Science.gov

Sample records for latitude-dependent solar wind

  1. Latitude dependence of solar wind velocity observed > or approx. =1 AU

    SciTech Connect

    Mitchell, D.G.; Roelof, E.C.; Wolfe, J.H.

    1981-01-01

    The large-scale solar wind velocity structure in the outer heliosphere has been systematically analyzed for Carrington rotations 1587-1541 (March 1972 to April 1976). Spacecraft data were taken from Imp 7/8 at earth, Pioneer 6, 8, and 9 near 1AU, and Pioneer 10 and 11 between 1.6 and 5 AU. Using the constant radial velocity solar wind approximation to map all of the velocity data to its high coronal emission heliolongitude, we examined the velocity structure observed at different spacecraft for latitudinal dependence and compared it with coronal structure in soft X rays and Ha absorption features. The constant radial velocity approximation usually remains self-consistent in decreasing or constant velocity solar wind out to 5 AU, enabling us to separate radial from latitudinal propagation effects. We found several examples of sharp nonmeridional stream boundaries in interplanetary space (approx.5/sup 0/ latitude in width), often directly associated with features in coronal X rays and Ha. In one structure there is evidence for significant (up to 40/sup 0/) nonradial flow of the plasma in the corona below the altitude of transition to super-Alfvenic flow.

  2. Latitude dependence of solar wind velocity observed at not less than 1 AU

    NASA Technical Reports Server (NTRS)

    Mitchell, D. G.; Roelof, E. C.; Wolfe, J. H.

    1981-01-01

    The large-scale solar wind velocity structure in the outer heliosphere has been systematically analyzed for Carrington rotations 1587-1541 (March 1972 to April 1976). Spacecraft data were taken from Imp 7/8 at earth, Pioneer 6, 8, and 9 near 1 AU, and Pioneer 10 and 11 between 1.6 and 5 AU. Using the constant radial velocity solar wind approximation to map all of the velocity data to its high coronal emission heliolongitude, the velocity structure observed at different spacecraft was examined for latitudinal dependence and compared with coronal structure in soft X-rays and H-alpha absorption features. The constant radial velocity approximation usually remains self-consistent in decreasing or constant velocity solar wind out to 5 AU, enabling us to separate radial from latitudinal propagation effects. Several examples of sharp nonmeridional stream boundaries in interplanetary space (about 5 deg latitude in width), often directly associated with features in coronal X-rays and H-alpha were found.

  3. Depth and latitude dependence of the solar internal angular velocity

    NASA Technical Reports Server (NTRS)

    Rhodes, Edward J., Jr.; Cacciani, Alessandro; Korzennik, Sylvain; Tomczyk, Steven; Ulrich, Roger K.; Woodard, Martin F.

    1990-01-01

    One of the design goals for the dedicated helioseismology observing state located at Mount Wilson Observatory was the measurement of the internal solar rotation using solar p-mode oscillations. In this paper, the first p-mode splittings obtained from Mount Wilson are reported and compared with those from several previously published studies. It is demonstrated that the present splittings agree quite well with composite frequency splittings obtained from the comparisons. The splittings suggest that the angular velocity in the solar equatorial plane is a function of depth below the photosphere. The latitudinal differential rotation pattern visible at the surface appears to persist at least throughout the solar convection zone.

  4. Depth and latitude dependence of the solar internal angular velocity

    SciTech Connect

    Rhodes, E.J. Jr.; Cacciani, A.; Korzennik, S.; Tomczyk, S.; Ulrich, R.K.; Woodard, M.F. JPL, Pasadena, CA Roma I Universita California Univ., Los Angeles )

    1990-03-01

    One of the design goals for the dedicated helioseismology observing state located at Mount Wilson Observatory was the measurement of the internal solar rotation using solar p-mode oscillations. In this paper, the first p-mode splittings obtained from Mount Wilson are reported and compared with those from several previously published studies. It is demonstrated that the present splittings agree quite well with composite frequency splittings obtained from the comparisons. The splittings suggest that the angular velocity in the solar equatorial plane is a function of depth below the photosphere. The latitudinal differential rotation pattern visible at the surface appears to persist at least throughout the solar convection zone. 43 refs.

  5. Time trends and latitude dependence of uveal and cutaneous malignant melanoma induced by solar radiation

    SciTech Connect

    Moan, J.; Setlow, R.; Cicarma, E.; Porojnicu, A. C.; Grant, W. B.; Juzeniene, A.

    2010-01-01

    In order to evaluate the role of solar radiation in uveal melanoma etiology, the time and latitude dependency of the incidence rates of this melanoma type were studied in comparison with those of cutaneous malignant melanoma (CMM). Norway and several other countries with Caucasian populations were included. There is a marked north - south gradient of the incidence rates of CMM in Norway, with three times higher rates in the south than in the north. No such gradient is found for uveal melanoma. Similar findings have been published for CMM in other Caucasian populations, with the exception of Europe as a whole. In most populations the ratios of uveal melanoma incidence rates to those of CMM tend to decrease with increasing CMM rates. This is also true for Europe, in spite of the fact that in this region there is an inverse latitude gradient of CMM, with higher rates in the north than in the south. In Norway the incidence rates of CMM have increased until about 1990 but have been constant, or even decreased (for young people) after that time, indicating constant or decreasing sun exposure. The uveal melanoma rates have been increasing after 1990. In most other populations the incidence rates of CMM have been increasing until recently while those of uveal melanoma have been decreasing. These data generally support the assumption that uveal melanomas are not generated by ultraviolet (UV) radiation and that solar UV, via its role in vitamin D photosynthesis, may have a protective effect.

  6. Latitude dependence of Thermospheric Neutral Winds and Plasma Drifts: Observations and modelling

    NASA Astrophysics Data System (ADS)

    Martinis, C.; Meriwether, J.; Biondi, M.; Niciewjewski, R.; Eccles, V.; Fesen, C.; Mendillo, M.

    2001-05-01

    We report on the coupling between thermospheric winds and ionospheric electrodynamics using the first coordinated set of low latitude groundbased diagnostics in the same longitude sector. All-sky imagers in Arequipa, Perú (16.5° S, 71.5° W, dip latitude = -2.7° ), and in Tucumán, Argentina (26.5° S, 65° W, dip latitude = -14.5° ), are used to track the plasma drift patterns of 630 nm airglow depletions associated with equatorial spread-F (ESF) events. A Fabry-Perot interferometer co-located in Arequipa, and a campaign-mode FPI in Carmen Alto, Chile (23.1° S, 69.4° W, dip latitude = -10.2° ), are used to obtain zonal neutral winds. Results for the solar minimum equinox periods of 1995-1997 suggest that low-latitude zonal neutral winds are slowed down by the presence of the Equatorial Ionization Anomaly (EIA) crests. Yet, plasma drifts obtained from airglow depletions measurements at Arequipa are smaller than results at Tucumán in the post-sunset period. During the post-midnight hours, the opposite pattern occurs. A comparison of the results with predictions by current neutral winds and plasma drifts models is also caried out The results from the observations establish that the neutral-ion dynamical coupling in the F-region involves a mix of influences from flux-tube integrated E and F-region conductivities, neutral wind shears in altitude, and ion drag effects due to the EIA.

  7. Latitude-Dependent Effects in the Stellar Wind of Eta Carinae

    NASA Technical Reports Server (NTRS)

    Smith, Nathan; Davidson, Kris; Gull, Theodore R.; Ishibashi, Kazunori; Hillier, D. John

    2002-01-01

    The Homunculus reflection nebula around eta Carinae provides the rare opportunity to observe the spectrum of a star from more than one direction. In the case of eta Car, the nebula's geometry is known well enough to infer how wind profiles vary with latitude. We present STIS spectra of several positions in the Homunculus, showing directly that eta Car has an aspherical and axisymmetric stellar wind. P Cygni absorption in Balmer lines depends on latitude, with relatively high velocities and strong absorption near the polar axis. Stronger absorption at high latitudes is surprising, and it suggests higher mass flux toward the poles, perhaps resulting from equatorial gravity darkening on a rotating star. Reflected profiles of He I lines are more puzzling, and offer clues to eta Car's wind geometry and ionization structure. During eta Car's high-excitation state in March 2000, the wind had a fast, dense polar wind, with higher ionization at low latitudes. Older STIS data obtained since 1998 reveal that this global stellar-wind geometry changes during eta Car's 5.5 year cycle, and may suggest that this star s spectroscopic events are shell ejections. Whether or not a companion star triggers these outbursts remains ambiguous. The most dramatic changes in the wind occur at low latitudes, while the dense polar wind remains relatively undisturbed during an event. The apparent stability of the polar wind also supports the inferred bipolar geometry. The wind geometry and its variability have critical implications for understanding the 5.5 year cycle and long-term variability, but do not provide a clear alternative to the binary hypothesis for generating eta Car s X-rays.

  8. A Companion as the Cause of Latitude-dependent Effects in the Wind of Eta Carinae

    NASA Astrophysics Data System (ADS)

    Groh, J. H.; Madura, T. I.; Hillier, D. J.; Kruip, C. J. H.; Weigelt, G.

    2012-11-01

    We analyze spatially resolved spectroscopic observations of the Eta Carinae binary system obtained with the Hubble Space Telescope/STIS. Eta Car is enshrouded by the dusty Homunculus nebula, which scatters light emitted by the central binary and provides a unique opportunity to study a massive binary system from different vantage points. We investigate the latitudinal and azimuthal dependence of H? line profiles caused by the presence of a wind-wind collision (WWC) cavity created by the companion star. Using two-dimensional radiative transfer models, we find that the wind cavity can qualitatively explain the observed line profiles around apastron. Regions of the Homunculus which scatter light that propagated through the WWC cavity show weaker or no H? absorption. Regions scattering light that propagated through a significant portion of the primary wind show stronger P Cygni absorption. Our models overestimate the H? absorption formed in the primary wind, which we attribute to photoionization by the companion, not presently included in the models. We can qualitatively explain the latitudinal changes that occur during periastron, shedding light on the nature of Eta Car's spectroscopic events. Our models support the idea that during the brief period of time around periastron when the primary wind flows unimpeded toward the observer, H? absorption occurs in directions toward the central object and Homunculus SE pole, but not toward equatorial regions close to the Weigelt blobs. We suggest that observed latitudinal and azimuthal variations are dominated by the companion star via the WWC cavity, rather than by rapid rotation of the primary star. Based on observations made with HST/STIS.

  9. A COMPANION AS THE CAUSE OF LATITUDE-DEPENDENT EFFECTS IN THE WIND OF ETA CARINAE

    SciTech Connect

    Groh, J. H.; Madura, T. I.; Weigelt, G.; Hillier, D. J.; Kruip, C. J. H.

