnetic</span> fields, and the coronal footprints of the sector boundaries on the source surface are characterized.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19750062208&hterms=polarity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dpolarity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19750062208&hterms=polarity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dpolarity"><span id="translatedtitle">Comparison of inferred and observed <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field polarities, 1970-1972</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.; Svalgaard, L.; Hedgecock, P. C.</p> <p>1975-01-01</p> <p>The inferred polarity (toward or away from the sun) of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field at earth using polar observations of the geomagnetic field has been compared with spacecraft observations. A list published by Svalgaard (1974) of the inferred field polarities in the period from 1970 to 1972 is found to be correct on 82% of the days. A near real-time (same day) method of inferring the polarity of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field using geomagnetic observations at Vostok and Thule is in use at the NOAA Space Environment Laboratory, Boulder, Colorado. During 1972, this method is found to be correct on 87% of the days. A list of 'well-defined' sector boundaries at earth from 1970 to 1972 is given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740048154&hterms=polarity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dpolarity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740048154&hterms=polarity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dpolarity"><span id="translatedtitle">The relation between the polarity of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and the polar geomagnetic field</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 relation between the azimuthal component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and the polar cap geomagnetic field is discussed. The geomagnetic effects can be described as produced by an ionospheric current system encircling the <span class="hlt">magnetic</span> pole. The sense of the current is clockwise during toward-sectors and reversed during away-sectors. The importance of this very direct solar-terrestrial relation is stressed. A recent <span class="hlt">magnetic</span> sunspot cycle model is discussed as inferred from this relationship, the basic feature being that the sun reproduces the same sector pattern during every sunspot cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999GeoRL..26..401O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999GeoRL..26..401O"><span id="translatedtitle">Multi-tube model for <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Osherovich, Vladimir A.; Fainberg, J.; Stone, R. G.</p> <p></p> <p>Measurements of the polytropic index γ inside a <span class="hlt">magnetic</span> cloud showed that there are two non-equal tubes inside the cloud [Fainberg et al., 1996; Osherovich et al., 1997]. For both tubes, γ < 1, but each tube has its own polytrope. We test equilibrium solutions which are a superposition of solutions with cylindrical and helical symmetry [Krat and Osherovich, 1978] as a new paradigm for a multi-tube model. Comparison of <span class="hlt">magnetic</span> and gas pressure profiles for these bounded MHD states with observations suggests that complex <span class="hlt">magnetic</span> clouds can be viewed as multiple helices embedded in a cylindrically symmetric flux rope.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880053447&hterms=ENERGY+SOLAR&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DENERGY%2BSOLAR','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880053447&hterms=ENERGY+SOLAR&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DENERGY%2BSOLAR"><span id="translatedtitle">Transport equations for low-energy solar particles in evolving <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>Ng, C. K.</p> <p>1988-01-01</p> <p>Two new forms of a simplified Fokker-Planck equation are derived for the transport of low-energy solar energetic particles in an evolving <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field, carried by a variable radial solar wind. An idealized solution suggests that the 'invariant' anisotropy direction reported by Allum et al. (1974) may be explained within the conventional theoretical framework. The equations may be used to relate studies of solar particle propagation to solar wind transients, and vice versa.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860064504&hterms=low+frequency+noise&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dlow%2Bfrequency%2Bnoise','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860064504&hterms=low+frequency+noise&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dlow%2Bfrequency%2Bnoise"><span id="translatedtitle">Low-frequency 1/f noise 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>Matthaeus, W. H.; Goldstein, M. L.</p> <p>1986-01-01</p> <p>Spacecraft observations of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field at 1 AU are shown to have frequency spectra with a 1/f dependence in the range 2.7-80 microHz. It is suggested that the 1/f spectrum results from the superposition of uncorrelated samples of solar surface turbulence that have log-normal distributions of correlation lengths corresponding to a scale-invariant distribution of correlation times over an appropriate range of parameters.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996JGR...10113303W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996JGR...10113303W"><span id="translatedtitle">Synthesis models of dayside field-aligned currents for strong <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field By</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Watanabe, Masakazu; Iijima, Takesi; Rich, Frederick J.</p> <p>1996-06-01</p> <p>Using particle and <span class="hlt">magnetic</span> field data acquired with DMSP-F6 and DMSP-F7 satellites, we have investigated <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) By dependence of the global pattern of plasma regime and field-aligned currents (FACs) on dayside high latitudes during strong IMF By (<span class="hlt">averaged</span> |By|>3.7 nT) and geomagnetically disturbed (mainly IMF Bz<0) periods. From particle data we have identified five plasma regimes: inner plasma sheet, outer plasma sheet, cleft, cusp, and mantle. All the plasma domains except the inner plasma sheet show By dependence in spatial distribution. Region 1 and ``traditional cusp'' currents appear in cusp/mantle domains, which we call midday region 1 and region 0 currents, respectively, in this paper. These currents perfectly reverse their flow directions depending on IMF By polarity. Traditional region 1 currents occurring in cleft and outer plasma sheet almost always flow into the ionosphere in the prenoon sector and flow away from the ionosphere in the postnoon sector regardless of By polarity. Thus the midday region 1 and region 0 current system that appears at local noon is not a simple continuation of flankside region 1/region 2 current system. Midday region 1 and region 0 currents are not necessarily balanced in intensity; region 0 current intensity occasionally exceeds midday region 1 current intensity. Furthermore, intensity imbalance also appears in cleft-associated region 1 currents; that is, region 1 current in the farside cleft from the reconnection site (``downstreamside'' cleft) is larger than region 1 current in the nearside cleft (``upstreamside'' cleft). On the basis of these observational facts we discuss the source mechanisms of the dayside FAC system: (1) directly coupled generation of region 0 and midday region 1 current in the cusp/mantle domains around noon and (2) generation of extra region 0 current in the tail magnetopause which is connected to the extra downstreamside cleft-associated region 1 current.</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</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> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFMSH41A2167H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013AGUFMSH41A2167H&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Magnetic</span> Field-line Twist in <span class="hlt">Interplanetary</span> Flux Ropes and its Implications for 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>Hu, Q.; Qiu, J.</p> <p>2013-12-01</p> <p><span class="hlt">Interplanetary</span> flux ropes, embedded within <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs), are often detected in-situ by spacecraft ACE, Wind, and STEREO. Both <span class="hlt">magnetic</span> field and plasma measurements sampled along the spacecraft path across the ICME structure are available for quantitative analysis. We apply the Grad-Shafranov reconstruction technique to examine the configuration of the flux ropes and to derive relevant physical quantities, such as <span class="hlt">magnetic</span> flux content, relative <span class="hlt">magnetic</span> helicity, and the field-line twist. We select recent events during the rising phase of enhanced solar activity, and utilize additional imaging observations from STEREO and SDO spacecraft. Both detailed analyses of solar source region characteristics including flaring and <span class="hlt">magnetic</span> reconnection sequence, and the corresponding flux rope structures will be presented. In particular, we examine the distribution of <span class="hlt">magnetic</span> field-line twist in flux ropes on nested cylindrical iso-surfaces of the <span class="hlt">magnetic</span> flux function. We compare the in-situ characterization of these flux-rope structures with their corresponding solar source region properties. We discuss the implications of such comparison for the origination of flux ropes on the Sun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920037011&hterms=magnetic+separation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmagnetic%2Bseparation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920037011&hterms=magnetic+separation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dmagnetic%2Bseparation"><span id="translatedtitle">Multipoint observations of planar <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field structures</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.; Lepping, R. P.; Dunlop, M. W.; Elliott, S.; Balogh, A.; Cowley, S. W. H.; Freeman, M. P.; Sibeck, D. G.</p> <p>1991-01-01</p> <p>IMF data made on November 1, 1984, by three spatially well-separated spacecraft in the solar wind are presented. The IMF measured by each of the spacecraft is found to consist of a multiplicity of structures within which the <span class="hlt">magnetic</span> field varies in parallel planes. The orientations of these planes at the three spacecraft locations are similar. The planes are inclined at a large angle to the ecliptic, and they lie almost perpendicular to the nominal Parker spiral direction in the ecliptic. Intercomparisons of the measurements at the various spacecraft show that the IMF features at one spacecraft are clearly reproduced at another, with time delays required for signal propagation. From these time delays and the mutual separations of the spacecraft, it is inferred that the structures are convecting with the ambient flow. Simultaneous observations made downstream of the bow shock in the magnetosheath reveal that the magnetosheath <span class="hlt">magnetic</span> field, too, is planar.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015TESS....121204H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015TESS....121204H&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Magnetic</span> Field-line Twist and Length Distributions inside <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Flux Ropes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hu, Qiang; Qiu, Jiong; Krucker, Sam</p> <p>2015-04-01</p> <p>​We report on the detailed and systematic study of field-line twist and length distributions within <span class="hlt">magnetic</span> flux ropes embedded in <span class="hlt">Interplanetary</span> Coronal Mass Ejections (ICMEs). The Grad-Shafranov reconstruction method is utilized together with a constant-twist nonlinear force-free (Gold-Hoyle) flux rope model and the commonly known Lundquist (linear force-free) model to reveal the close relation between the field-line twist and length in cylindrical flux ropes, based on in-situ spacecraft <span class="hlt">magnetic</span> field and plasma measurements. In particular, we utilize energetic electron burst observations at 1 AU together with associated type III radio emissions detected by the Wind spacecraft to provide unique measurements of <span class="hlt">magnetic</span> field-line lengths within selected ICME events. These direct measurements are compared with flux-rope model calculations to help assess the fidelity of different models and to provide diagnostics of internal structures. We show that our initial analysis of field-line twist indicates clear deviation from the Lundquist model, but better consistency with the Gold-Hoyle model. By using the different flux-rope models, we conclude that the in-situ direct measurements of field-line lengths are consistent with a flux-rope structure with spiral field lines of constant and low twist, largely different from that of the Lundquist model, especially for relatively large-scale flux ropes. We will also discuss the implications of our analysis of flux-rope structures on the origination and evolution processes in their corresponding solar source regions.</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://ntrs.nasa.gov/search.jsp?R=19950046378&hterms=solar+wind+magnetic+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsolar%2Bwind%2Bmagnetic%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950046378&hterms=solar+wind+magnetic+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsolar%2Bwind%2Bmagnetic%2Bfield"><span id="translatedtitle">The population of the magnetosphere by solar winds ions when the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is northward</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richard, Robert L.; Walker, Raymond J.; Ashour-Abdalla, Maha</p> <p>1994-01-01</p> <p>We have examined some possible entry mechanisms of solar wind ions into the magnetosphere by calculating the trajectories of thousands of non-interacting ions in the <span class="hlt">magnetic</span> and electric fields from a three dimensional global magnetohydrodynamic (MHD) simulation of the magnetosphere and the magnetosheath, under northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) conditions. Particles, launched in the solar wind, entered the magnetosphere and formed the low latitude boundary layer (LLBL), plasma sheet and a region of trapped particles near the Earth. The densities and temperatures we obtained in these regions were realistic, with the exception of trapped particle densities. The dominant entry mechanism was convection into the magnetosphere on reconnecting field lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1982Ge%26Ae..22.1016B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1982Ge%26Ae..22.1016B"><span id="translatedtitle">Dynamics of the frequency spectrum of fluctuations of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and cosmic rays</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bezrodnykh, I. P.; Kuzmin, V. A.; Kozlov, V. I.; Morozova, E. I.; Shafer, Iu. G.</p> <p>1982-12-01</p> <p>Prognoz-6 data on the dynamics of the fluctuation spectrum of low-energy cosmic-rays tends to support the hypothesis that the modulation of the cosmic-ray fluctuation spectrum has an <span class="hlt">interplanetary</span> origin. The results indicate that an analogous dynamics is observed in the fluctuation spectrum of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF), the dynamics in the frequency spectra of cosmic rays and the IMF occurring simultaneously. This suggests that the dynamics of the fluctuation spectrum of cosmic rays is conditioned by the dynamics of the IMF irregularity spectrum. The results also indicate the presence of two bursts of fluctuations of galactic cosmic rays and the IMF in the event of June 9-10, 1968, when the passage of a shock front was noted.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016AdSpR..58..175P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AdSpR..58..175P"><span id="translatedtitle">Draping of strongly flow-aligned <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field about the magnetopause</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petrinec, S. M.</p> <p>2016-07-01</p> <p>Many dynamic processes of the magnetosphere are directly driven by the solar wind and the occurrence of <span class="hlt">magnetic</span> merging at the magnetopause. The location of magnetopause <span class="hlt">magnetic</span> merging, or reconnection, is now fairly well understood when the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) contains large By and Bz components in relation to the Bx component (in Geocentric Solar Magnetospheric (GSM) coordinates). However, when the IMF contains a large X-component (i.e., is closely flow-aligned), it is not yet well understood how the shocked IMF drapes about the magnetopause, and how this affects the occurrence and location of <span class="hlt">magnetic</span> merging. In this initial study, we examine from observations how a nearly flow-aligned IMF drapes about the magnetopause. The results of this study are expected to be useful for comparisons with both analytic and global numerical models of the magnetosheath <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5192R&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.5192R&link_type=ABSTRACT"><span id="translatedtitle">Dependence of the location of the Martian <span class="hlt">magnetic</span> lobes on the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field direction</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Romanelli, Norberto; Mazelle, Christian; Bertucci, Cesar; Gomez, Daniel</p> <p>2016-04-01</p> <p>The <span class="hlt">magnetic</span> field topology surrounding the Martian atmosphere is mainly the result of gradients in the velocity of the solar wind (SW). Such variations in the SW velocity are in turn the result of a massloading process and forces associated with electric currents flowing around the ionosphere of Mars [Nagy et al 2004, Mazelle et al 2004, Brain et al 2015]. In particular, in the regions where the collisionless regime holds, the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) frozen into the SW piles up in front of the stagnation region of the flow. At the same time, the <span class="hlt">magnetic</span> field lines are stretched in the direction of the unperturbed SW as this stream moves away from Mars, giving rise to a magnetotail [Alfvén, 1957]. As a result and in contrast with an obstacle with and intrinsic global <span class="hlt">magnetic</span> field, the structure and organization of the <span class="hlt">magnetic</span> field around Mars depends on the direction of the IMF and its variabilities [Yeroshenko et al., 1990; Crider et al., 2004; Bertucci et al., 2003; Romanelli et al 2015]. In this study we use magnetometer data from the Mars Global Surveyor (MGS) spacecraft during portions of the premapping orbits of the mission to study the variability of the Martian-induced magnetotail as a function of the orientation of the IMF. The time spent by MGS in the magnetotail lobes during periods with positive solar wind flow-aligned IMF component B∥IMF suggests that their location as well as the position of the central polarity reversal layer (PRL) are displaced in the direction antiparallel to the IMF cross-flow component B⊥IMF . Analogously, in the cases where B∥IMF is negative, the lobes are displaced in the direction of B⊥IMF. We find this behavior to be compatible with a previously published B⊥IMF analytical model of the IMF draping, where for the first time, the displacement of a complementary reversal layer (denoted as IPRL for inverse polarity reversal layer) is deduced from first principles [Romanelli et al 2014]. We also</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Ap%26SS.361..242B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Ap%26SS.361..242B"><span id="translatedtitle">Role of solar wind speed and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field during two-step Forbush decreases caused by <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>Bhaskar, Ankush; Vichare, Geeta; Arunbabu, K. P.; Raghav, Anil</p> <p>2016-07-01</p> <p>The relationship of Forbush decreases (FDs) observed in Moscow neutron monitor with the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (B) and solar wind speed (Vsw) is investigated in detail for the FDs associated with <span class="hlt">Interplanetary</span> Coronal Mass Ejections (ICMEs) during 2001-2004. The classical two-step FD events are selected, and characteristics of the first step (mainly associated with shock), as well as of complete decrease (main phase) and recovery phase, are studied here. It is observed that the onset of FD occurs generally after zero to a few hours of shock arrival, indicating in the post-shock region that mainly sheath and ICME act as important drivers of FD. A good correlation is observed between the amplitude of B and associated FD magnitude observed in the neutron count rate of the main phase. The duration of the main phase observed in the neutron count rate also shows good correlation with B. This might indicate that stronger <span class="hlt">interplanetary</span> disturbances have a large dimension of <span class="hlt">magnetic</span> field structure which causes longer fall time of FD main phase when they transit across the Earth. It is observed that Vsw and neutron count rate time profiles show considerable similarity with each other during complete FD, especially during the recovery phase of FD. Linear relationship is observed between time duration/e-folding time of FD recovery phase and Vsw. These observations indicate that the FDs are influenced by the inhibited diffusion of cosmic rays due to the enhanced convection associated with the <span class="hlt">interplanetary</span> disturbances. We infer that the inhibited cross-field diffusion of the cosmic rays due to enhanced B is mainly responsible for the main phase of FD whereas the expansion of ICME contributes in the early recovery phase and the gradual variation of Vsw beyond ICME boundaries contributes to the long duration of FD recovery through reduced convection-diffusion.</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://adsabs.harvard.edu/abs/2015AGUFMSH14A..06R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSH14A..06R"><span id="translatedtitle">Predicting the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field using Approaches Based on Data Mining and Physical Models</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Riley, P.; Russell, C. T.; de Koning, C. A.; Biesecker, D. A.; Linker, J.; Owens, M. J.; Lugaz, N.; Martens, P.; Angryk, R.; Reinard, A.; Ulrich, R. K.; Horbury, T. S.; Pizzo, V. J.; Liu, Y.; Hoeksema, T.</p> <p>2015-12-01</p> <p>An accurate prediction of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field, and, in particular, its z-component (Bz) is a crucial capability for any space weather forecasting system, and yet, thus far, it has remained largely elusive (a point exemplified by the fact that no prediction center currently provides a forecast for Bz). In this presentation, we discuss the various physical processes that can produce non-zero values of Bz and summarize a selection of promising approaches that may ultimately lead to reliable forecasts of Bz. We describe the first steps we have taken to develop a framework for assessing these techniques, and show preliminary results of their efficacy.</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://ntrs.nasa.gov/search.jsp?R=19770034012&hterms=Geomagnetic+pulsations&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DGeomagnetic%2Bpulsations','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770034012&hterms=Geomagnetic+pulsations&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DGeomagnetic%2Bpulsations"><span id="translatedtitle"><span class="hlt">Magnetic</span> pulsations as a probe of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field - A test of the Borok B index</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.; Fleming, B. K.</p> <p>1976-01-01</p> <p>A <span class="hlt">magnetic</span> pulsation index based on the periods of Pc 2-4 pulsations as recorded in earth current measurements at the Borok Geophysical Observatory has been claimed to be a measure of the <span class="hlt">interplanetary</span> field. Tests of this index for the period 1972 to June 1974 show only a 27% success rate. However, a simple recalibration of the index improves the success rate to 51%. The success of the index indicates that the source of many terrestrial <span class="hlt">magnetic</span> pulsations is external to the magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920059735&hterms=electrodynamics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Delectrodynamics','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920059735&hterms=electrodynamics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Delectrodynamics"><span id="translatedtitle">Small-scale electrodynamics of the cusp with 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>Basinska, Ewa M.; Burke, William J.; Maynard, Nelson C.; Hughes, W. J.; Winningham, J. D.; Hanson, W. B.</p> <p>1992-01-01</p> <p>Possible low-altitude field signatures of merging occurring at high latitudes during a period of strong northward directed <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field are reported. Large electric and <span class="hlt">magnetic</span> field spikes detected at the poleward edge of the magnetosheathlike particle precipitation are interpreted as field signatures of the low-altitude footprint of such merging line locations. A train of phase-shifted, almost linearly polarized electric and <span class="hlt">magnetic</span> field fluctuations was detected just equatorward of the large electromagnetic spike. It is argued that these may be due to either ion cyclotron waves excited by penetrating magnetosheath ions or transient oscillations in the frame of convecting plasma, brought about by the sudden change in the flow at the magnetospheric end of the field line.</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.; Skjæveland, Å.; 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://ntrs.nasa.gov/search.jsp?R=19790045591&hterms=Longitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DLongitude','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790045591&hterms=Longitude&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DLongitude"><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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016GeoRL..43.7319Y&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016GeoRL..43.7319Y&link_type=ABSTRACT"><span id="translatedtitle">The influences of solar wind pressure and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field on global <span class="hlt">magnetic</span> field and outer radiation belt electrons</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, J.; Li, L. Y.; Cao, J. B.; Reeves, G. D.; Baker, D. N.; Spence, H.</p> <p>2016-07-01</p> <p>Using the Van Allen Probe in situ measured <span class="hlt">magnetic</span> field and electron data, we examine the solar wind dynamic pressure and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) effects on global <span class="hlt">magnetic</span> field and outer radiation belt relativistic electrons (≥1.8 MeV). The dynamic pressure enhancements (>2 nPa) cause the dayside <span class="hlt">magnetic</span> field increase and the nightside <span class="hlt">magnetic</span> field reduction, whereas the large southward IMFs (Bz-IMF < -2nT) mainly lead to the decrease of the nightside <span class="hlt">magnetic</span> field. In the dayside increased <span class="hlt">magnetic</span> field region (<span class="hlt">magnetic</span> local time (MLT) ~ 06:00-18:00, and L > 4), the pitch angles of relativistic electrons are mainly pancake distributions with a flux peak around 90° (corresponding anisotropic index A > 0.1), and the higher-energy electrons have stronger pancake distributions (the larger A), suggesting that the compression-induced betatron accelerations enhance the dayside pancake distributions. However, in the nighttime decreased <span class="hlt">magnetic</span> field region (MLT ~ 18:00-06:00, and L ≥ 5), the pitch angles of relativistic electrons become butterfly distributions with two flux peaks around 45° and 135° (A < 0). The spatial range of the nighttime butterfly distributions is almost independent of the relativistic electron energy, but it depends on the <span class="hlt">magnetic</span> field day-night asymmetry and the <span class="hlt">interplanetary</span> conditions. The dynamic pressure enhancements can make the nighttime butterfly distribution extend inward. The large southward IMFs can also lead to the azimuthal expansion of the nighttime butterfly distributions. These variations are consistent with the drift shell splitting and/or magnetopause shadowing effect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/pages/biblio/1304818-influences-solar-wind-pressure-interplanetary-magnetic-field-global-magnetic-field-outer-radiation-belt-electrons','SCIGOV-DOEP'); return false;" href="http://www.osti.gov/pages/biblio/1304818-influences-solar-wind-pressure-interplanetary-magnetic-field-global-magnetic-field-outer-radiation-belt-electrons"><span id="translatedtitle">The influences of solar wind pressure and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field on global <span class="hlt">magnetic</span> field and outer radiation belt electrons</span></a></p> <p><a target="_blank" href="http://www.osti.gov/pages">DOE PAGESBeta</a></p> <p>Yu, J.; Li, L. Y.; Cao, J. B.; Reeves, Geoffrey D.; Baker, D. N.; Spence, H.</p> <p>2016-07-22</p> <p>Using the Van Allen Probe in situ measured <span class="hlt">magnetic</span> field and electron data, we examine the solar wind dynamic pressure and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) effects on global <span class="hlt">magnetic</span> field and outer radiation belt relativistic electrons (≥1.8 MeV). The dynamic pressure enhancements (>2 nPa) cause the dayside <span class="hlt">magnetic</span> field increase and the nightside <span class="hlt">magnetic</span> field reduction, whereas the large southward IMFs (Bz-IMF < –2nT) mainly lead to the decrease of the nightside <span class="hlt">magnetic</span> field. In the dayside increased <span class="hlt">magnetic</span> field region (<span class="hlt">magnetic</span> local time (MLT) ~ 06:00–18:00, and L > 4), the pitch angles of relativistic electrons are mainly pancakemore » distributions with a flux peak around 90° (corresponding anisotropic index A > 0.1), and the higher-energy electrons have stronger pancake distributions (the larger A), suggesting that the compression-induced betatron accelerations enhance the dayside pancake distributions. However, in the nighttime decreased <span class="hlt">magnetic</span> field region (MLT ~ 18:00–06:00, and L ≥ 5), the pitch angles of relativistic electrons become butterfly distributions with two flux peaks around 45° and 135° (A < 0). The spatial range of the nighttime butterfly distributions is almost independent of the relativistic electron energy, but it depends on the <span class="hlt">magnetic</span> field day-night asymmetry and the <span class="hlt">interplanetary</span> conditions. The dynamic pressure enhancements can make the nighttime butterfly distribution extend inward. The large southward IMFs can also lead to the azimuthal expansion of the nighttime butterfly distributions. As a result, these variations are consistent with the drift shell splitting and/or magnetopause shadowing effect.« less</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/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 (|σ{sub m}| in [0.6: 1]), but extremely variable cross-helicity states (|σ{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 √(σ{sub m}{sup 2}+σ{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://ntrs.nasa.gov/search.jsp?R=19730051463&hterms=Statistical+Energy+Analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DStatistical%2BEnergy%2BAnalysis','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19730051463&hterms=Statistical+Energy+Analysis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DStatistical%2BEnergy%2BAnalysis"><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://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=19930042362&hterms=Magnetohydrodynamics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DMagnetohydrodynamics','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930042362&hterms=Magnetohydrodynamics&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3DMagnetohydrodynamics"><span id="translatedtitle">A global magnetohydrodynamic simulation of the magnetosheath and magnetosphere when the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is northward</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ogino, Tatsuki; Walker, Raymond I.; Ashour-Abdalla, Maha</p> <p>1992-01-01</p> <p>We have used a new high-resolution global magnetohydrodynamic simulation model to investigate the configuration of the magnetosphere when the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) is northward. For northward IMF the magnetospheric configuration is dominated by <span class="hlt">magnetic</span> reconnection at the tail lobe magnetopause tailward of the polar cusp. This results in a local thickening of the plasma sheet equatorward of the region of reconnection and the establishment of a convection system with two cells in each lobe. In the magnetosheath the plasma density and pressure decrease near the subsolar magnetopause, forming a depletion region. Along the flanks of the magnetosphere the magnetosheath flow is accelerated to values larger than the solar wind velocity. The magnetopause shape from the simulations is consistent with the empirically determined shape.</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> </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://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://ntrs.nasa.gov/search.jsp?R=19860056292&hterms=dbs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddbs','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860056292&hterms=dbs&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Ddbs"><span id="translatedtitle">On the association of <span class="hlt">magnetic</span> clouds with disappearing filaments. [<span class="hlt">interplanetary</span> phenomena associated with coronal mass ejection</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, R. M.; Hildner, E.</p> <p>1986-01-01</p> <p>Evidence is presented that an <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> cloud preceding an interaction region, observed at earth on January 24, 1974, is associated with the eruptive filament of disparition brusque (DB) near central meridian on January 18. The DB was also associated with a long-decay soft X ray transient and a long-duration gradual-rise-and-fall radio burst. To assess whether <span class="hlt">magnetic</span> clouds are generally associated with DBs, results from statistical testing of the relation of 33 <span class="hlt">magnetic</span> clouds (and 33 control samples without <span class="hlt">magnetic</span> clouds) to disappearing filaments near central meridian (approximately less than 45 deg central meridian distance) are presented. The hypothesis that <span class="hlt">magnetic</span> cloud are the 1-AU counterparts of either eruptive filaments or the coronal mass ejections which probably accompany them is supported. The major result is that disappearing filaments occur more frequently on the days when <span class="hlt">magnetic</span> clouds are launched than on control days, a result obtained with greater than 99 pct confidence. There is a suggestion that clouds following shocks, probably launched at times of solar flares, are not as strongly associated with disappearing filaments as are clouds launched less violently.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790061224&hterms=media+relations&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmedia%2Brelations','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790061224&hterms=media+relations&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dmedia%2Brelations"><span id="translatedtitle">Spatial distribution of large-scale solar <span class="hlt">magnetic</span> fields and their relation to 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>Levine, R. H.</p> <p>1979-01-01</p> <p>The spatial organization of the observed photospheric <span class="hlt">magnetic</span> field as well as its relation to the polarity of the IMF have been studied using high resolution magnetograms from the Kitt Peak National Observatory. Systematic patterns in the large scale field are due to contributions from both concentrated flux and more diffuse flux. The polarity of the photospheric field, determined on various spatial scales, correlates with the polarity of the IMF. Analyses based on several spatial scales in the photosphere suggest that new flux in the <span class="hlt">interplanetary</span> medium is often due to relatively small photospheric features which appear in the photosphere up to one month before they are manifest at the earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM51C2194D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM51C2194D"><span id="translatedtitle"><span class="hlt">Magnetic</span> and plasma response of the Earth's magnetosphere to <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>Du, A.; Cao, X.; Wang, R.; Zhang, Y.</p> <p>2013-12-01</p> <p>In this paper, we investigate the global response of magnetosphere to <span class="hlt">interplanetary</span> shock, and focus on the <span class="hlt">magnetic</span> and plasma variations related to aurora. The analysis utilizes data from simultaneous observations of <span class="hlt">interplanetary</span> shocks from available spacecraft in the solar wind and the Earth's magnetosphere such as ACE, Wind and SOHO in solar wind, LANL and GOES in outer magnetosphere, TC1 in the midinight neutral plasma sheet, Geotail and Polar in dusk side of plasma sheet, and Cluster in downside LLBL. The shock front speed is ~1051 km/s in the solar wind, and ~981km/s in the Earth's magnetosphere. The shock is propagating anti-sunward (toward the Earth) in the plasma frame with a speed of ~320 km/s. After the shock bumps at the magnetopause, the dayside aurora brightens, then nightside aurora brightens and expanses to poleward. During the aurora activity period, the fast earthward and tailward flows in plasma sheet are observed by TC1 (X~7.1 Re, Y~1.2 Re). The variation of <span class="hlt">magnetic</span> field and plasma in duskside of magnetosphere is weaker than that in dawnside. At low latitude boundary layer (LLBL), the Cluster spacecraft detected rolled-up large scale vortices generated by the Kelvin-Helmholtz instability (KHI). Toroidal oscillations of the <span class="hlt">magnetic</span> field in the LLBL might be driven by the Kelvin-Helmholtz instability. The strong IP shock highly compresses the magnetopause and the outer magnetosphere. This process may also lead to particle precipitation and auroral brightening (Zhou and Tsurutani, 1999; Tsurutani et al., 2001 and 2003).</p> </li> <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://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/cgi-bin/nph-data_query?bibcode=2007JGRA..112.2202D&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2007JGRA..112.2202D&link_type=ABSTRACT"><span id="translatedtitle">Separator reconnection at Earth's dayside magnetopause under generic northward <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>Dorelli, John C.; Bhattacharjee, Amitava; Raeder, Joachim</p> <p>2007-02-01</p> <p>We investigate the global properties of <span class="hlt">magnetic</span> reconnection at the dayside terrestrial magnetopause under generic northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) conditions. In particular, we consider a zero dipole tilt case where the y and z components of the IMF (in GSM coordinates) are equal in magnitude, using three-dimensional resistive magnetohydrodynamics (MHD) simulations to address the following questions: (1) What is the geometry of the dayside X line? (2) How is current density distributed over the magnetopause surface? Using a technique described by Geene (1992) to track the <span class="hlt">magnetic</span> nulls in the system, we identify the dayside X line as a <span class="hlt">magnetic</span> separator line, a segment of a <span class="hlt">magnetic</span> field line which extends across the dayside magnetopause, terminating in the cusps. We demonstrate that the separator line is the intersection of two separatrix surfaces which define volumes containing topologically distinct field lines. Parallel current density, proportional to the parallel electric field in our resistive MHD simulations, is distributed in a broad, thin sheet which extends across the separator line and terminates in the cusps. Thus separator reconnection at the dayside magnetopause displays features of both antiparallel (near the cusp nulls) and component (near the subsolar separator line) reconnection. We discuss some implications of our results for spacecraft observations of reconnection signatures.</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://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://ntrs.nasa.gov/search.jsp?R=19750043957&hterms=polarity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dpolarity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19750043957&hterms=polarity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dpolarity"><span id="translatedtitle">The latitude dependencies of the solar wind. [of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field polarity and configurations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Rosenberg, R. L.; Winge, C. R., Jr.</p> <p>1974-01-01</p> <p>The motion of spacecraft following the earth's orbit occurs within the solar latitude range of 7 deg 15 min N on approximately September 7 to 7 deg 15 min S on approximately March 6. The latitude dependencies so far detected within this range have shown that the photospheric dipole-like field of the sun makes very important contributions to the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) observed near the ecliptic. Changes in geomagnetic activity from even to odd numbered 11-year solar cycles are related to changes in the sun's dipolar field. The north-south IMF component and meridional, nonradial flow are important to a complete understanding of steady-state solar wind dynamics. Coronal conditions must be latitude-dependent in a way that accounts for the observed latitude dependence of the velocity and density of the solar wind.