    2012-11-01

    We analyze spatially resolved spectroscopic observations of the Eta Carinae binary system obtained with the Hubble Space Telescope/STIS. Eta Car is enshrouded by the dusty Homunculus nebula, which scatters light emitted by the central binary and provides a unique opportunity to study a massive binary system from different vantage points. We investigate the latitudinal and azimuthal dependence of H{alpha} line profiles caused by the presence of a wind-wind collision (WWC) cavity created by the companion star. Using two-dimensional radiative transfer models, we find that the wind cavity can qualitatively explain the observed line profiles around apastron. Regions of the Homunculus which scatter light that propagated through the WWC cavity show weaker or no H{alpha} absorption. Regions scattering light that propagated through a significant portion of the primary wind show stronger P Cygni absorption. Our models overestimate the H{alpha} absorption formed in the primary wind, which we attribute to photoionization by the companion, not presently included in the models. We can qualitatively explain the latitudinal changes that occur during periastron, shedding light on the nature of Eta Car's spectroscopic events. Our models support the idea that during the brief period of time around periastron when the primary wind flows unimpeded toward the observer, H{alpha} absorption occurs in directions toward the central object and Homunculus SE pole, but not toward equatorial regions close to the Weigelt blobs. We suggest that observed latitudinal and azimuthal variations are dominated by the companion star via the WWC cavity, rather than by rapid rotation of the primary star.

  10. Mapping the latitude dependence of the primary stellar wind of eta Carinae using the spectrum reflected on the Homunculus nebula

    NASA Astrophysics Data System (ADS)

    Odessey, Rachel

    2016-01-01

    The binary star Eta Carinae underwent a massive eruption in the 1840s, resulting in a huge nebula of ejected material, called the Homunculus. Despite preventing us from the direct view from the central source, the Homunculus acts like a mirror, allowing us to see the spectrum of the central binary system from different stellar latitudes. Therefore, by mapping the spectrum along the nebula we are actually probing the dependence of the spectrum with stellar latitude. Our project focuses on the P Cyg absorption component of H lines mostly in the optical and near-infrared wavelengths. in order to investigate the structure of the primary stellar wind. A full spectral mapping of the entire nebula was constructed by combining multiple dithered long slit observations using the ESO/X-Shooter high-resolution spectrograph. Such mapping allowed us to assemble a data cube containing the spectrum of each position along the nebula. Preliminary analysis confirms that the primary wind indeed has a deeper absorption component at high stellar latitudes (polar region). Also, contrary to our expectations, our analysis indicates that the polar region does not seem entirely radially symmetric in terms of density, which invites further investigation into the source of these discrepancies.

  11. Solar Wind Five

    NASA Technical Reports Server (NTRS)

    Neugebauer, M. (Editor)

    1983-01-01

    Topics of discussion were: solar corona, MHD waves and turbulence, acceleration of the solar wind, stellar coronae and winds, long term variations, energetic particles, plasma distribution functions and waves, spatial dependences, and minor ions.

  12. Solar wind models

    NASA Technical Reports Server (NTRS)

    Leer, Egil; Sandbaek, Ornulf

    1991-01-01

    The understanding of the solar wind is based upon Parker's (1958) description of a thermally driven subsonic - supersonic outflow from a fully ionized electron-proton corona. The basic physical processes of thermally driven solar wind models are discussed. Also studied are the effect of alpha particles in the corona on the solar wind proton flux. The acceleration of the solar wind by Alfven waves is discussed.

  13. Warming: mechanism and latitude dependence

    NASA Astrophysics Data System (ADS)

    Barkin, Yury

    2010-05-01

    Introduction. In the work it is shown, that in present warming of climate of the Earth and in style of its display a fundamental role the mechanism of the forced swing and relative oscillations of eccentric core of the Earth and its mantle plays. Relative displacements of the centers of mass of the core and the mantle are dictated by the features of orbital motions of bodies of solar system and nonineriality of the Earth reference frame (or ot the mantle) at the motion of the Earth with respect to a baricenter of solar system and at rotation of the planet. As a result in relative translational displacements of the core and the mantle the frequencies characteristic for orbital motion of all bodies of solar system, and also their combination are shown. Methods of a space geodesy, gravimetry, geophysics, etc. unequivocally and clearly confirm phenomenon of drift of the center of mass of the Earth in define northern direction. This drift is characterized by the significant velocity in about 5 mm/yr. The unique opportunity of its explanation consists in the natural assumption of existence of the unidirectional relative displacement (drift) the center of mass of the core and the center of mass of the mantle of the Earth. And this displacement (at superfluous mass of the core in 16.7 % from the mass of full the Earth) is characterized still more significant velocity in 2.6 cm/yr and occurs on our geodynamic studies in a direction to Taimyr peninsula. The dynamic explanation to century drift for today does not exist. It is possible to note, however, that data of observations of last years, indirectly testifying that similar drifts of the centers of mass in present epoch occur on other bodies of Solar system have been obtain: the Sun, Mars, the Titan, Enceladus, the Neptune, etc. We connect with mentioned phenomena the observed secular variations of natural processes on this celestial bodies. I.e. it is possible to assume, that observable eccentric positions of the centers of mass of some bodies of solar system and attributes of secular displacements of their centers of mass are universal and testify to relative translational displacements of shells of these bodies (such as the core, the mantle and others). And it means, that there is a highly effective mechanism of an active life of planets and satellites [1, 2]. This mechanism is distinct from the tidal mechanism of gravitational interaction of deformable celestial bodies. Its action is shown, for example, even in case if the core and the mantle are considered as absolutely rigid gravitating bodies, but separated by a is viscous-elastic layer. Classics of celestial mechanics did not consider gravitational interaction and relative translational displacement of the core and the mantle of the Earth. As our studies have shown the specified new mechanism is high energetic and allows to explain many of the phenomena earlier inaccessible to understanding in various geosciences, including climatology [1] - [5]. It has been shown, that secular changes in activity of all planetary processes on the Earth are connected with a secular drift of the core of the Earth, and are controlled by the core and are reflections and displays of the core drift [5]. It is naturally, that slow climatic changes are connected with drift of the core, with induced by this drift inversion changes in an atmosphere, ocean, with thermodynamic variations of state of layer D ', with changes and variations in mantle convection and in plume activity of the Earth. The drift of the core controls a transmission of heat in the top layers of the mantle and on a surface of the Earth, organizes volcanic and seismic activity of the Earth in planetary scale. The mechanism of a warming up of layers of the mantle and cyclic inversion changes of a climate. According to a developed geodynamic model all layers of the mantle at oscillations and motions of the core under action of its gravitational attraction test wide class of inversion deformations [1]. Thus the part of energy of deformations passes in heat by virtue of dissipation

  14. Solar Wind Magnetic Fields

    NASA Technical Reports Server (NTRS)

    Smith, E. J.

    1995-01-01

    The magnetic fields originate as coronal fields that are converted into space by the supersonic, infinitely conducting, solar wind. On average, the sun's rotation causes the field to wind up and form an Archimedes Spiral. However, the field direction changes almost continuously on a variety of scales and the irregular nature of these changes is often interpreted as evidence that the solar wind flow is turbulent.

  15. Solar wind composition

    NASA Technical Reports Server (NTRS)

    Ogilvie, K. W.; Coplan, M. A.

    1995-01-01

    Advances in instrumentation have resulted in the determination of the average abundances of He, C, N, O, Ne, Mg, Si, S, and Fe in the solar wind to approximately 10%. Comparisons with solar energetic particle (SEP) abundances and galactic cosmic ray abundances have revealed many similarities, especially when compared with solar photospheric abundances. It is now well established that fractionation in the corona results in an overabundance (with respect to the photosphere) of elements with first ionization potentials less than 10 eV. These observations have in turn led to the development of fractionation models that are reasonably successful in reproducing the first ionization (FIP) effect. Under some circumstances it has been possible to relate solar wind observations to particular source regions in the corona. The magnetic topologies of the source regions appear to have a strong influence on the fractionation of elements. Comparisons with spectroscopic data are particularly useful in classifying the different topologies. Ions produced from interstellar neutral atoms are also found in the solar wind. These ions are picked up by the solar wind after ionization by solar radiation or charge exchange and can be identified by their velocity in the solar wind. The pick-up ions provide most of the pressure in the interplanetary medium at large distances. Interstellar abundances can be derived from the observed fluxes of solar wind pick-up ions.

  16. Solar wind travel time

    NASA Astrophysics Data System (ADS)

    Russell, C. T.

    A useful rule of thumb in solar terrestrial studies is that the solar wind travels 4 Earth radii (RE) per minute. Long-term studies of solar wind velocity [e.g., Luhmann et al., 1993; 1994] show that the median velocity is about 420 km/s, corresponding to 3.96 RE min-1. The quartiles are about 370 km/s and 495 km/s, corresponding to 3.48 Re min-1 and 4.66 Re min-1 respectively. This number helps estimate the delays expected when observing a discontinuity at a solar wind monitor; one example is ISEE-3 when it was at the forward libration point (about 60 min). It is also helpful for estimating how much time passes before the dayside magnetosphere is compressed as denser solar wind flows by (about 2.5 min).

  17. Flank solar wind interaction

    NASA Technical Reports Server (NTRS)

    Moses, Stewart L.; Greenstadt, Eugene W.; Coroniti, Ferdinand V.

    1994-01-01

    In this report we will summarize the results of the work performed under the 'Flank Solar Wind Interaction' investigation in support of NASA's Space Physics Guest Investigator Program. While this investigation was focused on the interaction of the Earth's magnetosphere with the solar wind as observed by instruments on the International Sun-Earth Explorer (ISEE) 3 spacecraft, it also represents the culmination of decades of research performed by scientists at TRW on the rich phenomenology of collisionless shocks in space.

  18. The Solar Wind

    NASA Technical Reports Server (NTRS)

    Herring, J. R.; Licht, A. L.

    1960-01-01

    Parker's model of a spherically expanding corona, the "solar wind," is compared with D. E. Blackwell's observations of the 1954 minimum equatorial corona. A significant discrepancy is found between the predicted and the observed electron densities at distances from the sun greater than 20 solar radii. Blackwell's data are found to be consistent with a model in which the corona expands mostly within a disk less than 25 solar radii thick, lying within the sun's equatorial plane. The thickness of the disk as a function of distance from the sun is qualitatively explained in terms of magnetic pressure. The solar wind is found to have a considerable effect on the lunar atmosphere. First, the calculated density of the lunar atmosphere is greatly reduced by collisions with protons in the solar wind. If the flux of particles in this wind has the conventional values ranging between 10(exp 10) to 10(exp 11) per sq cm-sec, the calculations yield a lunar pressure of 10(exp -13) atmosphere of argon, in agreement with the value predicted by Elsmore and Whitfield on the basis of observations on the occultation of radio stars. Second, following a suggestion by Gold, it was found that the collisions of solar-wind protons with the lunar surface produce an atmosphere of cold neutral hydrogen with a density of 10(exp 5) per cu cm at the lunar surface. The density falls off at greater distances in accordance with the inverse-square law. Estimates indicate that the interaction of solar particles with the neutral hydrogen will produce an extended lunar ionosphere with a density of the order of 400 protons/cu cm in the vicinity of the moon.

  19. Latitude dependence of co-rotating shock acceleration

    NASA Technical Reports Server (NTRS)

    Gold, R. E.; Lanzerotti, L. J.; Maclennan, C. G.; Krimigis, S. M.