</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://hdl.handle.net/2060/19770005004','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19770005004"><span id="translatedtitle">Radio observations of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field structures out of the ecliptic</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fitzenreiter, R. J.; Fainberg, J.; Weber, R. R.; Alvarez, H.; Haddock, F. T.; Potter, W. H.</p> <p>1976-01-01</p> <p>New observations of the out-of-the ecliptic trajectories of type 3 solar radio bursts have been obtained from simultaneous direction finding measurements on two independent satellite experiments, IMP-6 with spin plane in the ecliptic, and RAE-2 with spin plane normal to the ecliptic. Burst exciter trajectories were observed which originated at the active region and then crossed the ecliptic plane at about 0.8 AU. A considerable large scale north-south component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field is followed by the exciters. The apparent north-south and east-west angular source sizes observed by the two spacecraft are approximately equal, and range from 25 deg at 600 KHz to 110 deg at 80 KHz.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040171460&hterms=solar+wind+magnetic+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsolar%2Bwind%2Bmagnetic%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040171460&hterms=solar+wind+magnetic+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsolar%2Bwind%2Bmagnetic%2Bfield"><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://adsabs.harvard.edu/abs/2012cosp...39...49A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012cosp...39...49A"><span id="translatedtitle">Substorm aurora and <span class="hlt">magnetic</span> tail dynamics during <span class="hlt">interplanetary</span> shock compression: 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>Angelopoulos, Vassilis; Zhou, Xiaoyan</p> <p>2012-07-01</p> <p>Fast and forward <span class="hlt">interplanetary</span> shocks compress and squeeze the Earth magnetosphere and cause a series of magnetospheric and ionospheric reactions. In addition to the enhancement of chorus, electromagnetic ion cyclotron (EMIC) waves and magnetospheric hiss, the ionospheric convection is enhanced as well. Shock aurora is generated, which is a phenomenon first an auroral brightness onset near local noon right after the shock impingement then followed by a fast anti-sunward auroral propagation along the oval. It has been found that substorm auroral activity can be significantly intensified by the shock compression when the shock upstream <span class="hlt">magnetic</span> field was in southward in a certain period of time. This paper will present recent results based on the THEMIS spacecraft and ground-based observations. With multiple spacecraft in the magnetotail, the complex dynamics of the compressed tail is identified and analyzed. Correlations between the tail dynamics and substorm auroral variations will be discussed. *On-leave from Jet Propulsion Laboratory</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/227160','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/227160"><span id="translatedtitle">ULF cusp pulsations: Diurnal variations and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field correlations with ground-based observations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>McHarg, M.G.; Olson, J.V.; Newell, P.T.</p> <p>1995-10-01</p> <p>In this paper the authors establish the Pc 5 <span class="hlt">magnetic</span> pulsation signatures of the cusp and boundary regions for the high-latitude dayside cusp region. These signatures were determined by comparing spectrograms of the <span class="hlt">magnetic</span> pulsations with optical observations of particle precipitation regions observed at the cusp. The ULF pulsations have a diurnal variation, and a cusp discriminant is proposed using a particular narrow-band feature in the pulsation spectrograms. The statistical distribution of this pattern over a 253-day period resembles the statistical cusp description using particle precipitation data from the Defense Meterological Satellite Program (DMSP). The distribution of the ground-based cusp discriminant is found to peak 1 hour earlier than the DMSP cusp distribution. This offset is due to the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) being predominantly negative B{sub y} for the period when the data were collected. The authors find the diurnal variations so repeatable that only three main categories have statistically different IMF distributions. The identification of the signatures in the <span class="hlt">magnetic</span> spectrograms of the boundary regions and central cusp allows the spectrogram to be used as a {open_quotes}time line{close_quotes} that shows when the station passed under different regions of the dayside oval. 36 refs., 11 figs., 1 tab.</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/cgi-bin/nph-data_query?bibcode=2013SoPh..284..129A&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2013SoPh..284..129A&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Magnetic</span> Field Configuration Models and Reconstruction Methods for <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>Al-Haddad, N.; Nieves-Chinchilla, T.; Savani, N. P.; Möstl, C.; Marubashi, K.; Hidalgo, M. A.; Roussev, I. I.; Poedts, S.; Farrugia, C. J.</p> <p>2013-05-01</p> <p>This study aims to provide a reference for different <span class="hlt">magnetic</span> field models and reconstruction methods for <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs). To understand the differences in the outputs of these models and codes, we analyzed 59 events from the Coordinated Data Analysis Workshop (CDAW) list, using four different <span class="hlt">magnetic</span> field models and reconstruction techniques; force-free fitting, magnetostatic reconstruction using a numerical solution to the Grad-Shafranov equation, fitting to a self-similarly expanding cylindrical configuration and elliptical, non-force-free fitting. The resulting parameters of the reconstructions for the 59 events are compared statistically and in selected case studies. The ability of a method to fit or reconstruct an event is found to vary greatly; this depends on whether the event is a <span class="hlt">magnetic</span> cloud or not. We find that the magnitude of the axial field is relatively consistent across models, but that the axis orientation of the ejecta is not. We also find that there are a few cases with different signs of the <span class="hlt">magnetic</span> helicity for the same event when we leave the boundaries free to vary, which illustrates that this simplest of parameters is not necessarily always clearly constrained by fitting and reconstruction models. Finally, we examine three unique cases in depth to provide a comprehensive idea of the different aspects of how the fitting and reconstruction codes work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012JGRA..117.4218N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRA..117.4218N"><span id="translatedtitle">Substorm-like magnetospheric response to a discontinuity in the Bx component 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>Nowada, M.; Lin, C.-H.; Pu, Z.-Y.; Fu, S.-Y.; Angelopoulos, V.; Carlson, C. W.; Auster, H.-U.</p> <p>2012-04-01</p> <p>We examined the magnetospheric <span class="hlt">magnetic</span> field and plasma responses to an encounter of a discontinuity in the Bx component of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). The striking variations of simultaneous solar wind dynamic pressure and IMF-Bz were not observed. Furthermore, we found that this IMF-Bx discontinuity was a heliospheric current sheet, separating two high-speed solar wind streams with different velocity and <span class="hlt">magnetic</span> polarity. In this study, the <span class="hlt">magnetic</span> field and plasma data were obtained from Time History of Events and Macroscale Interactions during Substorms (THEMIS), Cluster, and GOES to investigate the magnetospheric responses, and those were taken from ACE and Geotail to monitor the solar wind conditions. Simultaneous geomagnetic field variations from the ground observatories and aurora activity from Polar were also examined. When the discontinuity encountered the magnetosphere, THEMIS-D, -E, and THEMIS-A observed abrupt and transient <span class="hlt">magnetic</span> field and plasma variations in the dawnside near-Earth magnetotail and tail-flank magnetopause. Significant <span class="hlt">magnetic</span> field perturbations were not observed by Cluster as located in the duskside magnetotail at this time interval. Although simultaneous dipolarization and negative bay variations with Pi2 waves were observed by GOES and the ground observatories, global auroral activities were not found. Around the dawnside tail-flank magnetopause, THEMIS-C and -A experienced the magnetopause crossings due to the magnetopause surface waves induced by Kelvin-Helmholtz instability. These results suggest that the <span class="hlt">magnetic</span> field and plasma variations in the near-Earth magnetotail and tail-flank magnetopause were caused by moderate substorm-like phenomena and magnetopause surface waves. They also indicate that clear magnetospheric disturbances can be brought even without significant variations in the solar wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016P%26SS..129...74V&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016P%26SS..129...74V&link_type=ABSTRACT"><span id="translatedtitle">Effect of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field orientation and intensity in the mass and energy deposition on the Hermean 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>2016-09-01</p> <p>The aim of the present study is to simulate the interaction between the solar wind and the Hermean magnetosphere. We use the MHD code PLUTO in spherical coordinates with an axisymmetric multipolar expansion of the Hermean <span class="hlt">magnetic</span> field, to perform a set of simulations with different <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field orientations and intensities. We fix the hydrodynamic parameters of the solar wind to study the distortions driven by the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field in the topology of the Hermean magnetosphere, leading to variations of the mass and energy deposition distributions, the integrated mass deposition, the oval aperture, the area covered by open <span class="hlt">magnetic</span> field lines and the regions of efficient particle sputtering on the planet surface. The simulations show a correlation between the reconnection regions and the local maxima of plasma inflow and energy deposition on the planet surface.</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> </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/cgi-bin/nph-data_query?bibcode=2014AGUFMSH31A4104H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMSH31A4104H&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Magnetic</span> Field-line Length and Twist Distributions within <span class="hlt">Interplanetary</span> Flux Fopes from Wind Spacecraft Measurements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hu, Q.; Qiu, J.; Krucker, S.; Wang, L.; Wang, B.; Chen, Y.; Moestl, C.</p> <p>2014-12-01</p> <p>We report on the detailed and systematic study of field-line twist and length distributions within <span class="hlt">magnetic</span> flux ropes embedded in <span class="hlt">Interplanetary</span> Coronal Mass Ejections (ICMEs). In particular we will utilize energetic electron burst observations at 1 AU together with associated type III radio emissions detected by the Wind spacecraft to provide unique measurements of <span class="hlt">magnetic</span> field-line lengths within selected ICME events. These direct measurements will be compared with flux-rope model calculations to help assess the fidelity of different models and to provide diagnostics of internal structures. The Grad-Shafranov reconstruction method will be utilized together with a constant-twist nonlinear force-free (Gold-Hoyle) flux rope model and the commonly known Lundquist (linear force-free) model to reveal the close relation between the field-line twist and length in cylindrical flux ropes, based on in-situ Wind spacecraft <span class="hlt">magnetic</span> field and plasma measurements. We show that our initial analysis of field-line twist indicates clear deviation from the Lundquist model, but better consistency with the Gold-Hoyle model. We will also discuss the implications of our analysis of flux-rope structures on the origination and evolution processes in their corresponding solar source regions.</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 (ΦO) 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 μA 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</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://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/cgi-bin/nph-data_query?bibcode=2009AGUFMSA14A..08K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2009AGUFMSA14A..08K&link_type=ABSTRACT"><span id="translatedtitle">Enhanced Thermospheric Density: The Roles of East-West and 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>Knipp, D. J.; Drake, K. A.; Lei, J.; Crowley, G.</p> <p>2009-12-01</p> <p>During 2005 solar EUV energy input to the thermosphere waned as Solar Cycle 23 declined. The reduction allowed a clearer delineation of episodic density disturbances caused by geomagnetic storms. We show new views of these disturbances based on Poynting flux calculations from the Defense Meteorological Satellite Program (DMSP) F-series satellites, as well as from 1) accelerometer data from polar orbiting satellites, 2) the assimilative mapping of ionospheric electrodynamics (AMIE) procedure and 3) the Thermospheric Ionospheric Electrodynamic General Circulation Model (TIEGCM). The new Poynting flux estimates and TIEGCM results allow us to trace the origins of disturbances that are poorly specified by ground indices. In particular we find that intervals of enhanced northward <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field (IMF) combined with strong east-west components of the IMF allow significant electromagnetic energy input into localized dayside regions of the high-latitude thermosphere. In some cases this energy deposition is consistent with IMF-geomagnetic field merging tailward of the Earth’s <span class="hlt">magnetic</span> cusps. In other cases the energy is deposited in the vicinity of an extremely narrow convection throat. This mode of interaction provides little energy to the magnetotail; and instead concentrates the energy in the dayside thermosphere. We discuss the solar cycle variability of this type of interaction. as well as compare the relative value of Poynting flux and particle energy deposition for such events.</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/2016ApJ...826...15F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...826...15F"><span id="translatedtitle">Observations of an <span class="hlt">Interplanetary</span> Intermediate Shock Associated with a <span class="hlt">Magnetic</span> Reconnection Exhaust</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Feng, H. Q.; Li, Q. H.; Wang, J. M.; Zhao, G. Q.</p> <p>2016-07-01</p> <p>Two intermediate shocks (ISs) in <span class="hlt">interplanetary</span> space have been identified via one spacecraft observation. However, Feng et al. suggested that the analysis using a single spacecraft observation based only on the Rankine–Hugoniot (R-H) relations could misinterpret a tangential discontinuity (TD) as an IS. The misinterpretation can be fixed if two spacecraft observations are available. In this paper, we report an IS-like discontinuity associated with a <span class="hlt">magnetic</span> reconnection exhaust, which was observed by Wind on 2000 August 9 at 1 au. We investigated this discontinuity by fitting the R-H relations and referring to the Advanced Composition Explorer (ACE) observations. As a result, we found that the observed <span class="hlt">magnetic</span> field and plasma data satisfy the R-H relations well, and the discontinuity satisfies all the requirements of the 2\\to 3 type IS. Although the discontinuity cannot be identified strictly by using two spacecraft observations, in light of the ACE observations we consider that the discontinuity should be an IS rather than a TD.</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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.5006K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.5006K"><span id="translatedtitle">Observations of Particle Acceleration Associated with Small-Scale <span class="hlt">Magnetic</span> Islands Downstream of <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>Khabarova, Olga V.; Zank, Gary P.; Li, Gang; Malandraki, Olga E.; le Roux, Jakobus A.; Webb, Gary M.</p> <p>2016-04-01</p> <p>We have recently shown both theoretically (Zank et al. 2014, 2015; le Roux et al. 2015) and observationally (Khabarova et al. 2015) that dynamical small-scale <span class="hlt">magnetic</span> islands play a significant role in local particle acceleration in the supersonic solar wind. We discuss here observational evidence for particle acceleration at shock waves that is enhanced by the recently proposed mechanism of particle energization by both island contraction and the reconnection electric field generated in merging or contracting <span class="hlt">magnetic</span> islands downstream of the shocks (Zank et al. 2014, 2015; le Roux et al. 2015). Both observations and simulations suppose formation of <span class="hlt">magnetic</span> islands in the turbulent wake of heliospheric or <span class="hlt">interplanetary</span> shocks (ISs) (Turner et al. 2013; Karimabadi et al. 2014; Chasapis et al. 2015). A combination of the DSA mechanism with acceleration by <span class="hlt">magnetic</span> island dynamics explain why the spectra of energetic particles that are supposed to be accelerated at heliospheric shocks are sometimes harder than predicted by DSA theory (Zank et al. 2015). Moreover, such an approach allows us to explain and describe other unusual behaviour of accelerated particles, such as when energetic particle flux intensity peaks are observed downstream of heliospheric shocks instead of peaking directly at the shock according to DSA theory. Zank et al. (2015) predicted the peak location to be behind the heliospheric termination shock (HTS) and showed that the distance from the shock to the peak depends on particle energy, which is in agreement with Voyager 2 observations. Similar particle behaviour is observed near strong ISs in the outer heliosphere as observed by Voyager 2. Observations show that heliospheric shocks are accompanied by current sheets, and that IS crossings always coincide with sharp changes in the IMF azimuthal angle and the IMF strength, which is typical for strong current sheets. The presence of current sheets in the vicinity of ISs acts to <span class="hlt">magnetically</span></p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.7737R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.7737R"><span id="translatedtitle">Dependence of the location of the Martian <span class="hlt">magnetic</span> lobes on the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field direction: Observations from Mars Global Surveyor</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Romanelli, N.; Bertucci, C.; Gómez, D.; Mazelle, C.</p> <p>2015-09-01</p> <p>We use magnetometer data from the Mars Global Surveyor (MGS) spacecraft during portions of the premapping orbits of the mission to study the variability of the Martian-induced magnetotail as a function of the orientation of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). The time spent by MGS in the magnetotail lobes during periods with positive solar wind flow-aligned IMF component B∥IMF suggests that their location as well as the position of the central polarity reversal layer (PRL) are displaced in the direction antiparallel to the IMF cross-flow component B⊥IMF. Analogously, in the cases where B∥IMF is negative, the lobes are displaced in the direction of B⊥IMF. This behavior is compatible with a previously published analytical model of the IMF draping, where for the first time, the displacement of a complementary reversal layer (denoted as IPRL for inverse polarity reversal layer) is deduced from first principles.</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=4π|Br|r2 measured by distant spacecraft over the values obtained through measurements at the Earth’s 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 =4π·(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/2008cosp...37.3183T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.3183T"><span id="translatedtitle">Coherence between <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field at ACE and geomagnetic observatory data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Thomson, David J.</p> <p></p> <p>µnullDespite considerable evidence that oscillations in geomagnetic observatory data are driven by oscillations in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF), the subject remains contentious. At least two of the reasons for this are physical: first, geomagnetic data consists of background components plus local effects due to ionospheric currents and convection so that the data is complicated; second, at frequencies below about 10 uHz, gas pressure in the solar wind is usually larger than <span class="hlt">magnetic</span> pressure and, because most of the power is at low frequencies, the more easily observed effects of the gas pressure dominates. The third reason is that much of the analysis of these effects has been done using statistical techniques that are poorly matched to the task. Here we use long sections of data at one-minute resolution from the St. John's, Ottawa, and Victoria observatories together with IMF data from the ACE spacecraft. It is well established that solar p-modes, (approximately 5 minutes period) of a given degree are spaced by approximately 136 uHz and, as one cannot separate the various degrees in <span class="hlt">magnetic</span> field data, long data sections - more than ten days - are required to obtain adequate frequency resolution. Using the nine series of geomagnetic data as one group and the three from ACE as a second, we compute canonical coherences between the two groups. The peak coherences, mostly corresponding to low degree solar modes, are so high that they cannot occur by chance. These peaks are superimposed on a coherent background, possibly from unresolved modes or from a fossil turbulence signature. The coherences are higher at high frequencies, 5 mHz and above, than they are at low frequencies.</p> </li> <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://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://adsabs.harvard.edu/abs/2004JGRA..10912203E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JGRA..10912203E"><span id="translatedtitle">Global control of merging by the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field: Cluster observations of dawnside flank magnetopause reconnection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eriksson, S.; Elkington, S. R.; Phan, T. D.; Petrinec, S. M.; RèMe, H.; Dunlop, M. W.; Wiltberger, M.; Balogh, A.; Ergun, R. E.; André, M.</p> <p>2004-12-01</p> <p>Detailed Cluster observations of flank magnetopause reconnection are presented for two events on the Northern and the Southern Hemispheric dawnside flanks when the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) clock angle ? = arctan(By/Bz) is within ˜45° of the equatorial plane. The event selection is based on the relative proximity between the Cluster spacecraft 1 position and the predicted magnetospheric sash where antiparallel merging is expected to develop. MHD simulations performed for the two events indicate that the Cluster spacecraft were passing through the MHD sash region in the Northern Hemisphere on 30 June 2001, while crossing the magnetopause equatorward of the Southern Hemispheric sash on 29 May 2001. Accelerated and decelerated plasma flows relative to the magnetosheath velocity were detected by Cluster on both occasions. The Walén test confirms that the observed ΔV is directly correlated with the predicted <span class="hlt">magnetic</span> field rotation ΔB/? with the expected direction of the normal <span class="hlt">magnetic</span> field and so we interpret them as speed changes due to <span class="hlt">magnetic</span> reconnection. The observed directions of ΔV compare very well with the location of the simulated MHD sash relative to Cluster. The <span class="hlt">magnetic</span> field shear in the locally tangential plane of the magnetopause ranges between 171° and 177° for the 30 June event in good agreement with antiparallel merging at the MHD sash. The corresponding local field shear for the 29 May event is only 144°, either suggesting a component merging site in the direction of the sash or indicating that Cluster is farther away from the location where the neutral line was initially formed as compared with the 30 June event. A comparison between the projected regions of antiparallel and component merging onto the magnetopause and the quasi-steady direction of plasma acceleration detected by Cluster on 29 May and 30 June support the view that the IMF controls the expected global location of <span class="hlt">magnetic</span> reconnection at limited regions of the</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://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://adsabs.harvard.edu/abs/2014AGUFMSH42A..05R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH42A..05R"><span id="translatedtitle">Propagation and Evolution of <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Clouds: Global Simulations and Comparisons with Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Riley, P.; Ben-Nun, M.; Linker, J.; Torok, T.; Lionello, R.; Downs, C.</p> <p>2014-12-01</p> <p>In this talk, we explore the evolution of <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs), and fast <span class="hlt">magnetic</span> clouds (MCs) in particular. We address three specific issues. First, What are the large-scale forces acting on ejecta as they travel from the Sun to 1 AU through a realistic ambient solar wind, and how does they affect the large-scale structure of the event? Second, what are the dominant waves/shocks associated with fast ICMEs? And third, how are the properties of ICMEs different during cycle 24 than during the previous cycle? To accomplish these objectives, we employ a variety of numerical approaches, including global resistive MHD models that incorporate realistic energy transport processes. We also compare and contrast model results with both remote solar and in-situ measurements of ICMEs at 1 AU and elsewhere, including the so-called ``Bastille Day'' event of July 14, 2000, and the more recent ``extreme ICME'' observed by STEREO-A on July 23, 2012.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFM.P41B2074M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFM.P41B2074M"><span id="translatedtitle">Multi-parameter Correlation of Jovian Radio Emissions with Solar Wind and <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>MacDowall, R. J.; Golla, T.; Reiner, M. J.; Farrell, W. M.</p> <p>2015-12-01</p> <p>Variability of the numerous varieties of Jovian radio emission has been associated with aspects of solar wind (SW) and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) parameters outside the magnetosphere. Here we demonstrate multiple-parameter correlations that relate each of several Jovian emissions, including bKOM and quasi-periodic bursts, to the SW and IMF impacting the Jovian magnetosphere. The data used are from the Ulysses spacecraft with radio data from the Unified Radio and Plasma wave (URAP) instrument, which provides high-quality remote radio observations of the Jovian emissions. The URAP observations are correlated with SW and IMF data from the relevant instruments on Ulysses, propagated to the nose of the Jovian magnetosphere with a sophisticated code. Because the aphelion of the Ulysses orbit was at the Jovian distance from the Sun, Ulysses spent ample time near Jupiter in 1991-1992 and 2003-2004, which are the intervals analyzed. Our results can be inverted such that radio observations by a Jovian orbiter, such as Cassini or Juno, are able to identify SW/IMF changes based on the behavior of the radio emissions.</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/2016EGUGA..18.5025K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.5025K"><span id="translatedtitle">Predicting the <span class="hlt">magnetic</span> structure of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds and their sheath regions: Space weather perspective</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kilpua, Emilia</p> <p>2016-04-01</p> <p><span class="hlt">Magnetic</span> clouds and their turbulent sheath regions drive the majority of intense space weather storms. The magnitude and the details of the <span class="hlt">magnetic</span> storm (timing, affected current systems, response of the high energy radiation belt electron fluxes, etc.) depend strongly on the <span class="hlt">magnetic</span> topology of the CME flux rope and whether the sheath region makes a significant contribution. Sheath regions are particularly geoeffective due to their large-amplitude <span class="hlt">magnetic</span> field fluctuations and high Alfven Mach numbers, which may enhance solar wind - magnetospheric coupling efficiency. In this presentation I will present examples of space weather responses driven by different CME structures to demonstrate the necessity to develop detailed prediction models/scenarios for different <span class="hlt">magnetic</span> field configurations and characteristics. The constraints for solar observations and models will be also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012cosp...39.2080V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012cosp...39.2080V"><span id="translatedtitle">Magnetopause position dependence on the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field: Bz or cone angle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Verigin, Mikhail; Galina, Kotova; Tatrallyay, Mariella; Erdos, Geza</p> <p>2012-07-01</p> <p>New magnetopause model is developed that is applicable for large <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) values. It is shown that magnetopause observations by the Prognoz satellites can be described by the following 2-D model: [X(Y)=r_{0} -\\frac{D^{2} }{2π ^{2} R_{0} } \\tan ^{2} (\\frac{π Y}{D} )] where X is the geocentric distance in the aberrated solar wind direction, Y is the distance from the X-axis, r_{0} =11.16R_{e} \\cdot P^{{-1 6}} is the subsolar magnetopause distance, R_{0} =16.51R_{e} \\cdot P^{{-1 6}} is the subsolar magnetopause curvature radius, D=98.06R_{e} \\cdot P^{{-1 6}} is the magnetotail asymptotic downstream diameter, and P is the total thermal and <span class="hlt">magnetic</span> pressure at the magnetopause nose. This pressure can be evaluated as: [P=kρ V^{2} (1+\\frac{4Sin^{2} \\vartheta _{bv} }{kM_{a}^{2} } +\\frac{4Sin^{2} \\vartheta _{bv} }{kM_{a}^{2} } \\sqrt{1+\\frac{kM_{a}^{2} }{2Sin^{2} \\vartheta _{bv} } } ),] where ρ V^{2} is the solar wind ram pressure, k ≈ 0.88, Ma is the solar wind Alfvenic Mach number , and \\vartheta _{bv} is the cone angle between the solar wind and IMF directions. The above model describes the magnetopause position reasonably well also at geostationary ˜ 6.6Re GOES 10, 12 orbits. Additional check of the model is based on a fair reproduction of the subsolar magnetopause dependence on \\vartheta _{bv} that was found recently in THEMIS observations. This work was partially supported by stocktickerRAS P4, P22 programs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AcAau..68.1430S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AcAau..68.1430S"><span id="translatedtitle">Superconducting <span class="hlt">magnets</span> and mission strategies for protection from ionizing radiation in <span class="hlt">interplanetary</span> manned missions and <span class="hlt">interplanetary</span> habitats</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>2011-05-01</p> <p>First order evaluations for active shielding based on superconducting <span class="hlt">magnetic</span> lenses were made in the past in ESA supported studies. The present increasing interest of permanent space complexes, to be considered in the far future as 'bases' rather than 'stations', located in 'deep' space (as it has been proposed for the L1 libration's point between Earth and Moon, or for Stations in orbit around Mars), requires that this preliminary activity continues, envisaging the problem of the protection from cosmic ray (CR) action at a scale allowing long permanence in 'deep' space, not only for a relatively small number of dedicated astronauts but also to citizens conducting there 'normal' activities. Part of the personnel of such a 'deep space base' should stay and work there for a long period of time. It is proposed that the activities and life of these personnel will be concentrated in a sector protected from Galactic CR (GCR) during the whole duration of their mission. In the exceptional case of an intense flux of Solar Energetic Protons (SEP), this sector could be of use as a shelter for all the other personnel normally located in other sectors of the Space Base. The realization of the <span class="hlt">magnetic</span> protection of the long permanence sector by well-established current materials and techniques is in principle possible, but not workable in practice for the huge required mass of the superconductor, the too low operating temperature (10-15 K) and the corresponding required cooling power and thermal shielding. However the fast progress in the production of reliable High Temperature Superconducting (HTS) or MgB 2 cables and of cryocoolers suitable for space operation opens the perspective of practicable solutions. In fact these cables, when used at relatively low temperature, but in any case higher than for NbTi and Nb 3Sn, show a thermodynamically much better behavior. Quantitative evaluations for the protection of the sector of the 'Space Base' to be protected from GCRs (and</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://ntrs.nasa.gov/search.jsp?R=20110023536&hterms=car+events&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcar%2Bevents','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110023536&hterms=car+events&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dcar%2Bevents"><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</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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.2948S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.2948S"><span id="translatedtitle">MESSENGER observations of the response of Mercury's magnetosphere to northward and southward <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>Slavin, James</p> <p></p> <p>M. H. Acũa (2), B. J. Anderson (3), D. N. Baker (4), M. Benna (2), S. A. Boardsen (1), G. n Gloeckler (5), R. E. Gold (3), G. C. Ho (3), H. Korth (3), S. M. Krimigis (3), S. A. Livi (6), R. L. McNutt Jr. (3), J. M. Raines (5), M. Sarantos (1), D. Schriver (7), S. C. Solomon (8), P. Travnicek (9), and T. H. Zurbuchen (5) (1) Heliophysics Science Division, NASA GSFC, Greenbelt, MD 20771, USA, (2) Solar System Exploration Division, NASA GSFC, Greenbelt, MD 20771, USA, (3) The Johns Hopkins University Applied Physics Laboratory, Laurel, MD 20723, USA, (4) Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303, USA, (5) Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, MI 48109, USA (6) Southwest Research Institute, San Antonio, TX 28510, USA, (7) Institute for Geophysics and Planetary Physics, University of California, Los Angeles, CA 90024, USA, (8) Department of Terrestrial <span class="hlt">Magnetism</span>, Carnegie Institution of Washington, DC 20015, USA, and (9) Institute of Atmospheric Physics, Prague, Czech Republic, 14131 MESSENGER's 14 January 2008 encounter with Mercury has provided new observations of the solar wind interaction with this planet. Here we report initial results concerning this miniature magnetosphere's response to the north-south component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). This is the component of the IMF that is expected to exert the greatest influence over the structure of the magnetopause and the processes responsible for energy transfer into the magnetosphere. The IMF was northward immediately prior to and following the passage of the MESSENGER spacecraft through this small magnetosphere. However, several-minute episodes of southward IMF were observed in the magnetosheath during the inbound portion of the encounter. Evidence for reconnection at the dayside magnetopause in the form of welldeveloped flux transfer events (FTEs) was observed in the magnetosheath following some of</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 ∣δ$\\theta$1∣ and ∣δ$\\theta$2∣ continuously increase until both MC-driven shock fronts are merged into a stronger compound one. The ∣δ$\\theta$1∣, ∣δ$\\theta$2∣, and total deflection angle Δ$\\theta$ (Δ$\\theta$ = ∣δ$\\theta$1∣ + ∣δ$\\theta$2∣) reach their corresponding maxima when the initial eruptions of both MCs are at an appropriate angular difference. Moreover, with the increase of MC2's initial speed, the OC becomes more intense, and the enhancement of δ$\\theta$1 is much more sensitive to δ$\\theta$2. The ∣δ$\\theta$1∣ is generally far less than the ∣δ$\\theta$2∣, and the unusual case of ∣δ$\\theta$1∣ $\\simeq$ ∣δ$\\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</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://ntrs.nasa.gov/search.jsp?R=19950046667&hterms=bivariate&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbivariate','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950046667&hterms=bivariate&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dbivariate"><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://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Roelof, Edmond C.; Sibeck, David G.</p> <p>1993-01-01</p> <p>We 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). We represent the magnetopause (for X(sub GSE) greater than -40 R(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 Inp and B(sub z). We define 12 overlapping bins in a normalized dimensionless (p, B(sub z)) `control space' and fit an ellipsoid to those magnetopause crossings having (p, B(sub z)) values within each bin. We also calculate the bivariate (Inp, B(sub z)) moments to second order over each bin in control space. We can then calculate the six control-space expansion coefficients for each of the three ellipsoid parameters in configuration space. From these coefficients we can derive useful diagnosis 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. We 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.</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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011JGRA..11611316K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2011JGRA..11611316K&link_type=ABSTRACT"><span id="translatedtitle">Response of thermosphere density to changes in <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field sector polarity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kwak, Y.-S.; Kim, K.-H.; Deng, Y.; Forbes, J. M.</p> <p>2011-11-01</p> <p>A systematic analysis of the thermospheric density response to changes in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) sector polarity is carried out. For this purpose we use a high-latitude southern thermospheric total mass density near 400 km altitude, derived from the high-accuracy accelerometer on board the Challenging Minisatellite Payload (CHAMP) spacecraft in 2003, a period of a well-defined IMF sector polarity change. The IMF sector polarity changes appear to strongly influence the high-latitude thermospheric density variations, especially in equinox seasons. After normalization to a constant solar flux level, densities in the Southern Hemisphere near the March equinox show a significant differences, depending on whether the IMF field polarity is toward the Sun (“toward sector,” i.e., +Bx and -By) or away from the Sun (“away sector,” i.e., -Bx and +By). Densities in the toward sector near the March equinox increase before the sector boundary passes the Earth, with strong enhancements in the cusp region and the premidnight sector. Densities in the away sector near the March equinox decrease before the sector boundary passes the Earth, with a significant decrease in the early morning hours. On the other hand, near the September equinox, densities in the Southern Hemisphere do not show significant changes associated with the IMF sector polarity changes. The IMF By and the Bz offsets associated with the IMF sector polarity changes are related to specific behaviors in terms of thermospheric densities. In the toward (away) sector near the March equinox, IMF conditions that increase (decrease) the high-latitude southern thermospheric densities, the negative (positive) By and the negative (positive) Bz offsets, are maintained. On the other hand, in the toward (away) sector near the September equinox, the negative (positive) IMF By condition, which increases (decreases) the high-latitude southern thermospheric densities, and the positive (negative) IMF Bz offset</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JASTP.115...52C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JASTP.115...52C"><span id="translatedtitle">IMF By-controlled field-aligned currents in the magnetotail during 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>Cheng, Z. W.; Shi, J. K.; Dunlop, M.; Liu, Z. X.</p> <p>2014-08-01</p> <p>The influence of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) By component on the field-aligned currents (FACs) in the plasma sheet boundary layer (PSBL) in the magnetotail during the northward IMF were investigated using the data from Cluster. There are 748 FACs cases selected to do analysis. We present that the IMF By component plays a very important role in controlling the flow direction of the FACs in the PSBL in the magnetotail. In the northern hemisphere, the influence of the positive (negative) IMF By is an earthward (tailward) FACs. To the contrary, in the southern hemisphere, the effect of the positive (negative) IMF By is a tailward (earthward) FACs. There is a clear north-south asymmetry of the polarity of the FACs in the PSBL when IMF By is positive or negative, and this asymmetry of the polarity is more distinct when IMF By is positive. The FAC density is controlled by IMF By only when |IMF By| is large. When |IMF By| is more than 10 nT the absolute FAC density in the PSBL has an obvious positive correlation with the |IMF By|. When |IMF By| is less than 10 nT, there is no correlation between the absolute FAC density and |IMF By|. There is a clear dusk-dawn asymmetry in the current densities for the FACs in the PSBL, with the dawn currents appearing larger than the dusk currents. The FAC with the largest (smallest) density is located in the range of 0100≤MLT<0200 (2100≤MLT<2200).</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=20080015820&hterms=magnetic+modeling&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dmagnetic%2Bmodeling','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080015820&hterms=magnetic+modeling&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dmagnetic%2Bmodeling"><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> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19730057099&hterms=Analysis+synthesis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DAnalysis%2Bsynthesis','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19730057099&hterms=Analysis+synthesis&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3DAnalysis%2Bsynthesis"><span id="translatedtitle">Analysis and synthesis of coronal and <span class="hlt">interplanetary</span> energetic particle, plasma, and <span class="hlt">magnetic</span> field observations over three solar rotations.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Roelof, E. C.; Krimigis, S. M.</p> <p>1973-01-01</p> <p>In a previous paper (Krimigis et al., 1971), simultaneous observations in 1967 of solar particle events at low (less than 1 MeV) energies were presented. In the present paper, the full complement of simultaneous plasma, <span class="hlt">magnetic</span> field, and energetic particle data is combined, and a complete analysis is made of all the events discussed in the original paper. The essential concept of 'collimated convection' is introduced, whereby the bulk velocity along the field lines of low-energy solar particles is independent of solar local plasma velocity, and the particles are strongly collimated along the field line with no transverse velocity component other than that of the field line itself. Collimated convection effects are shown to exist in small-scale convection and large-scale evolution of particle fluxes; the particle fluxes are, in turn, used to delineate the small-scale and large-scale evolution of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. Use of collimated convection is made in demonstrating a technique whereby energetic particle intensity profiles in the <span class="hlt">interplanetary</span> medium can be related to equatorial high coronal <span class="hlt">magnetic</span> field structures, by using the instantaneous solar wind velocity. This technique is applied in mapping particle intensities from Mariner 5 onto H alpha synoptic charts of chromospheric <span class="hlt">magnetic</span> field structures for Carrington rotations 1523 to 1525.</p> </li> <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. Ö.; 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 ν=1.8×108m2s-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 ΔϕPC is 29.9+/-1.4kV for VSW=400kms-1 and ΣP=6mho, which is in reasonable agreement with results inferred from satellite observations. About half of ΔϕPC can be attributed to the LLBLs with the</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://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://adsabs.harvard.edu/abs/2016cosp...41E1531P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E1531P"><span id="translatedtitle">A Robust Method to Predict the Near-Sun and <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Strength of Coronal Mass Ejections: Parametric and Case Studies</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patsourakos, Spiros; Georgoulis, Manolis K.</p> <p>2016-07-01</p> <p>Predicting the near-Sun, and particularly the <span class="hlt">Interplanetary</span> (IP), <span class="hlt">magnetic</span> field structure of Coronal Mass Ejections (CMEs) and <span class="hlt">interplanetary</span> counterparts (ICMEs) is a topic of intense research activity. This is because Earth-directed CMEs with strong southward <span class="hlt">magnetic</span> fields are responsible for the most powerful geomagnetic storms. We have recently developed a simple two-tier method to predict the <span class="hlt">magnetic</span> field strength of CMEs in the outer corona and in the IP medium, using as input the <span class="hlt">magnetic</span>-helicity budget of the source solar active region and stereoscopic coronagraphic observations. Near-Sun CME <span class="hlt">magnetic</span> fields are obtained by utilizing the principle of <span class="hlt">magnetic</span> helicity conservation of flux-rope CMEs for coronagraphic observations. <span class="hlt">Interplanetary</span> propagation of the inferred values is achieved by employing power-law prescriptions of the radial evolution of the CME-ICME <span class="hlt">magnetic</span> fields. We hereby present a parametric study of our method, based on the observed statistics of input parameters, to infer the anticipated range of values for the near-Sun and <span class="hlt">interplanetary</span> CME-ICME <span class="hlt">magnetic</span> fields. This analysis is complemented by application of our method to several well-observed major CME-ICME events.</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://adsabs.harvard.edu/abs/2016cosp...41E.393D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016cosp...41E.393D"><span id="translatedtitle">Energetic particle transport and acceleration within 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>Dalla, Silvia</p> <p>2016-07-01</p> <p>The propagation through space of energetic particles accelerated at the Sun and in the inner heliosphere is governed by the characteristics of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. At large scales, the <span class="hlt">average</span> Parker spiral configuration, on which transient <span class="hlt">magnetic</span> structures may be superimposed, dominates the transport, while at smaller scales turbulence scatters the particles and produces field line meandering. This talk will review the classical 1D approach to <span class="hlt">interplanetary</span> transport, mainly applied to Solar Energetic Particles (SEPs), as well as alternative models which allow for effects such as scattering perpendicular to the <span class="hlt">average</span> <span class="hlt">magnetic</span> field and field line meandering. The recently emphasized role of drifts in the propagation of SEPs will be discussed. The presentation will also review processes by which particle acceleration takes place within the <span class="hlt">interplanetary</span> medium and the overall way in which acceleration and transport shape in-situ observations of energetic particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E2806R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E2806R"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Charged Dust <span class="hlt">Magnetic</span> Clouds Striking the Magnetosphere: Coordinated Space-based and Ground-based Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Russell, C. T.; Chi, Peter; Lai, Hairong</p> <p></p> <p>In general, asteroids, meteoroids and dust do not interact with the plasma structures in the solar system, but after a collision between fast moving bodies the debris cloud contains nanoscale dust particles that are charged and behave like heavy ions. Dusty <span class="hlt">magnetic</span> clouds are then accelerated to the solar wind speed. While they pose no threat to spacecraft because of the particle size, the coherency imposed by the <span class="hlt">magnetization</span> of the cloud allows the cloud to interact with the Earth’s magnetosphere as well as the plasma in the immediate vicinity of the cloud. We call these clouds <span class="hlt">Interplanetary</span> Field Enhancements (IFEs). These IFEs are a unique class of <span class="hlt">interplanetary</span> field structures that feature cusp-shaped increases and decreases in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and a thin current sheet. The occurrence of IFEs is attributed to the interaction between the solar wind and dust particles produced in inter-bolide collisions. Previous spacecraft observations have confirmed that IFEs move with the solar wind. When IFEs strike the magnetosphere, they may distort the magnetosphere in several possible ways, such as producing a small indentation, a large scale compression, or a glancing blow. In any event if the IFE is slowed by the magnetosphere, the compression of the Earth’s field should be seen in the ground-based <span class="hlt">magnetic</span> records that are continuously recorded. Thus it is important to understand the magnetospheric response to IFE arrival. In this study, we investigate the IFE structure observed by spacecraft upstream of the magnetosphere and the induced <span class="hlt">magnetic</span> field perturbations observed by networks of ground magnetometers, including the THEMIS, CARISMA, McMAC arrays in North America and the IMAGE array in Europe. We find that, in a well-observed IFE event on December 24, 2006, all ground magnetometer stations observed an impulse at approximately 1217 UT when the IFE was expected to arrive at the Earth’s magnetopause. These ground stations spread across</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.4784P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.4784P"><span id="translatedtitle">Predicting the near-Sun and <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field of CMEs using photospheric magnetograms and coronagraph images</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Patsourakos, Spiros; Georgoulis, Manolis</p> <p>2016-04-01</p> <p>Earth-directed Coronal Mass Ejections (CMEs) containing a strong southward <span class="hlt">magnetic</span>-field component upon arrival at 1 AU statistically account for the most powerful geomagnetic storms. Unfortunately, though, we currently lack routine diagnostics of the <span class="hlt">magnetic</span> field of CMEs and its evolution in the inner heliosphere and the <span class="hlt">interplanetary</span> (IP) medium. We hereby present a simple, yet powerful and easy-to-implement, method to deduce the near-Sun and IP <span class="hlt">magnetic</span> field entrained in CMEs, by using photospheric magnetograms of the solar source regions and multi-viewpoint coronagraph images of the corresponding CMEs. The method relies on the principle of <span class="hlt">magnetic</span>-helicity conservation in low plasma-beta, flux-rope CMEs and a power-law prescription of the radial evolution of the CME <span class="hlt">magnetic</span> field in the IP medium. We outline a parametric study based on the observed statistics of input parameters to calculate a matrix of <span class="hlt">magnetic</span>-field solutions for 10000 synthetic CMEs. The robustness and possible limitations / ramifications of the method are deduced by a comparison with the distributions of the predicted CME-ICME <span class="hlt">magnetic</span> fields at 0.3 and 1 AU using actual Messenger and ACE published observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SpWea..14...56S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SpWea..14...56S"><span id="translatedtitle">Magnetohydrodynamic simulation of <span class="hlt">interplanetary</span> propagation of multiple coronal mass ejections with internal <span class="hlt">magnetic</span> flux rope (SUSANOO-CME)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Shiota, D.; Kataoka, R.</p> <p>2016-02-01</p> <p>Coronal mass ejections (CMEs) are the most important drivers of various types of space weather disturbance. Here we report a newly developed magnetohydrodynamic (MHD) simulation of the solar wind, including a series of multiple CMEs with internal spheromak-type <span class="hlt">magnetic</span> fields. First, the polarity of the spheromak <span class="hlt">magnetic</span> field is set as determined automatically according to the Hale-Nicholson law and the chirality law of Bothmer and Schwenn. The MHD simulation is therefore capable of predicting the time profile of the southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field at the Earth, in relation to the passage of a <span class="hlt">magnetic</span> cloud within a CME. This profile is the most important parameter for space weather forecasts of <span class="hlt">magnetic</span> storms. In order to evaluate the current ability of our simulation, we demonstrate a test case: the propagation and interaction process of multiple CMEs associated with the highly complex active region NOAA 10486 in October to November 2003, and present the result of a simulation of the solar wind parameters at the Earth during the 2003 Halloween storms. We succeeded in reproducing the arrival at the Earth's position of a large amount of southward <span class="hlt">magnetic</span> flux, which is capable of causing an intense <span class="hlt">magnetic</span> storm. We find that the observed complex time profile of the solar wind parameters at the Earth could be reasonably well understood by the interaction of a few specific CMEs.</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://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://adsabs.harvard.edu/abs/2016AdSpR..58..218A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016AdSpR..58..218A"><span id="translatedtitle">The Kelvin-Helmholtz instability under Parker-Spiral <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field conditions at the magnetospheric flanks</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Adamson, E.; Nykyri, K.; Otto, A.</p> <p>2016-07-01</p> <p>We have generated fully three-dimensional, high-resolution magnetohydrodynamic (MHD) simulations of the Kelvin-Helmholtz (KH) Instability during Parker-Spiral <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field (IMF) conditions at the dawnside magnetospheric flank magnetopause. Results of these simulations show that, although the draping of a strong tangential <span class="hlt">magnetic</span> field component around the magnetopause, tailward of the terminator (due to the Parker-Spiral orientation), tends to stabilize the growth of such instabilities within the shear-flow plane, Kelvin-Helmholtz waves with a k -vector tilted out of this plane may, nonetheless, develop into the nonlinear phase. This result suggests that obliquely propagating KH waves may contribute to the dawn-dusk asymmetries observed in plasma sheet parameters.</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://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=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://ntrs.nasa.gov/search.jsp?R=19950029575&hterms=sun+facts&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsun%2Bfacts','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950029575&hterms=sun+facts&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsun%2Bfacts"><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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850044803&hterms=sun+bear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dsun%2Bbear','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850044803&hterms=sun+bear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dsun%2Bbear"><span id="translatedtitle"><span class="hlt">Magnetic</span> fields on the sun and the north-south component of transient variations of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field at 1 AU</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Tang, F.; Akasofu, S.-I.; Smith, E.; Tsurutani, B.</p> <p>1985-01-01</p> <p>In order to study the relationship between solar <span class="hlt">magnetic</span> fields and the transient variations of the north-south component B(Z) of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) at 1 AU, flares from unusual north-south oriented active regions, large IMF B(Z) events, and large flares with comprehensive flare index higher than 12 were collected. The associated IMF B(Z) changes or the <span class="hlt">magnetic</span> field of the initiating flares are investigated. For those cases where an association between a transient B(Z) variation and an initiating flare is plausible, it is found that, for a given flare field, the orientation of the corresponding transient variation of B(Z) may be in agreement with the flare field, opposite to it, or more often, fluctuating in both magnitude and direction. Conversely, an IMF B(Z) event may originate in a flare field in the same <span class="hlt">magnetic</span> orientation, opposite to it, or in the east-west orientation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820029723&hterms=ZHUANG&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DZHUANG','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820029723&hterms=ZHUANG&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DZHUANG"><span id="translatedtitle">The influence of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and thermal pressure on the position and shape of the magnetopause</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zhuang, H. C.; Russell, C. T.; Walker, R. J.</p> <p>1981-01-01</p> <p>An ellipsoidal model, in which the size of an ellipsoid of revolution with a constant eccentricity is inversely proportional to the sixth root of the stream pressure of the solar wind, is used to represent the location of the dayside magnetopause and to study the influences of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and thermal pressure on its location. The effects of the IMF and thermal pressure on the location of the magnetopause are calculated analytically by using the Chapman-Ferraro theory. The changes in magnetopause size, shape and orientation caused by including the thermal pressure are inversely proportional to the square of the sonic Mach number of the solar wind and are sufficient to explain the observed slight departure of the magnetotail from the expected aberration due to the earth's orbital motion. The results suggest that little angular momentum is being carried away from the sun by the solar wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5313607','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5313607"><span id="translatedtitle">On the electrodynamical state of the auroral ionosphere during northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field: A transpolar arc case study</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Marklund, G.T.; Blomberg, L.G. ); Murphree, J.S.; Elphinstone, R.D. ); Zanetti, L.J.; Erlandson, R.E. ); Sandahl, I. ); de la Beaujardiere, O. ); Opgenoorth, H. ); Rich, F.J. )</p> <p>1991-06-01</p> <p>The ionospheric electrodynamical state has been reconstructed for a transpolar arc event during northward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field conditions. An extensive set of observations by Viking and other satellites and by ground-based radars has been used to provide realistic model input data or to verify the modeling results. The resulting convection pattern is found to be consistent with the Viking electric field and intimately linked to the prevalent auroral distribution. It is characterized by a large evening cell, well extended across noon and split up by two separated potential minima, and a minor crescent-shaped morning cell. The convection signatures are found to vary a lot along the transpolar arc depending on the relative role of the arc-associated convection and the ambient convection. The transpolar arc is generally embedded in antisunward convective flow except near the connection points with the auroral oval, where sunward flow exists in localized regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016EGUGA..18.1261P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.1261P"><span id="translatedtitle">A data-driven coupled modeling approach to predicting the <span class="hlt">magnetic</span> structure of <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>Pomoell, Jens; Kilpua, Emilia; Isavnin, Alexey; Palmerio, Erika; Lumme, Erkka</p> <p>2016-04-01</p> <p>Unraveling the formation and evolution of coronal mass ejections from the Sun to the Earth remains one of the outstanding goals in current solar-terrestrial physics and space weather research. In this work, we present our data-driven modeling principle designed to tackle specifically the question of predicting the <span class="hlt">magnetic</span> structure of <span class="hlt">interplanetary</span> coronal mass ejections. Our modeling paradigm consists of three components: a) a data-driven non-potential model of the coronal <span class="hlt">magnetic</span> field up to 2.5 RSun fed by a time-sequence of vector magnetograms b) a versatile flux rope <span class="hlt">magnetic</span> field model c) a three-dimensional MHD model that computes self-consistently the dynamics in the inner heliosphere from 0.1 AU up to the orbit of Mars (Euhforia). The key feature of our approach is to employ a flux rope model in Euhforia whose parameters are determined solely through data-driven modeling. While the time-dependent kinematics and morphology of the flux rope are fitted using EUV and coronagraph observations, the <span class="hlt">magnetic</span> parameters are directly obtained from the data-driven coronal model. In addition to presenting the modeling scheme, we showcase results of the modeling using well-observed case studies and comparisons with in-situ observations. Finally, we discuss future horizons for our model.</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%3D60%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%3D60%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> <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> </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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SoPh..291.2049H&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016SoPh..291.2049H&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Type IV Bursts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hillaris, A.; Bouratzis, C.; Nindos, A.</p> <p>2016-08-01</p> <p>We study the characteristics of moving type IV radio bursts that extend to hectometric wavelengths (<span class="hlt">interplanetary</span> type IV or type {IV}_{{IP}} bursts) and their relationship with energetic phenomena on the Sun. Our dataset comprises 48 <span class="hlt">interplanetary</span> type IV bursts observed with the Radio and Plasma Wave Investigation (WAVES) instrument onboard Wind in the 13.825 MHz - 20 kHz frequency range. The dynamic spectra of the Radio Solar Telescope Network (RSTN), the Nançay Decametric Array (DAM), the Appareil de Routine pour le Traitement et l' Enregistrement Magnetique de l' Information Spectral (ARTEMIS-IV), the Culgoora, Hiraso, and the Institute of Terrestrial <span class="hlt">Magnetism</span>, Ionosphere and Radio Wave Propagation (IZMIRAN) Radio Spectrographs were used to track the evolution of the events in the low corona. These were supplemented with soft X-ray (SXR) flux-measurements from the Geostationary Operational Environmental Satellite (GOES) and coronal mass ejections (CME) data from the Large Angle and Spectroscopic Coronagraph (LASCO) onboard the Solar and Heliospheric Observatory (SOHO). Positional information of the coronal bursts was obtained by the Nançay Radioheliograph (NRH). We examined the relationship of the type IV events with coronal radio bursts, CMEs, and SXR flares. The majority of the events (45) were characterized as compact, their duration was on <span class="hlt">average</span> 106 minutes. This type of events was, mostly, associated with M- and X-class flares (40 out of 45) and fast CMEs, 32 of these events had CMEs faster than 1000 km s^{-1}. Furthermore, in 43 compact events the CME was possibly subjected to reduced aerodynamic drag as it was propagating in the wake of a previous CME. A minority (three) of long-lived type {IV}_{{IP}} bursts was detected, with durations from 960 minutes to 115 hours. These events are referred to as extended or long duration and appear to replenish their energetic electron content, possibly from electrons escaping from the corresponding coronal</p> </li> <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/1988KosIs..26..324E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1988KosIs..26..324E"><span id="translatedtitle">Structure of <span class="hlt">interplanetary</span> streams according to plasma and <span class="hlt">magnetic</span>-field measurements on Prognoz-6 during November 25-26, 1977</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Eroshenko, E. G.; Ivanov, K. G.; Verigin, M. I.; Kotova, G. A.; Stiazhkin, V. A.</p> <p>1988-03-01</p> <p>The Prognoz-6 satellite studied <span class="hlt">magnetic</span>-field and plasma disturbances in the <span class="hlt">interplanetary</span> medium near the earth during the passage of an isolated flare stream and a quasi-steady stream from a coronal hole on November 25-26, 1977 (the fourth STIP period). Data indicate the strongly oblique incidence of the stream on the earth's magnetosphere, and provide evidence of the meridional flattening of this stream. The characteristics of the <span class="hlt">magnetic</span> cloud from the isolated flare were investigated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920059359&hterms=heat+Solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dheat%2BSolar','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920059359&hterms=heat+Solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dheat%2BSolar"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field connection to the sun during electron heat flux dropouts in the solar wind</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lin, R. P.; Kahler, S. W.</p> <p>1992-01-01</p> <p>The paper discusses observations of 2- to 8.5-keV electrons, made by measurements aboard the ISEE 3 spacecraft during the periods of heat flux decreases (HFDs) reported by McComas et al. (1989). In at least eight of the total of 25 HFDs observed, strong streaming of electrons that were equal to or greater than 2 keV outward from the sun was recorded. In one HFD, an impulsive solar electron event was observed with an associated type III radio burst, which could be tracked from the sun to about 1 AU. It is concluded that, in many HFDs, the <span class="hlt">interplanetary</span> field is still connected to the sun and that some energy-dependent process may produce HFDs without significantly perturbing electrons of higher energies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/869326','DOE-PATENT-XML'); return false;" href="http://www.osti.gov/scitech/servlets/purl/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.; Birx, Daniel L.; Cook, Edward G.; Miller, John L.</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://www.osti.gov/scitech/biblio/207234','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/207234"><span id="translatedtitle">Three-dimensional position and shape of the bow shock and their variation with Alfvenic, sonic and magnetosonic Mach numbers and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field orientation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Peredo, M.; Mazur, E.; Slavin, J.A.</p> <p>1995-05-01</p> <p>A large set of bow shock crossings (i.e., 1392) observed by 17 spacecraft has been used to explore the three-dimensional shape and location of the Earth`s bow shock and its dependence on solar wind and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) conditions. This study investigates deviations from gas dynamic flow models associated with the <span class="hlt">magnetic</span> terms in the magnetohydrodynamic (MHD) equations. Empirical models predicting the statistical position and shape of the bow shock for arbitrary values of the solar wind pressure, IMF, and Alfvenic Mach number (M{sub A}) have been derived. Individual crossings have been taken into consideration by normalizing the observed crossings to the <span class="hlt">average</span> value <p> = 3.1 nPa. The resulting data set has been used to fit three-dimensional bow shock surfaces and to explore the variations in these surfaces with sonic (M{sub S}), Alfvenic (M{sub A}) and magnetosonic (M{sub MS}) Mach numbers. Analysis reveals that among the three Mach numbers, M{sub A} provides the best ordering of the least square bow shock curves. The subsolar shock is observed to move Earthward while the flanks flare outward in response to decreasing M{sub A}; the net change represents a 6-10% effect. Variations due to changes in the IMF orientation were investigated by rotating the crossings into geocentric <span class="hlt">interplanetary</span> medium coordinates. This study confirms a north-south versus east-west asymmetry and quantifies its variation with M{sub S}, M{sub A}, M{sub MS}, and IMF orientation. A 2-7% effect is measured, with the asymmetry being more pronounced at low Mach numbers. Combining the bow shock models with the magnetopause model of Roelof and Sibeck, variations in the magnetopause size at the subpolar point is found to be 1.46; at dawn and dusk, the ratios are found to be 1.89 and 1.93, respectively. The subsolar magnetosheath thickness is used to derive the polytropic index {gamma} according to the empirical relation of Spreiter. 55 refs., 6 figs., 3 tabs.</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://www.ncbi.nlm.nih.gov/pubmed/11776989','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11776989"><span id="translatedtitle">Radiation shielding of astronauts in <span class="hlt">interplanetary</span> flights: the CREAM surveyor to Mars and the <span class="hlt">magnetic</span> lens system for a spaceship.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Spillantini, P; Taccetti, F; Papini, P; Rossi, L; Casolino, M</p> <p>2001-01-01</p> <p>The radiation absorbed by astronauts during <span class="hlt">interplanetary</span> flights is mainly due to cosmic rays of solar origin (SCR). In the most powerful solar flares the dose absorbed in few hours can exceed that cumulated in one year of exposition to the galactic component of cosmic rays (GCR). At energies above the minimum one needed to cross the walls of the spaceship there are extrapolations and guesses, but no data, on the angular distribution of SCR's, an information that is necessary for establishing whatever defence strategy. It was therefore proposed of sending to Mars a measurement device, that should continuously collect data during the travel, and possibly also in the orbit around Mars and on the Mars surface. The device should identify the particle and privilege the completeness in the measurement of its parameters. In fact the high energy electrons travel at speed of the light and could be used in the and future dangerous proton component. Also the much less abundant but individually more dangerous ions should be identified. The device should indeed include a <span class="hlt">magnetic</span> spectrometer and a high granularity range telescope, and a good time of flight measurement. ASI is supporting an assessment study of a possible mission of such a device on board of the 2005 probe to Mars. A parallel technical study is also in progress to define the workable techniques and the possible configurations of a system of <span class="hlt">magnetic</span> lenses for protecting the crew of a spaceship. PMID:11776989</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016ApJS..224...27S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJS..224...27S"><span id="translatedtitle">A Statistical Study of the <span class="hlt">Average</span> Iron Charge State Distributions inside <span class="hlt">Magnetic</span> Clouds 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>Song, H. Q.; Zhong, Z.; Chen, Y.; Zhang, J.; Cheng, X.; Zhao, L.; Hu, Q.; Li, G.</p> <p>2016-06-01</p> <p><span class="hlt">Magnetic</span> clouds (MCs) are the <span class="hlt">interplanetary</span> counterparts of coronal <span class="hlt">magnetic</span> flux ropes. They can provide valuable information regarding flux rope characteristics at their eruption stage in the corona, which is unable to be explored in situ at present. In this paper, we make a comprehensive survey of the <span class="hlt">average</span> iron charge-state (< Q> {Fe}) distributions inside 96 MCs for solar cycle 23 using Advanced Composition Explorer (ACE) data. Since the < Q> {Fe} in the solar wind are typically around 9+ to 11+, the Fe charge state is defined as being high when the < Q> {Fe} is larger than 12+, which implies the existence of a considerable amount of Fe ions with high charge states (e.g., ≥16+). The statistical results show that the < Q> {Fe} distributions of 92 (∼96%) MCs can be classified into four groups with different characteristics. In group A (11 MCs), the < Q> {Fe} shows a bi-modal distribution with both peaks being higher than 12+. Group B (4 MCs) presents a unimodal distribution of < Q> {Fe}, with its peak being higher than 12+. In groups C (29 MCs) and D (48 MCs), the < Q> {Fe} remains higher and lower than 12+ throughout ACE’s passage through the MC, respectively. Possible explanations of these distributions are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.3902C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.3902C"><span id="translatedtitle">Maps of <span class="hlt">average</span> ionospheric vorticity ordered by relationship with the open-closed <span class="hlt">magnetic</span> field line boundary</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chisham, Gareth</p> <p>2015-04-01</p> <p>Spatiotemporal variations of ionospheric vorticity are a measure of the dynamical coupling of the magnetosphere to the ionosphere via <span class="hlt">magnetic</span> field-aligned currents (FACs). Indeed, ionospheric vorticity measurements have often been used as proxy measurements for FACs. Previously, we have determined statistical models of ionospheric vorticity using 6 years of ionospheric convection velocity measurements made by the SuperDARN HF radar network in the northern hemisphere ionosphere and shown that the spatial variation of these probability distributions is well organised according to the well-established large-scale FAC structure in the polar ionosphere. However, to date, these statistical models have been parameterised solely by the state of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF), and as such do not account for the range of polar cap sizes that occur for a single IMF state. This leads to a distortion of the shape of the resulting statistical maps that makes features in the statistical variations appear smoother than those in instantaneous/short-time <span class="hlt">averaged</span> measurements. This is because the <span class="hlt">averaging</span> process does not consider the variable size of the polar cap, by which spatial features in the ionospheric vorticity variation are ordered. Using open-closed <span class="hlt">magnetic</span> field line boundary measurements determined from FUV imager data from the IMAGE spacecraft, we investigate the parameterisation of the statistical ionospheric vorticity models with polar cap size in addition to the state of the IMF. The results of this analysis have implications for other statistical models determined in this way, such as those for FACs and ionospheric convection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989Ge%26Ae..29..304I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989Ge%26Ae..29..304I"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> cloud from the solar flare of Nov. 22, 1977</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ivanov, K. G.; Stiazhkin, V. A.; Kharshiladze, A. F.</p> <p>1989-04-01</p> <p>Attention is given to experimental Bx, By, and Bz profiles of the IMF measured by the Prognoz-6, ISEE-2, and IMP-8 satellites during the passage of a <span class="hlt">magnetic</span> cloud from the intense solar flare of Nov. 22, 1977. These profiles are compared with a theoretical model of a force-free diffusion-pinch <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910042730&hterms=coils+mr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcoils%2Bmr','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910042730&hterms=coils+mr&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dcoils%2Bmr"><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/2015MsT..........2M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MsT..........2M"><span id="translatedtitle">Statistical Study of <span class="hlt">Interplanetary</span> Coronal Mass Ejections with Strong <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>Murphy, Matthew E.</p> <p></p> <p>Coronal Mass Ejections (CMEs) with strong <span class="hlt">magnetic</span> fields (B ) are typically associated with significant Solar Energetic Particle (SEP) events, high solar wind speed and solar flare events. Successful prediction of the arrival time of a CME at Earth is required to maximize the time available for satellite, infrastructure, and space travel programs to take protective action against the coming flux of high-energy particles. It is known that the <span class="hlt">magnetic</span> field strength of a CME is linked to the strength of a geomagnetic storm on Earth. Unfortunately, the correlations between strong <span class="hlt">magnetic</span> field CMEs from the entire sun (especially from the far side or non-Earth facing side of the sun) to SEP and flare events, solar source regions and other relevant solar variables are not well known. New correlation studies using an artificial intelligence engine (Eureqa) were performed to study CME events with <span class="hlt">magnetic</span> field strength readings over 30 nanoteslas (nT) from January 2010 to October 17, 2014. This thesis presents the results of this study, validates Eureqa to obtain previously published results, and presents previously unknown functional relationships between solar source <span class="hlt">magnetic</span> field data, CME initial speed and the CME <span class="hlt">magnetic</span> field. These new results enable the development of more accurate CME <span class="hlt">magnetic</span> field predictions and should help scientists develop better forecasts thereby helping to prevent damage to humanity's space and Earth assets.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860056271&hterms=russell+saunders&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Drussell%2Bsaunders','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860056271&hterms=russell+saunders&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Drussell%2Bsaunders"><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://adsabs.harvard.edu/abs/1989Ge%26Ae..29..265I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989Ge%26Ae..29..265I"><span id="translatedtitle">An <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> cloud from the solar flare of November 22, 1977.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ivanov, K. G.; Styazhkin, V. A.; Kharshiladze, A. F.</p> <p>1989-10-01</p> <p>Experimental profiles of Bx, By, and Bz, the components of the IMF, obtained by the Prognoz-6, ISEE-2, and IMP-8 satellites during their passage through a <span class="hlt">magnetic</span> cloud from the powerful solar flare of November 22 are compared with the theoretical model of a force-free <span class="hlt">magnetic</span> field of a diffusion pinch. It is found that qualitative agreement between theory and experiment occurs for the permissible configuration and kinematic characteristics of a circular cylinder approximating the cloud.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015Ge%26Ae..55..158G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015Ge%26Ae..55..158G"><span id="translatedtitle">The <span class="hlt">magnetic</span> hole as plasma inhomogeneity in the solar wind and related <span class="hlt">interplanetary</span> medium perturbations</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>2015-03-01</p> <p>We considered <span class="hlt">magnetic</span> hole-type plasma structures with a constant total pressure, which are often observed in the flux of the solar wind. The interaction between a linear <span class="hlt">magnetic</span> hole and the front of the primary or bow shock wave before the Earth's magnetosphere was studied, and the appearance of a fast shock wave in the magnetosheath and displacement of the bow shock front in the direction of the Earth's magnetosphere is described. The <span class="hlt">magnetic</span> hole in the scope of the MHD theory is considered a plasma inhomogeneity bounded by two tangential discontinuities: the front and rear boundaries. Based on the MHD theory of nonlinear interactions of solar wind discontinuity structures with a <span class="hlt">magnetic</span> hole, the appearance of new automodel and MHD shock waves inside the <span class="hlt">magnetic</span> hole is shown. The obtained results, which provide evidence of a change in the configuration of the <span class="hlt">magnetic</span> hole and a displacement of the bow shock front due to the perturbation from the solar wind, are qualitatively verified in many aspects by observations performed earlier by the Cluster and ACE spacecrafts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19830051481&hterms=Magnetic+memory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DMagnetic%2Bmemory','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19830051481&hterms=Magnetic+memory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DMagnetic%2Bmemory"><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/2016ApJ...823L..30Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016ApJ...823L..30Z"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Sector from Solar Wind around Pluto (SWAP) Measurements of Heavy Ion Pickup near Pluto</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zirnstein, E. J.; McComas, D. J.; Elliott, H. A.; Weidner, S.; Valek, P. W.; Bagenal, F.; Stern, S. A.; Ennico, K.; Olkin, C. B.; Weaver, H. A.; Young, L. A.</p> <p>2016-06-01</p> <p>On 2015 July 14, the New Horizons spacecraft flew by the Pluto system. The Solar Wind Around Pluto (SWAP) instrument on board New Horizons, which detects ions in the energy per charge range ˜0.035 to 7.5 keV/q, measured the unique interaction between the solar wind and Pluto's atmosphere. Immediately after the closest approach, SWAP detected a burst of heavy ion counts when the instrument's field of view (FOV) was aligned north and south of the Sun–Pluto line and approximately normal to the solar wind flow direction, suggesting their origin as heavy neutral atoms from Pluto that were ionized and being picked up by the solar wind. The trajectories of heavy pickup ions depend on the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF). New Horizons is not equipped with a magnetometer, and we cannot directly measure the IMF. However, we can utilize SWAP's measurements and instrument FOV during this brief period of time to determine the most likely sector of the IMF that could reproduce SWAP's observations of heavy ion pickup. We find that the IMF was most likely in an outward sector, or retrograde to the planets’ motion, during the Pluto encounter, and that the heavy ions detected by SWAP are more likely {{{CH}}4}+ than {{{{N}}}2}+. This supports the existence of a methane exosphere at Pluto.</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> </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://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://ntrs.nasa.gov/search.jsp?R=19850051368&hterms=System+Solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSystem%2BSolar','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850051368&hterms=System+Solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DSystem%2BSolar"><span id="translatedtitle">Theoretical interpretation of the observed <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field radial variation in the outer solar system</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.; Thomas, B. T.; Nerney, S. F.