    1985-01-01

    Energetic particle observations in the outer heliosphere (approx 12 A. U.) by the LECP instruments on the Voyager 1 and Voyager 2 spacecraft are discussed that show a definite latitude dependence of the number and intensity of particle enhancements produced by corotating interplanetary regions during an interval when no solar energetic particle events were observed. The particle enhancements are fewer in number and less intense at higher (approx 20 deg.) heliolatitudes. However, the similar spectral shapes of the accelerated particles at the two spacecraft indicate that the acceleration process is the same at the two latitudes, but less intense at the higher latitude.

  20. Heliomagnetic latitude dependence of the heliospheric magnetic field

    NASA Astrophysics Data System (ADS)

    Burton, M. E.; Smith, E. J.; Balogh, A.; Murphy, N.

    1996-07-01

    ICE and IMP-8 magnetic field data from 1984-1988 have been analyzed in a magnetic coordinate system defined by the orientation of the solar magnetic dipole. The heliomagnetic latitude dependence of the radial component of the magnetic field (Br) has then been investigated in a wide range of magnetic latitudes above and below the heliospheric current sheet (HCS). Br reverses sign abruptly across the current sheet, consistent with the solar magnetic field models of Pneuman and Kopp [1971] and Wolfson [1985] but inconsistent with the source surface models [Hoeksema, 1986]. No evidence is found for an asymmetry in the magnetic field suggested by earlier studies of interplanetary magnetic field data [Luhmann, 1987, Burton, 1990]. A slight (~.03 nT per degree) latitude gradient has been found which is consistent with the MHD model of Pneuman and Kopp and the recent model of Zhao and Hoeksema [1995].

  1. Personal overview of solar wind 6

    SciTech Connect

    Gosling, J.T.

    1987-01-01

    The author reviews papers presented at the Solar Wind 6 Proceedings. The particular topics discussed are solar wind acceleration theory, heliosphere production of solar winds, coronal mass ejections, interplanetary shock disturbance, and solar wind ionic composition. A concern for the steady decline in solar wind observations is expressed. (LSP)

  2. Latitude dependence of narrow bipolar pulse emissions

    NASA Astrophysics Data System (ADS)

    Ahmad, M. R.; Esa, M. R. M.; Cooray, V.; Baharudin, Z. A.; Hettiarachchi, P.

    2015-06-01

    In this paper, we present a comparative study on the occurrence of narrow bipolar pulses (NBPs) and other forms of lightning flashes across various geographical areas ranging from northern regions to the tropics. As the latitude decreased from Uppsala, Sweden (59.8N) to South Malaysia (1.5N), the percentage of NBP emissions relative to the total number of lightning flashes increased significantly from 0.13% to 12%. Occurrences of positive NBPs were more common than negative NBPs at all observed latitudes. However, as latitudes decreased, the negative NBP emissions increased significantly from 20% (Uppsala, Sweden) to 45% (South Malaysia). Factors involving mixed-phase region elevations and vertical extents of thundercloud tops are invoked to explain the observed results. These factors are fundamentally latitude dependent. Our results suggest that the NBP emission rate is not a useful measure to monitor thunderstorm severity because regular tropical thunderstorms, where relatively high NBP emissions occur, lack suitable conditions to become severe (i.e., there is modest convective available potential energy and a lack of baroclinity in such regions). Observations of significantly high negative NBP occurrences together with very rare occurrences of positive cloud-to-ground flashes and isolated breakdown pulses in tropical thunderstorms are indicative of a stronger negative screening layer magnitude and weaker lower positive charge region magnitude than those in northern regions.

  3. Solar wind stream interfaces

    NASA Technical Reports Server (NTRS)

    Gosling, J. T.; Asbridge, J. R.; Bame, S. J.; Feldman, W. C.

    1978-01-01

    Results are presented for a superposed epoch analysis of discontinuous solar wind interfaces. The average time-space profiles of stream interfaces are discussed with reference to fluid properties (flow speed, pressure ridge, density, electron and proton temperatures) and kinetic properties (electron core and halo, flow speed fluctuations, electron heat flux, alpha particles). Other aspects of stream interfaces are described, such as the persistence of individual interfaces, shock associations, the sector boundaries of the interplanetary magnetic field, and sudden impulses in the geomagnetic field. Interface position is considered in terms of the observed temperature jump. A conceptual model of high-speed stream evolution is proposed.

  4. Venus: Interaction with Solar Wind

    NASA Astrophysics Data System (ADS)

    Russell, C.; Luhmann, J.; Murdin, P.

    2002-07-01

    The solar wind interaction with VENUS provides the archetypal interaction of a flowing magnetized PLASMA with a PLANETARY IONOSPHERE. Mars interacts with the solar wind in much the same way as does Venus, while the rotating plasma in the Saturnian magnetosphere is believed to interact similarly with its moon, Titan (see SATURN: MAGNETOSPHERE INTERACTION WITH TITAN). The interaction of the Jovian ...

  5. Solar wind photoplate study

    NASA Technical Reports Server (NTRS)

    Scott, B. W.; Voorhies, H. G.

    1972-01-01

    An ion sensitive emulsion detection system has been considered for use in a cycloidal focusing mass spectrometer to measure the various atomic species which comprise the solar plasma. The responses of Ilford Q2 and Kodak SC7 emulsions were measured with N(+) ions at 6 keV to 10 keV, He(++) ions at 750 eV to 2500 eV, and H(+) ions at 550 eV to 1400 eV. These ions have the approximate range of velocities (about 300-500 km/sec) encountered in the solar wind. The work was carried out on a specially prepared magnetic sector mass analyzer. Characteristic response curves were generated, each one utilizing approximately 50 data points at three or more current densities. In addition to the ion response, measurements of the response of these emulsions to a photon flux simulating the visible portion of the solar spectrum were made. The results obtained will be presented in detail and interpreted in relation to other data available for these emulsions.

  6. Wind and solar powered turbine

    NASA Technical Reports Server (NTRS)

    Wells, I. D.; Koh, J. L.; Holmes, M. (inventors)

    1984-01-01

    A power generating station having a generator driven by solar heat assisted ambient wind is described. A first plurality of radially extendng air passages direct ambient wind to a radial flow wind turbine disposed in a centrally located opening in a substantially disc-shaped structure. A solar radiation collecting surface having black bodies is disposed above the fist plurality of air passages and in communication with a second plurality of radial air passages. A cover plate enclosing the second plurality of radial air passages is transparent so as to permit solar radiation to effectively reach the black bodies. The second plurality of air passages direct ambient wind and thermal updrafts generated by the black bodies to an axial flow turbine. The rotating shaft of the turbines drive the generator. The solar and wind drien power generating system operates in electrical cogeneration mode with a fuel powered prime mover.

  7. Wind and Solar Curtailment: Preprint

    SciTech Connect

    Lew, D.; Bird, L.; Milligan, M.; Speer, B.; Wang, X.; Carlini, E. M.; Estanqueiro, A.; Flynn, D.; Gomez-Lazaro, E.; Menemenlis, N.; Orths, A.; Pineda, I.; Smith, J. C.; Soder, L.; Sorensen, P.; Altiparmakis, A.; Yoh, Y.

    2013-09-01

    High penetrations of wind and solar generation on power systems are resulting in increasing curtailment. Wind and solar integration studies predict increased curtailment as penetration levels grow. This paper examines experiences with curtailment on bulk power systems internationally. It discusses how much curtailment is occurring, how it is occurring, why it is occurring, and what is being done to reduce curtailment. This summary is produced as part of the International Energy Agency Wind Task 25 on Design and Operation of Power Systems with Large Amounts of Wind Power.

  8. Highly Alfvenic Slow Solar Wind

    NASA Technical Reports Server (NTRS)

    Roberts, D. Aaron

    2010-01-01

    It is commonly thought that fast solar wind tends to be highly Alfvenic, with strong correlations between velocity and magnetic fluctuations, but examples have been known for over 20 years in which slow wind is both Alfvenic and has many other properties more typically expected of fast solar wind. This paper will present a search for examples of such flows from more recent data, and will begin to characterize the general characteristics of them. A very preliminary search suggests that such intervals are more common in the rising phase of the solar cycle. These intervals are important for providing constraints on models of solar wind acceleration, and in particular the role waves might or might not play in that process.

  9. STATIONARITY IN SOLAR WIND FLOWS

    SciTech Connect

    Perri, S.; Balogh, A. E-mail: a.balogh@imperial.ac.u

    2010-05-01

    By using single-point measurements in space physics it is possible to study a phenomenon only as a function of time. This means that we cannot have direct access to information about spatial variations of a measured quantity. However, the investigation of the properties of turbulence and of related phenomena in the solar wind widely makes use of an approximation frequently adopted in hydrodynamics under certain conditions, the so-called Taylor hypothesis; indeed, the solar wind flow has a bulk velocity along the radial direction which is much higher than the velocity of a single turbulent eddy embedded in the main flow. This implies that the time of evolution of the turbulent features is longer than the transit time of the flow through the spacecraft position, so that the turbulent field can be considered frozen into the solar wind flow. This assumption allows one to easily associate time variations with spatial variations and stationarity to homogeneity. We have investigated, applying criteria for weak stationarity to Ulysses magnetic field data in different solar wind regimes, at which timescale and under which conditions the hypothesis of stationarity, and then of homogeneity, of turbulence in the solar wind is well justified. We extend the conclusions of previous studies by Matthaeus and Goldstein to different parameter ranges in the solar wind. We conclude that the stationarity assumption in the inertial range of turbulence on timescales of 10 minutes to 1 day is reasonably satisfied in fast and uniform solar wind flows, but that in mixed, interacting fast, and slow solar wind streams the assumption is frequently only marginally valid.

  10. Wind in the Solar System

    ERIC Educational Resources Information Center

    McIntosh, Gordon

    2010-01-01

    As an astronomy instructor I am always looking for commonly experienced Earthly phenomena to help my students and me understand and appreciate similar occurrences elsewhere in the solar system. Recently I wrote short "TPT" articles on frost and precipitation. The present article is on winds in the solar system. A windy day or storm might motivate

  11. Wind in the Solar System

    ERIC Educational Resources Information Center

    McIntosh, Gordon

    2010-01-01

    As an astronomy instructor I am always looking for commonly experienced Earthly phenomena to help my students and me understand and appreciate similar occurrences elsewhere in the solar system. Recently I wrote short "TPT" articles on frost and precipitation. The present article is on winds in the solar system. A windy day or storm might motivate…

  12. Wind and solar powered turbine

    SciTech Connect

    Wells, I.D.; Holmes, M.; Kohn, J.L.

    1984-02-28

    A power generating station having a generator driven by solar heat assisted ambient wind is disclosed. A first plurality of radially extending air passages direct ambient wind to a radial flow wind turbine disposed in a centrally located opening in a substantially disc-shaped structure. A solar radiation collecting surface having black bodies is disposed above the first plurality of air passages and in communication with a second plurality of radial air passages. A cover plate enclosing the second plurality of radial air passages is transparent so as to permit solar radiation to effectively reach the black bodies. The second plurality of air passages direct ambient wind and thermal updrafts generated by the black bodies to an axial flow turbine which also derives additional motive power from the air mass exhausted by the radial flow turbine. The rotating shaft of the turbines drive the generator. The solar and wind driven power generating system operates in electrical cogeneration mode with a fuel powered prime mover. The system is particularly adapted to satisfy the power requirements of a relatively small community located in a geographic area having favorable climatic conditions for wind and solar powered power generation.