</p> <p>1985-01-01</p> <p>Observations of the azimuthal component of the IMF are evaluated through the use of an MHD model which shows the effect of <span class="hlt">magnetic</span> flux tubes opening in the outer solar system. It is demonstrated that the inferred meridional transport of <span class="hlt">magnetic</span> flux is consistent with predictions by the MHD model. The computed azimuthal and radial <span class="hlt">magnetic</span> flux deficits are almost identical to the observations. It is suggested that the simplest interpretation of the observations is that meridional flows are created by a direct body force on the plasma. This is consistent with the analytic model of Nerney and Suess (1975), in which such flux deficits in the IMF arise naturally from the meridional gradient in the spiralling field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21448705','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21448705"><span id="translatedtitle">EVOLUTION OF A CORONAL MASS EJECTION AND ITS <span class="hlt">MAGNETIC</span> FIELD 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>Kunkel, V.; Chen, J.</p> <p>2010-06-01</p> <p>This Letter presents the first theoretical study of the dynamics of a coronal mass ejection (CME) observed by STEREO-A/B. The CME was continuously tracked by SECCHI-A, providing position-time data from eruption to 1 AU. The ejecta was intersected by STEREO-B at 1 AU, where the <span class="hlt">magnetic</span> field and plasma parameters were measured. The observed CME trajectory and the evolution of the CME <span class="hlt">magnetic</span> field are modeled using the semianalytic erupting flux-rope model. It is shown that the best-fit theoretical solution is in good agreement-within 1% of the measured CME trajectory in the 1 AU field of view-and is consistent with the in situ <span class="hlt">magnetic</span> field and plasma data at 1 AU.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890056315&hterms=heat+Solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dheat%2BSolar','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890056315&hterms=heat+Solar&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dheat%2BSolar"><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/2060/19840005008','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840005008"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Alfvenic fluctuations: A statistical study of the directional variations of the <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>Bavassano, B.; Mariani, F.</p> <p>1983-01-01</p> <p><span class="hlt">Magnetic</span> field data from HELIOS 1 and 2 are used to test a stochastic model for Alfvenic fluctuations recently proposed. A reasonable matching between observations and predictions is found. A rough estimate of the correlation length of the observed fluctuations is inferred.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5839089','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5839089"><span id="translatedtitle">The <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field B sub y -dependent field-aligned current in the dayside polar cap under quiet conditions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yamauchi, M. Kyoto Univ. ); Araki, T. )</p> <p>1989-03-01</p> <p>Spatial distribution and temporal variation of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) B{sub y}-dependent cusp region field-aligned currents (FACs) during quiet periods were studied by use of <span class="hlt">magnetic</span> data observed by Magsat. The analysis was made for 11 events (each event lasts more than one and a half days) when the IMF B{sub y} component was steadily large and B{sub x} was relatively small ({vert bar}B{sub z}{vert bar} < {vert bar}B{sub y}{vert bar}). Results of the analysis of total 62 half-day periods for the IMF B{sub y}-dependent cusp region FAC are summarized as follows: (1) the IMF B{sub y}-dependent cusp region FAC is located at around 86{degree}-87{degree} invariant latitude local noon, which is more poleward than the location of the IMF B{sub z}-dependent cusp region FAC; (2) the current density of this FAC is greater than previous studies ({ge} 4 {mu}A/m{sup 2} for IMF B{sub y} = 6 nT); (3) there are two time scales for the IMF B{sub y}-dependent cusp region FAC to appear: the initial rise of the current is on a short time scale, {approximately} 10 min, and it is followed by a gradual increase on a time scale of several hours to a half day; (4) the seasonal change of this FAC is greater than that of the nightside region 1 or region 2 FACs; (5) the IMF B{sub z}-dependent cusp region FAC is not well observed around the cusp when the IMF B{sub y}-dependent cusp region FAC is intense.</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/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 Alfvénic 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/2015AGUFMSH33A2450W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSH33A2450W"><span id="translatedtitle">Complexity Variations in the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field between 0.4 and 5.3 AU</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Weygand, J. M.; Kivelson, M.; Velli, M.; Gekelman, W. N.; Khurana, K. K.; Angelopoulos, V.; Walker, R. J.</p> <p>2015-12-01</p> <p>We have investigated how the character of <span class="hlt">magnetic</span> fluctuations of solar wind plasma depends on radial distance from the Sun. We use measurements of the <span class="hlt">magnetic</span> field taken at different distances from the Sun by different spacecraft: Helios between 0.4 and 1 AU, ACE and Wind at about 1 AU, and Ulysses at about 5.3 AU. Data intervals are selected to contain only what appear to be random fluctuations and to exclude solar wind structures such as coronal mass ejections, co-rotating interaction regions, heliospheric current sheets, shocks, etc. With these data we calculate the Jensen-Shannon complexity as a function of permutation entropy. Jensen-Shannon complexity maps indicate if the fluctuations in the <span class="hlt">magnetic</span> fields are stochastic (low complexity and high entropy), or if they exhibit minimal or maximal complexity and lower entropy. The Jensen-Shannon complexity values determined from the spacecraft measurements evolve from moderate complexity and high entropy at 0.4 AU to lower complexity and higher entropy farther from the Sun. We interpret these data to mean that as the solar wind plasma expands outward, the <span class="hlt">magnetic</span> field fluctuations evolve from chaotic (i.e., low dimensionality, deterministic fluctuations) to turbulent (i.e., low dimensionality, non-deterministic fluctuations). By separating the <span class="hlt">magnetic</span> fluctuations into slow solar wind (<450 km/s) and fast solar wind (>550 km/s), we find that the younger solar wind (transported outward rapidly) has higher complexity than the older solar wind (transported outward slowly). These results can be tested by Solar Probe Plus to be launched in 2018.</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> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6931558','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6931558"><span id="translatedtitle">Variations of the ionospheric plasma concentration in the region of the main ionospheric trough during the <span class="hlt">magnetic</span> storm of December 18-19, 1978, in connection with measurements of 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>Gdalevich, G.L.; Afonin, V.V.; Eliseev, A.Y.; Kolomiitsev, O.P.; Ozerov, V.D.; Soboleva, T.N.</p> <p>1986-07-01</p> <p>Data from the Kosmos-900 satellite are used to examine variations of the ion concentration in the region of the main ionospheric trough at altitudes of about 500 km during the storm of December 18-19, 1978. These variations of ion densities are compared with the variations of the parameters of the <span class="hlt">interplanetary</span> medium, in particular, with the E /sub y/ = -VB /sub z/ component of the <span class="hlt">interplanetary</span> electric field. The results of the comparison are discussed. A scheme is proposed for the formation and motion of the trough during <span class="hlt">magnetic</span> disturbances.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011ApJ...729..113A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011ApJ...729..113A"><span id="translatedtitle">Mean <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field Measurement Using the ARGO-YBJ Experiment</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Aielli, G.; Bacci, C.; Bartoli, B.; Bernardini, P.; Bi, X. J.; Bleve, C.; Bolognino, I.; Branchini, P.; Budano, A.; Bussino, S.; Calabrese Melcarne, A. K.; Camarri, P.; Cao, Z.; Cappa, A.; Cardarelli, R.; Catalanotti, S.; Cattaneo, C.; Celio, P.; Chen, S. Z.; Chen, T. L.; Chen, Y.; Creti, P.; Cui, S. W.; Dai, B. Z.; D'Alí Staiti, G.; Danzengluobu; Dattoli, M.; De Mitri, I.; D'Ettorre Piazzoli, B.; De Vincenzi, M.; Di Girolamo, T.; Ding, X. H.; Di Sciascio, G.; Feng, C. F.; Feng, Zhaoyang; Feng, Zhenyong; Galeazzi, F.; Galeotti, P.; Gargana, R.; Giroletti, E.; Gou, Q. B.; Guo, Y. Q.; He, H. H.; Hu, Haibing; Hu, Hongbo; Huang, Q.; Iacovacci, M.; Iuppa, R.; James, I.; Jia, H. Y.; Labaciren; Li, H. J.; Li, J. Y.; Li, X. X.; Liberti, B.; Liguori, G.; Liu, C.; Liu, C. Q.; Liu, M. Y.; Liu, J.; Lu, H.; Ma, X. H.; Mancarella, G.; Mari, S. M.; Marsella, G.; Martello, D.; Mastroianni, S.; Meng, X. R.; Montini, P.; Ning, C. C.; Pagliaro, A.; Panareo, M.; Perrone, L.; Pistilli, P.; Qu, X. B.; Rossi, E.; Ruggieri, F.; Saggese, L.; Salvini, P.; Santonico, R.; Shen, P. R.; Sheng, X. D.; Shi, F.; Stanescu, C.; Surdo, A.; Tan, Y. H.; Vallania, P.; Vernetto, S.; Vigorito, C.; Wang, B.; Wang, H.; Wu, C. Y.; Wu, H. R.; Xu, B.; Xue, L.; Yan, Y. X.; Yang, Q. Y.; Yang, X. C.; Yao, Z. G.; Yuan, A. F.; Zha, M.; Zhang, H. M.; Zhang, JiLong; Zhang, JianLi; Zhang, L.; Zhang, P.; Zhang, X. Y.; Zhang, Y.; Zhaxisangzhu; Zhou, X. X.; Zhu, F. R.; Zhu, Q. Q.; Zizzi, G.; ARGO-YBJ COLLABORATION</p> <p>2011-03-01</p> <p>The Sun blocks cosmic-ray particles from outside the solar system, forming a detectable shadow in the sky map of cosmic rays detected by the ARGO-YBJ experiment in Tibet. Because the cosmic-ray particles are positively charged, the <span class="hlt">magnetic</span> field between the Sun and the Earth deflects them from straight trajectories and results in a shift of the shadow from the true location of the Sun. Here, we show that the shift measures the intensity of the field that is transported by the solar wind from the Sun to the Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910070191&hterms=ONG&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DONG','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910070191&hterms=ONG&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DONG"><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=19900031671&hterms=magnetic+fields+interactions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bfields%2Binteractions','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900031671&hterms=magnetic+fields+interactions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bfields%2Binteractions"><span id="translatedtitle"><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field enhancements - Evidence for solar wind dust trail interactions</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>1990-01-01</p> <p><span class="hlt">Magnetic</span> disturbances related to the passage of the asteroid 2201 Oljato are described. It is pointed out that the process leading to these disturbances must be associated with material in the orbit of Oljato and not the Oljato asteroid itself. Using data from latest space observations, the statistical association of these disturbances with the orbit of 2201 Oljato is updated, and the possible mechanisms for causing the disturbances are discussed. The phenomenon is considered to be associated with comet-like processes in the solar wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930062111&hterms=Magnetic+reversal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DMagnetic%2Breversal','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930062111&hterms=Magnetic+reversal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DMagnetic%2Breversal"><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://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=20120016557&hterms=regression+model&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dregression%2Bmodel','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20120016557&hterms=regression+model&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dregression%2Bmodel"><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</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://ntrs.nasa.gov/search.jsp?R=19820047466&hterms=magnetic+separation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmagnetic%2Bseparation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820047466&hterms=magnetic+separation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmagnetic%2Bseparation"><span id="translatedtitle">Factors controlling degree of correlation between ISEE 1 and ISEE 3 <span class="hlt">interplanetary</span> <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>Crooker, N. U.; Siscoe, G. L.; Russell, C. T.; Smith, E. J.</p> <p>1982-01-01</p> <p>Correlation variability between ISEE 1 and 3 IMF measurements is investigated, and factors governing the variability are discussed. About 200 two-hour periods when correlation was good, and 200 when correlation was poor, are examined, and both IMF variance and spacecraft separation distance in the plane perpendicular to the earth-sun line exert substantial control. The scale size of <span class="hlt">magnetic</span> features is larger when variance is high, and abrupt changes in the correlation coefficient from poor to good or good to poor in adjacent two-hour intervals appear to be governed by the sense of change of IMF variance and vice versa. During periods of low variance, good correlations are most likely to occur when the distance between ISEE 1 and 3 perpendicular to the IMF is less than 20 earth radii.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..1616849T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..1616849T"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tylka, Allan J.; Ko, Yuan-Kuen; Keong Ng, Chee; Wang, Yi-Ming; Dietrich, William F.</p> <p>2014-05-01</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 ~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 ~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 but less pronounced than 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.</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/2013AGUFMSH32B..05T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSH32B..05T"><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 (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tylka, A. J.; Ko, Y.; Ng, C. K.; Wang, Y.; Dietrich, W. F.</p> <p>2013-12-01</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 ~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 ~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://adsabs.harvard.edu/abs/2013ApJ...776...92K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApJ...776...92K"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ko, Yuan-Kuen; Tylka, Allan J.; Ng, Chee K.; Wang, Yi-Ming; Dietrich, William F.</p> <p>2013-10-01</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. 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-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</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</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/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://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://ntrs.nasa.gov/search.jsp?R=20040031460&hterms=Cane&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DCane','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040031460&hterms=Cane&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DCane"><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://adsabs.harvard.edu/abs/2004JGRA..109.4215C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004JGRA..109.4215C"><span id="translatedtitle">MHD simulations of Earth's bow shock: <span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field orientation effects on shape and position</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chapman, J. F.; Cairns, Iver H.; Lyon, J. G.; Boshuizen, Christopher R.</p> <p>2004-04-01</p> <p>The location and geometry of Earth's bow shock vary considerably with the solar wind conditions. More specifically, Earth's bow shock is formed by the steepening of fast mode waves, whose speed vms depends upon the angle θbn between the local shock normal n and the <span class="hlt">magnetic</span> field vector BIMF, as well as the Alfvén and sound speeds (vA and cS). Since vms is a minimum for θbn = 0° and low Alfvén Mach number MA, and maximum for θbn = 90° and high MA, this implies that as θIMF (the angle between BIMF and vsw) varies, the magnitude of vms should vary also across the shock, leading to changes in shape. This paper presents 3-D MHD simulation data which illustrate the changes in shock location and geometry in response to changes in θIMF and MA, for 1.4 ≤ MA ≤ 9.7 and 0° ≤ θIMF ≤ 90°. Specifically, for oblique IMF the shock's geometry is shown to become skewed in planes containing BIMF (e.g., the x - z plane). This is also emphasized in the terminator plane data, where the shock is best represented by ellipses, with centers translated along the z axis. For the θIMF = 90° simulations the shock is symmetric about the x axis in both the x - y and x - z planes. Simulations for field-aligned flow (θIMF = 0°) show a dimpling of the nose of the shock as MA → 1. The simulations also illustrate the general movement of the shock in response to changes in MA; high MA shocks are found closer to Earth than low MA shocks. 's [1991] magnetopause model is used in the simulations, and we discuss the limitations of this, as well as the expected results using a self-consistent model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950029559&hterms=Magnetic+reversal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DMagnetic%2Breversal','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950029559&hterms=Magnetic+reversal&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DMagnetic%2Breversal"><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</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> <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/2014APS..DPPNP8095Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014APS..DPPNP8095Z"><span id="translatedtitle">Bounce <span class="hlt">averaged</span> diffusion coefficients in a physics based <span class="hlt">magnetic</span> field geometry from RAM-SCB</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, Lei; Yu, Yiqun; Delzanno, Gian Luca; Jordanova, Vania K.</p> <p>2014-10-01</p> <p>In this work we explore wave-particle interaction in the radiation belt. By applying quasilinear theory, we obtain the particle diffusion coefficients in both pitch angle and energy for different configurations of the Earth's <span class="hlt">magnetic</span> field. 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 RAM-SCB, a code that models the Earth's ring current and provide a realistic modeling of the Earth's <span class="hlt">magnetic</span> field. The bounce <span class="hlt">averaged</span> electron pitch angle diffusion coefficients are calculated for each <span class="hlt">magnetic</span> field configuration. The equatorial pitch angle, wave frequency and spectral distribution of whistler waves are shown to affect the bounce <span class="hlt">averaged</span> diffusion coefficients. In addition, wave-particle resonance is significantly influenced by the <span class="hlt">magnetic</span> field configuration: in storm conditions, diffusion is strongly reduced for some equatorial pitch angles.</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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730002060','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002060"><span id="translatedtitle">Microstructure of 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>Burlaga, L. F.</p> <p>1972-01-01</p> <p>High time resolution measurements of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and plasma reveal a complex microstructure which includes hydromagnetic wave and discontinuities. The identification of hydromagnetic waves and discontinuities, their statistical properties, their relation to large-scale structure, and their relative contribution to power spectra are discussed.</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 χirr and stress σ 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 σ 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 σ 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 - σ calibration curve.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19860061040&hterms=russell+saunders&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Drussell%2Bsaunders','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860061040&hterms=russell+saunders&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Drussell%2Bsaunders"><span id="translatedtitle">The <span class="hlt">average</span> <span class="hlt">magnetic</span> field draping and consistent plasma properties of the Venus magnetotail</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.; Spence, H. E.; Russell, C. T.; Saunders, M. A.</p> <p>1986-01-01</p> <p>The detailed <span class="hlt">average</span> draping pattern of the <span class="hlt">magnetic</span> field in the deep Venus magnetotail is examined. The variability of the data ordered by spatial location is studied, and the groundwork is laid for developing a coordinate system which measured locations with respect to the tail structures. The reconstruction of the tail in the presence of flapping using a new technique is shown, and the <span class="hlt">average</span> variations in the field components are examined, including the <span class="hlt">average</span> field vectors, cross-tail current density distribution, and J x B forces as functions of location across the tail. The <span class="hlt">average</span> downtail velocity is derived as a function of distance, and a simple model based on the field variations is defined from which the <span class="hlt">average</span> plasma acceleration is obtained as a function of distance, density, and temperature.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM43B4285Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM43B4285Z"><span id="translatedtitle">Bounce <span class="hlt">averaged</span> diffusion coefficients in a physics based <span class="hlt">magnetic</span> field geometry from RAM-SCB</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhao, L.; Yu, Y.; Delzanno, G. L.; Jordanova, V.</p> <p>2014-12-01</p> <p>Local acceleration via whistler wave and particle interaction plays an important role in particle dynamics in the radiation belt. In this work we explore wave-particle interaction in different <span class="hlt">magnetic</span> field configurations related to the 17 March, 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 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-<span class="hlt">averaged</span> electron pitch angle, energy and mixed term diffusion coefficients are calculated for each <span class="hlt">magnetic</span> field configuration. It is shown that the <span class="hlt">magnetic</span> field can have a significant influence on the diffusion coefficients via the wave-particle resonance condition. In addition, the equatorial pitch angle, wave frequency and spectral distribution of whistler waves also affect the bounce-<span class="hlt">averaged</span> diffusion coefficients in particle energy range from KeV to MeV. Part of the ongoing work will focus on the phase space density evolution based on the Fokker-Planck equation with the bounce-<span class="hlt">averaged</span> diffusion coefficients previously calculated.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMGP51B3724E&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2014AGUFMGP51B3724E&link_type=ABSTRACT"><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/2015STP.....1c..11K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015STP.....1c..11K"><span id="translatedtitle">Effect of geomagnetic activity, solar wind and parameters of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field on regularities in intermittency of Pi2 geomagnetic pulsations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kurazhkovskaya, Nadezhda; Klain, Boris</p> <p>2015-09-01</p> <p>We present the results of investigation of the influence of geomagnetic activity, solar wind and parameters of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) on properties of the intermittency of midlatitude burst series of Pi2 geomagnetic pulsations observed during magnetospheric substorms on the nightside (substorm Pi2) and in the absence of these phenomena (nonsubstorm Pi2). We considered the index α as a main characteristic of intermittency of substorm and nonsubstorm Pi2 pulsations. The index α characterizes the slope of the cumulative distribution function of Pi2 burst amplitudes. The study indicated that the value and dynamics of the index α varies depending on the planetary geomagnetic activity, auroral activity and the intensity of magnetospheric ring currents. In addition, the forms of dependences of the index α; on the density n, velocity V, dynamic pressure Pd of the solar wind and IMF Bx-component are different. The behavior of the index α depending on the module of B, By- and Bz-components is similar. We found some critical values of V, Pd, B, By- and Bz-components, after reaching of which the turbulence of the magnetotail plasma during substorm development is decreased. The revealed patterns of the intermittency of Pi2 pulsations can be used for qualitative assessment of turbulence level in the magnetotail plasma depending on changing <span class="hlt">interplanetary</span> conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSM11B2290V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSM11B2290V"><span id="translatedtitle">Sector structure of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field in the second half of the 19th century inferred from ground-based magnetometers</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vokhmyanin, M.; Ponyavin, D. I.</p> <p>2012-12-01</p> <p><span class="hlt">Interplanetary</span> <span class="hlt">magnetic</span> field (IMF) polarities can be inferred in the pre-satellite era using Svalgaard-Mansurov effect, according to which different IMF directions lead to different geomagnetic variations at polar stations. Basing on this effect we propose a method to derive a sector structure of the IMF when only ground based data are available. Details of the method and results have been presented in our recent paper: Vokhmyanin, M. V., and D. I. Ponyavin (2012), Inferring <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field polarities from geomagnetic variations, J. Geophys. Res., 117, A06102, doi:10.1029/2011JA017060. Using data from eight stations: Sitka, Sodankyla, Godhavn, Lerwick, Thule, Baker Lake, Vostok and Mirny, we reconstructed sector structure back to 1905. The quality of inferring from 1965 to 2005 ranges between 78% and 90% depending on the used set of stations. Our results show both high success rate and good agreement with the well-known Russell-McPherron and Rosenberg-Coleman effects. In the current study we applied the technique to historical data of Helsinki observatory where digital versions of hourly geomagnetic components are available from 1844 to 1897. Helsinki station stopped operates at the beginning of 20th century. Thus, to create a model describing the local Svalgaard-Mansurov effect we analyzed data from Nurmijarvi station located near the same region. The success rate of reconstruction from 1965 to 2005 is around 82%. So we assume that the IMF polarities obtained for the period 1869-1889 have sufficient quality. Inferred sector structure at this time consists of two sectors typically for all declining phases of solar activity cycle. Catalogue of IMF proxies seem to be important in analyzing structure and dynamics of solar <span class="hlt">magnetic</span> fields in the past.; Left: Bartels diagram of IMF sector structure inferred from Helsinki data. Right: sunspot number indicating solar cycles.</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/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</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=20110007246&hterms=Sol&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DSol','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110007246&hterms=Sol&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3DSol"><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://ntrs.nasa.gov/search.jsp?R=20070023320&hterms=Cane&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCane','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070023320&hterms=Cane&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCane"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Coronal Mass Ejections During 1996 - 2007</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>2007-01-01</p> <p><span class="hlt">Interplanetary</span> coronal mass ejections, the <span class="hlt">interplanetary</span> counterparts of coronal mass ejections at the Sun, are the major drivers of <span class="hlt">interplanetary</span> shocks in the heliosphere, and are associated with modulations of the galactic cosmic ray intensity, both short term (Forbush decreases caused by the passage of the shock, post-shock sheath, and ICME), and possibly with longer term modulation. Using several in-situ signatures of ICMEs, including plasma temperature, and composition, <span class="hlt">magnetic</span> fields, and cosmic ray modulations, made by near-Earth spacecraft, we have compiled a "comprehensive" list of ICMEs passing the Earth since 1996, encompassing solar cycle 23. We summarize the properties of these ICMEs, such as their occurrence rate, speeds and other parameters, the fraction of ICMEs that are classic <span class="hlt">magnetic</span> clouds, and their association with solar energetic particle events, halo CMEs, <span class="hlt">interplanetary</span> shocks, geomagnetic storms, shocks and cosmic ray decreases.</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://ntrs.nasa.gov/search.jsp?R=19950047166&hterms=earths+magnetic+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dearths%2Bmagnetic%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950047166&hterms=earths+magnetic+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dearths%2Bmagnetic%2Bfield"><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://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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008cosp...37.1624K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2008cosp...37.1624K&link_type=ABSTRACT"><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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMAE13B3377W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMAE13B3377W"><span id="translatedtitle">High precision lightning measurements using coherent <span class="hlt">averaging</span> of long-distance <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>Weinert, J. L.; Cummer, S. A.</p> <p>2014-12-01</p> <p>Measurement of <span class="hlt">magnetic</span> fields produced by lightning has many advantages over other methods of lightning characterization. Because low frequency <span class="hlt">magnetic</span> fields produced by lightning decay slowly with distance, <span class="hlt">magnetic</span> field measurements can be performed at large distances, often in the range of thousands of kilometers. As we have shown previously, coherent time-aligned <span class="hlt">averaging</span> of similar lightning events can overcome many limiting factors associated with <span class="hlt">magnetic</span> field measurements at large distances, such as sensitivity, as well as both environmental and sensor noise. Using such a method, it is possible to achieve as broadband noise level of tens of femtotesla, allowing for the detection of signals produced by current moments of a few hundred amp-kilometers. In this work, we present the results of investigation of lightning from four thunderstorms from summer 2013, each located several hundreds of kilometers from the measurement location. Cloud-to-ground (CG) events of both positive and negative polarities are compared between storms, allowing precise, quantitative measurement of flash processes with relatively small current moments, such as continuing currents and leader development. By comparing events from several storms, some conclusions about consistency of processes for both positive and negative CG flashes can be made.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790055689&hterms=solar+minimum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dsolar%2Bminimum','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790055689&hterms=solar+minimum&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dsolar%2Bminimum"><span id="translatedtitle"><span class="hlt">Average</span> photospheric poloidal and toroidal <span class="hlt">magnetic</span> field components near solar minimum</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Duvall, T. L., Jr.; Scherrer, P. H.; Svalgaard, L.; Wilcox, J. M.</p> <p>1979-01-01</p> <p><span class="hlt">Average</span> (over longitude and time) photospheric <span class="hlt">magnetic</span> field components are derived from 3-min Stanford magnetograms made near the solar minimum of cycle 21. The <span class="hlt">average</span> magnetograph signal is found to behave as the projection of a vector for measurements made across the disk. The poloidal field exhibits the familiar dipolar structure near the poles, with a measured signal in the line Fe I 5250 A of about 1 G. At low latitudes the poloidal field has the polarity of the poles, but is of reduced magnitude (about 0.1 G). A net photospheric toroidal field with a broad latitudinal extent is found. The polarity of the toroidal field is opposite in the northern and southern hemispheres and has the same sense as subsurface flux tubes giving rise to active regions of solar cycle 21. These observations are used to discuss large-scale electric currents crossing the photosphere and angular momentum loss to the solar wind.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/12111954','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/12111954"><span id="translatedtitle">Phase coherent <span class="hlt">averaging</span> in <span class="hlt">magnetic</span> resonance spectroscopy using interleaved navigator scans: compensation of motion artifacts and <span class="hlt">magnetic</span> field instabilities.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Thiel, Thorsten; Czisch, Michael; Elbel, Gregor K; Hennig, Juergen</p> <p>2002-06-01</p> <p>The quality of spectra in (1)H <span class="hlt">magnetic</span> resonance spectroscopy (MRS) is strongly affected by temporal signal instabilities during the acquisition. One reason for these instabilities are hardware imperfections, e.g., drifts of the main <span class="hlt">magnetic</span> field in superconducting <span class="hlt">magnets</span>. This is of special concern in high-field systems where the specification of the field stability is close to the spectral linewidth. A second major potential source of artifacts, particularly in clinical MRS, is patient motion. Using standard acquisition schemes of phase-cycled <span class="hlt">averaging</span> of the individual acquisitions, long-term effects (field drifts) as well as changes on a shorter time scale (motion) can severely reduce spectral quality. The new technique for volume-selective MRS presented here is based on the additional interleaved acquisition of a navigator signal during the recovery time of the metabolite acquisition. It corrects for temporal signal instabilities by means of a deconvolution of the metabolite and the navigator signal. This leads to phase-corrected individual metabolite scans and upon summation to a phase-coherent <span class="hlt">averaging</span> scheme. The interleaved navigator acquisition does not require any user interaction or supervision, while sequence efficiency is maintained. PMID:12111954</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6772193','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6772193"><span id="translatedtitle">The <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field B[sub y] effects on large-scale field-aligned currents near local noon: Contributions from cusp part and noncusp part</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yamauchi, M.; Lundin, R.; Woch, J. )</p> <p>1993-04-01</p> <p>latitudinals develop a model to account for the effect of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) B[sub y] component on the dayside field-aligned currents (FACs). As part of the model the FACs are divided into a [open quotes]cusp part[close quotes] and a [open quotes]noncusp part[close quotes]. The authors then propose that the cusp part FACs shift in the longitudinal direction while the noncusplike part FACs shift in both longitudinal and latitudinal directions in response to the y component of the IMF. If combined, it is observed that the noncusp part FAC is found poleward of the cusp part FAC system when the y component of the IMF is large. These two FAC systems flow in the same direction. They reinforce one another, creating a strong FAC, termed the DPY-FAC. The model also predicts that the polewardmost part of the DPY-FAC flows on closed field lines, even in regions conventionally occupied by the polar cap. Results of the model are successfully compared with particle and <span class="hlt">magnetic</span> field data from Viking missions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950053481&hterms=swimming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dswimming','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950053481&hterms=swimming&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dswimming"><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://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://adsabs.harvard.edu/abs/2005RScI...76h3911A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005RScI...76h3911A"><span id="translatedtitle">HyReSpect: A broadband fast-<span class="hlt">averaging</span> spectrometer for nuclear <span class="hlt">magnetic</span> resonance of <span class="hlt">magnetic</span> materials</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Allodi, G.; Banderini, A.; De Renzi, R.; Vignali, C.</p> <p>2005-08-01</p> <p>We announce the successful development of a homemade frequency-swept nuclear <span class="hlt">magnetic</span> resonance (NMR) spectrometer entirely designed and built at the University of Parma, optimized for the study of <span class="hlt">magnetic</span> materials but also offering good performance as a general-purpose instrument for solid-state NMR. The spectrometer features heterodyne-based pulser and receiver with four-quadrant phase shifting and quadrature detection; a 150 MHz digital signal processor as a digital pulser for timing and control functions, capable of triggering events with a resolution of 6.6 ns; a two-channel 12 bit 25MS/s digitizer hosted by a personal computer; and a graphical user interface control program running under Linux, which also integrates external field and temperature controls. The receiver exhibits a flat response from 8 up to 670 MHz, a frequency span suitable for the investigation of <span class="hlt">magnetic</span> transition metal compounds (V, Co, Mn, Cu), and intrinsic dead time of less than 2μs, as required with the fast-relaxing NMR signals often encountered in <span class="hlt">magnetic</span> materials. The rf design employing only one external signal generator, and the fast-<span class="hlt">averaging</span> performance of the system (more than 10 000 repetitions per second), are probably the most remarkable features of our apparatus.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950058919&hterms=geocentric&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dgeocentric','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950058919&hterms=geocentric&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dgeocentric"><span id="translatedtitle">Three-dimensional position and shape of the bow shock and their variation with Alfvenic, sonic and magnetosonic Mach numbers and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</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>Peredo, M.; Slavin, J. A.; Mazur, E.; Curtis, S. A.</p> <p>1995-01-01</p> <p>A large set of bow shock crossings (i.e., 1392) observed by 17 spacecraft has been used to explore the three-dimensional shape and location of the Earth's bow shock and its dependence on solar wind and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) conditions. This study investigates deviations from gas dynamic flow models associated with the <span class="hlt">magnetic</span> terms in the magnetohydrodynamic (MHD) equations. Empirical models predicting the statistical position and shape of the bow shock for arbitrary values of the solar wind pressure, IMF, and Alfvenic Mach number (M(sub A)) have been derived. The resulting data set has been used to fit three-dimensional bow shock surfaces and to explore the variations in these surfaces with sonic (M(sub S)), Alfvenic (M(sub A)) and magnetosonic (M(sub MS)) Mach numbers. Analysis reveals that among the three Mach numbers, M(sub A) provides the best ordering of the least square bow shock curves. The subsolar shock is observed to move Earthward while the flanks flare outward in response to decreasing M(sub A); the net change represents a 6-10% effect. Variations due to changes in the IMF orientation were investigated by rotating the crossings into geocentric <span class="hlt">interplanetary</span> medium coordinates. Past studies have suggested that the north-south extent of the bow shock surface exceeds the east-west dimension due to asymmetries in the fast mode Mach cone. This study confirms such a north-south versus east-west asymmetry and quantifies its variation with M(sub S), M(sub A), M(sub MS), and IMF orientation. A 2-7% effect is measured, with the asymmetry being more pronounced at low Mach numbers. Combining the bow shock models with the magnetopause model of Roelof and Sibeck (1993), variations in the magnetosheath thickness at different local times are explored. The ratio of the bow shock size to the magnetopause size at the subpolar point is found to be 1.46; at dawn and dusk, the ratios are found to be 1.89 and 1.93, respectively. The subsolar magnetosheath</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/2011hst..prop12800V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011hst..prop12800V"><span id="translatedtitle">Velocity measurement of the <span class="hlt">interplanetary</span> hydrogen</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vincent, Frederic</p> <p>2011-10-01</p> <p>We are proposing to use HST/STIS over a single orbit to make Lyman-alpha observations of the <span class="hlt">interplanetary</span> hydrogen during the March-April period of this year {2012}. This special request is driven by a recent reanalysis of HST data {Vincent et al. 2011, published after the last call for proposals}.The heliospheric interface results from the interaction of the solar wind and the interstellar medium {ISM}. Within the heliosphere, the <span class="hlt">interplanetary</span> hydrogen {IPH} flows at an <span class="hlt">average</span> speed of about 23 km/sec, carrying the signature of the ISM and the heliospheric interface. The IPH has been observed for decades through the backscattering of solar Lyman-alpha photons and solar cycle 23 provided the first partial temporal map of the IPH velocity. It is now well established that the IPH velocity depends on solar activity. Moreover some analyses suggested that it may be also affected by the obliquity of the interstellar <span class="hlt">magnetic</span> field, yielding a change of 1-2 km/sec.However a combination of the uncertainty of some measurements {e.g. GHRS} and the clustering of others near points on the cycle make it difficult to identify an unambiguous trend. Only one limited set is able to show a cycle dependence, but these represent an annual <span class="hlt">average</span> and do not match the existing models. The best approach to address these issues is a new set of yearly spectroscopic measurements for at least a half solar cycle. Since we are currently just leaving a solar maximum, it is essential to start immediately in order to have an adequate baseline for temporal measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19810034177&hterms=laws+gravity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dlaws%2Bgravity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810034177&hterms=laws+gravity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dlaws%2Bgravity"><span id="translatedtitle">Orbit-<span class="hlt">averaged</span> behavior of <span class="hlt">magnetic</span> control laws for momentum unloading</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Camillo, P. J.; Markley, F. L.