  13. Solar wind theory and modelling

    NASA Technical Reports Server (NTRS)

    Hansteen, Viggo H.

    1995-01-01

    The outflow of coronal plasma into interplanetary space is a consequence of the coronal heating process. Therefore the formation of the corona and the acceleration of the solar wind should be treated as a single problem. Traditionally the mass or particle flux emanating from the extended corona has been thought of as being determined by the coronal temperature or scale height and the coronal (base) density. This argument follows from considerations of the momentum balance of the corona-wind system from which one obtains models of a close to hydrostatic corona out to the critical point where the flow becomes supersonic. With this approach to the acceleration of the wind is has been difficult to reconcile the relatively small variation observed in the proton flux at 1 AU with the predicted exponential dependence of the proton flux on the coronal temperature. In this talk we would like to emphasize another approach in which coronal energetics play the primary role. The deposition of energy into the corona through some 'mechanical' energy flux is balanced by the various energy sinks available to the corona and the sum of these processes determine the coronal structure, i.e. its temperature and density. The corona loses energy through heat conduction into the transition region, through radiative losses, and through the gravitational potential energy and kinetic energy put into the solar wind itself. We will show from a series of models of the chromosphere transition region-corona-solar wind system that most of the energy deposited in a magnetically open region will go into the solar wind, with roughly half going into kinetic energy and half into lifting the plasma out of the solar gravity field. The coronal base density will adjust itself in such a way that the heat conductive flux flowing into the transition region is radiated away in the upper chromosphere. The coronal temperature is set by the requirements that most of the deposited energy goes into accelerating the solar wind; the coronal scale height will adjust itself so that the solar wind energy losses conform to the amplitude of the input energy. These processes are modified by the 'mode' of energy deposition, and we will show the effects on coronal structure of changing the parameters describing coronal heating as well as the effects of including a helium fluid in the models. However, the location, scale height and/or form of the energy deposition (i.e. heating or direct acceleration) are not too important for the solar wind, the coronal density and temperature structure will vary with the 'mode' of energy deposition, but the solar wind mass flux depends mainly on the amplitude of the energy flux.

  14. Photoionization in the Solar Wind

    NASA Astrophysics Data System (ADS)

    Landi, E.; Lepri, S. T.

    2015-10-01

    In this work we investigate the effects of photoionization on the charge state composition of the solar wind. Using measured solar EUV and X-ray irradiance, the Michigan Ionization Code and a model for the fast and slow solar wind, we calculate the evolution of the charge state distribution of He, C, N, O, Ne, Mg, Si, S, and Fe with and without including photoionization for both types of wind. We find that the solar radiation has significant effects on the charge state distribution of C, N, and O, causing the ionization levels of these elements to be higher than without photoionization; differences are largest for oxygen. The ions commonly observed for elements heavier than O are much less affected, except in ICMEs where Fe ions more ionized than 16+ can also be affected by the solar radiation. We also show that the commonly used O7+/O6+ density ratio is the most sensitive to photoionization; this sensitivity also causes the value of this ratio to depend on the phase of the solar cycle. We show that the O7+/O6+ ratio needs to be used with caution for solar wind classification and coronal temperature estimates, and recommend the C6+/C4+ ratio for these purposes.

  15. Persistence of solar wind features

    NASA Technical Reports Server (NTRS)

    Rucker, H. O.; Rabl, G. K. F.; Desch, M. D.

    1986-01-01

    Using data from the plasma and magnetometer experiments on board the Voyagers 1 and 2 during the approach to Jupiter, solar wind persistence is investigated over the period from January 1978 (Voyager 1 passing by Voyager 2) through February 1979. The trajectories of both spacecraft provided a unique opportunity to study the radial evolution and variation of the solar wind over about 3 AU, and to analyze the persistence of solar wind features along the radially increasing separation distance of both Voyagers. Some emphasis is placed on a period of DOY (day of year) 152 through 212, 1978, in which the observed propagation delay time of solar wind signatures between both Voyagers significantly deviates from the expected delay time. A decrease in the correlation coefficient of the corresponding Voyager 1 and 2 data profiles indicates a remarkable change of the solar wind flow. This period in question coincides to a great extent with the interval V of June-July 1978, selected by STIP (Study of Travelling Interplanetary Phenomena).

  16. Solar wind absorption by Venus

    NASA Technical Reports Server (NTRS)

    Gombosi, T. I.; Cravens, T. E.; Nagy, A. F.; Elphic, R. C.; Russell, C. T.

    1980-01-01

    The portion of solar wind interacting with the dayside ionosphere and atmosphere of Venus was determined based on magnetic field fluctuations in the ionosheath and the interaction with the upper neutral atmosphere above the ionopause. Fluctuations with the ratio of the number of particles intersecting the daytide ionopause to the total number of particles of 0.3 suggest that about 0.3% of solar wind may be absorbed. Most of fast H atoms resulting from the charge exchange interactions with the atmosphere escape; some of the energy deposition processes produce observable signatures (such as a narrow Lyman alpha emission region), but penetrating solar wind particles do not control the physical and/or chemical structure of the daytime Venus ionosphere.

  17. Eight-moment approximation solar wind models

    NASA Technical Reports Server (NTRS)

    Olsen, Espen Lyngdal; Leer, Egil

    1995-01-01

    Heat conduction from the corona is important in the solar wind energy budget. Until now all hydrodynamic solar wind models have been using the collisionally dominated gas approximation for the heat conductive flux. Observations of the solar wind show particle distribution functions which deviate significantly from a Maxwellian, and it is clear that the solar wind plasma is far from collisionally dominated. We have developed a numerical model for the solar wind which solves the full equation for the heat conductive flux together with the conservation equations for mass, momentum, and energy. The equations are obtained by taking moments of the Boltzmann equation, using an 8-moment approximation for the distribution function. For low-density solar winds the 8-moment approximation models give results which differ significantly from the results obtained in models assuming the gas to be collisionally dominated. The two models give more or less the same results in high density solar winds.

  18. Coronal holes as sources of solar wind

    NASA Technical Reports Server (NTRS)

    Nolte, J. T.; Krieger, A. S.; Timothy, A. F.; Gold, R. E.; Roelof, E. C.; Vaiana, G.; Lazarus, A. J.; Sullivan, J. D.; Mcintosh, P. S.

    1976-01-01

    We investigate the association of high-speed solar wind with coronal holes during the Skylab mission by: (1) direct comparison of solar wind and coronal X-ray data; (2) comparison of near-equatorial coronal hole area with maximum solar wind velocity in the associated streams; and (3) examination of the correlation between solar and interplanetary magnetic polarities. We find that all large near-equatorial coronal holes seen during the Skylab period were associated with high-velocity solar wind streams observed at 1 AU.

  19. 77 FR 61597 - Avalon Wind, LLC; Avalon Wind 2, LLC; Catalina Solar, LLC; Catalina Solar 2, LLC; Pacific Wind...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-10

    ... Energy Regulatory Commission Avalon Wind, LLC; Avalon Wind 2, LLC; Catalina Solar, LLC; Catalina Solar 2, LLC; Pacific Wind Lessee, LLC; Pacific Wind 2, LLC; Valentine Solar, LLC; EDF Renewable Development, Inc.; Notice of Petition for Declaratory Order Take notice that on September 27, 2012, Avalon...

  20. Comet Borrelly Slows Solar Wind

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Over 1300 energy spectra taken on September 22, 2001 from the ion and electron instruments on NASA's Deep Space 1 span a region of 1,400,000 kilometers (870,000 miles) centered on the closest approach to the nucleus of comet Borrelly. A very strong interaction occurs between the solar wind (horizontal red bands to left and right in figure) and the comet's surrounding cloud of dust and gas, the coma. Near Deep Space 1's closest approach to the nucleus, the solar wind picked up charged water molecules from the coma (upper green band near the center), slowing the wind sharply and creating the V-shaped energy structure at the center.

    Deep Space 1 completed its primary mission testing ion propulsion and 11 other advanced, high-risk technologies in September 1999. NASA extended the mission, taking advantage of the ion propulsion and other systems to undertake this chancy but exciting, and ultimately successful, encounter with the comet. More information can be found on the Deep Space 1 home page at http://nmp.jpl.nasa.gov/ds1/ .

    Deep Space 1 was launched in October 1998 as part of NASA's New Millennium Program, which is managed by JPL for NASA's Office of Space Science, Washington, D.C. The California Institute of Technology manages JPL for NASA.

  1. Solar energy tracking structure incorporating wind spoilers

    SciTech Connect

    Frohardt, M.W.; Hartz, K.H.; Hardee, P.C.

    1989-12-19

    This patent describes a solar energy tracking assembly. The assembly producing reduced torque loading forces due to wind on the rotating portion of the tracking assembly. The solar energy tracking assembly comprised of: a fixed position base having one end securely fixed to the ground and having the second end supporting the remaining tracking assembly components; solar energy collecting means comprising a moving structure frame and at least one solar collecting element attached thereto means for rotating the solar energy collecting means in relation to the sun in order that the solar energy collecting means maintain the proper attitude for collection of incident solar energy; and a wind spoiler assembly.

  2. The Solar Wind Ion Composition Spectrometer

    NASA Technical Reports Server (NTRS)

    Gloeckler, G.; Geiss, J.; Balsiger, H.; Bedini, P.; Cain, J. C.; Fisher, J.; Fisk, L. A.; Galvin, A. B.; Gliem, F.; Hamilton, D. C.

    1992-01-01

    The Solar Wind Ion Composition Spectrometer (SWICS) on Ulysses is designed to determine uniquely the elemental and ionic-charge composition, and the temperatures and mean speeds of all major solar-wind ions, from H through Fe, at solar wind speeds ranging from 175 km/s (protons) to 1280 km/s (Fe(8+)). The instrument, which covers an energy per charge range from 0.16 to 59.6 keV/e in about 13 min, combines an electrostatic analyzer with postacceleration, followed by a time-of-flight and energy measurement. The measurements made by SWICS will have an impact on many areas of solar and heliospheric physics, in particular providing essential and unique information on: (1) conditions and processes in the region of the corona where the solar wind is accelerated; (2) the location of the source regions of the solar wind in the corona; (3) coronal heating processes; (4) the extent and causes of variations in the composition of the solar atmosphere; (5) plasma processes in the solar wind; (6) the acceleration of energetic particles in the solar wind; (7) the thermalization and acceleration of interstellar ions in the solar wind, and their composition; and (8) the composition, charge states, and behavior of the plasma in various regions of the Jovian magnetosphere.

  3. Multifractals in the solar wind

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.