</p> <p>1980-01-01</p> <p>Analytical formulas are derived for orbit-<span class="hlt">averaged</span> behavior of <span class="hlt">magnetic</span> control laws for unloading the excess angular momentum of a spacecraft reaction wheel control system in the presence of secular environmental torques. The specific example of an axially symmetric spacecraft with an inertially fixed attitude for which the dominant environmental torque is the gravity-gradient torque is treated in detail, but extensions of the general approach to other inertially fixed and earth-pointing spacecraft are discussed. The analytical formulas are compared to detailed simulations performed for the Solar Maximum Mission spacecraft, and agreement to within 10% is found. The analytical formulas can be used in place of detailed simulations for preliminary studies, and can be used to find selected cases giving the most stringent tests of momentum unloading capability for which detailed simulations may be performed.</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> </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://ntrs.nasa.gov/search.jsp?R=19780065152&hterms=track+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dtrack%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19780065152&hterms=track+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dtrack%2Bfield"><span id="translatedtitle">The 3-dimensional radio mapping experiment /SBH/ on ISEE-C. [<span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field structure for solar wind flow studies using type 3 bursts</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Knoll, R.; Epstein, G.; Hoang, S.; Huntzinger, G.; Steinberg, J. L.; Fainberg, J.; Grena, F.; Stone, R. G.; Mosier, S. R.</p> <p>1978-01-01</p> <p>The SBH experiment on ISEE-C will provide maps of the large scale structure of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field from ten solar radii altitude to the earth orbit, in and out of the ecliptic. The SBH instrument will track type III solar radio bursts at 24 frequencies in the range 30 kHz-2 MHz thus providing the positions of 24 points along the line of force which guides the electrons producing the radio radiation. The antennas are two dipoles: one (90 m long) in the spin plane, the other (15 m long) along the spin axis. The receiver was designed for high sensitivity (0.3 microV in 3 kHz BW), high intermodulation rejection (80 dB/1 microV input for order 2 products), large dynamic range (70 dB), high selectivity (-30-dB response 6.5 kHz away from the center frequency of 10.7 MHz for the 3 kHz BW channels), and high reliability (expected orbital life: 3 years).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5225720','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5225720"><span id="translatedtitle">Prompt arrival of solar energetic particles from far eastern events: The role of large-scale <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field structure</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Richardson, I.G.; Cane, H.V.; von Rosenvinge, T.T. )</p> <p>1991-05-01</p> <p>Intensity-time profiles of solar energetic particle enhancements generally show an asymmetry with respect to the heliolongitude of the associated solar event. Particles arrive promptly form events to the west of an observer because of good <span class="hlt">magnetic</span> connection whereas particle enhancements from poorly connected eastern source regions usually show much slower onsets. However, some 15% of eastern events do show prompt onsets. Two prompt particle enhancements associated with eastern solar events are studied using data from the Goddard Space Flight Center instruments on the ISEE 3 and IMP 8 spacecraft. In both events the prompt particle onset was observed when the spacecraft were in a postshock plasma region, apparently within a <span class="hlt">magnetic</span> bottle. They suggest that the <span class="hlt">magnetic</span> bottle extended back to the Sun and served as a channel for fast particle propagation to the spacecraft. Particles accelerated at an expanding coronal shock initiated by the eastern event could be injected onto field lines in the foot of the bottle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910052371&hterms=magnetic+bottle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bbottle','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910052371&hterms=magnetic+bottle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bbottle"><span id="translatedtitle">Prompt arrival of solar energetic particles from far eastern events - The role of large-scale <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field structure</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.; Von Rosenvinge, T. T.</p> <p>1991-01-01</p> <p>Intensity-time profiles of solar energetic particle enhancements generally show an asymmetry with respect to the heliolongitude of the associated solar event. Particles arrive promptly from events to the west of an observer because of good <span class="hlt">magnetic</span> connection, whereas particle enhancements from poorly connected eastern source regions usually show much slower onsets. However, some 15 percent of eastern events do show prompt onsets. Two prompt particle enhancements associated with eastern solar events are studied using data from the Goddard Space Flight Center instruments on the ISEE 3 and IMP 8 spacecraft. In both events the prompt particle onset was observed when the spacecraft were in a postshock plasma region, apparently within a <span class="hlt">magnetic</span> bottle. It is suggested that the <span class="hlt">magnetic</span> bottle extended back to the sun and served as a channel for fast particle propagation to the spacecraft. Particles accelerated at an expanding coronal shock initiated by the eastern event could be injected onto field lines in the foot of the bottle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/277398','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/277398"><span id="translatedtitle"><span class="hlt">Average</span> <span class="hlt">magnetic</span> moments of pre-yrast high spin states in {sup 166,165}Hf</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Weissman, L.; Hass, M.; Broude, C.</p> <p>1996-01-01</p> <p>The <span class="hlt">average</span> <span class="hlt">magnetic</span> moments of high spin states in Hf isotopes were determined in a transient field measurement at the 14 MV Koffler accelerator of the Weizmann Institute. The reaction {sup 130}Te({sup 40}Ca,{ital xn}){sup 166,165}Hf at beam energies from 167 to 182.5 MeV was used to populate different high spin regions and provide the recoiling Hf nuclei with sufficient velocity to traverse the 2.9 mg/cm{sup 2} Gd ferromagnetic layer. Standard double ratios and angular distributions for various low level transitions were measured to determine precession angles. These carry information regarding the <span class="hlt">average</span> {ital g} factor of unobservable transitions at medium excitation. To obtain a more quantitative analysis regarding the time-decay history of the {gamma} cascade, Monte Carlo simulations of the cascade were carried out. The significance of the results for understanding the single particle nature of these pre-yrast levels is discussed. {copyright} {ital 1996 The American Physical Society.}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950057064&hterms=solar+wind+magnetic+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsolar%2Bwind%2Bmagnetic%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950057064&hterms=solar+wind+magnetic+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsolar%2Bwind%2Bmagnetic%2Bfield"><span id="translatedtitle">Cusp/cleft auroral activity in relation to solar wind dynamic pressure, <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field B(sub z) and B(sub y)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sandholt, P. E.; Farrugia, C. J.; Burlaga, L. F.; Holtet, J. A.; Moen, J.; Lybekk, B.; Jacobsen, B.; Opsvik, D.; Egeland, A.; Lepping, R.</p> <p>1994-01-01</p> <p>Continuous optical observations of cusp/cleft auroral activities within approximately equal to 09-15 MLT and 70-76 deg <span class="hlt">magnetic</span> latitude are studied in relation to changes in solar wind dynamic pressure and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) variability. The observed latitudinal movements of the cusp/cleft aurora in response to IMF B(sub z) changes may be explained as an effect of a variable <span class="hlt">magnetic</span> field intensity in the outer dayside magnetosphere associated with the changing intensity of region 1 field-aligned currents and associated closure currents. Ground <span class="hlt">magnetic</span> signatures related to such currents were observed in the present case (January 10, 1993). Strong, isolated enhancements in solar wind dynamic pressure (Delta p/p is greater than or equal to 0.5) gave rise to equatorward shifts of the cusp/cleft aurora, characteristic auroral transients, and distinct ground <span class="hlt">magnetic</span> signatures of enhanced convection at cleft latitudes. A sequence of auroral events of approximately equal to 5-10 min recurrence time, moving eastward along the poleward boundary of the persistent cusp/cleft aurora in the approximately equal to 10-14 MLT sector, during negative IMF B(sub z) and B(sub y) conditions, were found to be correlated with brief pulses in solar wind dynamic pressure (0.1 is less than Delta p/p is less than 0.5). Simultaneous photometer observations from Ny Alesund, Svalbard, and Danmarkshavn, Greenland, show that the events often appeared on the prenoon side (approximately equal to 10-12 MLT), before moving into the postnoon sector in the case we study here, when IMF B(sub y) is less than 0. In other cases, similar auroral event sequences have been observed to move westward in the prenoon sector, during intervals of positive B(sub y). Thus a strong prenoon/postnoon asymmetry of event occurence and motion pattern related to the IMF B(sub y) polarity is observed. We find that this category of auroral event sequence is stimulated bursts of electron precipitation</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003A%26A...400..729K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003A%26A...400..729K"><span id="translatedtitle">Suprathermal proton and alpha -particle bursts (E/q = 6.5-225 keV/e) observed by the WIND-, ACE- and IMP8-S/C during depressions 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>Kirsch, E.; Mall, U.</p> <p>2003-03-01</p> <p>The present study deals with suprathermal proton (E/q=6.5-225 keV/e) and alpha -particle bursts measured by the WIND-SMS experiment in the <span class="hlt">interplanetary</span> space. They reach up to ~ 5-20 times the solar wind speed and last from a few minutes up to ~ 30 min. Measurements obtained simultaneously by the Solar Wind Ion Composition Sensor SWICS (E/q=0.5-31.5 keV/e) were also available for this study, as well as <span class="hlt">magnetic</span> field and particle data recorded by ACE near the Libration point L1 and the IMP8-S/C near the Earth. In order to exclude particles escaping from the magnetosphere or accelerated by the Earth's bow shock, <span class="hlt">interplanetary</span> shocks, coronal mass ejections and corotating interaction regions, we selected ion bursts which were associated with a distinct decrease in the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field magnitude and with changes in the azimuthal and tangential field direction. Such changes have been known for a long time as <span class="hlt">magnetic</span> holes or field depressions. We interpret these signatures as a manifestation of a reconnection process in the <span class="hlt">interplanetary</span> space near the heliospheric current sheet at about 1 AU distance from the Sun and show for the first time that thermal particles can be accelerated up to ~ 100 keV/e. The suprathermal particles are most likely accelerated in the electric field of the X-line. Inductive electric fields caused by changes in the field magnitude could also be responsible for the particle acceleration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/245185','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/245185"><span id="translatedtitle">Viking observations of a reverse convection cell developing in response to a northward turning of 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>Henderson, M.G.; Murphree, J.S.</p> <p>1996-04-15</p> <p>The authors report the development of a reverse sense convection cell in the polar ionosphere from auroral images coming from UV Viking probes. The cell was observed to grow on the dusk side of the north polar oval, near the transpolar arcs. As it grew it seemed to displace the arc system toward dawn. They compare their observations with a model in which <span class="hlt">magnetic</span> merging in the magnetopause produces such convection cells, typically associated with horse-collar or teardrop auroral features.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930039184&hterms=magnetic+coupling&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bcoupling','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930039184&hterms=magnetic+coupling&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bcoupling"><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://ntrs.nasa.gov/search.jsp?R=19930037002&hterms=lockwood&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D80%26Ntt%3Dlockwood','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930037002&hterms=lockwood&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAuthor-Name%26N%3D0%26No%3D80%26Ntt%3Dlockwood"><span id="translatedtitle">Dayside ionospheric convection changes in response to long-period <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field oscillations - Determination of the ionospheric phase velocity</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.; Freeman, M. P.; Southwood, D. J.; Cowley, S. W.; Lockwood, M.; Samson, J. C.; Farrugia, C. J.; Hughes, T. J.</p> <p>1992-01-01</p> <p>Ground <span class="hlt">magnetic</span> field perturbations recorded by the CANOPUS magnetometer network in the 7 to 13 MLT sector are used to examine how reconfigurations of the dayside polar ionospheric flow take place in response to north-south changes of the IMF. During the 6-h interval in question, IMF Bz oscillates between +/- 7 nT with about a 1-h period. Corresponding variations in the ground <span class="hlt">magnetic</span> disturbance are observed which we infer are due to changes in ionospheric flow. Cross correlation of the data obtained from two ground stations at 73.5 deg <span class="hlt">magnetic</span> latitude, but separated by about 2 hours in MLT, shows that changes in the flow are initiated in the prenoon sector (about 10 MLT) and then spread outward toward dawn and dusk with a phase speed of about 5 km/s over the longitude range about 8 to 12 MLT, slowing to about 2 km/s outside this range. Cross correlating the data from these ground stations with IMP 8 IMF Bz records produces a MLT variation in the ground response delay relative to the IMF which is compatible with these deduced phase speeds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMSH44A..07C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMSH44A..07C"><span id="translatedtitle">The Flux of Open and Torroidal <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field as a Function of Heliolatitude and Solar Cycle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Connick, D. E.; Smith, C. W.; Schwadron, N. A.</p> <p>2008-12-01</p> <p>Analyses performed during the previous 11-year phase of the solar cycle attempted to measure the flux of open and toroidal <span class="hlt">magnetic</span> field lines [Bieber and Rust, ApJ, 453, 911, 1995] and associate the toroidal flux with coronal mass ejections (CMEs) [Smith and Phillips, JGR, 102, 249, 1997]. Since that time Ulysses has made three polar passes and spent at least eight years at polar latitudes, enabling us to examine the underlying assumption of the earlier studies that using near-ecliptic latitude measurements could serve as a proxy for polar-latitude observations. We find confirmation of the claims that the present solar minimum has experienced a strong decrease in open flux, but we also find evidence of past conditions at this same level. We find that torroidal flux is virtually negligable at higher latitudes as measured by the Ulysses spacecraft, even during times of solar maximum, and attribute this to the sub-photospheric winding of the Sun's <span class="hlt">magnetic</span> field as illustrated by the familiar butterfly diagram. Our observations of the rate of toroidal flux ejection, 7 × 1022 Mx/year, sets a lower limit on the amount of <span class="hlt">magnetic</span> flux that can be ejected by CMEs near solar maximum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870027662&hterms=magnetic+fields+interactions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bfields%2Binteractions','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870027662&hterms=magnetic+fields+interactions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bfields%2Binteractions"><span id="translatedtitle">An MHD simulation of the effects of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field By component on the interaction of the solar wind with the earth's magnetosphere during 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>Ogino, T.; Walker, R. J.; Ashour-Abdalla, M.; Dawson, J. M.</p> <p>1986-01-01</p> <p>The interaction between the solar wind and the earth's magnetosphere has been studied by using a time-dependent three-dimensional MHD model in which the IMF pointed in several directions between dawnward and southward. When the IMF is dawnward, the dayside cusp and the tail lobes shift toward the morningside in the northern magnetosphere. The plasma sheet rotates toward the north on the dawnside of the tail and toward the south on the duskside. For an increasing southward IMF component, the plasma sheet becomes thinner and subsequently wavy because of patchy or localized tail reconnection. At the same time, the tail field-aligned currents have a filamentary layered structure. When projected onto the northern polar cap, the filamentary field-aligned currents are located in the same area as the region 1 currents, with a pattern similar to that associated with auroral surges. <span class="hlt">Magnetic</span> reconnection also occurs on the dayside magnetopause for southward IMF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.9519L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.9519L"><span id="translatedtitle">Influence of <span class="hlt">interplanetary</span> solar wind sector polarity on the ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>liu, jing</p> <p>2014-05-01</p> <p>Knowledge of solar sector polarity effects on the ionosphere may provide some clues in understanding of the ionospheric day-to-day variability. A solar-terrestrial connection ranging from solar sector boundary (SB) crossings, geomagnetic disturbance and ionospheric perturbations has been demonstrated. The increases in <span class="hlt">interplanetary</span> solar wind speed within three days are seen after SB crossings, while the decreases in solar wind dynamic pressure and <span class="hlt">magnetic</span> field intensity immediately after SB crossings are confirmed by the superposed epoch analysis results. Furthermore, the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) Bz component turns from northward to southward in March equinox and June solstice as the Earth passes from a solar sector of outward to inward directed <span class="hlt">magnetic</span> fields, whereas the reverse situation occurs for the transition from toward to away sectors. The F2 region critical frequency (foF2) covering about four solar cycles and total electron content (TEC) during 1998-2011 are utilized to extract the related information, revealing that they are not modified significantly and vary within the range of 15% on <span class="hlt">average</span>. The responses of the ionospheric TEC to SB crossings exhibit complex temporal and spatial variations and have strong dependencies on season, latitude, and solar cycle. This effect is more appreciable in equinoctial months than in solstitial months, which is mainly caused by larger southward Bz components in equinox. In September equinox, latitudinal profile of relative variations of foF2 at noon is featured by depressions at high latitudes and enhancements in low-equatorial latitudes during IMF away sectors. The negative phase of foF2 is delayed at solar minimum relative to it during other parts of solar cycle, which might be associated with the difference in longevity of major <span class="hlt">interplanetary</span> solar wind drivers perturbing the Earth's environment in different phases of solar cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19880059341&hterms=average+wind+speeds&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Daverage%2Bwind%2Bspeeds','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19880059341&hterms=average+wind+speeds&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Daverage%2Bwind%2Bspeeds"><span id="translatedtitle">The <span class="hlt">average</span> configuration of the induced Venus magnetotail</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.; Spence, H. E.; Russell, C. T.</p> <p>1987-01-01</p> <p>The interaction of the solar-wind flow with Venus is discussed as well as the morphology of <span class="hlt">magnetic</span>-field-line draping in the Venus magnetotail. Emphasis is placed on the importance of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field X-component in controlling the configuration of field draping in this induced magnetotail. The <span class="hlt">average</span> <span class="hlt">magnetic</span> configuration of this magnetotail is studied. A connection is made between the derived consistent plasma flow speed and density and the observational energy/charge range and sensitivity of the Pioneer Venus Orbiter plasma analyzer.</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://hdl.handle.net/2060/19760016026','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760016026"><span id="translatedtitle">Preliminary investigation of <span class="hlt">interplanetary</span> shock structure: Quasi-parallel shocks</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.</p> <p>1974-01-01</p> <p>Pioneer 9's <span class="hlt">magnetic</span> field and plasma data were studied to develop arguments for or against the observation of oblique <span class="hlt">interplanetary</span> shocks. Structural classifications are defined, and the justification for seeking these classifications in the solar wind are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AnGeo..29..839T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AnGeo..29..839T"><span id="translatedtitle">The solar and <span class="hlt">interplanetary</span> causes of the recent minimum in geomagnetic activity (MGA23): a combination of midlatitude small coronal holes, low IMF BZ variances, low solar wind speeds and low solar <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>Tsurutani, B. T.; Echer, E.; Gonzalez, W. D.</p> <p>2011-05-01</p> <p>Minima in geomagnetic activity (MGA) at Earth at the ends of SC23 and SC22 have been identified. The two MGAs (called MGA23 and MGA22, respectively) were present in 2009 and 1997, delayed from the sunspot number minima in 2008 and 1996 by ~1/2-1 years. Part of the solar and <span class="hlt">interplanetary</span> causes of the MGAs were exceptionally low solar (and thus low <span class="hlt">interplanetary</span>) <span class="hlt">magnetic</span> fields. Another important factor in MGA23 was the disappearance of equatorial and low latitude coronal holes and the appearance of midlatitude coronal holes. The location of the holes relative to the ecliptic plane led to low solar wind speeds and low IMF (Bz) variances (σBz2) and normalized variances (σBz2/B02) at Earth, with concomitant reduced solar wind-magnetospheric energy coupling. One result was the lowest ap indices in the history of ap recording. The results presented here are used to comment on the possible solar and <span class="hlt">interplanetary</span> causes of the low geomagnetic activity that occurred during the Maunder Minimum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMSM53A1653S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMSM53A1653S"><span id="translatedtitle">Control of the Polarity of the <span class="hlt">Interplanetary</span> <span class="hlt">Magnetic</span> Field on the Dawn-Dusk Symmetry of the Magnetopause</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.; Jhuang, B.; Song, P.; Safrankova, J.; Nemecek, Z.; Russell, C. T.; Chen, S.</p> <p>2008-12-01</p> <p>The solar wind dynamic pressure is reduced when the solar wind flows around the magnetosphere due to the diversion of the flows. The magnetopause is the boundary where the reduced dynamic pressure is balanced with the <span class="hlt">magnetic</span> pressure of the compressed magnetosphere by the solar wind. The size and shape of the magnetopause have long been considered among the most important parameters in Solar Terrestrial physics. Previous models of the size and shape of the magnetopause often assumed the axis- symmetry of the magnetopause with respect to the Sun-Earth line. With a large number of magnetopause crossings by ISEE-1 and -2, AMPTE/IRM, Hawkeye, Geotail, Interball-1, and Magion-4, we are able to consider the asymmetry of the magnetopuase. In the Shue et al. [1997] model, the magnetopause was modeled by two parameters, r0 and alpha, representing the subsolar standoff distance and the flaring level of the magnetopause, respectively. Parameter alpha was assumed to be independent of phi in the Shue et al. [1997] model, where phi is the angle between the Z axis and the mapping of the radial vector of the magnetopause on the YZ plane. In the present study we allow alpha to be a function of phi. We separate crossings with different phis and fit them in each bin to the new functional form proposed by Shue et al. [1997]. We find that the magnetopause is symmetric in the dawn-dusk direction for northward IMF. However, its size on the dawnside becomes larger when the IMF is southward. The function of alpha in terms of phi can be combined with the 2-D Shue et al. [1997] model into a 3-D magnetopause model. (Shue, J.-H., J. K. Chao, H. C. Fu, C. T. Russell, P. Song, K. K. Khurana, and H. J. Singer, A new functional form to study the solar wind control of the magnetopause size and shape, J. Geophys. Res., 102, 9497, 1997.)</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://hdl.handle.net/2060/19750017288','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750017288"><span id="translatedtitle"><span class="hlt">Interplanetary</span> field and plasma during initial phase of geomagnetic storms</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Patel, V. L.; Wiskerchen, M. J.</p> <p>1975-01-01</p> <p>Twenty-three geomagnetic storm events during 1966 to 1970 were studied by using simultaneous <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and plasma parameters. Explorer 33 and 35 field and plasma data were analyzed on large-scale (hourly) and small-scale (3 min.) during the time interval coincident with the initial phase of the geomagnetic storms. The solar-ecliptic Bz component turns southward at the end of the initial phase, thus triggering the main phase decrease in Dst geomagnetic field. The By component also shows large fluctuations along with Bz. When there are no clear changes in the Bz component, the By shows abrupt changes at the main phase onset. On the small-scale, behavior of the <span class="hlt">magnetic</span> field and electric field were studied in detail for the three events; it is found that the field fluctuations in By, Bz and Ey and Ez are present in the initial phase. In the large-scale, the behavior field remains quiet because the small-scale variations are <span class="hlt">averaged</span> out. It appears that large as well as small time scale fluctuations in the <span class="hlt">interplanetary</span> field and plasma help to alter the internal electromagnetic state of the magnetosphere so that a ring current could causing a geomagnetic storm decrease.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016SpWea..14..343C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016SpWea..14..343C"><span id="translatedtitle"><span class="hlt">Interplanetary</span> space weather effects on Lunar Reconnaissance Orbiter avalanche photodiode performance</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Clements, E. B.; Carlton, A. K.; Joyce, C. J.; Schwadron, N. A.; Spence, H. E.; Sun, X.; Cahoy, K.</p> <p>2016-05-01</p> <p>Space weather is a major concern for radiation-sensitive space systems, particularly for <span class="hlt">interplanetary</span> missions, which operate outside of the protection of Earth's <span class="hlt">magnetic</span> field. We examine and quantify the effects of space weather on silicon avalanche photodiodes (SiAPDs), which are used for <span class="hlt">interplanetary</span> laser altimeters and communications systems and can be sensitive to even low levels of radiation (less than 50 cGy). While ground-based radiation testing has been performed on avalanche photodiode (APDs) for space missions, in-space measurements of SiAPD response to <span class="hlt">interplanetary</span> space weather have not been previously reported. We compare noise data from the Lunar Reconnaissance Orbiter (LRO) Lunar Orbiter Laser Altimeter (LOLA) SiAPDs with radiation measurements from the onboard Cosmic Ray Telescope for the Effects of Radiation (CRaTER) instrument. We did not find any evidence to support radiation as the cause of changes in detector threshold voltage during radiation storms, both for transient detector noise and long-term <span class="hlt">average</span> detector noise, suggesting that the approximately 1.3 cm thick shielding (a combination of titanium and beryllium) of the LOLA detectors is sufficient for SiAPDs on <span class="hlt">interplanetary</span> missions with radiation environments similar to what the LRO experienced (559 cGy of radiation over 4 years).</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://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/2012JGRA..117.8335L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012JGRA..117.8335L"><span id="translatedtitle">Influence of <span class="hlt">interplanetary</span> solar wind sector polarity on the ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Jing; Liu, Libo; Zhao, Biqiang; Wan, Weixing</p> <p>2012-08-01</p> <p>Knowledge of solar sector polarity effects on the ionosphere may provide some clues in understanding of the ionospheric day-to-day variability and "hysteresis" effect on foF2. Ionospheric response to changes in solar sector polarity has not been fully documented previously, partly due to the limitation of observations. In this study, a solar-terrestrial connection ranging from solar sector boundary (SB) crossings, geomagnetic disturbances and ionospheric perturbations has been demonstrated. The increases in <span class="hlt">interplanetary</span> solar wind speed within three days are seen after SB crossings, while the decreases in solar wind dynamic pressure and <span class="hlt">magnetic</span> field intensity immediately after SB crossings are confirmed by the superposed epoch analysis results. Furthermore, the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) Bz component turns from northward to southward in March equinox and June solstice as the Earth passes from a solar sector of outward to inward directed <span class="hlt">magnetic</span> fields, whereas the reverse situation occurs for the transition from toward to away sectors. The IMF Bz component for the same solar sector polarity has opposite signs between March equinox and September equinox, and also between June solstice and December solstice. In order to know how the ionosphere reacts to the <span class="hlt">interplanetary</span> solar wind variations linkage of SB crossings, the F2 region critical frequency (foF2) covering about four solar cycles and total electron content (TEC) during 1998-2011 are utilized to extract the related information, revealing that they are not modified significantly and vary within the range of ±15% on <span class="hlt">average</span>. The responses of the ionospheric TEC to SB crossings exhibit complex temporal and spatial variations and have strong dependencies on season, latitude, and solar cycle. This effect is more appreciable in equinoctial months than in solstitial months, which is mainly caused by larger southwardBzcomponents in equinox. In September equinox, latitudinal profile of relative</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012cosp...39.1247M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012cosp...39.1247M&link_type=ABSTRACT"><span id="translatedtitle">High Amplitude Events in relation to <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>Mishra, Rajesh Kumar; Agarwal Mishra, Rekha</p> <p>2012-07-01</p> <p>The Sun emits the variable solar wind which interacts with the very local interstellar medium to form the heliosphere. Hence variations in solar activity strongly influence <span class="hlt">interplanetary</span> space, from the Sun's surface out to the edge of the heliosphere. Superimposed on the solar wind are mass ejections from the Sun and/or its corona which, disturb the <span class="hlt">interplanetary</span> medium - hence the name "<span class="hlt">interplanetary</span> disturbances". <span class="hlt">Interplanetary</span> disturbances are the sources of large-scale particle acceleration, of disturbances in the Earth's magnetosphere, of modulations of galactic cosmic rays in short, they are the prime focus for space weather studies. The investigation deals with the study of cosmic ray intensity, solar wind plasma and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field parameters variation due to <span class="hlt">interplanetary</span> disturbances (<span class="hlt">magnetic</span> clouds) during an unusual class of days i.e. high amplitude anisotropic wave train events. The high amplitude anisotropic wave train events in cosmic ray intensity has been identified using the data of ground based Goose Bay neutron monitor and studied during the period 1981-94. Even though, the occurrence of high amplitude anisotropic wave trains does not depend on the onset of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds. But the possibility of occurrence of these events cannot be overlooked during the periods of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> cloud events. It is observed that solar wind velocity remains higher (> 300) than normal and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field B remains lower than normal on the onset of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> cloud during the passage of these events. It is also noted from the superposed epoch analysis of cosmic ray intensity and geomagnetic activity for high amplitude anisotropic wave train events during the onset of <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> clouds that the increase in cosmic ray intensity and decrease in geomagnetic activity start not at the onset of <span class="hlt">magnetic</span> clouds but after few days. The north south component of IMF (Bz), IMF (B), proton</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015PhFl...27i3101M&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015PhFl...27i3101M&link_type=ABSTRACT"><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 π/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/2016EGUGA..1810819B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..1810819B"><span id="translatedtitle">Multipoint study of <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>Blanco-Cano, Xochitl; Kajdic, Primoz; Russell, Christopher T.; Aguilar-Rodriguez, Ernesto; Jian, Lan K.; Luhmann, Janet G.</p> <p>2016-04-01</p> <p><span class="hlt">Interplanetary</span> (IP) shocks are driven in the heliosphere by <span class="hlt">Interplanetary</span> Coronal Mass Ejections (ICMEs) and Stream Interaction Regions (SIRs). These shocks perturb the solar wind plasma, and play an active role in the acceleration of ions to suprathermal energies. Shock fronts evolve as they move from the Sun. Their surfaces can be far from uniform and be modulated by changes in the ambient solar wind (<span class="hlt">magnetic</span> field orientation, flow velocity), shocks rippling, and perturbations upstream and downstream from the shocks, i.e., electromagnetic waves. In this work we use multipoint observations from STEREO, WIND, and MESSENGER missions to study shock characteristics at different helio-longitudes and determine the properties of the waves near them. We also determine shock longitudinal extensions and foreshock sizes. The variations of geometry along the shock surface can result in different extensions of the wave and ion foreshocks ahead of the shocks, and in different wave modes upstream and downtream of the shocks. We find that the ion foreshock can extend up to 0.2 AU ahead of the shock, and that the upstream region with modified solar wind/waves can be very asymmetric.</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://adsabs.harvard.edu/abs/1981JGZG...50..101R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1981JGZG...50..101R"><span id="translatedtitle">The 3 January 1978 <span class="hlt">interplanetary</span> shock event as observed by energetic particle, plasma and <span class="hlt">magnetic</span> field devices on board of Helios-1, Helios-2 and Prognoz-6</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Richter, A. K.; Keppler, E.; Rosenbauer, H.; Verigin, M. I.; Gringauts, K. I.; Kurt, V. G.; Stolpovskii, V. G.; Neubauer, F. M.; Gombosi, T.; Somogyi, A.</p> <p></p> <p>The paper investigates different characteristics of the <span class="hlt">interplanetary</span> medium and of secondary enhancements in the energetic particle fluxes in regions before, at and after a flare generated <span class="hlt">interplanetary</span> shock wave. The shock exhibits the properties of both an R- and F-type shock event, and the pre-shock intensity enhancements of energetic particles can be explained by a cumulative first-order Fermi acceleration process of successive reflections of the particles at the shock. Post-shock intensity enhancements of energetic particles are due to an acceleration of the particles by the shockwave and/or a trapping of the particles in the downstream region. The energetic particle enhancements at the shock cannot be explained uniquely by the shock drift accleration mechanism, and highly oblique shocks can be accompanied by energetic particle intensity increases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870035857&hterms=strength+enhancement&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dstrength%2Benhancement','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870035857&hterms=strength+enhancement&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dstrength%2Benhancement"><span id="translatedtitle"><span class="hlt">Interplanetary</span> flux enhancements - Comparison with cometary models and observations</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.; Phillips, J. L.; Luhmann, J. G.; Fedder, J. A.</p> <p>1986-01-01</p> <p><span class="hlt">Interplanetary</span> field enhancements (IFE's) are unusual nearly symmetric increases in the strength of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field lasting tens of minutes to hours. Examples of <span class="hlt">interplanetary</span> field enhancements are compared with MHD models and with the data obtained by the ICE spacecraft at Giacobini-Zinner. These comparisons suggest that the varying properties of IFE's are due to the fact that some events are due to passages in front of the nucleus, others in the near tail and yet others in the distant tail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/27490064','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/27490064"><span id="translatedtitle">Heat equation inversion framework for <span class="hlt">average</span> SAR calculation from <span class="hlt">magnetic</span> resonance thermal imaging.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Alon, Leeor; Sodickson, Daniel K; Deniz, Cem M</p> <p>2016-10-01</p> <p>Deposition of radiofrequency (RF) energy can be quantified via electric field or temperature change measurements. <span class="hlt">Magnetic</span> resonance imaging has been used as a tool to measure three dimensional small temperature changes associated with RF radiation exposure. When duration of RF exposure is long, conversion from temperature change to specific absorption rate (SAR) is nontrivial due to prominent heat-diffusion and conduction effects. In this work, we demonstrated a method for calculation of SAR via an inversion of the heat equation including heat-diffusion and conduction effects. This method utilizes high-resolution three dimensional <span class="hlt">magnetic</span> resonance temperature images and measured thermal properties of the phantom to achieve accurate calculation of SAR. Accuracy of the proposed method was analyzed with respect to operating frequency of a dipole antenna and parameters used in heat equation inversion. Bioelectromagnetics. 37:493-503, 2016. © 2016 Wiley Periodicals, Inc. PMID:27490064</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://adsabs.harvard.edu/abs/2014PhDT........37L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014PhDT........37L"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Field Enhancements: The Interaction between Solar Wind and <span class="hlt">Interplanetary</span> Dusty Plasma Released by <span class="hlt">Interplanetary</span> Collisions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lai, Hairong</p> <p></p> <p><span class="hlt">Interplanetary</span> field enhancements (IFEs) are unique large-scale structures in the solar wind. During IFEs, the <span class="hlt">magnetic</span>-field strength is significantly enhanced with little perturbation in the solar-wind plasma. Early studies showed that IFEs move at nearly the solar-wind speed and some IFEs detected at 0.72AU by Pioneer Venus Orbiter (PVO) are associated with material co-orbiting with asteroid Oljato. To explain the observed IFE features, we develop and test an IFE formation hypothesis: IFEs result from interactions between the solar wind and clouds of nanoscale charged dust particles released in <span class="hlt">interplanetary</span> collisions. This hypothesis predicts that the <span class="hlt">magnetic</span> field drapes and the solar wind slows down in the upstream. Meanwhile the observed IFE occurrence rate should be comparable with the detectable <span class="hlt">interplanetary</span> collision rate. Based on this hypothesis, we can use the IFE occurrence to determine the spatial distribution and temporal variation of <span class="hlt">interplanetary</span> objects which produce IFEs. To test the hypothesis, we perform a systematic survey of IFEs in the <span class="hlt">magnetic</span>-field data from many spacecraft. Our datasets cover from 1970s to present and from inner than 0.3AU to outer than 5 AU. In total, more than 470 IFEs are identified and their occurrences show clustering features in both space and time. We use multi-spacecraft simultaneous observations to reconstruct the <span class="hlt">magnetic</span>-field geometry and find that the <span class="hlt">magnetic</span> field drapes in the upstream region. The results of a superposed epoch study show that the solar wind slows down in the upstream and there is a plasma depletion region near the IFE centers. In addition, the solar-wind slowdown and plasma depletion feature are more significant in larger IFEs. The mass contained in IFEs can be estimated by balancing the solar-wind pressure force exerted on the IFEs against the solar gravity. The solar-wind slowdown resultant from the estimated mass is consistent with the result in superposed epoch study. The</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.3951V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.3951V"><span id="translatedtitle">Statistical features of the global polarity reversal of the Venusian induced magnetosphere in response to the polarity change in <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>Vech, Daniel; Stenberg, Gabriella; Nilsson, Hans; Edberg, Niklas J. T.; Opitz, Andrea; Szegő, Károly; Zhang, Tielong; Futaana, Yoshifumi</p> <p>2016-05-01</p> <p>In this study we present the first statistical analysis on the effects of heliospheric current sheet crossings on the induced magnetosphere of Venus. These events are of particular interest because they lead to the reconfiguration of the induced magnetosphere with opposite polarity. We use a statistical approach based on 117 orbit pairs, and we study the spatial distribution of the heavy ion flux measurements in the plasma environment of Venus. The <span class="hlt">average</span> and median heavy ion flux measurements are compared before and after the polarity reversal events. The results show that after the events the <span class="hlt">average</span> and median heavy ion fluxes in the magnetotail are reduced by the factors of 0.75 ± 0.09 and 0.52, respectively. We find that even if a passage of a current sheet is a short time scale event lasting about 10 min, its effect on the near-Venus plasma environment lasts for a few hours. We conclude that the observations show similarities to the previous comet studies and the polarity reversal of the induced magnetosphere might be accompanied with dayside reconnection and <span class="hlt">magnetic</span> disconnection of the plasma tail from the planetary ionosphere.</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/servlets/purl/6059621','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6059621"><span id="translatedtitle"><span class="hlt">Average</span> configuration of the induced venus magnetotail</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>McComas, D.J.; Spence, H.E.; Russell, C.T.</p> <p>1985-01-01</p> <p>In this paper we discuss the interaction of the solar wind flow with Venus and describe the morphology of <span class="hlt">magnetic</span> field line draping in the Venus magnetotail. In particular, we describe the importance of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) X-component in controlling the configuration of field draping in this induced magnetotail, and using the results of a recently developed technique, we examine the <span class="hlt">average</span> <span class="hlt">magnetic</span> configuration of this magnetotail. The derived J x B forces must balance the <span class="hlt">average</span>, steady state acceleration of, and pressure gradients in, the tail plasma. From this relation the <span class="hlt">average</span> tail plasma velocity, lobe and current sheet densities, and <span class="hlt">average</span> ion temperature have been derived. In this study we extend these results by making a connection between the derived consistent plasma flow speed and density, and the observational energy/charge range and sensitivity of the Pioneer Venus Orbiter (PVO) plasma analyzer, and demonstrate that if the tail is principally composed of O/sup +/, the bulk of the plasma should not be observable much of the time that the PVO is within the tail. Finally, we examine the importance of solar wind slowing upstream of the obstacle and its implications for the temperature of pick-up planetary ions, compare the derived ion temperatures with their theoretical maximum values, and discuss the implications of this process for comets and AMPTE-type releases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/253482','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/253482"><span id="translatedtitle">Stability of force-free Taylor states in a new version of <span class="hlt">magnetic</span> flux-<span class="hlt">averaged</span> magnetohydrodynamics</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pfirsch, D.; Sudan, R.N.</p> <p>1996-01-01</p> <p>It is observed that the recently developed <span class="hlt">magnetic</span> flux-<span class="hlt">averaged</span> magnetohydrodynamics (AMHD) [Phys. Plasmas {bold 1}, 2488 (1994)] is incompatible with Taylor{close_quote}s theorem, which states that the lowest-energy state of force-free equilibria based on the conservation of the helicity integral is absolutely stable for vanishingly small resistivity. By a modification of the Lagrangian from which AMHD is derived, a modified version of AMHD that is compatible with Taylor{close_quote}s theorem is obtained. It also provides an energy principle for examining the linear instability of resistive equilibria, which has a great advantage over resistive MHD. {copyright} {ital 1996 American Institute of Physics.}</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 spin–echo, 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/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/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> Alfvén 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> Alfvén 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> Alfvén 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 Walén relation. The robustness of this technique is verified by applying to simulated pure Alfvén waves with two separate frequencies and contaminated by pink colored noises in a varying solar wind stream. Furthermore, in our approach, more properties of Alfvén 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 Alfvén waves near 1 AU are frequently found during these two intervals.</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://ntrs.nasa.gov/search.jsp?R=19810043396&hterms=sediment+analyses&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsediment%2Banalyses','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810043396&hterms=sediment+analyses&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsediment%2Banalyses"><span id="translatedtitle">Analysis of <span class="hlt">interplanetary</span> dust collections</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.; Pilachowski, L.; Olszewski, E.; Hodge, P. W.</p> <p>1980-01-01</p> <p><span class="hlt">Interplanetary</span> dust particles collected in the form of micrometeorites in the stratosphere and meteor ablation spherules in deep sea sediments are possibly a relatively unbiased sample of the micrometeoroid complex near 1 AU. Detailed laboratory analysis of the particles has provided information on physical properties which may be useful in modeling a variety of aspects of <span class="hlt">interplanetary</span> dust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/399362','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/399362"><span id="translatedtitle">A pure permanent <span class="hlt">magnet</span>-two plane focusing-tapered wiggler for a high <span class="hlt">average</span> power FEL</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Fortgang, C.M.</p> <p>1996-11-01</p> <p>A high-<span class="hlt">average</span> power FEL is under construction at Los Alamos. The FEL will have aspects of both an oscillator and a SASE (self-amplified spontaneous emission) device. That is, a high-gain and high- extraction efficiency wiggler will be used with a very low-Q optical resonator. FEL simulations reveal that a tapered wiggler with two- plane focusing is required to obtain desired performance. The wiggler is comprised of a I meter long untapered section followed by a 1 meter tapered section. The taper is achieved with the <span class="hlt">magnetic</span> gap and not the wiggler period which is constant at 2 cm. The gap is tapered from 5.9 mm to 8.8 mm. The, gap, rather than the period, is tapered to avoid vignetting of the 16 {mu}m optical beam. Two-plane focusing is necessary to maintain high current density and thus high gain through out the 2 meter long wiggler. Several <span class="hlt">magnetic</span> designs have been considered for the wiggler. The leading candidate approach is a pure permanent wiggler with pole faces that are cut to roughly approximate the classical parabolic pole face design. Focusing is provided by the sextupole component of the wiggler <span class="hlt">magnetic</span> field and is often called ``natural`` or ``betatron`` focusing. Details of the design will be presented.</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>Grün, E.; Dikarev, V.; Frisch, P. C.; Graps, A.; Kempf, S.; Krüger, 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</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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AIPC.1358..385H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AIPC.1358..385H"><span id="translatedtitle">The Third <span class="hlt">Interplanetary</span> Network</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hurley, K.; Golenetskii, S.; Aptekar, R.; Mazets, E.; Pal'Shin, V.; Frederiks, D.; Mitrofanov, I. G.; Golovin, D.; Kozyrev, A.; Litvak, M.; Sanin, A. B.; Boynton, W.; Fellows, C.; Harshman, K.; Starr, R.; von Kienlin, A.; Rau, A.; Yamaoka, K.; Ohno, M.; Fukazawa, Y.; Takahashi, T.; Tashiro, M.; Terada, Y.; Murakami, T.; Makishima, K.; Barthelmy, S.; Cummings, J.; Gehrels, N.; Krimm, H.; Cline, T.; Goldsten, J.; Del Monte, E.; Feroci, M.; Marisaldi, M.; Briggs, M.; Connaughton, V.; Meegan, C.; Smith, D. M.; Wigger, C.; Hajdas, W.</p> <p>2011-08-01</p> <p>The 3rd <span class="hlt">interplanetary</span> network (IPN), which has been in operation since 1990, presently consists of 9 spacecraft: AGILE, Fermi, RHESSI, Suzaku, and Swift, in low Earth orbit; INTEGRAL, in eccentric Earth orbit with apogee 0.5 light-seconds Wind, up to ~7 light-seconds from Earth; MESSENGER, en route to Mercury; and Mars Odyssey, in orbit around Mars. The IPN operates as a full-time, all-sky monitor for transients down to a threshold of about 6×10-7 erg cm-2 or 1 photon cm-2 s-1. It detects ~335 cosmic gamma-ray bursts per year. These events are generally not the same ones detected by narrower field of view instruments such as Swift, INTEGRAL IBIS, SuperAGILE, and MAXI; the localization accuracy is in the several arcminute and above range. The data are publicly available and can be utilized for a wide variety of studies.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016JGRA..121.1294C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016JGRA..121.1294C"><span id="translatedtitle"><span class="hlt">Average</span> field-aligned current configuration parameterized by solar wind conditions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Carter, J. A.; Milan, S. E.; Coxon, J. C.; Walach, M.-T.; Anderson, B. J.</p> <p>2016-02-01</p> <p>We present the first large-scale comparison of the spatial distribution of field-aligned currents as measured by the Active Magnetosphere and Planetary Electrodynamics Response Experiment, with the location and brightness of the <span class="hlt">average</span> auroral oval, determined from the Imager for Magnetopause-to-Aurora Global Exploration far ultraviolet instrument. These distributions are compared under the same <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field magnitude and clock angle conditions. The field-aligned currents and auroral oval drop to lower latitudes, as the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field becomes both increasingly stronger in magnitude and increasingly southward. We find that the region 2 currents are more closely aligned with the distribution of auroral UV emission, whether that be in the discrete auroral zone about dusk or in the postmidnight diffuse aurora sector. The lack of coincidence between the region 1 field-aligned currents with the auroral oval in the dusk sector is contrary to expectation.</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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012PhDT.......113C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012PhDT.......113C&link_type=ABSTRACT"><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</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/2060/19850026502','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/1989RpScT...2....6Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989RpScT...2....6Y"><span id="translatedtitle">Structure of <span class="hlt">interplanetary</span> fluxes based on plasma and <span class="hlt">magnetic</span> field measurements by Prognoz-6 satellite on 25-26 November 1977</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yeroshenko, Ye. G.; Ivanov, K. G.; Verigin, M. I.; Kotova, G. A.; Styazhkin, V. A.</p> <p>1989-01-01</p> <p>Two fluxes from a flare and a coronal hole on 25 to 26 November 1977 were observed aboard the Prognoz-6 satellite. A comparative analysis is presented of the <span class="hlt">magnetic</span> and plasma data based on these observations and observations of other Soviet and American spacecraft which were located at that time near a line between the Sun and the Earth. The Prognoz-6 data recored disturbances in the <span class="hlt">magnetic</span> field and plasma near the Earth during passage of the isolated flare flux and the quasisteady flux from the coronal hole. A perpendicular to the head of the shock wave of the flare flux was found. The <span class="hlt">magnetic</span> cloud from the flare was measured over a period of 19 hours as an area of relatively strong field, sparse plasma with near regular variations of all B components. The normal and inner structure of the <span class="hlt">magnetic</span> cloud magnetopause were measured. More than 10 intersections with the leading edge of the magnetospheric shock wave were recorded while the geomagnetosphere was within the <span class="hlt">magnetic</span> cloud, indicating an increase in the cross section of the transient area as the magnetosphere and cloud interacted. The boundary of the quasisteady flux was identified and had almost the same changes in plasma and <span class="hlt">magnetic</span> field parameters as the flare flux boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.2616Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.2616Z"><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 17 March 2013 storm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</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 gyroresonant wave-particle interaction and quasi-linear diffusion in different <span class="hlt">magnetic</span> field configurations related to the 17 March 2013 storm. We consider the Earth's <span class="hlt">magnetic</span> dipole field as a reference and compare the results against nondipole 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 <span class="hlt">Magnetic</span> Local Time (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 gyroresonant 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 17 March 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> <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/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 ΔH at Colaba-Alibag observatories. The estimated IEFy values using Dst and ΔHABG 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=20070023318&hterms=Cane&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCane','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070023318&hterms=Cane&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCane"><span id="translatedtitle">A Survey of <span class="hlt">Interplanetary</span> Coronal Mass Ejections During 1996 - 2007</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richardson, Ian; Cane, Hilary</p> <p>2007-01-01</p> <p><span class="hlt">Interplanetary</span> coronal mass ejections, the <span class="hlt">interplanetary</span> counterparts of coronal mass ejections at the Sun, are the major drivers of <span class="hlt">interplanetary</span> shocks in the heliosphere, and are associated with modulations of the galactic cosmic ray intensity, both short term (Forbush decreases caused by the passage of the shock, post-shock sheath, and ICME) and possibly with longer term modulation. Using several in-situ signatures of ICMEs, including plasma temperature, and composition, <span class="hlt">magnetic</span> fields, and cosmic ray modulations, made by near-Earth spacecraft, we have compiled a "comprehensive" list of ICMEs passing the Earth since 1996, encompassing solar cycle 23. We summarize the properties of these ICMEs, such as their occurrence rate, speeds, association with solar energetic particle events, shocks and cosmic ray decreases.</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://ntrs.nasa.gov/search.jsp?R=19990053118&hterms=rubidium&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%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%3D80%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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36.2777L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36.2777L"><span id="translatedtitle">The Space Weather Effect of <span class="hlt">Interplanetary</span> Shock Parameters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Li, Changxing; Wang, Chi</p> <p></p> <p>The ring current is the key element in the <span class="hlt">magnetic</span> storms in the near-Earth space which absorbs and stores geomagnetic storm energy and then releases it slowly over subsequent days and weeks Understanding the structure and property of the ring current can lead to more accurate predictions of the space environment of the inner magnetosphere for the ongoing rapid development of human activities When a sudden increase in the solar wind dynamic pressure following an <span class="hlt">interplanetary</span> shock IPS compresses the Earth magnetosphere the inner magnetospheric currents significantly intensify especially the ring current However how the <span class="hlt">interplanetary</span> shock triggers the <span class="hlt">magnetic</span> storm and how it affects the intensification and the decay of the ring current are not fully understood For this purpose we statistically study how critical parameters of an IPS such as the orientation and the strength of the IPS correlate with the geomagnetic indices such as Dst SYM and ASY which relate to the disturbances in the ring current In order to investigate the effectiveness of an IPS on the near Earth space environment we apply Gaussian wavelet transform method to the solar wind plasma and the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field data from WIND and ACE satellites to determine the critical parameters of the IPS We have successfully identified more than 300 IPSs from the archives of WIND and ACE measurements The initial results have shows that 1 Gaussian wavelet transform method has good responses to the changing features of <span class="hlt">interplanetary</span> shocks 2 The lag time</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1200613','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/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> <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> </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://ntrs.nasa.gov/search.jsp?R=20070016645&hterms=Cane&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DCane','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070016645&hterms=Cane&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DCane"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Shocks and "Suprathermal" Flare Particles</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.; Richardson, I. G.; vonRosenvinge, T. T.</p> <p>2006-01-01</p> <p>We use ion-composition data from ACE/ULEIS, low energy electrons from ACE/EPAM, high energy protons from SoHO/ERNE, radio data from Wind/WAVES, and solar wind data from ACE/SWEPAM and ACE/MAG to investigate the solar and <span class="hlt">interplanetary</span> circumstances near the times of passage of near-Earth shocks. We are particularly interested in claims that local acceleration by some <span class="hlt">interplanetary</span> shocks produces Fe/O > 0.3 ('Fe-rich' shocks). The choice of the specific interval used to calculate the Fe/O ratio is extremely important because shock-accelerated particles can be masked by particles from flare events, related or unrelated to the shock, that have Fe/O > 0.3. We conclude that shock- accelerated populations have Fe/0<0.3. We illustrate 5 events which have been reported to be Fe-rich and for which Fe/O increases with energy in the 0.5-2 MeV/nuc range. We find that in each case there are direct flare particles included in the <span class="hlt">averaging</span> time interval. We also demonstrate that the Fe/O ratio increases as a result of the <span class="hlt">averaging</span> time interval being too large.</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>Valdés-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://hdl.handle.net/2060/20120009629','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20120009629"><span id="translatedtitle">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</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. 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.</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/2060/19810012468','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19810012468"><span id="translatedtitle">Fine-scale characteristics of <span class="hlt">interplanetary</span> sector</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.; Neubauer, F. M.; Barnstoff, H.</p> <p>1980-01-01</p> <p>The structure of the <span class="hlt">interplanetary</span> sector boundaries observed by Helios 1 within sector transition regions was studied. Such regions consist of intermediate (nonspiral) <span class="hlt">average</span> field orientations in some cases, as well as a number of large angle directional discontinuities (DD's) on the fine scale (time scales 1 hour). Such DD's are found to be more similar to tangential than rotational discontinuities, to be oriented on <span class="hlt">average</span> more nearly perpendicular than parallel to the ecliptic plane to be accompanied usually by a large dip ( 80%) in B and, with a most probable thickness of 3 x 10 to the 4th power km, significantly thicker previously studied. It is hypothesized that the observed structures represent multiple traversals of the global heliospheric current sheet due to local fluctuations in the position of the sheet. There is evidence that such fluctuations are sometimes produced by wavelike motions or surface corrugations of scale length 0.05 - 0.1 AU superimposed on the large scale structure.</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://adsabs.harvard.edu/abs/2015AGUFMSH53A2469W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSH53A2469W"><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, R. M.; Lugaz, N.; Philpott, L. C.; Schwadron, N.; Farrugia, C. J.; Anderson, B. J.; Smith, C. W.</p> <p>2015-12-01</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, the first spacecraft since the 1980s to make in-situ measurements at distances < 0.5 AU, presents a unique opportunity for observing the innermost heliosphere. It also allows studies of ICME evolution as they expand and propagate outward, interacting with the solar wind. In order to catalog ICME events observed by MESSENGER, we design a strict set of selection criteria to identify them based on <span class="hlt">magnetic</span> field observations only, since reliable solar wind plasma observations are not available from MESSENGER. We identify 61 ICME events observed by the MESSENGER Magnetometer between 2011 and 2014, and present statistical analyses of ICME properties at Mercury. In addition, using existing datasets 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 heliospheric distance, r. We have also established three different lines of evidence that ICME deceleration continues beyond the orbit of Mercury: 1) we find a shallow decrease with distance of ˜r-0.45 for the ICME shock speed from Mercury to 1 AU, 2) the <span class="hlt">average</span> transit speed from the Sun to Mercury for ICMEs in our catalog is ˜20% faster than the <span class="hlt">average</span> speed from the Sun to 1 AU, 3) the ICME transit time to 1 AU has a weaker dependence on the CME initial coronagraphic speed, as compared to what we predict based on our MESSENGER ICME catalog. Based on our results, future ICME propagation studies should account for ICME speed changes beyond Mercury's heliocentric distances to improve ICME arrival time forecasting. Our ICME database will also 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://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://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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SoPh..290..919T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015SoPh..290..919T&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Propagation Behavior of the Fast Coronal Mass Ejection on 23 July 2012</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Temmer, M.; Nitta, N. V.</p> <p>2015-03-01</p> <p>The fast coronal mass ejection (CME) on 23 July 2012 caused attention because of its extremely short transit time from the Sun to 1 AU, which was shorter than 21 h. In situ data from STEREO-A revealed the arrival of a fast forward shock with a speed of more than 2200 km s-1 followed by a <span class="hlt">magnetic</span> structure moving with almost 1900 km s-1. We investigate the propagation behavior of the CME shock and <span class="hlt">magnetic</span> structure with the aim to reproduce the short transit time and high impact speed as derived from in situ data. We carefully measured the 3D kinematics of the CME using the graduated cylindrical shell model and obtained a maximum speed of 2580±280 km s-1 for the CME shock and 2270±420 km s-1 for its <span class="hlt">magnetic</span> structure. Based on the 3D kinematics, the drag-based model (DBM) reproduces the observational data reasonably well. To successfully simulate the CME shock, the ambient flow speed needs to have an <span class="hlt">average</span> value close to the slow solar wind speed (450 km s-1), and the initial shock speed at a distance of 30 R ⊙ should not exceed ≈ 2300 km s-1, otherwise it would arrive much too early at STEREO-A. The model results indicate that an extremely small aerodynamic drag force is exerted on the shock, smaller by one order of magnitude than <span class="hlt">average</span>. As a consequence, the CME hardly decelerates in <span class="hlt">interplanetary</span> space and maintains its high initial speed. The low aerodynamic drag can only be reproduced when the density of the ambient solar wind flow, in which the fast CME propagates, is decreased to ρ sw=1 - 2 cm-3 at the distance of 1 AU. This result is consistent with the preconditioning of <span class="hlt">interplanetary</span> space by a previous CME.</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://hdl.handle.net/2060/19720000603','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19720000603"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Trajectories, Encke Method (ITEM)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Whitlock, F. H.; Wolfe, H.; Lefton, L.; Levine, N.</p> <p>1972-01-01</p> <p>Modified program has been developed using improved variation of Encke method which avoids accumulation of round-off errors and avoids numerical ambiguities arising from near-circular orbits of low inclination. Variety of <span class="hlt">interplanetary</span> trajectory problems can be computed with maximum accuracy and efficiency.</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://adsabs.harvard.edu/abs/2013ApJ...777...32X','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApJ...777...32X"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Xiong, Ming; Davies, Jackie A.; Feng, Xueshang; Owens, Mathew J.; Harrison, Richard A.; Davis, Chris J.; Liu, Ying D.</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 ∥ 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 Ivpropr -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 sheath and the mass of plasma at that position M sheath can be inferred from the polarization of the shock-associated enhancement in WL radiance. From the FR measurements, the local B ∥sheath at r 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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E.202B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E.202B&link_type=ABSTRACT"><span id="translatedtitle">Cosmic rays, conditions in <span class="hlt">interplanetary</span> space and geomagnetic variations during solar cycles 19-24</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Biktash, Lilia</p> <p>2016-07-01</p> <p>We have studied conditions in <span class="hlt">interplanetary</span> space, which can have an influence on galactic and solar cosmic rays (CRs). In this connection the solar wind and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field parameters and CRs variations have been compared with geomagnetic activity represented by the equatorial Dst and Kp indices beginning from 1955 to the end 2015. The indices are in common practice in the solar wind-magnetosphere-ionosphere interaction studies and they are the final product of this interaction. The important drivers in <span class="hlt">interplanetary</span> medium which have effect on cosmic rays as CMEs (coronal mass ejections) and CIRs (corotating interaction regions) undergo very strong changes during their propagation to the Earth. Correlation of sunspot numbers and long-term variations of cosmic rays do not adequately reflect peculiarities concerned with the solar wind arrival to 1 AU also. Moreover records of in situ space measurements of the IMF and most other indicators of solar activity cover only a few decades and have a lot of gaps for calculations of long-term variations. Because of this, in such investigations, the geomagnetic indices have some inestimable advantage as continuous series other the solar wind measurements. We have compared the yearly <span class="hlt">average</span> variations of the indices and of the solar wind parameters with cosmic ray data from Moscow, Climax, Halekala and Oulu neutron monitors during the 20-24 solar cycles. During the descending phases of the solar cycles the long-lasting solar wind high speed streams occurred frequently and were the primary contributors to the recurrent Dst variations and had effects on cosmic rays variations. We show that long-term Dst and Kp variations in these solar cycles were correlated with cosmic ray count rates and can be used for prediction of CR variations. Climate change in connection with evolution of CRs variations is discussed.</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://ntrs.nasa.gov/search.jsp?R=19850024742&hterms=respect&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Drespect','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850024742&hterms=respect&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Drespect"><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 pacecraft 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 at Voyager 2 during periods when both spacecraft are first north 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://ntrs.nasa.gov/search.jsp?R=20110015529&hterms=Cane&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCane','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110015529&hterms=Cane&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCane"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Circumstances of Quasi-Perpendicular <span class="hlt">Interplanetary</span> Shocks in 1996-2005</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>2010-01-01</p> <p>The angle (theta(sub Bn)) between the normal to an <span class="hlt">interplanetary</span> shock front and the upstream <span class="hlt">magnetic</span> field direction, though often thought of as a property "of the shock," is also determined by the configuration of the <span class="hlt">magnetic</span> field immediately upstream of the shock. We investigate the <span class="hlt">interplanetary</span> circumstances of 105 near-Earth quasi-perpendicular shocks during 1996-2005 identified by theta(sub Bn) greater than or equal to 80 degrees and/or by evidence of shock drift particle acceleration. Around 87% of these shocks were driven by <span class="hlt">interplanetary</span> coronal mass ejections (ICMEs); the remainder were probably the forward shocks of corotating interaction regions. For around half of the shocks, the upstream field was approximately perpendicular to the radial direction, either east-west or west-east or highly inclined to the ecliptic. Such field directions will give quasi-perpendicular configurations for radially propagating shocks. Around 30% of the shocks were propagating through, or closely followed, ICMEs at the time of observation. Another quarter were propagating through the heliospheric plasma sheet (HPS), and a further quarter occurred in slow solar wind that did not have characteristics of the HPS. Around 11% were observed in high-speed streams, and 7% in the sheaths following other shocks. The fraction of shocks found in high-speed streams is around a third of that expected based on the fraction of the time when such streams were observed at Earth. Quasi-perpendicular shocks are found traveling through ICMEs around 2-3 times more frequently than expected. In addition, shocks propagating through ICMEs are more likely to have larger values of theta(sub Bn) than shocks outside ICMEs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.P21C3927K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.P21C3927K"><span id="translatedtitle">Development with MESSENGER Data of a Model of 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, H.; Tsyganenko, N. A.; Johnson, C. L.; Philpott, L. C.; Anderson, B. J.; Al Asad, M.; Solomon, S. C.; McNutt, R. L., Jr.</p> <p>2014-12-01</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 that is confined within a magnetopause shape derived from Magnetometer observations by the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft. The model consists of individual modules for <span class="hlt">magnetic</span> fields of internal origin, approximated by a dipole of magnitude 190 nT RM3, where RM is Mercury's radius, offset northward by 479 km along the spin axis, and of external origin resulting from currents flowing on the magnetopause boundary and in the cross-tail current sheet. The cross-tail current is prescribed having a disk shape near the planet and extending into a Harris sheet at larger distances. The magnitude of the tail current is fit to minimize the root mean square residual between the <span class="hlt">magnetic</span> field within the magnetosphere observed by MESSENGER and the model field. The <span class="hlt">magnetic</span> field contribution from each module is shielded individually by a scalar potential function consisting of Cartesian harmonic expansions with linear and non-linear coefficients, which are fit to minimize the root-mean-square normal <span class="hlt">magnetic</span> field component at the magnetopause. The resulting model resembles the observed <span class="hlt">magnetic</span> field better than the previously developed paraboloid model in regions that are close to the magnetopause, i.e., at northern high latitudes and on the dayside. It will allow more accurate characterization of crustal <span class="hlt">magnetization</span>, which may be observed during low-altitude orbits in the final months of the MESSENGER mission.</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> </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://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/2013ApJ...772....2P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013ApJ...772....2P"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pogorelov, N. V.; Suess, S. T.; Borovikov, S. N.; Ebert, R. W.; McComas, D. J.; Zank, G. P.</p> <p>2013-07-01</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°, 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://ntrs.nasa.gov/search.jsp?R=19960021344&hterms=polarity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpolarity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021344&hterms=polarity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dpolarity"><span id="translatedtitle">The emergence of different polarity photospheric flux as the cause of CMEs and <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>Bravo, S.</p> <p>1995-01-01</p> <p>Here we discuss the effect that the emergence of flux with a polarity opposed to that previously established in a certain photospheric region. can have on the <span class="hlt">magnetic</span> structure of the solar atmosphere. We show that such a flux emergence may lead to the ejection of coronal material into the <span class="hlt">interplanetary</span> medium (a CME) and also to a rapid change in the velocity of the solar wind from the region, which may eventually lead to the formation of an <span class="hlt">interplanetary</span> shock.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35.3506S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35.3506S"><span id="translatedtitle">Sudden impulse and <span class="hlt">interplanetary</span> shock parameters correlation near the south atlantic geomagnetic anomaly</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Santos, J.; Echer, E.; Gonzalez, W.; Alves, M.; Trivedi, N.; Gonzalez, A.; Vieira, L.; dal Lago, A.; Guarnieri, F.; Schuch, N.</p> <p></p> <p>In this work we intend to perform a comparative study of the sudden impulse (SI) response to <span class="hlt">interplanetary</span> shocks near the South Atlantic Geomagnetic Anomaly (SAGA) region. A total of 34 events were selected for analysis during September 2000 -- December 2001. The magnetospheric SI response was studied using ground-based geomagnetic station SMS (29.4°S, 53.82°W) located near SAGA center. To compare we use also stations out of the SAGA's influence. The geomagnetic symmetrical (SYM) index was also employed in order to characterize the <span class="hlt">average</span> SI response. Solar wind data were obtained from plasma and <span class="hlt">magnetic</span> field detectors on board the ACE spacecraft, orbiting L1 point. Since the total geomagnetic field strength is low in SAGA, the SI response might be different inside and outside the SAGA region. This subject is assessed by correlative analyses among solar shock parameters and SI amplitudes.</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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.6061O&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016EGUGA..18.6061O&link_type=ABSTRACT"><span id="translatedtitle"><span class="hlt">Interplanetary</span> density models as inferred from solar Type III bursts</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Oppeneiger, Lucas; Boudjada, Mohammed Y.; Lammer, Helmut; Lichtenegger, Herbert</p> <p>2016-04-01</p> <p>We report on the density models derived from spectral features of solar Type III bursts. They are generated by beams of electrons travelling outward from the Sun along open <span class="hlt">magnetic</span> field lines. Electrons generate Langmuir waves at the plasma frequency along their ray paths through the corona and the <span class="hlt">interplanetary</span> medium. A large frequency band is covered by the Type III bursts from several MHz down to few kHz. In this analysis, we consider the previous empirical density models proposed to describe the electron density in the <span class="hlt">interplanetary</span> medium. We show that those models are mainly based on the analysis of Type III bursts generated in the <span class="hlt">interplanetary</span> medium and observed by satellites (e.g. RAE, HELIOS, VOYAGER, ULYSSES,WIND). Those models are confronted to stereoscopic observations of Type III bursts recorded by WIND, ULYSSES and CASSINI spacecraft. We discuss the spatial evolution of the electron beam along the <span class="hlt">interplanetary</span> medium where the trajectory is an Archimedean spiral. We show that the electron beams and the source locations are depending on the choose of the empirical density models.