    1992-01-01

    Multifractals have been observed in the solar wind in several contexts. The velocity fluctuations observed by Voyager 2 near 8 AU have the structure of intermittent turbulence which has multifractal scaling symmetry. The velocity fluctuations in corotating streams at 1 AU and near 6 AU also have multifractal structure, and the structure evolves significantly between 1 AU and 6 AU. Multifractal scaling has also been observed in the magnetic field strength, density and temperature in recurrent streams at 1 AN and in large-scale fluctuations the magnetic field strength at 25 AU.

  4. The solar wind in the third dimension

    NASA Technical Reports Server (NTRS)

    Neugebauer, M.

    1995-01-01

    For many years, solar-wind physicists have been using plasma and field data acquired near the ecliptic plane together with data on the scintillation of radio sources and remote sensing of structures in the solar corona to estimate the properties of the high-latitude solar wind, Because of the highly successful Ulysses mission, the moment of truth is now here. This talk summarizes the principal differences between the high and low latitude solar winds at the declining phase of the solar-activity cycle and between the Ulysses observations and expectations.

  5. MHD Waves in the Solar Wind

    NASA Astrophysics Data System (ADS)

    Ofman, L.

    This chapter focuses on reviewing several observational aspects of magnetohydrodynamic (MHD) waves in the solar wind, in particular on Alfvén waves, Alfvénic turbulent spectrum, and their role in heating and accelerating the solar wind. It also reviews computational models that incorporate Alfvén waves as the driving source of the wind in the lower corona (coronal holes) and in the inner heliosphere, with emphasis on multi-dimensional models. Evidence for MHD waves in the solar wind is obtained from interplanetary scintillation (IPS) observations using Earth-based radio telescope observations of distant (galactic) radio sources. The solar wind electron density variability in the line of sight affects the received radio signal. The propagating fluctuations and their correlations are used to estimate the solar wind velocity and the wave amplitude in the parallel and the perpendicular directions in line of sight.

  6. Simulations of Solar Wind Turbulence

    NASA Technical Reports Server (NTRS)

    Goldstein, Melvyn L.; Usmanov, A. V.; Roberts, D. A.

    2008-01-01

    Recently we have restructured our approach to simulating magnetohydrodynamic (MHD) turbulence in the solar wind. Previously, we had defined a 'virtual' heliosphere that contained, for example, a tilted rotating current sheet, microstreams, quasi-two-dimensional fluctuations as well as Alfven waves. In this new version of the code, we use the global, time-stationary, WKB Alfven wave-driven solar wind model developed by Usmanov and described in Usmanov and Goldstein [2003] to define the initial state of the system. Consequently, current sheets, and fast and slow streams are computed self-consistently from an inner, photospheric, boundary. To this steady-state configuration, we add fluctuations close to, but above, the surface where the flow become super-Alfvenic. The time-dependent MHD equations are then solved using a semi-discrete third-order Central Weighted Essentially Non-Oscillatory (CWENO) numerical scheme. The computational domain now includes the entire sphere; the geometrical singularity at the poles is removed using the multiple grid approach described in Usmanov [1996]. Wave packets are introduced at the inner boundary such as to satisfy Faraday's Law [Yeh and Dryer, 1985] and their nonlinear evolution are followed in time.

  7. The solar wind mass flux problem

    NASA Technical Reports Server (NTRS)

    Leer, E.; Holzer, T. E.

    1991-01-01

    The variation of the proton flux with coronal temperature and density in thermally driven solar wind models is discussed. It is shown that the rapid increase of the proton flux with increasing temperature can be reduced by adiabatic cooling of the expanding plasma. A significant coronal helium abundance can also act as a 'regulator' for the solar wind proton flux.

  8. Solar Wind Interaction with Venus

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Luhmann, J. G.; Ma, Y. J.; Villarreal, M. N.; Zhang, T. L.

    2014-04-01

    Venus Express, which was inserted into orbit in mid-2006, has added significantly to the knowledge gained from Pioneer Venus from 1978 to 1992. This observational database interpreted in terms of modern multi-fluid codes and hybrid simulations has deepened our understanding of Earth's very different twin sister planet. Furthermore, the very different orbits of VEX and PVO has allowed the more complete mapping of the volume of space around the planet. Now the bow shock has been probed over its full surface, the ionosphere mapped everywhere, and the tail studied from the ionosphere to 12 Venus radii. Some unexpected discoveries have been made. The exospheric hydrogen at Venus, unlike that at Mars,does not produce ion-cyclotron waves, perhapsbecause the stronger gravity of Venus produces a smaller geocorona. The solar wind interaction drapes the magnetic field around the planet, and a strong layer of magnetic field builds up at low altitudes. While the layer does not appear to penetrate into the dayside atmosphere (perhaps diffusing only slowly through the low atmosphere), it does appear to dip into the atmosphere at night. Surprisingly, over the poles, this layer is most strongly seen when the IMF BY component has a positive Y-component in Venus- Solar-Orbital coordinates. Multi-fluid simulations show that this result is consistent with the pressure of significant ion densities of ions with quite different mass which causes magnetic polarity control of the ion flow over the terminators. Reconnection is found in the tail close to the planet, and the structure of the outer tail found by PVO is confirmed to exist in the inner tail by VEX. When combined, the VEX and PVO Data provide a very comprehensive picture of the physics of the solar wind interaction with the ionosphere of Venus.

  9. Sources of solar wind over the solar activity cycle.

    PubMed

    Poletto, Giannina

    2013-05-01

    Fast solar wind has been recognized, about 40years ago, to originate in polar coronal holes (CHs), that, since then, have been identified with sources of recurrent high speed wind streams. As of today, however, there is no general consensus about whether there are, within CHs, preferential locations where the solar wind is accelerated. Knowledge of slow wind sources is far from complete as well. Slow wind observed in situ can be traced back to its solar source by backward extrapolation of magnetic fields whose field lines are streamlines of the outflowing plasma. However, this technique often has not the necessary precision for an indisputable identification of the region where wind originates. As the Sun progresses through its activity cycle, different wind sources prevail and contribute to filling the heliosphere. Our present knowledge of different wind sources is here summarized. Also, a Section addresses the problem of wind acceleration in the low corona, as inferred from an analysis of UV data, and illustrates changes between fast and slow wind profiles and possible signatures of changes along the solar cycle. A brief reference to recent work about the deep roots of solar wind and their changes over different solar cycles concludes the review. PMID:25685421

  10. Sources of solar wind over the solar activity cycle

    PubMed Central

    Poletto, Giannina

    2012-01-01

    Fast solar wind has been recognized, about 40years ago, to originate in polar coronal holes (CHs), that, since then, have been identified with sources of recurrent high speed wind streams. As of today, however, there is no general consensus about whether there are, within CHs, preferential locations where the solar wind is accelerated. Knowledge of slow wind sources is far from complete as well. Slow wind observed in situ can be traced back to its solar source by backward extrapolation of magnetic fields whose field lines are streamlines of the outflowing plasma. However, this technique often has not the necessary precision for an indisputable identification of the region where wind originates. As the Sun progresses through its activity cycle, different wind sources prevail and contribute to filling the heliosphere. Our present knowledge of different wind sources is here summarized. Also, a Section addresses the problem of wind acceleration in the low corona, as inferred from an analysis of UV data, and illustrates changes between fast and slow wind profiles and possible signatures of changes along the solar cycle. A brief reference to recent work about the deep roots of solar wind and their changes over different solar cycles concludes the review. PMID:25685421

  11. Expansion effects on solar wind hybrid simulations

    SciTech Connect

    Parashar, Tulasi N.; Velli, Marco; Goldstein, Bruce E.

    2013-06-13

    Ion kinetic simulations of the solar wind using hybrid codes can model local wave input, heating and instabilities, but generally do not include long term evolution effects in the expanding solar wind. We further develop the expanding box model used in earlier studies to include the mirror force effects and study their role in the evolution of the proton distribution functions in the outer corona and inner heliosphere. The mirror force, significant in the acceleration region of the solar wind, is required for consistency with the conservation of magnetic moment of particles in the expanding wind. We present preliminary results from the modified 1D expanding box hybrid (EBHM) simulations.

  12. The solar wind-magnetosphere-ionosphere system

    PubMed

    Lyon

    2000-06-16

    The solar wind, magnetosphere, and ionosphere form a single system driven by the transfer of energy and momentum from the solar wind to the magnetosphere and ionosphere. Variations in the solar wind can lead to disruptions of space- and ground-based systems caused by enhanced currents flowing into the ionosphere and increased radiation in the near-Earth environment. The coupling between the solar wind and the magnetosphere is mediated and controlled by the magnetic field in the solar wind through the process of magnetic reconnection. Understanding of the global behavior of this system has improved markedly in the recent past from coordinated observations with a constellation of satellite and ground instruments. PMID:10856203

  13. The abundances of elements and isotopes in the solar wind

    NASA Technical Reports Server (NTRS)

    Gloeckler, George; Geiss, Johannes

    1988-01-01

    Studies of the chemical and isotopic composition of the solar wind are reviewed. Solar wind abundance measurements are discussed and solar wind, coronal, and photospheric abundances for elements between H and Fe are presented. Also, consideration is given to the determination of the solar wind isotopic composition of the noble gases using foil collection techniques and the observation of solar wind heavy ions with the mass per charge spectrometer on ISEE-3. Other topics include solar wind observations with solid state detectors, solar wind abundances in the magnetosheath and the plasma sheet, and high-mass resolution measurements of chemical elements and isotopes in the solar wind.

  14. Solar- and wind-powered irrigation systems

    NASA Astrophysics Data System (ADS)

    Enochian, R. V.

    1982-02-01

    Five different direct solar and wind energy systems are technically feasible for powering irrigation pumps. However, with projected rates of fossil fuel costs, only two may produce significant unsubsidied energy for irrigation pumping before the turn of the century. These are photovoltaic systems with nonconcentrating collectors (providing that projected costs of manufacturing solar cells prove correct); and wind systems, especially in remote areas where adequate wind is available.

  15. Solar energy system with wind vane

    SciTech Connect

    Grip, Robert E

    2015-11-03

    A solar energy system including a pedestal defining a longitudinal axis, a frame that is supported by the pedestal and that is rotateable relative to the pedestal about the longitudinal axis, the frame including at least one solar device, and a wind vane operatively connected to the frame to urge the frame relative to the pedestal about the longitudinal axis in response to wind acting on the wind vane.

  16. The quiescent corona and slow solar wind

    NASA Technical Reports Server (NTRS)

    Noci, G.; Kohl, J. L.; Antonucci, E.; Tondello, G.; Huber, M. C. E.; Fineschi, S.; Gardner, L. D.; Korendyke, C. M.; Nicolosi, P.; Romoli, M.; Spadaro, D.; Maccari, L.; Raymond, J. C.; Siegmund, O. H. W.; Benna, C.; Ciaravella, A.; Giordano, S.; Michels, J.; Modigliani, A.; Naletto, G.

    1997-01-01

    The observations of the ultraviolet coronagraph spectrometer (UVCS), operating onboard the Solar and Heliospheric Observatory (SOHO) spacecraft, are discussed. The purpose of the UVCS is the study of the quiescent coronal streamer and the slow solar wind. The observations started in January 1996. Polarized radiance data in the visible continuum were obtained. Some characteristics of the coronal streamer from the UVCS recorded data are discussed. A model for the source of the slow solar wind in the inner corona is proposed.