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19860022023','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19860022023"><span id="translatedtitle">Coronal and <span class="hlt">interplanetary</span> propagation, <span class="hlt">interplanetary</span> acceleration, cosmic-ray observations by deep space network and anomalous component</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>1986-01-01</p> <p>The purpose is to provide an overview of the contributions presented in sessions SH3, SH1.5, SH4.6 and SH4.7 of the 19th International Cosmic Ray Conference. These contributed papers indicate that steady progress continues to be made in both the observational and the theoretical aspects of the transport and acceleration of energetic charged particles in the heliosphere. Studies of solar and <span class="hlt">interplanetary</span> particles have placed emphasis on particle directional distributions in relation to pitch-angle scattering and <span class="hlt">magnetic</span> focusing, on the rigidity and spatial dependence of the mean free path, and on new propagation regimes in the inner and outer heliosphere. Coronal propagation appears in need of correlative multi-spacecraft studies in association with detailed observation of the flare process and coronal <span class="hlt">magnetic</span> structures. <span class="hlt">Interplanetary</span> acceleration has now gone into a consolidation phase, with theories being worked out in detail and checked against observation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996JGR...10119973O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996JGR...10119973O"><span id="translatedtitle">Propagation of an <span class="hlt">interplanetary</span> shock along the heliospheric plasma sheet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Odstrčil, D.; Dryer, M.; Smith, Z.</p> <p>1996-09-01</p> <p>Propagation of an <span class="hlt">interplanetary</span> shock along the heliospheric plasma sheet (HPS) is simulated using a high-resolution numerical MHD model in the meridional plane. The ambient solar wind contains two opposite orientations of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field above and below the equatorial plane. These regions are separated by a thin transition layer that represents the heliospheric current sheet contained within the HPS. A pulse is introduced at the inner boundary (0.1 AU) into this steady state to initiate the <span class="hlt">interplanetary</span> shock. The HPS with its weaker intensity of the <span class="hlt">magnetic</span> field, larger mass density, and slower flow velocity modifies the global shock structure. A dimple is formed at the forward shock front, a reverse dimple is formed at the reverse shock, and the contact discontinuity is significantly distorted. Weak compression of the HPS occurs beyond the forward shock front due to the postshock increase of the azimuthal <span class="hlt">magnetic</span> pressure. Although slight collimation of mass flow takes place toward the axis of the HPS, an antisunward protrusion (``pimple'') within the shock front's dimple did not form in our simulation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2000ESASP.456...23C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2000ESASP.456...23C"><span id="translatedtitle">Circumstellar, Cometary and <span class="hlt">Interplanetary</span> Dust</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crovisier, J.</p> <p>2000-11-01</p> <p>The Infrared Space Observatory made us available for the first time the full infrared spectrum of cosmic dust in a variety of astrophysical environments. I review what we learned from ISO on the composition of dust in the Solar System (cometary and <span class="hlt">interplanetary</span>) and in circumstellar discs around young or evolved stars, what are the commonalities and parallels between dust in these different environments, and what this tells us on the cosmic dust cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19940016180&hterms=1076&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231076','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940016180&hterms=1076&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2526%25231076"><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://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://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/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/cgi-bin/nph-data_query?bibcode=2016cosp...41E.966K&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016cosp...41E.966K&link_type=ABSTRACT"><span id="translatedtitle">Dynamics of the 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</p> <p>2016-07-01</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 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 geomagnetic storms associated with disturbance storm time (Dst) decreases 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 those provided by SOHO, ACE and geomagnetic stations like WDC-Kyoto are utilized in the study. It is observed that the yearly occurrences of geomagnetic storm are strongly correlated with 11-year sunspot cycle, but no significant correlation between the maximum and minimum phase of solar cycle have been found. It is also found that solar cycle-23 is remarkable for occurrence of intense geomagnetic storms during its declining phase. The detailed results are discussed in this paper.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850026510','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850026510"><span id="translatedtitle">The local characteristic function of <span class="hlt">interplanetary</span> particle propagation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Green, G.; Schlueter, W.</p> <p>1985-01-01</p> <p>An easily measurable intensity function which characterizes the <span class="hlt">interplanetary</span> propagation of charged solar flare particles is presented. This function is nearly time invariant during a solar event despite the large variations of intensity and anisotropy, but varies from event to event. It characterizes the systematic and stochastic forces of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field which focus and scatter the particles in pitch angle. The model of focused transport shows that this function is essentially determined by the local shape and amplitude of the pitch angle diffusion coefficient kappa (mu) and by the local value of the focusing length. The time profile of the solar particle injection is typically of negligible influence. The local characteristic function may be used as a powerful new tool for a systematic analysis of flare particle angular distributions, Examples are given.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730002067','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002067"><span id="translatedtitle"><span class="hlt">Interplanetary</span> shock waves and the structure of solar wind disturbances</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hundhausen, A. J.</p> <p>1972-01-01</p> <p>Observations and theoretical models of <span class="hlt">interplanetary</span> shock waves are reviewed, with emphasis on the large-scale characteristics of the associated solar wind disturbances and on the relationship of these disturbances to solar activity. The sum of observational knowledge indicates that shock waves propagate through the solar wind along a broad, roughly spherical front, ahead of plasma and <span class="hlt">magnetic</span> field ejected from solar flares. Typically, the shock front reaches 1 AU about two days after its flare origin, and is of intermediate strength. Not all large flares produce observable <span class="hlt">interplanetary</span> shock waves; the best indicator of shock production appears to be the generation of both type 2 and type 4 radio bursts by a flare. Theoretical models of shock propagation in the solar wind can account for the typically observed shock strength, transit time, and shape.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996AIPC..382..457O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996AIPC..382..457O"><span id="translatedtitle">Interaction of an <span class="hlt">interplanetary</span> shock with the heliospheric plasma sheet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Odstrčil, D.; Dryer, M.; Smith, Z.</p> <p>1996-07-01</p> <p>The interaction of an <span class="hlt">interplanetary</span> shock with the heliospheric plasma sheet (HPS) is simulated using the 2 12D MHD model in the meridional plane. The shock structure is generated by a velocity pulse and consists of a strong broad forward shock (FS) with a concave shape and a much weaker and narrower reverse shock (RS) with a convex shape. The flat equatorial HPS, with its larger mass density and slower flow velocity, modifies this shock structure. A dimple is formed at the FS and a reverse dimple is formed at the RS. A large distortion of the heliospheric current sheet (HCS) occurs when the velocity pulse is introduced outside the HPS. The interaction of a shock with the HPS leads to very large southward values of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field due to an effect of shock compression, field-line draping, and deflection of the HCS.</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://ntrs.nasa.gov/search.jsp?R=19740034379&hterms=1091&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231091','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740034379&hterms=1091&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231091"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Lyman-beta emissions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Paresce, F.</p> <p>1973-01-01</p> <p>Derivation of the intensity of the diffuse hydrogen Lyman-beta glow at 1025 A which is due to resonance scattering of the solar H I 1025 A line by interstellar and <span class="hlt">interplanetary</span> hydrogen. Two sources of neutral hydrogen are considered: the local interstellar medium interacting with the solar system, and the dust deionization of the H(+) component of the solar wind. It is shown that if the dust geometrical factor is less than or equal to five quintillionths per cm, observations of backscattered Lyman-beta radiation will provide a unique determination of the density and temperature of the local interstellar medium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008AGUFMSH24A..04R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008AGUFMSH24A..04R"><span id="translatedtitle">Multisatellite Observations of <span class="hlt">Interplanetary</span> Field Enhancements</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Russell, C. T.; Weimer, D. R.; Jian, L. K.; Lai, H. R.; Luhmann, J. G.</p> <p>2008-12-01</p> <p><span class="hlt">Interplanetary</span> Field Enhancements (IFEs) are <span class="hlt">magnetic</span> structures in the solar wind that have a cusp-shaped maximum in the field strength with a strong current sheet often near the central peak. These structures generally last an hour or more. They have a tendency to be seen more often at specific ecliptic longitudes, have been identified on occasion with particular small solar system bodies (asteroid 2201 Oljato and comet 122P/ De Vico) and attributed to the interaction of the solar wind with charged dust. On occasion they are detected nearly simultaneously by several spacecraft. Multispacecraft detection have been made with PVO, Venera-13 and Venera-14; with ISEE 1 and ISEE 3 and more recently with STEREO A and B, ACE and Wind. In this paper we use a delay matching algorithm developed by D. Weimer on the IFE of December 24, 2006 detected by 4 spacecraft. While the IFE is crossing the four spacecraft separated in Y by 90 Re and in X by 160 Re the measured delay was close to the calculated advection time. Along the apparent center line of the event the delay was close to 4 minutes. This event together with previous events are consistent with IFEs being <span class="hlt">magnetic</span> structures that are convecting outward from the Sun with nearly, but slightly slower than, the solar wind velocity. We need to understand the occurrence rate of such structures and their physical cause because if this hypothesis is true, they may be responsible for accelerating dust out of the inner solar system.</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=19880052777&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=19880052777&hterms=Luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%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/cgi-bin/nph-data_query?bibcode=2016JGRA..121.1062B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016JGRA..121.1062B&link_type=ABSTRACT"><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=19960021314&hterms=conservation+mass&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dconservation%2Bmass','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021314&hterms=conservation+mass&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dconservation%2Bmass"><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://hdl.handle.net/2060/19990010034','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990010034"><span id="translatedtitle">Performance of a Bounce-<span class="hlt">Averaged</span> Global Model of Super-Thermal Electron Transport in the Earth's <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>McGuire, Tim</p> <p>1998-01-01</p> <p>In this paper, we report the results of our recent research on the application of a multiprocessor Cray T916 supercomputer in modeling super-thermal electron transport in the earth's <span class="hlt">magnetic</span> field. In general, this mathematical model requires numerical solution of a system of partial differential equations. The code we use for this model is moderately vectorized. By using Amdahl's Law for vector processors, it can be verified that the code is about 60% vectorized on a Cray computer. Speedup factors on the order of 2.5 were obtained compared to the unvectorized code. In the following sections, we discuss the methodology of improving the code. In addition to our goal of optimizing the code for solution on the Cray computer, we had the goal of scalability in mind. Scalability combines the concepts of portabilty with near-linear speedup. Specifically, a scalable program is one whose performance is portable across many different architectures with differing numbers of processors for many different problem sizes. Though we have access to a Cray at this time, the goal was to also have code which would run well on a variety of architectures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JMagR.251...71G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JMagR.251...71G"><span id="translatedtitle">Noise reduction of nuclear <span class="hlt">magnetic</span> resonance (NMR) transversal data using improved wavelet transform and exponentially weighted moving <span class="hlt">average</span> (EWMA)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ge, Xinmin; Fan, Yiren; Li, Jiangtao; Wang, Yang; Deng, Shaogui</p> <p>2015-02-01</p> <p>NMR logging and core NMR signals acts as an effective way of pore structure evaluation and fluid discrimination, but it is greatly contaminated by noise for samples with low <span class="hlt">magnetic</span> resonance intensity. Transversal relaxation time (T2) spectrum obtained by inversion of decay signals intrigued by Carr-Purcell-Meiboom-Gill (CPMG) sequence may deviate from the truth if the signal-to-noise ratio (SNR) is imperfect. A method of combing the improved wavelet thresholding with the EWMA is proposed for noise reduction of decay data. The wavelet basis function and decomposition level are optimized in consideration of information entropy and white noise estimation firstly. Then a hybrid threshold function is developed to avoid drawbacks of hard and soft threshold functions. To achieve the best thresholding values of different levels, a nonlinear objective function based on SNR and mean square error (MSE) is constructed, transforming the problem to a task of finding optimal solutions. Particle swarm optimization (PSO) is used to ensure the stability and global convergence. EWMA is carried out to eliminate unwanted peaks and sawtooths of the wavelet denoised signal. With validations of numerical simulations and experiments, it is demonstrated that the proposed approach can reduce the noise of T2 decay data perfectly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950004550&hterms=exposure+dust&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dexposure%2Bdust','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950004550&hterms=exposure+dust&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dexposure%2Bdust"><span id="translatedtitle">Solar system exposure histories 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>Nier, Alfred O.</p> <p>1994-01-01</p> <p>The topics discussed include the following: stratospheric collection of <span class="hlt">interplanetary</span> dust particles (IDP's); sources of <span class="hlt">interplanetary</span> dust particles; and solar wind and noble gas isotopic ratios in IDP's.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930053283&hterms=earths+magnetic+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dearths%2Bmagnetic%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930053283&hterms=earths+magnetic+field&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dearths%2Bmagnetic%2Bfield"><span id="translatedtitle">The interaction of a <span class="hlt">magnetic</span> cloud with the Earth - Ionospheric convection in the Northern and Southern Hemispheres for a wide range of quasi-steady <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>Freeman, M. P.; Farrugia, C. J.; Burlaga, L. F.; Hairston, M. R.; Greenspan, M. E.; Ruohoniemi, J. M.; Lepping, R. P.</p> <p>1993-01-01</p> <p>Observations are presented of the ionospheric convection in cross sections of the polar cap and auroral zone as part of the study of the interaction of the Earth's magnetosphere with the <span class="hlt">magnetic</span> cloud of January 13-15, 1988. For strongly northward IMF, the convection in the Southern Hemisphere is characterized by a two-cell convection pattern comfined to high latitudes with sunward flow over the pole. The strength of the flows is comparable to that later seen under southward IMF. Superimposed on this convection pattern there are clear dawn-dusk asymmetries associated with a one-cell convection component whose sense depends on the polarity of the <span class="hlt">magnetic</span> cloud's large east-west <span class="hlt">magnetic</span> field component. When the cloud's <span class="hlt">magnetic</span> field turns southward, the convection is characterized by a two-cell pattern extending to lower latitude with antisunward flow over the pole. There is no evident interhemispheric difference in the structure and strength of the convection. Superimposed dawn-dusk asymmetries in the flow patterns are observed which are only in part attributable to the east-west component of the <span class="hlt">magnetic</span> field.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870057371&hterms=IPL&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DIPL','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870057371&hterms=IPL&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DIPL"><span id="translatedtitle">Solar cycle study of <span class="hlt">interplanetary</span> Lyman-alpha variations - Pioneer Venus Orbiter sky background results</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ajello, J. M.; Stewart, A. I.; Thomas, G. E.; Graps, A.</p> <p>1987-01-01</p> <p>PVO observations of the <span class="hlt">interplanetary</span> Ly-alpha (IPL) background, obtained over an entire solar cycle (SC) from 1979 to 1985, are compiled and analyzed statistically, along with data from other instruments and earlier solar cycles. The results are presented in extensive tables and graphs and characterized in detail. Findings reported include SC variation of 1.8 for the longitudinally <span class="hlt">averaged</span> IPL intensity (in agreement with the variation of the 27-d disk-<span class="hlt">averaged</span> integrated solar Ly-alpha flux), yearly <span class="hlt">averaged</span> ecliptic H-atom lifetime at 1 AU equal to 1.0 Ms at solar minimum and 1.5 Ms at solar maximum, <span class="hlt">interplanetary</span> H density equal to 0.07 + or - 0.01/cu cm, and <span class="hlt">interplanetary</span> H/He within the heliopause but far from the sun of 7 + or - 3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19850012177','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19850012177"><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://ntrs.nasa.gov/search.jsp?R=19760050070&hterms=equations+linear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dequations%2Blinear','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760050070&hterms=equations+linear&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dequations%2Blinear"><span id="translatedtitle">A quasi-linear kinetic equation for cosmic rays 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>Luhmann, J. G.</p> <p>1976-01-01</p> <p>A kinetic equation for <span class="hlt">interplanetary</span> cosmic rays is set up with the aid of weak-plasma-turbulence theory for an idealized radially symmetric model of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. As a starting point, this treatment invokes the Vlasov equation instead of the traditional Fokker-Planck equation. Quasi-linear theory is applied to obtain a momentum diffusion equation for the heliocentric frame of reference which describes the interaction of cosmic rays with convecting <span class="hlt">magnetic</span> irregularities in the solar-wind plasma. Under restricted conditions, the well-known equation of solar modulation can be obtained from this kinetic equation.</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=19770051690&hterms=average+wind+speeds&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Daverage%2Bwind%2Bspeeds','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770051690&hterms=average+wind+speeds&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Daverage%2Bwind%2Bspeeds"><span id="translatedtitle">On the high correlation between long-term <span class="hlt">averages</span> of solar wind speed and geomagnetic activity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Crooker, N. U.; Feynman, J.; Gosling, J. T.</p> <p>1977-01-01</p> <p>Six-month and yearly <span class="hlt">averages</span> of solar-wind speed from 1962 to 1975 are shown to be highly correlated with geomagnetic activity as measured by <span class="hlt">averages</span> of the Ap index. On the same time scale the correlation between the southward component of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field and geomagnetic activity is poor. Previous studies with hourly <span class="hlt">averages</span> gave opposite results. The better correlation with the southward component on an hourly time scale is explained by its large variation compared with the relatively constant solar-wind speed. However, on a yearly time scale the magnitude of the variations in both parameters are about the same. This problem can be solved by invoking an energy transfer mechanism which is proportional to the first power of the southward component and a higher power of the solar-wind speed.</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/cgi-bin/nph-data_query?bibcode=2015ApJ...803...96S&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ApJ...803...96S&link_type=ABSTRACT"><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 ȯ , 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://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/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://adsabs.harvard.edu/abs/1989ApJ...337..528T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989ApJ...337..528T"><span id="translatedtitle">Infrared emission from <span class="hlt">interplanetary</span> dust</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</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.</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://ntrs.nasa.gov/search.jsp?R=19860063127&hterms=exposure+dust&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dexposure%2Bdust','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19860063127&hterms=exposure+dust&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dexposure%2Bdust"><span id="translatedtitle">Ion bombardment 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>Johnson, R. E.; Lanzerotti, L. J.</p> <p>1986-01-01</p> <p>It is thought that a fraction of the <span class="hlt">interplanetary</span> dust particles (IDP's) collected in the stratosphere by high-flying aircraft represent materials ejected from comets. An investigation is conducted regarding the effects of ion bombardment on these particles, taking into account information on ion tracks and carbon in IDP's and laboratory data on charged particle bombardment of surfaces. It is found that the observational discovery of particle tracks in certain IDP's clearly indicates the exposure of these particles to approximately 10,000 years of 1-AU equivalent solar-particle fluences. If some erasure of the tracks occurs, which is likely when an IDP enters the upper atmosphere, then somewhat longer times are implied. The effects of the erosion and enhanced adhesion produced by ions are considered.</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> </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://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/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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060036361&hterms=ionospheric+storm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dionospheric%2Bstorm','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060036361&hterms=ionospheric+storm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dionospheric%2Bstorm"><span id="translatedtitle"><span class="hlt">Magnetic</span> Storms</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.; Kamide, Y.</p> <p>1996-01-01</p> <p>This talk provides a brief summary of the first conference devoted entirely to <span class="hlt">magnetic</span> storms. Topics cover the relevant phenomena at the Sun/corona, propogation of these structures through <span class="hlt">interplanetary</span> space, the response of the magnetosphere to interaction with these <span class="hlt">interplanetary</span> structures, the formation of the storm time ring current (in particular the oxygen content of the ring-current), and storm ionospheric effects and ground based effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016GeoRL..43.1810J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016GeoRL..43.1810J"><span id="translatedtitle">The auroral ionosphere TEC response to 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>Jin, Yaqi; Zhou, Xiaoyan; Moen, Jøran I.; Hairston, Marc</p> <p>2016-03-01</p> <p>This letter investigates the global total electron content (TEC) response in the auroral ionosphere to an <span class="hlt">interplanetary</span> shock on 8 March 2012, using GPS TEC data from three pierce point chains. One is a longitudinal chain along ~65° <span class="hlt">magnetic</span> latitude (MLAT) from ~19 <span class="hlt">magnetic</span> local time (MLT) through dayside to 03 MLT clockwise; one meridional chain is around 14 MLT from 88° to 59° MLAT; and the third one is a chain along ~75° MLAT from ~14 to 00 MLT clockwise. The first chain clearly presents a TEC signal propagation away from ~14 MLT, indicating the shock impact location. Such a propagation is well consistent with the diffuse shock aurora propagation, and the impact location is well predicted by the shock normal direction calculated using the Geotail solar wind and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field data. The meridional chain reveals a very fast TEC signal equatorward expansion at ~45 km/s, which is the manifestation of the shock impact and further compression near the subsolar magnetopause. While TEC along the high-latitude chain varies randomly, lacking any pattern, it is consistent with the discrete aurora dynamics along the poleward boundary of the auroral oval. These findings strongly support the shock aurora mechanisms of adiabatic compression and field-aligned current establishment or enhancement, suggest that due to the same mechanisms a shock-generated TEC variation is a "duplication" of the shock aurora from the global picture to the auroral forms and their dynamics, and open the door for the TEC to be an important tool to understand the solar wind and geospace coupling. These results, for the first time, reveal the prompt, intense, and global ionospheric TEC response to the <span class="hlt">interplanetary</span> fast-forward shock.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ApJ...813...85L&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015ApJ...813...85L&link_type=ABSTRACT"><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.; Viñas, 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/2060/19900020833','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://ntrs.nasa.gov/search.jsp?R=19750058039&hterms=Energy+intensity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D40%26Ntt%3DEnergy%2Bintensity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19750058039&hterms=Energy+intensity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DTitle%26N%3D0%26No%3D40%26Ntt%3DEnergy%2Bintensity"><span id="translatedtitle">On the anisotropies of <span class="hlt">interplanetary</span> low-energy proton intensities</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pesses, M. E.; Sarris, E. T.</p> <p>1975-01-01</p> <p>Explorer 35 proton anisotropic flux data (proton energies between 0.3 and 6.3 MeV) and simultaneous <span class="hlt">magnetic</span> field measurements were used to supply more information on the propagation characteristics of low-energy protons in the <span class="hlt">interplanetary</span> medium. During the rising portions of the proton events, large field-aligned anisotropies were observed. During the decaying part of the proton events, either radial anisotropy or near-isotropy was noticed. In addition, certain observations made during the decaying part of the proton events revealed anisotropies deviating significantly from the radial direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19880001358','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19880001358"><span id="translatedtitle">Interaction of <span class="hlt">interplanetary</span> shocks with nonuniform ambient solar wind</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.; Sheu, J. H.</p> <p>1987-01-01</p> <p>Three <span class="hlt">interplanetary</span> shock wave events are selected from the plasma and <span class="hlt">magnetic</span> field data of Helios 1 and 2, IMP-8, and Voyagers 1 and 2 for study of the interactions of a weak interplantary shock with a nonuniform ambient solar wind. These events occurred during the periods 22-26 November 1977, 1-7 January 1978, and 2-5 April 1979, respectively. It is found that the shock surfaces of these events are highly distorted. In addition, a portion of the shock surface may be degenerated into a disturbance which does not satisfy the Rankine-Hugoniot jump conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989imds.book.1985K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989imds.book.1985K"><span id="translatedtitle"><span class="hlt">Interplanetary</span> medium data book, supplement 4, 1985-1988</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>King, Joseph H.</p> <p>1989-09-01</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://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://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://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 Alfvén 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=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://hdl.handle.net/2060/20090008672','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20090008672"><span id="translatedtitle">Hypersonic <span class="hlt">Interplanetary</span> Flight: Aero Gravity Assist</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Bowers, Al; Banks, Dan; Randolph, Jim</p> <p>2006-01-01</p> <p>The use of aero-gravity assist during hypersonic <span class="hlt">interplanetary</span> flights is highlighted. Specifically, the use of large versus small planet for gravity asssist maneuvers, aero-gravity assist trajectories, launch opportunities and planetary waverider performance are addressed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080012702','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080012702"><span id="translatedtitle">Mars Reconnaissance Orbiter <span class="hlt">Interplanetary</span> Cruise 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; Graat, Eric; Halsell, Allen; Highsmith, Dolan; Long, Stacia; Bhat, Ram; Demcak, Stuart; Higa, Earl; Mottinger, Neil; Jah, Moriba</p> <p>2007-01-01</p> <p>Carrying six science instruments and three engineering payloads, the Mars Reconnaissance Orbiter (MRO) is the first mission in a low Mars orbit to characterize the surface, subsurface, and atmospheric properties with unprecedented detail. After a seven-month <span class="hlt">interplanetary</span> cruise, MRO arrived at Mars executing a 1.0 km/s Mars Orbit Insertion (MOI) maneuver. MRO achieved a 430 km periapsis altitude with the final orbit solution indicating that only 10 km was attributable to navigation prediction error. With the last <span class="hlt">interplanetary</span> maneuver performed four months before MOI, this was a significant accomplishment. This paper describes the navigation analyses and results during the 210-day <span class="hlt">interplanetary</span> cruise. As of August 2007 MRO has returned more than 18 Terabits of scientific data in support of the objectives set by the Mars Exploration Program (MEP). The robust and exceptional <span class="hlt">interplanetary</span> navigation performance paved the way for a successful MRO mission.</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/2005HvaOB..29..251B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005HvaOB..29..251B"><span id="translatedtitle">Geoeffective and Climate-Influencing Solar 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>Baranyi, T.; Ludmány, A.</p> <p></p> <p>Several connections have been detected and demonstrated between solar <span class="hlt">magnetic</span> conditions and climatic responses which hint at a highly complicated mechanism of sun-climate relations through plasma streams. The present contribution overviews our results about the possible factors of this mechanism. The main factor is the negative value of the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> B_z component which exhibits a fairly complex behaviour. Its strength is influenced by the solar dipole cycle, the nature of ejected plasma (CME or fast stream), the <span class="hlt">magnetic</span> topology of the CME and the position of the Earth (Rosenberg-Coleman and Russell-McPherron effects). The persistence of the negative B_z is also effective. The impacts of these features can be pointed out in the climatic responses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730002072','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730002072"><span id="translatedtitle"><span class="hlt">Interplanetary</span> double-shock ensembles with anomalous electrical conductivity</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dryer, M.</p> <p>1972-01-01</p> <p>Similarity theory is applied to the case of constant velocity, piston-driven, shock waves. This family of solutions, incorporating the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field for the case of infinite electric conductivity, represents one class of experimentally observed, flare-generated shock waves. This paper discusses the theoretical extension to flows with finite conductivity (presumably caused by unspecified modes of wave-particle interactions). Solutions, including reverse shocks, are found for a wide range of <span class="hlt">magnetic</span> Reynolds numbers from one to infinity. Consideration of a zero and nonzero ambient flowing solar wind (together with removal of <span class="hlt">magnetic</span> considerations) enables the recovery of earlier similarity solutions as well as numerical simulations. A limited comparison with observations suggests that flare energetics can be reasonably estimated once the shock velocity, ambient solar wind velocity and density, and ambient azimuthal Alfven Mach number are known.</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=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_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://adsabs.harvard.edu/abs/2003JChPh.118.8584P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003JChPh.118.8584P"><span id="translatedtitle">Nuclear <span class="hlt">magnetic</span> resonance chemical shifts with the statistical <span class="hlt">average</span> of orbital-dependent model potentials in Kohn-Sham density functional theory</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Poater, Jordi; van Lenthe, Erik; Baerends, Evert Jan</p> <p>2003-05-01</p> <p>In this paper, an orbital-dependent Kohn-Sham exchange-correlation potential, the so-called statistical <span class="hlt">average</span> of (model) orbital potentials, is applied to the calculation of nuclear <span class="hlt">magnetic</span> resonance chemical shifts of a series of simple molecules containing H, C, N, O, and F. It is shown that the use of this model potential leads to isotropic chemical shifts which are substantially improved over both local and gradient-corrected functionals, especially for nitrogen and oxygen atoms. This improvement in the chemical shift calculations can be attributed to the increase in the gap between highest occupied and lowest unoccupied orbitals, thus correcting the excessively large paramagnetic contributions, which have been identified to give deficient chemical shifts with both the local-density approximation and with gradient-corrected functionals. This is in keeping with the improvement by the statitical <span class="hlt">average</span> of orbital model potentials for response properties in general and for excitation energies in particular. The present results are comparable in accuracy to those previously reported with self-interaction corrected functionals by Patchovskii et al., but still inferior to those obtained with accurate Kohn-Sham potentials by Wilson and Tozer. However, the present approach is computationally expedient and routinely applicable to all systems, requiring virtually the same computational effort as local-density and generalized-gradient calculations.</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://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://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 ≤ 250γ 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 Hα, 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 Hα, 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://ntrs.nasa.gov/search.jsp?R=19790041801&hterms=alpha+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dalpha%2Bradiation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790041801&hterms=alpha+radiation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dalpha%2Bradiation"><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/2014AGUFMSM31D4230P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM31D4230P"><span id="translatedtitle">On the high correlation between storm sudden commencements and <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, W.; Lee, J.; Oh, S.; Yi, Y.</p> <p>2014-12-01</p> <p>Storm Sudden Commencements (SSCs) occur due to sudden compression of <span class="hlt">magnetic</span> field and current enhancement in the magnetopause, which is generally believed to be caused by <span class="hlt">interplanetary</span> shock. However, neither all geomagnetic storms exhibit the SSC nor all SSCs are accompanied by <span class="hlt">interplanetary</span> shocks. In this study, we search for geomagnetic storms without SSC using the SYM-H index data which is provided by the World Data Center for Geomagnetism Kyoto (WDC Geomag, Kyoto) during the period of 1998-2010. We also investigate the physical conditions such as density and velocity of protons, IMF Bz and total field strength provided by Advanced Composition Explorer (ACE) satellite. Finally, we classify the geomagnetic storms into two groups depending on whether or not accompanied by SSC and then further classify them based on their association with <span class="hlt">interplanetary</span> shocks. Physical characteristics of the storms in each group will briefly be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19950017408','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19950017408"><span id="translatedtitle">LDEF <span class="hlt">Interplanetary</span> Dust Experiment (IDE) results</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Oliver, John P.; Singer, S. F.; Weinberg, J. L.; Simon, C. G.; Cooke, W. J.; Kassel, P. C.; Kinard, W. H.; Mulholland, J. D.; Wortman, J. J.</p> <p>1995-01-01</p> <p>The <span class="hlt">Interplanetary</span> Dust Experiment (IDE) provided high time resolution detection of microparticle impacts on the Long Duration Exposure Facility satellite. Particles, in the diameter range from 0.2 microns to several hundred microns, were detected impacting on six orthogonal surfaces of the gravity-gradient stabilized LDEF spacecraft. The total sensitive surface area was about one square meter, distributed between LDEF rows 3 (Wake or West), 6 (South), 9 (Ram or East), 12 (North), as well as the Space and Earth ends of LDEF. The time of each impact is known to an accuracy that corresponds to better than one degree in orbital longitude. Because LDEF was gravity-gradient stabilized and <span class="hlt">magnetically</span> damped, the direction of the normal to each detector panel is precisely known for each impact. The 11 1/2 month tape-recorded data set represents the most extensive record gathered of the number, orbital location, and incidence direction for microparticle impacts in low Earth orbit. Perhaps the most striking result from IDE was the discovery that microparticle impacts, especially on the Ram, South, and North surfaces, were highly episodic. Most such impacts occurred in localized regions of the orbit for dozens or even hundreds of orbits in what we have termed Multiple Orbit Event Sequences (MOES). In addition, more than a dozen intense and short-lived 'spikes' were seen in which impact fluxes exceeded the background by several orders of magnitude. These events were distributed in a highly non-uniform fashion in time and terrestrial longitude and latitude.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUSM..GP31C04F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUSM..GP31C04F"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Electric Field Control of Field-Aligned Currents: Polar Magnetometer Observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fleishman, M.; Russell, C. T.</p> <p>2001-05-01</p> <p>ACE and Wind measurements of the solar wind velocity and <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field have been used to calculate the <span class="hlt">interplanetary</span> electric field during passages of the Polar spacecraft above the southern auroral oval. Periods of the quasi-steady <span class="hlt">interplanetary</span> electric field have been identified when the Polar spacecraft was transiting the auroral and polar regions both just in front of the terminator above the lit ionosphere and just behind the terminator above the dark ionosphere. The east-west <span class="hlt">magnetic</span> perturbation observed was then used as a measure of the local field-aligned current density and extrapolated to a common altitude. Independent of whether the <span class="hlt">interplanetary</span> electric field (IEF) is from dawn to dusk or dusk to dawn a significant field-aligned current always exists. The magnitude of its perturbation field for dusk to dawn IEF is about 180 nT. For dawn to dusk IEF the <span class="hlt">magnetic</span> perturbation is roughly proportional to the dawn-dusk component of the IEF. The strength of the field-aligned current does not depend on whether the ionosphere under the spacecraft is in sunlight or in darkness.</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://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=20110013494&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=20110013494&hterms=Butterfly&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%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</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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ApJ...828L...7F&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2016ApJ...828L...7F&link_type=ABSTRACT"><span id="translatedtitle">Separating Nightside <span class="hlt">Interplanetary</span> and Ionospheric Scintillation with LOFAR</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Fallows, R. A.; Bisi, M. M.; Forte, B.; Ulich, Th.; Konovalenko, A. A.; Mann, G.; Vocks, C.</p> <p>2016-09-01</p> <p>Observation of <span class="hlt">interplanetary</span> scintillation (IPS) beyond Earth-orbit can be challenging due to the necessity to use low radio frequencies at which scintillation due to the ionosphere could confuse the <span class="hlt">interplanetary</span> contribution. A recent paper by Kaplan et al. presenting observations using the Murchison Widefield Array (MWA) reports evidence of nightside IPS on two radio sources within their field of view. However, the low time cadence of 2 s used might be expected to <span class="hlt">average</span> out the IPS signal, resulting in the reasonable assumption that the scintillation is more likely to be ionospheric in origin. To check this assumption, this Letter uses observations of IPS taken at a high time cadence using the Low Frequency Array (LOFAR). <span class="hlt">Averaging</span> these to the same as the MWA observations, we demonstrate that the MWA result is consistent with IPS, although some contribution from the ionosphere cannot be ruled out. These LOFAR observations represent the first of nightside IPS using LOFAR, with solar wind speeds consistent with a slow solar wind stream in one observation and a coronal mass ejection expected to be observed in another.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950056921&hterms=gsm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dgsm','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950056921&hterms=gsm&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dgsm"><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://adsabs.harvard.edu/abs/2016EGUGA..18.3009G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016EGUGA..18.3009G"><span id="translatedtitle">Waves associated with <span class="hlt">interplanetary</span> shocks: Types and properties</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Goncharov, Oleksandr; Nemecek, Zdenek; Safrankova, Jana; Prech, Lubomir; Koval, Andriy; Wilson, Lynn B., III; Zastenker, Georgy N.</p> <p>2016-04-01</p> <p><span class="hlt">Interplanetary</span> (IP) shocks are often associated with high-frequency (several Hz) wave packets in both upstream and downstream regions. These waves could be resolved in Wind fast <span class="hlt">magnetic</span> field data but the time resolution of plasma instruments is insufficient for their detection. The BMSW instrument onboard the Spektr-R spacecraft measures solar wind parameters with a resolution of 32 ms and it allows a detailed analysis of these waves. Our previous analysis of subcritical low-Mach-number fast forward shocks has shown that the both upstream and downstream waves conserve over the spacecraft separation of the order of 200 Re and their wavelengths are directly proportional to the shock ramp thickness that is controlled by the ion thermal gyroradius. Comparing observations of both Wind and Spektr-R spacecraft, we discuss a nature of these waves in both regions and their properties and their dependence on upstream solar wind and <span class="hlt">magnetic</span> field parameters.</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://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://adsabs.harvard.edu/abs/2015JGRA..120.4669L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.4669L"><span id="translatedtitle">Energetic electron response to <span class="hlt">interplanetary</span> shocks at geosynchronous orbit</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Liu, Y.; Zong, Q.-G.</p> <p>2015-06-01</p> <p><span class="hlt">Interplanetary</span> (IP) shocks have great impacts on Earth's magnetosphere, especially in causing global dynamic changes of energetic particles. In order to study the response of energetic electrons (50keV-1.5MeV) at geosynchronous orbit to IP shocks, we have systematically analyzed 215 IP shock events based on ACE, GOES, and LANL observations during 1998-2007. Our study shows that after the shock arrival low-energy electron fluxes increase at geosynchronous orbit. However, in higher energy channels fluxes show smaller increases and eventually become unchanged or even decrease. The oscillations of electron fluxes following the shock arrival have also been studied in this paper. Statistical analysis revealed a frequency preference for 2.2 mHz and 3.3 mHz oscillations of energetic electron fluxes. The amplitude of these oscillations is larger under southward <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) than under northward IMF. Furthermore, oscillations from high-energy and low-energy electron fluxes show different phase characteristics and power distributions. The phase angles of the oscillations are the same in the dawn, dusk, and noon sectors for low-energy channels (50-500keV), while they have a π/2 difference between two adjacent local time sectors for high-energy channels (0.5-1.5MeV). The wave power distribution of electron fluxes shows different dawn-dusk asymmetries for low-energy channels and high-energy channels. The results presented in this paper provide an energetic particle point of view of the magnetospheric response to the <span class="hlt">interplanetary</span> shock impact.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000011205&hterms=against+thought+unique&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dagainst%2Bthought%2Bunique','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000011205&hterms=against+thought+unique&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dagainst%2Bthought%2Bunique"><span id="translatedtitle">"Driverless" Shocks 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, N.; Kaiser, M. L.; Lara, A.</p> <p>1999-01-01</p> <p>Many <span class="hlt">interplanetary</span> shocks have been detected without an obvious driver behind them. These shocks have been thought to be either blast waves from solar flares or shocks due to sudden increase in solar wind speed caused by interactions between large scale open and closed field lines of the Sun. We investigated this problem using a set of <span class="hlt">interplanetary</span> shock detected {\\it in situ} by the Wind space craft and tracing their solar origins using low frequency radio data obtained by the Wind/WAVES experiment. For each of these "driverless shocks" we could find a unique coronal mass ejections (CME) event observed by the SOHO (Solar and Heliospheric Observatory) coronagraphs. We also found that these CMEs were ejected at large angles from the Sun-Earth line. It appears that the "driverless shocks" are actually driver shocks, but the drivers were not intercepted by the spacecraft. We conclude that the <span class="hlt">interplanetary</span> shocks are much more extended than the driving CMEs.</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> </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://adsabs.harvard.edu/abs/2010cosp...38.1850P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010cosp...38.1850P"><span id="translatedtitle">About Shape of an <span class="hlt">Interplanetary</span> Shock Front.</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Petukhov, Ivan; Petukhov, Stanislav</p> <p></p> <p>The form of an <span class="hlt">interplanetary</span> shock front has been investigated by the statistical method. Results of determination the components of normals to the <span class="hlt">interplanetary</span> shock fronts obtained from data of ACE experiment during from 1998 to 2003 years (about 200 measurements) are used. North-south asymmetry of shock amount about 15% is revealed. Possibly, it is caused by more activity of the north semi-sphere of the Sun. East-west asymmetry of shock area are obtained. At probability 95% values of asymmetry more 0.53 and less 0.65 at most probability 0.59. Here asymmetry is ratio west part of area to whole area of shock front. Possibly, it is formed at propagation of a shock in <span class="hlt">interplanetary</span> space. The reason of asymmetry may be self-generation turbulence by the accelerated particles which influences on velocity of shock propagation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007AGUFMSH33A1089M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007AGUFMSH33A1089M"><span id="translatedtitle">Helium at <span class="hlt">Interplanetary</span> Discontinuities: ACE STEREO Observations and Simulations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Moebius, E.; Kucharek, H.; Allegrini, F.; Desai, M.; Klecker, B.; Popecki, M.; Farrugia, C.; Galvin, A.; Bochsler, P.; Karrer, R.; Opitz, A.; Simunac, K.</p> <p>2007-12-01</p> <p>ACE/SEPICA observations showed that, on <span class="hlt">average</span>, energetic He+ is after H+ and He2+ the third most abundant energetic particle species in the heliosphere. Depending on the type of the energetic population the He+/He2+ ratio can reach unusually high values in the energy range 250 - 800keV/n ratios up to unity. As a major source of energetic He+ <span class="hlt">interplanetary</span> pickup ions have been identified that are preferentially accelerated at co-rotating interaction regions (CIRs), transient interaction regions (TIRs), and <span class="hlt">interplanetary</span> traveling shocks. Most recent data from STEREO/PLASTIC in the energy range of 0.2-80keV/Q show clear evidence of abundant He+ at <span class="hlt">interplanetary</span> discontinuities. Thus PLASTIC extends the energy range into injection region of the source. Furthermore, ACE/ULEIS and ACE/SEPICA measurements showed that very often 3He2+ and He+ are also accelerated simultaneously at CME-driven IP shocks. This is surprising because, these to species originate from different sources. However, this may indicate that the injection, or the acceleration efficiency of the accelerator for different source population may be similar. From observations, however, this cannot be differentiated easily. In numerical simulations this can be done because there is control over species and distribution functions. In a numerical study we applied test particle simulations and multi-dimensional hybrid simulations to address the contribution of source, injection and acceleration efficiency at shocks to the variability of the helium ratio. These, simulations with and without superimposed turbulence in the shock region will be compared with observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002APS..APRN17049C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002APS..APRN17049C"><span id="translatedtitle">The <span class="hlt">Interplanetary</span> GRB Network in 2002</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. L.; Barthelmy, S. D.; Hurley, K. C.; Anfimov, D.; Mitrofanov, I.; Golenetskii, S.; Mazets, E.; Crew, G.; Ricker, G.; Frontera, F.; Montanari, E.; Guidorzi, C.; Feroci, M.</p> <p>2002-04-01</p> <p>The <span class="hlt">Interplanetary</span> GRB Network (IPN) has been recently enhanced with the successful addition of the Mars Odyssey mission. This compensates for the loss in 2001 of the asteroid mission NEAR, reconstituting a fully long-baseline <span class="hlt">interplanetary</span> triangle with Ulysses, also in deep space, and with GGS-Wind, BeppoSAX and HETE-2, near the Earth. The operation of the renewed IPN has been demonstrated with the detection of many SGR and solar events in recent months, and with an appropriate detection rate of GRBs. The observations to date and the afterglow detections that the IPN has enabled will be outlined, and the future performance will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20150008672&hterms=celestial+navigation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcelestial%2Bnavigation','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20150008672&hterms=celestial+navigation&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dcelestial%2Bnavigation"><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://adsabs.harvard.edu/abs/2008SpWea...6.1003C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008SpWea...6.1003C"><span id="translatedtitle"><span class="hlt">Interplanetary</span> Space Weather and Its Planetary Connection</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crosby, Norma; Bothmer, Volker; Facius, Rainer; Grießmeier, Jean-Mathias; Moussas, Xenophon; Panasyuk, Mikhail; Romanova, Natalia; Withers, Paul</p> <p>2008-01-01</p> <p><span class="hlt">Interplanetary</span> travel is not just a science fiction scenario anymore, but a goal as realistic as when our ancestors started to cross the oceans. With curiosity driving humans to visit other planets in our solar system, the understanding of <span class="hlt">interplanetary</span> space weather is a vital subject today, particularly because the physical conditions faced during a space vehicle's transit to its targeted solar system object are crucial to a mission's success and vital to the health and safety of spacecraft crew, especially when scheduling planned extravehicular activities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840065488&hterms=wave+length&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwave%2Blength','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840065488&hterms=wave+length&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwave%2Blength"><span id="translatedtitle">Scale lengths in quasi-parallel shocks. [<span class="hlt">interplanetary</span> and earth bow waves</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scudder, J. D.; Burlaga, L. F.; Greenstadt, E. W.</p> <p>1984-01-01</p> <p>A review was carried out of ISEE and Voyager spacecraft magnetometer data to determine if quasi-parallel bow shocks are really broad, disordered regions. The key parameter was the deceleration scale (thickness, Lp) across which random energy would need to increase and a localized electrostatic field (E) would be present. Lp would define the breadth of the shock and be associated with a plasma deceleration. The ISEE 1 satellite collected data on the electron density, bulk speed, <span class="hlt">magnetic</span> intensity, and electron temperature in November 1977 during five traverses of the bow shock. Similar data were gathered from an <span class="hlt">interplanetary</span> shock wave in 1981. The evidence supported the concept of a plasma deceleration across a thin layer (Lp) in both types of shocks. The layers were about 50 times (<span class="hlt">interplanetary</span>) and 20 times (earth) thinner than surrounding <span class="hlt">magnetic</span> fluctuation regions. It is asserted that the regions of deceleration, although much thinner, are the actual shocks and not the entire regions of <span class="hlt">magnetic</span> fluctuations.</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/1995sowi.confR..45S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995sowi.confR..45S"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</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=19960021319&hterms=plasma+expansion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dplasma%2Bexpansion','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021319&hterms=plasma+expansion&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dplasma%2Bexpansion"><span id="translatedtitle">Interaction of an <span class="hlt">interplanetary</span> shock with the heliospheric plasma sheet</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Odstrcil, D.; Dryer, M.; Smith, Z.</p> <p>1995-01-01</p> <p><span class="hlt">Interplanetary</span> shocks often propagate along the heliospheric plasma sheet (HPS) where the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) changes its polarity. This problem is investigated by the time-dependent 2.5-D MHD numerical model in the meridional plane. An example of computation is shown in the figure using density (log) contours and IMF vectors. Values of plasma parameters along the HPS fluctuate in time due to the Kelvin-Helmholtz instability. The HPS with its decreased intensity of the IMF as well as with its increased mass density causes a dimple in the shock structure (relatively weak for the forward shock, significant for the reverse shock, and very large for the contact discontinuity). Beyond the forward shock, the HPS is slightly compressed due to the post-shock increase of the azimuthal IMF component. Then follows expansion of the HPS surrounded by the highly-deformed contact discontinuity. A significant draping of IMF lines occurs around this structure that increases the meridional component of the IMF. This can cause a favorable condition for initiation of a geomagnetic storm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021311&hterms=magnetic+bottle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmagnetic%2Bbottle','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021311&hterms=magnetic+bottle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmagnetic%2Bbottle"><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/1995sowi.conf...47O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995sowi.conf...47O"><span id="translatedtitle">Interaction of an <span class="hlt">interplanetary</span> shock with the heliospheric plasma sheet</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Odstrcil, D.; Dryer, M.; Smith, Z.</p> <p>1995-06-01</p> <p><span class="hlt">Interplanetary</span> shocks often propagate along the heliospheric plasma sheet (HPS) where the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field (IMF) changes its polarity. This problem is investigated by the time-dependent 2.5-D MHD numerical model in the meridional plane. An example of computation is shown in the figure using density (log) contours and IMF vectors. Values of plasma parameters along the HPS fluctuate in time due to the Kelvin-Helmholtz instability. The HPS with its decreased intensity of the IMF as well as with its increased mass density causes a dimple in the shock structure (relatively weak for the forward shock, significant for the reverse shock, and very large for the contact discontinuity). Beyond the forward shock, the HPS is slightly compressed due to the post-shock increase of the azimuthal IMF component. Then follows expansion of the HPS surrounded by the highly-deformed contact discontinuity. A significant draping of IMF lines occurs around this structure that increases the meridional component of the IMF. This can cause a favorable condition for initiation of a geomagnetic storm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AGUFMSH53A2473B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSH53A2473B"><span id="translatedtitle">Multispacecraft study of <span class="hlt">interplanetary</span> shocks 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>Blanco-Cano, X.; Kajdic, P.; Russell, C. T.; Aguilar-Rodriguez, E.; Jian, L.; Luhmann, J. G.</p> <p>2015-12-01</p> <p><span class="hlt">Interplanetary</span> (IP) shocks propagate through the heliosphere perturbing the solar wind plasma. They can be driven by <span class="hlt">Interplanetary</span> Coronal Mass Ejections (ICMEs) and Stream Interaction Regions (SIRs). They play an active role in the acceleration of ions to suprathermal energies. Shock fronts evolve as they move from the Sun. Their surfaces can be far from uniform and be modulated by changes in the solar wind (<span class="hlt">magnetic</span> field orientation, flow velocity), and perturbations upstream and downstream from the shocks, i.e., electromagnetic waves. In this work we use multispacecraft data (STEREO, WIND, ACE) to study shock characteristics at different helio-longitudes and determine the properties of the waves near them. We also determine shock longitudinal extensions and foreshock sizes. The variations of geometry along the shock surface can result in different extensions of the wave and ion foreshocks ahead of the shocks, and in different wave modes upstream and downtream of the shocks. Thus, the region with modified solar wind ahead of the shocks can be very asymmetric.</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=19960021296&hterms=SEPS&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DSEPS','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021296&hterms=SEPS&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DSEPS"><span id="translatedtitle">Local and global scattering properties of the <span class="hlt">interplanetary</span> medium obtained from Solar Energetic Particles (SEPs)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wibberenz, G.; Hatzky, R.; Bieber, J. W.</p> <p>1995-01-01</p> <p>Solar energetic particles can be used as probes for the turbulence level in the <span class="hlt">interplanetary</span> medium. It is of general interest to compare the LOCAL scattering properties near an observer with GLOBAL properties which characterize the <span class="hlt">average</span> scattering along the <span class="hlt">magnetic</span> field. We discuss various methods by which the scattering conditions can be determined: (1) overall fits of observed particle intensities and anisotropies to a transport model; (2) evaluation of the steady-state pitch angle distribution; and (3) suitably normalized angular distributions during the intensity maximum of a particle event. Energetic particle data from HELIOS 1/2 are analyzed, and the mean free paths obtained with the different methods are compared with each other. As a result one can state: (1) for a number of solar particle events the radial mean free path is essentially constant between the Sun and Helios; and (2) large variations in the degree of scattering exist from one event to the other. These results indicate the existence of 'regimes' where the amount of particle scattering is relatively constant over extended regions in radius and azimuth, but with marked differences from one regime to the other.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920032089&hterms=ide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dide','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920032089&hterms=ide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dide"><span id="translatedtitle">LDEF <span class="hlt">Interplanetary</span> Dust Experiment - Techniques for identification and study of long-lived orbital debris clouds</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Singer, S. F.; Oliver, J. P.; Weinberg, J. L.; Cooke, W. J.; Montague, N. L.; Mulholland, J. D.; Wortman, J. J.; Kassel, P. C.; Kinard, W. H.</p> <p>1991-01-01</p> <p>The Long Duration Exposure Facility (LDEF) is a 12-sided, 4.3-m-diameter, 9.1-m-long cylinder designed and built by NASA Langley to carry experiments for extended periods in space. The LDEF was first placed in orbit by the Shuttle Challenger on 7 April 1984 and recovered by the Shuttle Columbia in January 1990, only days before it was expected to burn up in the earth's atmosphere. The <span class="hlt">Interplanetary</span> Dust Experiment (IDE) was designed to detect impacts of extra-terrestrial particles and orbital debris. The IDE detectors (which covered about 1 sq m of the surface of LDEF) were sensitive to particles ranging in size from about 0.2 to 100 microns. Data were recorded for 11.5 months before the supply of <span class="hlt">magnetic</span> tape was exhausted. Examination of the LDEF IDE dataset shows that impacts often occurred in 'bursts', during which numerous impacts occurred in a short time (typically 3-5 min) at a rate much greater than the <span class="hlt">average</span> impact rate. In several cases, such events reoccurred each time the LDEF returned to the same point in its orbit. Such multi-orbit event sequences were found to extend for as many as 25 or more orbits.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.4112K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.4112K"><span id="translatedtitle">Properties and drivers of fast <span class="hlt">interplanetary</span> shocks near the orbit of the Earth (1995-2013)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kilpua, E. K. J.; Lumme, E.; Andreeova, K.; Isavnin, A.; Koskinen, H. E. J.</p> <p>2015-06-01</p> <p>We present a comprehensive statistical analysis spanning over a solar cycle of the properties and drivers of traveling fast forward and fast reverse <span class="hlt">interplanetary</span> shocks. We combine statistics of 679 shocks between 1995 and 2013 identified from the near-Earth (Wind and ACE) and STEREO-A observations. We find that fast forward shocks dominate over fast reverse shocks in all solar cycle phases except during solar minimum. Nearly all fast reverse shocks are driven by slow-fast stream interaction regions (SIRs), while coronal mass ejections (CMEs) are the principal drivers of fast forward shocks in all phases except at solar minimum. The occurrence rate and median speeds of CME-driven fast forward shocks follow the sunspot cycle, while SIR-associated shocks do not show such correspondence. The strength of the shock (characterized by the magnetosonic Mach number and by the upstream to downstream <span class="hlt">magnetic</span> field and density ratio) shows relatively little variations over solar cycle. However, the shocks were slightly stronger during the ascending phase of a relatively weak solar cycle 24 than during the previous ascending phase. The CME- and SIR-driven fast forward shocks and fast reverse shocks have distinct upstream solar wind conditions, which reflect to their relative strengths. We found that CME-driven shocks are on <span class="hlt">average</span> stronger and faster, and they show broader distributions of shock parameters than the shocks driven by SIRs.</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/cgi-bin/nph-data_query?bibcode=2012LPICo1679.4146W&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2012LPICo1679.4146W&link_type=ABSTRACT"><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://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://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> </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://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1981P%26SS...29..635C&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1981P%26SS...29..635C&link_type=ABSTRACT"><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://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cloutier, P. A.; Tascione, T. F.; Daniell, R. E.</p> <p>1981-06-01</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://ntrs.nasa.gov/search.jsp?R=19740038948&hterms=magnetic+bottle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmagnetic%2Bbottle','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740038948&hterms=magnetic+bottle&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dmagnetic%2Bbottle"><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> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMSH51A2436T&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AGUFMSH51A2436T&link_type=ABSTRACT"><span id="translatedtitle">Characterizing <span class="hlt">Interplanetary</span> Structures of Long-Lasting Ionospheric Storm Events</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tandoi, C.; Dong, Y.; Ngwira, C. M.; Damas, M. C.</p> <p>2015-12-01</p> <p>Geomagnetic storms can result in periods of heightened TEC (Total Electron Content) in Earth's ionosphere. These periods of change in TEC (dTEC) can have adverse impacts on a technological society, such as scintillation of radio signals used by communication and navigation satellites. However, it is unknown which exact properties of a given storm cause dTEC. We are comparing different solar wind properties that result in a significant long-lasting dTEC to see if there are any patterns that remain constant in these storms. These properties, among others, include the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field By and Bz components, the proton density, and the flow speed. As a preliminary investigation, we have studied 15 solar storms. Preliminary results will be presented. In the future, we hope to increase our sample size and analyze over 80 different solar storms, which result in significant dTEC.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/11543201','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/11543201"><span id="translatedtitle">Radiation shielding of spacecraft in manned <span class="hlt">interplanetary</span> flights.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Spillantini, P; Taccetti, F; Papini, P; Rossi, L</p> <p>2000-04-01</p> <p>During the <span class="hlt">interplanetary</span> flights the crewmembers will be exposed to cosmic ray radiation with great risk for their health. The absorbed dose due to CR depends on the galactic (GCR) or solar (SCR) origin. GCRs are isotropic and relatively high in energy and deliver a dose nearly constant with time that can be reduced only by means of "heavy" passive protection. The outer walls of the spacecraft usually shield the SCRs up to a few tens of MeV, but during some exceptional solar bursts, a great number of particles, mainly protons, are ejected at higher energies. In this case the dose delivered in a few hours by a solar burst can easily exceed 1 year cumulated dose by GCRS. The high-energy component of SCRs is quasi-directional so that a shielding system based on a superconductive <span class="hlt">magnetic</span> lens can reduce the daily dose of SCRs to the level delivered by GCRS. PMID:11543201</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20070026139&hterms=environmental+assessment&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Denvironmental%2Bassessment','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070026139&hterms=environmental+assessment&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Denvironmental%2Bassessment"><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://adsabs.harvard.edu/abs/2015AGUFMSH21A2387K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AGUFMSH21A2387K"><span id="translatedtitle">Anomalous Ion Charge State Behavior In <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>Kocher, M.; Lepri, S. T.; Landi, E.; Zhao, L.</p> <p>2015-12-01</p> <p>A recent analysis of solar wind charge state composition measurements from the ACE/SWICS instrument showed that the expected correlation between the frozen-in values of the O7/O6 and C6/C5 ratios was violated in ~5% of the slow solar wind in the 1998-2011 period (Zhao et al. 2015). In this work we determine that such anomalous behavior is also found in over 40% of <span class="hlt">Interplanetary</span> Coronal Mass Ejections (ICMEs), as identified by Richardson and Cane (2010). An analysis of the plasma composition during these events reveals significant depletions in densities of fully stripped ions of Carbon, Oxygen, and Nitrogen. We argue that these events are indicators of ICME plasma acceleration via <span class="hlt">magnetic</span> reconnection near the freeze-in region of Carbon and Oxygen above the solar corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004AGUFMSH31A1147N','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004AGUFMSH31A1147N"><span id="translatedtitle">Latitudinal dependence of solar proton flux derived from <span class="hlt">interplanetary</span> Lyman alpha emission</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Nakagawa, H.; Fukunishi, H.; Watanabe, S.; Takahashi, Y.; Taguchi, M.; Bertaux, J.; Quemerais, E.; Lallement, R.</p> <p>2004-12-01</p> <p>There is a uniform flow of the <span class="hlt">interplanetary</span> hydrogen in the solar system. The distribution of <span class="hlt">interplanetary</span> neutral hydrogen is sensitive to solar wind proton flux, which has a latitudinal distribution, because <span class="hlt">interplanetary</span> neutral hydrogen atoms are mainly ionized through a process of charge-exchange with solar wind protons (contributing to 80% of the total ionization rate). Rucinski et al. [1996] estimated the ionization rate of the <span class="hlt">interplanetary</span> hydrogen in an <span class="hlt">average</span> solar activity condition: 6.4±0.14 [10E-7/s] for charge exchange with protons. The most practical technique for determining the latitudinal dependence of the <span class="hlt">interplanetary</span> hydrogen is observation of resonant backscatter of solar Lyman ƒ¿ emission at 121.6 nm. The <span class="hlt">interplanetary</span> Lyman ƒ¿ emission has been measured by the ultraviolet imaging spectrometer (UVS) on board the Nozomi spacecraft crusing on its Mars transfer orbit with a periapsis of 1 AU and an apoapsis 1.5 AU from the Sun. The field-of-view of UVS is perpendicular to the spin axis of the spacecraft, which is controlled toward the Earth. The spatial resolution of UVS is 1.41 degrees in a plane perpendicular to the spin axis and 0.29 degrees in a plane including the spin axis. Spatial distributions are obtained from the full sky scanning of UVS with spin and orbital motions of the Nozomi spacecraft. One-year UVS data enable us to construct a full sky image of Lyman ƒ¿ emission. We present the results obtained from Nozomi/UVS data analysis for the period of 1999-2002. From a fitting of model calculations to the observed data, it is confirmed that a latitudinal anisotropy with the higher ionization region at the equator is reduced toward solar maximum. Finally, higher ionization region are found at the poles than at the equator near solar maximum. Basically, this change is produced by variations in the latitudinal dependence of persistent solar wind proton flux. However, proton flux from transient CMEs also affects the</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://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://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://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://ntrs.nasa.gov/search.jsp?R=19930022495&hterms=phenomena+wave&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dphenomena%2Bwave','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930022495&hterms=phenomena+wave&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dphenomena%2Bwave"><span id="translatedtitle">Plasma wave phenomena observed at <span class="hlt">interplanetary</span> shocks by the Ulysses URAP experiment</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lengyel-Frey, D.; Macdowall, R. J.; Stone, R. G.; Hoang, S.; Pantellini, F.; Canu, P.; Cornilleau-Wehrlin, N.; Balogh, A.; Forsyth, R.</p> <p>1992-01-01</p> <p>Results of a study of 24 <span class="hlt">interplanetary</span> shocks observed by the Unified Radio and Plasma Wave Experiment (URAP) on the Ulysses spacecraft are presented. These shocks, observed between approximately 1 and 4 AU, display a variety of wave phenomena similar to those detected in earlier studies of shocks near 1 AU. The correspondence of the observed low frequency <span class="hlt">magnetic</span> and electric field waves with the parallel index of refraction for whistler waves was investigated. Observed B/E ratios are found to be typically about a factor of 0.7 times the computed index of refraction, supporting the whistler interpretation of these waves, but also implying a prevalent electrostatic wave component which may be due to whistlers propagating at an angle to the <span class="hlt">interplanetary</span> <span class="hlt">magnetic</span> field. A statistical correlation of the amplitudes of the various types of waves with shock and solar wind properties is presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19760043979&hterms=phenomena+wave&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dphenomena%2Bwave','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760043979&hterms=phenomena+wave&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dphenomena%2Bwave"><span id="translatedtitle">Analysis of the 31 Oct 1972 <span class="hlt">interplanetary</span> shock wave and associated unusual phenomena</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ipavich, F. M.; Lepping, R. P.</p> <p>1975-01-01</p> <p>We analyze in detail the disturbed time period Oct. 31-Nov. 1, 1972 using <span class="hlt">magnetic</span> field, plasma, and energetic particle data as well as <span class="hlt">magnetic</span> field data. In particular, we discuss an <span class="hlt">interplanetary</span> forward shock wave accompanied by a traditional shock-spike event in the energetic particles, a large tangential discontinuity correlated with a geomagnetic storm main phase, and a reverse <span class="hlt">interplanetary</span> shock. This forward and reverse shock pair was caused by a 2N solar flare which occurred some 47 hours earlier. We also discuss an unusual rarefaction in the solar wind following (and probably related to) the shock pair, wherein the Alfven Mach number abruptly decreased from about 4.5 to about 1.5, allowing the earth's bow shock to move outward at least 20 earth radii beyond its nominal position.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930055986&hterms=Media+transport&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DMedia%2Btransport','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930055986&hterms=Media+transport&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DMedia%2Btransport"><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://adsabs.harvard.edu/abs/1984isap.book...81V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1984isap.book...81V"><span id="translatedtitle">Some results of investigations conducted in the <span class="hlt">interplanetary</span> medium using the wide-angle plasma detectors on the Prognoz-6 spacecraft</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Verigin, M. I.</p> <p></p> <p>Measurements of the ion and electron components of plasma in the <span class="hlt">magnetic</span> field and energetic particle fluxes in <span class="hlt">interplanetary</span> space were obtained using a wide-angle plasma detector. The effect of two solar-flare events in November 1977 and January 1978 on the energetic characteristics of <span class="hlt">interplanetary</span> space was analyzed on the basis of the plasma measurements. It is found that protons can be accelerated to energies of several MeV in oblique shock waves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AN....336..749B&link_type=ABSTRACT','NASAADS'); return false;" href="http://adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2015AN....336..749B&link_type=ABSTRACT"><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/2060/20040171195','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</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19780032247&hterms=Bispectral+Index&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DBispectral%2BIndex','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19780032247&hterms=Bispectral+Index&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DBispectral%2BIndex"><span id="translatedtitle">Bispectral analysis of meter wavelength <span class="hlt">interplanetary</span> scintillation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Armstrong, J. W.</p> <p>1977-01-01</p> <p>The bispectrum of <span class="hlt">interplanetary</span> scintillation is investigated. Rice-squared and lognormal point-source intensity probability density functions are used to derive model bispectra as functionals of the intensity autocovariance. Simultaneous observations of the source CTA 21 at 270, 340, and 470 MHz are analyzed to produce scintillation indices, skewness parameters, and bispectra, which are compared with the models for the cases of weak, intermediate, and strong scattering. The results obtained for CTA 21 are shown to rule out lognormal statistics for <span class="hlt">interplanetary</span> scintillation over the frequency range from 340 to 470 MHz. It is found that the observed bispectra correspond well with the predictions of the Rice-squared model for weak and intermediate scattering, but are systematically different from model bispectra computed by assuming a point source in the case of strong scattering.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1989Metic..24...43R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1989Metic..24...43R"><span id="translatedtitle">Tin in a chondritic <span class="hlt">interplanetary</span> dust particle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rietmeijer, F. J. M.</p> <p>1989-03-01</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_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. Their policies may differ from this site.</small> </div> </center> <div id="footer-wrapper"> <div class="footer-content"> <div id="footerOSTI" class=""> <div class="row"> <div class="col-md-4 text-center col-md-push-4 footer-content-center"><small><a href="http://www.science.gov/disclaimer.html">Privacy and Security</a></small> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center col-md-pull-4 footer-content-left"> <img src="http://www.osti.gov/images/DOE_SC31.png" alt="U.S. Department of Energy" usemap="#doe" height="31" width="177"><map style="display:none;" name="doe" id="doe"><area shape="rect" coords="1,3,107,30" href="http://www.energy.gov" alt="U.S. Deparment of Energy"><area shape="rect" coords="114,3,165,30" href="http://www.science.energy.gov" alt="Office of Science"></map> <a ref="http://www.osti.gov" style="margin-left: 15px;"><img src="http://www.osti.gov/images/footerimages/ostigov53.png" alt="Office of Scientific and Technical Information" height="31" width="53"></a> <div class="visible-sm visible-xs push_footer"></div> </div> <div class="col-md-4 text-center footer-content-right"> <a href="http://www.osti.gov/nle"><img src="http://www.osti.gov/images/footerimages/NLElogo31.png" alt="National Library of Energy" height="31" width="79"></a> <a href="http://www.science.gov"><img src="http://www.osti.gov/images/footerimages/scigov77.png" alt="science.gov" height="31" width="98"></a> <a href="http://worldwidescience.org"><img src="http://www.osti.gov/images/footerimages/wws82.png" alt="WorldWideScience.org" height="31" width="90"></a> </div> </div> </div> </div> </div> <p><br></p> </div><!-- container --> </body> </html>