  17. Solar cycle changes in the high latitude solar wind

    NASA Technical Reports Server (NTRS)

    Rickett, B. J.; Coles, W. A.

    1980-01-01

    Measurements of the solar wind velocity during the period 1971-79 using the technique of interplanetary scintillation are discussed. The average wind speed was faster than 500 km/s at latitudes above 30 deg for most of 1973-77. The fast polar stream, observed to become much narrower in 1978-79 is examined. The narrowing of the polar streams coincided with the emergence of sunspots at midlatitudes, with the start of the new solar cycle, and with a corresponding contraction of the polar coronal holes. The theory that the solar magnetic field controls the large scale structure of the solar wind is discussed in relation to the results.

  18. Solar Wind Acceleration and the Dynamic Character of the Polar Solar Wind

    NASA Astrophysics Data System (ADS)

    Jackson, B. V.; Yu, H.; Hick, P. P.; Buffington, A.

    2013-12-01

    SOHO LASCO C2 and STEREO SECCHI COR 2 coronagraph images, when analyzed using correlation tracking techniques, show a surprising result in regions ordinarily thought of as 'quiet' solar wind above the poles in coronal hole regions. Here, the observed solar wind outflow is not the static well-ordered flow and gradual acceleration normally expected of quiescent polar hole regions. Rather, coronagraph images show outflow in polar coronal holes as intermittent highly-variable solar wind speed structures. We compare measurements of this highly-variable solar wind structure using different coronagraphs, and compare these structures with coronal brightness. Measurement of the mean velocities derived with height show the solar wind acceleration and are compared with mass flux and other determinations of the solar wind outflow in the large polar coronal hole regions. We also compare these measurements with IPS velocities obtained at large solar distances from the Sun at approximately these same times.

  19. Global Network of Slow Solar Wind

    NASA Technical Reports Server (NTRS)

    Crooker, N. U.; Antiochos, S. K.; Zhao, X.; Neugebauer, M.

    2012-01-01

    The streamer belt region surrounding the heliospheric current sheet (HCS) is generally treated as the primary or sole source of the slow solar wind. Synoptic maps of solar wind speed predicted by the Wang-Sheeley-Arge model during selected periods of solar cycle 23, however, show many areas of slow wind displaced from the streamer belt. These areas commonly have the form of an arc that is connected to the streamer belt at both ends. The arcs mark the boundaries between fields emanating from different coronal holes of the same polarity and thus trace the paths of belts of pseudostreamers, i.e., unipolar streamers that form over double arcades and lack current sheets. The arc pattern is consistent with the predicted topological mapping of the narrow open corridor or singular separator line that must connect the holes and, thus, consistent with the separatrix-web model of the slow solar wind. Near solar maximum, pseudostreamer belts stray far from the HCS-associated streamer belt and, together with it, form a global-wide web of slow wind. Recognition of pseudostreamer belts as prominent sources of slow wind provides a new template for understanding solar wind stream structure, especially near solar maximum.

  20. Anisotropic turbulence in the solar wind

    NASA Technical Reports Server (NTRS)

    Matthaeus, W. H.; Bieber, J. W.; Zank, G. P.

    1995-01-01

    Solar wind turbulence has been viewed traditionally as composed of parallel propagating ('slab' fluctuations) or otherwise as isotropic turbulence. A variety of recent investigations, reviewed here, indicate that the spectrum may contain a significant admixture of two dimensional fluctuations, having variations mainly perpendicular to the local magnetic field. These indications come from simulations, from the theory of nearly incompressible MHD, from cosmic ray transport studies and from transport theory for solar wind turbulence, as well as from interpretations of direct observations. Thus, solar wind turbulence may be more like bundles of spaghetti than like parallel phase fronts.

  1. Multifractality and chaos in the solar wind

    NASA Astrophysics Data System (ADS)

    Macek, Wiesław M.

    2002-07-01

    We analyze a time series of velocities of the solar wind plasma stream including Alfvénic fluctuations measured in situ by the Helios spacecraft in the inner heliosphere, which is the region of space dominated by the solar wind flow. We calculate the generalized dimensions directly from the cleaned experimental signal. The resulting spectrum of dimensions shows multifractal structure of the solar wind in the inner heliosphere. The obtained multifractal spectrum is consistent with that for the multifractal measure on the self-similar weighted Cantor set.

  2. On periodicity of solar wind phenomena

    NASA Technical Reports Server (NTRS)

    Verma, V. K.; Joshi, G. C.

    1995-01-01

    We have investigated the rate of occurrence of solar wind phenomena observed between 1972-1984 using power spectrum analysis. The data have been taken from the high speed solar wind (HSSW) streams catalogue published by Mavromichalaki et al. (1988). The power spectrum analysis of HSSW events indicate that HSSW stream events have a periodicity of 9 days. This periodicity of HSSW events is 1/3 of the 27 days period of coronal holes which are the major source of solar wind events. In our opinion the 9 days period may be the energy build up time to produce the HSSW stream events.

  3. DSCOVR High Time Resolution Solar Wind Measurements

    NASA Astrophysics Data System (ADS)

    Szabo, A.

    2012-12-01

    The Deep Space Climate Observatory (DSCOVR), previously known as Triana, spacecraft is expected to be launched in late 2014. It will carry a fluxgate magnetometer, Faraday Cup solar wind detector and a top-hat electron electrostatic analyzer. The Faraday Cup will provide an unprecedented 10 vectors/sec time resolution measurement of the solar wind proton and alpha reduced distribution functions. Coupled with the 40 vector/sec vector magnetometer measurements, the identification of specific wave modes in the solar wind will be possible for the first time. The science objectives and data products of the mission will be discussed.

  4. DSCOVR High Time Resolution Solar Wind Measurements

    NASA Technical Reports Server (NTRS)

    Szabo, Adam

    2012-01-01

    The Deep Space Climate Observatory (DSCOVR), previously known as Triana, spacecraft is expected to be launched in late 2014. It will carry a fluxgate magnetometer, Faraday Cup solar wind detector and a top-hat electron electrostatic analyzer. The Faraday Cup will provide an unprecedented 10 vectors/sec time resolution measurement of the solar wind proton and alpha reduced distribution functions. Coupled with the 40 vector/sec vector magnetometer measurements, the identification of specific wave modes in the solar wind will be possible for the first time. The science objectives and data products of the mission will be discussed.

  5. Alfvn wave interactions in the solar wind

    NASA Astrophysics Data System (ADS)

    Webb, G. M.; McKenzie, J. F.; Hu, Q.; le Roux, J. A.; Zank, G. P.

    2012-11-01

    Alfvn wave mixing (interaction) equations used in locally incompressible turbulence transport equations in the solar wind are analyzed from the perspective of linear wave theory. The connection between the wave mixing equations and non-WKB Alfven wave driven wind theories are delineated. We discuss the physical wave energy equation and the canonical wave energy equation for non-WKB Alfven waves and the WKB limit. Variational principles and conservation laws for the linear wave mixing equations for the Heinemann and Olbert non-WKB wind model are obtained. The connection with wave mixing equations used in locally incompressible turbulence transport in the solar wind are discussed.

  6. Properties of the very slow solar wind

    NASA Astrophysics Data System (ADS)

    Sanchez-Diaz, Eduardo; Segura, Kevin; Rouillard, Alexis P.; Lavraud, Benoit

    2015-04-01

    Solar wind plasma data taken between 0.29-0.9 AU by the twin HELIOS spacecraft reveals the frequent occurrence of very low radial wind speeds (200 < V < 300 km/s), very rarely measured near 1 AU. By analysing the occurrence as a function of heliocentric distance and time, we show that it is primarly measured inside 0.5 AU and mostly during solar maximum, although some very slow wind events were also measured during short periods at solar minimum. We show that the very slow wind is frequently measured during the passage of the solar wind plasma sheet usually detected in the vicinity of the heliospheric current sheet. By tracing these slow events back to the Sun and using a potential field reconstruction of the coronal magnetic field based on magnetograms taken by Mount Wilson Observatory, we compare the speed of the very slow wind with the geometry of the magnetic flux tube at its source. We discuss theoretical mechanisms that could explain the abundance and origin of this very slow wind, we also stress the importance of these findings for our understanding of solar wind structure. This study was carried out as part of the HELCATS FP7 project.

  7. Solar wind observations by Lyman alpha

    NASA Technical Reports Server (NTRS)

    Kyroelae, E.; Summanen, T.

    1995-01-01

    The interaction between the solar wind and the local interstellar matter takes place at two distinct regions. The plasma component of the interstellar matter meets the solar wind at the heliospheric interface region and it is excluded from entering into the heliosphere. The neutral component consisting mainly of the hydrogen atoms flows through the whole heliosphere. It gets, however, partly ionized by charge exchange collisions with solar wind protons and energetic photons from the Sun. The neutral atom trajectories are also affected by the radiation pressure from the Sun. While the properties of the interface region are still too sparsely known to be useful for solar wind studies the neutral H distribution near the Sun has been used successfully for this purpose. Measuring Lyman alpha light scattered by neutral hydrogen atoms can serve as a remote sensing measurement of the solar wind's three-dimensional and temporal distribution. In this work we will particularly focus on the solar cycle effects on the neutral hydrogen distribution and how it affects the solar wind monitoring.

  8. Turbulence in the Solar Atmosphere and Solar Wind

    NASA Astrophysics Data System (ADS)

    Petrosyan, A.; Balogh, A.; Goldstein, M. L.; Lorat, J.; Marsch, E.; Petrovay, K.; Roberts, B.; von Steiger, R.; Vial, J. C.

    2010-10-01

    The objective of this review article is to critically analyze turbulence and its role in the solar atmosphere and solar wind, as well as to provide a tutorial overview of topics worth clarification. Although turbulence is a ubiquitous phenomenon in the sun and its heliosphere, many open questions exist concerning the physical mechanisms of turbulence generation in solar environment. Also, the spatial and temporal evolution of the turbulence in the solar atmosphere and solar wind are still poorly understood. We limit the scope of this paper (leaving out the solar interior and convection zone) to the magnetized plasma that reaches from the photosphere and chromosphere upwards to the corona and inner heliosphere, and place particular emphasis on the magnetic field structures and fluctuations and their role in the dynamics and radiation of the coronal plasma. To attract the attention of scientists from both the fluid-dynamics and space-science communities we give in the first two sections a phenomenological overview of turbulence-related processes, in the context of solar and heliospheric physics and with emphasis on the photosphere-corona connection and the coupling between the solar corona and solar wind. We also discuss the basic tools and standard concepts for the empirical analysis and theoretical description of turbulence. The last two sections of this paper give a concise review of selected aspects of oscillations and waves in the solar atmosphere and related fluctuations in the solar wind. We conclude with some recommendations and suggest topics for future research.

  9. Pluto's interaction with the solar wind

    NASA Technical Reports Server (NTRS)

    Bagenal, Fran; Mcnutt, Ralph L., Jr.

    1989-01-01

    If Pluto's atmospheric escape rate is significantly greater than 1.5 x 10 to the 27th molecules/s then the interaction with the tenuous solar wind at 30 A.U. will be like that of a comet. There will be extensive ion pick-up upstream and the size of the interaction region will vary directly with variations in the solar wind flux. If the escape flux is much less, then one expects that the solar wind will be deflected around Pluto's ionosphere in a Venus-like interaction. In either case, the weak interplanetary magnetic field at 30 A.U. results in very large gyroradii for the picked-up ions and a thick bow shock, necessitating a kinetic treatment of the interaction. Strong variations in the size of the interaction region are expected on time scales of days due to changes in the solar wind.

  10. Genesis Solar Wind Array Collector Cataloging Status

    NASA Astrophysics Data System (ADS)

    Burkett, P. J.; Rodriguez, M. C.; Calaway, M. C.; Allton, J. H.

    2009-03-01

    A focused characterization task was initiated in May 2008 to document the largest array fragments in the Genesis solar wind collection. To date, the collection consists of 3460 samples. By area, total percentage of cataloged array material is 18%.

  11. Turbulence in solar wind and laboratory plasmas

    SciTech Connect

    Carbone, V.

    2010-06-16

    Recent studies of plasma turbulence based on measurements within solar wind and laboratory plasmas has been discussed. Evidences for the presence of a turbulent energy cascade, using the Yaglom's law for MHD turbulence, has been provided through data from the Ulysses spacecraft. This allows, for the first time, a direct estimate of the turbulent energy transfer rate, which can contribute to the in situ heating of the solar wind. The energy cascade has been evidenced also for ExB electrostatic turbulence in laboratory magnetized plasmas using measurements of intermittent transport (bursty turbulence) at the edge of the RFX-mod reversed field pinch plasma device. Finally the problem of the dispersive region of turbulence in solar wind above the ion-cyclotron frequency, where a spectral break is usually observed, and the problem of dissipation in a collisionless fluid as the solar wind, are briefly discussed.

  12. Solar wind behavior throughout the heliosphere

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.

    1993-01-01

    Observations and interpretations of solar wind behavior in the heliosphere are reviewed. The spiral magnetic field, the heliospheric vortex street, multifractals and large-scale fluctuations, and intermittent turbulence are examined. Voyager observations of the outer heliosphere are stressed.

  13. Electrostatic Solitary Waves in the Solar Wind: Evidence for Instability at Solar Wind Current Sheets

    NASA Technical Reports Server (NTRS)

    Malaspina, David M.; Newman, David L.; Wilson, Lynn Bruce; Goetz, Keith; Kellogg, Paul J.; Kerstin, Kris

    2013-01-01

    A strong spatial association between bipolar electrostatic solitary waves (ESWs) and magnetic current sheets (CSs) in the solar wind is reported here for the first time. This association requires that the plasma instabilities (e.g., Buneman, electron two stream) which generate ESWs are preferentially localized to solar wind CSs. Distributions of CS properties (including shear angle, thickness, solar wind speed, and vector magnetic field change) are examined for differences between CSs associated with ESWs and randomly chosen CSs. Possible mechanisms for producing ESW-generating instabilities at solar wind CSs are considered, including magnetic reconnection.

  14. Solar Corona/Wind Composition and Origins of the Solar Wind

    NASA Astrophysics Data System (ADS)

    Lepri, S. T.; Gilbert, J. A.; Landi, E.; Shearer, P.; von Steiger, R.; Zurbuchen, T.

    2014-12-01

    Measurements from ACE and Ulysses have revealed a multifaceted solar wind, with distinctly different kinetic and compositional properties dependent on the source region of the wind. One of the major outstanding issues in heliophysics concerns the origin and also predictability of quasi-stationary slow solar wind. While the fast solar wind is now proven to originate within large polar coronal holes, the source of the slow solar wind remains particularly elusive and has been the subject of long debate, leading to models that are stationary and also reconnection based - such as interchange or so-called S-web based models. Our talk will focus on observational constraints of solar wind sources and their evolution during the solar cycle. In particular, we will point out long-term variations of wind composition and dynamic properties, particularly focused on the abundance of elements with low First Ionization Potential (FIP), which have been routinely measured on both ACE and Ulysses spacecraft. We will use these in situ observations, and remote sensing data where available, to provide constraints for solar wind origin during the solar cycle, and on their correspondence to predictions for models of the solar wind.

  15. Solar wind observations near the sun

    NASA Technical Reports Server (NTRS)

    Armstrong, J. W.; Coles, W. A.; Rickett, B. J.; Kojima, M.

    1986-01-01

    Observations of interplanetary scintillations with the VLA telescope are reported. The solar wind in the accelerating region from 3 to 12 solar radii was observed by scintillation of the radio source 3C279. The results obtained outside of 7 solar radii showed good agreement with previous work but observations between 3 and 4.5 solar radii were new and unexpected. Turbulence in the solar wind has a spatially anisotropic structure elongated in the radial direction, the flow direction being also in the radial direction. An abrupt change of both the velocity and the spatial anisotropy of turbulence was found at distances from 3 to 4.5 solar radii. There is a large random velocity component inside of 12 solar radii which is comparable to the bulk flow speed, and it has a spatially anisotropic probability distribution. From the measured cross-correlation functions, evidence which may be related to the complex structure of the magnetic field is found.

  16. Magnetic energy flow in the solar wind.

    NASA Technical Reports Server (NTRS)

    Modisette, J. L.

    1972-01-01

    Discussion of the effect of rotation (tangential flow) of the solar wind on the conclusions of Whang (1971) suggesting an increase in the solar wind velocity due to the conversion of magnetic energy to kinetic energy. It is shown that the effect of the rotation of the sun on the magnetic energy flow results in most of the magnetic energy being transported by magnetic shear stress near the sun.

  17. Sulfur abundances in the solar wind measured by SWICS on Ulysses. [Solar Wind Ion Composition Spectrometer

    NASA Technical Reports Server (NTRS)

    Shafer, C. M.; Gloeckler, G.; Galvin, A. B.; Ipavich, F. M.; Geiss, J.; Von Steiger, R.; Ogilvie, K.

    1993-01-01

    One of the nine experiments on Ulysses (launched October, 1990), the Solar Wind Ion Composition Spectrometer, utilizes an energy per charge deflection system along with time of flight technology to uniquely determine the mass and mass per charge of solar wind particles. Thus the composition of various solar wind types can be analyzed. Using the SWICS data accumulated during the in-ecliptic phase of the mission, we have determined the sulfur abundance, relative to silicon, in two different types of solar wind: transient and coronal hole associated flows. Sulfur is of extreme interest because it is one of the few elements that lies in the transitional region of the FIP-dependent relative abundance enrichment function, observed for solar energetic particles and some types of solar wind flows.

  18. The Genesis Solar Wind Sample Return Mission

    NASA Technical Reports Server (NTRS)

    Wiens, Roger C.; Burnett, Donald S.; Neugebauer, Marcia; Sasaki, Chester; Sevilla, Donald; Stansbery, Eileen; Clark, Ben; Smith, Nick; Oldham, Lloyd

    1990-01-01

    The Genesis spacecraft was launched on August 8 from Cape Canaveral on a journey to become the first spacecraft to return from interplanetary space. The fifth in NASA's line of low-cost Discovery-class missions, its goal is to collect samples of solar wind and return them to Earth for detailed isotopic and elemental analysis. The spacecraft is to collect solar wind for over two years, while circling the L1 point 1.5 million km sunward of the earth, before heading back for a capsule-style re-entry in September, 2004. After parachute deployment, a mid-air helicopter recovery will be used to avoid a hard landing. The mission has been in the planning stages for over ten years. Its cost, including development, mission operations, and sample analysis, is approximately $209M. The Genesis science team, headed by principal investigator Donald Burnett of Caltech, consists of approximately 20 co-investigators from universities and science centers around the country and internationally. The spacecraft consists of a relatively flat spacecraft bus containing most of the subsystem components, situated below a sample return capsule (SRC) which holds the solar-wind collection substrates and an electrostatic solar wind concentrator. Some of the collectors are exposed throughout the collection period, for a sample of bulk solar wind, while others are exposed only to certain solar wind regimes, or types of flow. Ion and electron spectrometers feed raw data to the spacecraft control and data-handling (C&DH) unit, which determines ion moments and electron flux geometries in real time. An algorithm is used to robotically decide between interstream (IS), coronal hole (CH), and coronal mass ejection (CME) regimes, and to control deployment of the proper arrays to sample these wind regimes independently. This is the first time such a solar-wind decision algorithm has been used on board a spacecraft.

  19. The Automatic Solar Synoptic Analyzer and Solar Wind Prediction

    NASA Astrophysics Data System (ADS)

    Hong, S.; Kim, J.; Han, J.; Kim, Y.

    2014-12-01

    Automatic Solar Synoptic Analyzer (ASSA) is an automatic software system of identifying sunspot groups, coronal holes, and filament channels which are three major solar sources causing the space weather. Coronal holes, the sources of high speed solar wind stream, cause many of disturbances to the geomagnetic field. We have developed a solar wind prediction model using artificial neural network technique with the ASSA coronal hole data archive of the period of from 1997 to 2013. When the ASSA generated coronal hole data archive, images of SOHO EIT 195 and SDO AIA 193 were used for morphological identification and then SOHO MDI Magnetograms and SDO HMI Magnetograms were used for quantitative verification. In this presentation, we will characterize coronal hole area and solar mean field variation over both the period of solar cycle 24 and the inclining phase of solar cycle 25 and present correlations among coronal hole data(area, location and polarity etc.); the corresponding solar wind velocity; and geomagnetic indices. Those study results were used when selecting training data sets into the artificial neural network. The initial evaluation results of the solar wind prediction model will be also presented.

  20. The Genesis Mission Solar Wind Collection: Solar-Wind Statistics over the Period of Collection

    NASA Technical Reports Server (NTRS)

    Barraclough, B. L.; Wiens, R. C.; Steinberg, J. E.; Reisenfeld, D. B.; Neugebauer, M.; Burnett, D. S.; Gosling, J.; Bremmer, R. R.

    2004-01-01

    The NASA Genesis spacecraft was launched August 8, 2001 on a mission to collect samples of solar wind for 2 years and return them to earth September 8, 2004. Detailed analyses of the solar wind ions implanted into high-purity collection substrates will be carried out using various mass spectrometry techniques. These analyses are expected to determine key isotopic ratios and elemental abundances in the solar wind, and by extension, in the solar photosphere. Further, the photospheric composition is thought to be representative of the solar nebula with a few exceptions, so that the Genesis mission will provide a baseline for the average solar nebula composition with which to compare present-day compositions of planets, meteorites, and asteroids. The collection of solar wind samples is almost complete. Collection began for most substrates in early December, 2001, and is scheduled to be complete on April 2 of this year. It is critical to understand the solar-wind conditions during the collection phase of the mission. For this reason, plasma ion and electron spectrometers are continuously monitoring the solar wind proton density, velocity, temperature, the alpha/proton ratio, and angular distribution of suprathermal electrons. Here we report on the solar-wind conditions as observed by these in-situ instruments during the first half of the collection phase of the mission, from December, 2001 to present.

  1. Solar Wind Interaction With the Lunar Environment

    NASA Astrophysics Data System (ADS)

    Halekas, J. S.

    2005-12-01

    The Earth's Moon, lacking a substantial atmosphere or global magnetic field, presents one of the simpler obstacles to solar wind flow in our solar system. Despite this apparent simplicity, a rich array of interesting plasma physics occurs in the lunar environment. To first order, the Moon is completely unshielded from solar wind plasma and solar photons, and direct incidence of solar wind plasma can lead to implantation of volatiles and ion sputtering and pickup. The solar wind is blocked by the lunar obstacle, resulting in a plasma void on the night side. A potential drop across the wake boundary is generated as solar wind electrons attempt to refill the wake cavity, resulting in a tenuous high-temperature electron population and anisotropic ion beams in the wake. A system of diamagnetic currents is formed on the boundary surface, enhancing the magnetic field in the wake and reducing the field around it. Meanwhile, waves are generated by the unstable particle distributions generated by this interaction. On the day side, photon-driven positive charging of the lunar surface occurs. On the night side, on the other hand, charging is controlled by the tenuous wake plasma, and is generally electron-driven and negative. When the Moon traverses the Earth's magnetotail and is exposed to low-density plasma in the tail lobes and high-temperature plasma in the plasmasheet, extreme surface charging of up to hundreds of V positive and several keV negative can occur. Lunar surface charging may affect ion sputtering and likely results in significant dust transport. The presence of remanent crustal magnetism causes significant perturbations to this picture. Some crustal fields are large enough to stand off the solar wind (possibly affecting solar wind volatile implantation), and we observe large shock-like magnetic enhancements upstream from the largest crustal sources. The occurence of these "limb shocks" depends on solar wind parameters, suggesting that the crustal sources are only large enough and strong enough for solar wind plasma to react in a fluid-like way for certain upstream conditions.

  2. Response of Solar Wind on Extreme Solar Activity

    NASA Astrophysics Data System (ADS)

    Suzuki, T. K.

    2015-09-01

    We investigate how the mass loss by the solar wind depends on the solar activity levels, particularly focusing on the solar wind during extremely high activity. We perform forward-type magnetohydrodynamical (MHD) numerical experiments for Alfvn wave-driven solar winds with a wide range of the input Poynting flux from the photosphere. Increasing the magnetic field strength and the turbulent velocity at the solar photosphere from the current solar level, the mass loss rate rapidly increases at first owing to the suppression of the reflection of the Alfvn waves. The surface materials are lifted up by the magnetic pressure associated with the Alfvn waves, and the cool dense chromosphere is extended to ? 10% of the stellar radius. The dense atmospheres enhance the radiative losses and eventually most of the input Poynting energy from the surface escapes by the radiation. As a result, there is no more sufficient energy remained for the kinetic energy of the wind; the solar wind saturates for the extreme activity level, as observed in Wood et al. The saturation level is positively correlated with the average magnetic field strength contributed from open flux tubes. If the field strength is a few times larger than the present level, the mass loss rate could be as high as 1000 times.

  3. Are There Natural Categories of Solar Wind?

    NASA Astrophysics Data System (ADS)

    Roberts, D. A.; Sipes, T.; Karimabadi, H.

    2014-12-01

    What seem to be the most obvious categories of solar wind, such as fast and slow, often turn out to be difficult to pin down on closer examination. For example, while slow winds tend to be dense and nonAlfvenic, there are significant exceptions, with some slow winds being not only very Alfvenic but also exhibiting many fast wind traits. Here we use "unsupervised" data mining to look for "natural" solar wind types. We use a set of variables to represent the state of the system and apply what are now standard algorithms to look for natural clustering of these variables. We have done this process for the solar wind density, speed, a carbon charge state ratio (6+ to 5+), the cross-helicity, and the "residual energy." When using the first three of these, we find two groups that tend to be slow and fast, but with the boundary between the groups that is a combination of speed and density. When all five variables are used, the best characterization of the states is as three basic groups in the cross-helicity vs residual energy space, i.e., in terms of "turbulence" measures rather than simple parameters. The three-variable case is largely but not completely reproduced in its subspace. We will suggest what the results could mean for the understanding of issues such as solar wind acceleration.

  4. Solar Wind Forecasting with Coronal Holes

    NASA Astrophysics Data System (ADS)

    Robbins, S.; Henney, C. J.; Harvey, J. W.

    2006-02-01

    An empirical model for forecasting solar wind speed related geomagnetic events is presented here. The model is based on the estimated location and size of solar coronal holes. This method differs from models that are based on photospheric magnetograms (e.g., Wang Sheeley model) to estimate the open field line configuration. Rather than requiring the use of a full magnetic synoptic map, the method presented here can be used to forecast solar wind velocities and magnetic polarity from a single coronal hole image, along with a single magnetic full-disk image. The coronal hole parameters used in this study are estimated with Kitt Peak Vacuum Telescope He I 1083 nm spectrograms and photospheric magnetograms. Solar wind and coronal hole data for the period between May 1992 and September 2003 are investigated. The new model is found to be accurate to within 10% of observed solar wind measurements for its best 1-month period, and it has a linear correlation coefficient of 0.38 for the full 11 years studied. Using a single estimated coronal hole map, the model can forecast the Earth directed solar wind velocity up to 8.5 days in advance. In addition, this method can be used with any source of coronal hole area and location data.

  5. Properties of Minor Ions In the Solar Wind and Implications for the Background Solar Wind Plasma

    NASA Technical Reports Server (NTRS)

    Esser, Ruth; Wagner, William (Technical Monitor)

    2002-01-01

    Ion charge states measured in situ in interplanetary space carry information on the properties of the solar wind plasma in the inner corona. The goal of the proposal is to determine coronal plasma conditions that produce the in situ observed charge states. This study is carried out using solar wind models, coronal observations, ion fraction calculations and in situ observations.

  6. New Horizons Solar Wind Around Pluto Solar Wind (SWAP) Measurements from 5 to 23 AU

    NASA Astrophysics Data System (ADS)

    Elliott, H. A.; McComas, D. J.; Delamere, P. A.

    2012-12-01

    This year the Solar Wind Around Pluto (SWAP) instrument on the New Horizons (NH) spacecraft collected 79 days of solar wind measurements during hibernation, about 30 days of data during annual checkout operations, and has begun recording another 168 days of data in hibernation which will be played back next year. The currently available NH-SWAP solar wind observations now span from about 5.1 to 23.4 AU. We examine how the peak solar wind speed in the New Horizons measurements vary with distance, report on progress toward automating the fitting of the SWAP solar wind count rate distributions, and take an initial look at the solar wind temperature-speed relationship beyond 11 AU. Since most of the SWAP solar wind observations were collected while spinning, and ions from the entire field-of-view (10 by 276 degrees) are focused onto one pair of coincidence Channel Electron Multiplier, we need to evaluate the effect of spinning on the measured rates. By comparing the 3-axis stabilized, to the rolling and spinning measurements, we strive to assess spin variations in the observed SWAP count rates and develop techniques to account for them. To test our analysis, we fit simulated count rate distributions to quantify how well our technique recovers the input solar wind conditions.

  7. Multiple spacecraft study of solar wind dynamics

    NASA Astrophysics Data System (ADS)

    Gonzalez-Esparza, A.; Romero Hernandez, E.

    2011-12-01

    We combined simultaneous solar wind observations from five different spacecraft: Helios 1, Helios 2, IMP-8, Voyager 1 and Voyager 2, from November 1977 to February 1978 (ascending phase of solar cycle 21). During this period the large-scale dynamics of the solar wind near of the ecliptic plane was characterized by transient forward shocks (TFSs), Coronal Mass Eyections (CMEs), stream interaction regions (SIRs), and complex and variable magnetic sector structures. We characterize the solar wind streams observed by the five spacecraft. We employ maps of large-scale features to study the location of TFSs and SIRs with respect to the magnetic sector structure detected by each spacecraft. We study the geometry of the SIRs by analyzing the orientation of their Stream Interaction Regions. We study the variations of the sheath width for all the shock-CME events.

  8. The solar cycle variation of the solar wind helium abundance

    NASA Technical Reports Server (NTRS)

    Ogilvie, K. W.; Hirshberg, J.

    1974-01-01

    A critical survey was made of the experimental evidence for a variation of the relative abundance by number h, (n alpha/np), of helium in the solar wind. The abundance is found to vary by delta h = 0.01 + or - 0.01 from 0.035 to 0.045 over solar cycle 20. Changes in the average bulk speed during the solar activity cycle was insufficient to account for this increase in h with the solar cycle. The slope of the linear relation between h and the plasma bulk speed is also found to vary, being greatest around solar maximum. An attempt is made to explain the 30% variation in h as the result of the variation in the number of major solar flares over a solar cycle. These obvious transients are apparently not numerous enough to explain the observed variation, but the reasonable expectation remains that the transients observed recently by Skylab which may occur more frequently than major flares could augment those associated with major flares. Since the solar wind flux is not observed to increase at solar maximum, the abundance of Helium cannot be proportional to the proton flux leaving the sun unless the solar wind comes from a smaller area of the sun at maximum than at minimum.

  9. Predicting solar wind conditions at Mars

    NASA Astrophysics Data System (ADS)

    Fry, C. D.; Dryer, M.; Sun, W.; Deehr, C. S.; Akasofu, S.; McKenna-Lawlor, S.; Lario, D.

    2004-05-01

    High energy particles generated during solar/interplanetary 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 interplanetary 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 interplanetary 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 inner heliosphere, including at the location of Mars. We are also conducting retrospective Mars space weather studies by simulating solar wind conditions during significant solar event periods and comparing modeling results with disturbance signatures observed at Mars. These signatures include enhancements in the energetic particle environment at Mars, and instrument anomalies on spacecraft orbiting Mars. We will present recent study results.

  10. Solar wind electron measurements from the Wind spacecraft

    NASA Astrophysics Data System (ADS)

    Bale, S. D.

    2014-12-01

    The Wind spacecraft has been on orbit for 20 years and produced a wealth solar wind science. In this talk, I will describe results from the Three Dimensional Plasma (3DP) instrument on Wind. In particular, we will use measurements of 1 AU electron distribution functions to show that the thermal electron bulk speed lags the proton speed and that this velocity difference is controlled by Coulomb collisions. By integrating the equation of dynamical friction back into the inner heliosphere, we infer that the plasma environment of the corona (within 20 Rs) is higher kinetic.

  11. Solar Metallicity Derived from in situ Solar Wind Composition

    NASA Astrophysics Data System (ADS)

    von Steiger, R.; Zurbuchen, T. H.

    2016-01-01

    We use recently released solar wind compositional data to determine the metallicity of the Sunthe fraction per unit mass that is composed of elements heavier than He. We focus on a present-day solar sample available to us, which is the least fractionated solar wind from coronal holes near the poles of the Sun. Using these data, we derive a metallicity of Z = 0.0196 0.0014, which is significantly larger than recent published values based on photospheric spectroscopy, but consistent with results from helioseismology.

  12. The Three-Dimenstional Solar Wind at Solar Activity Minimum

    NASA Technical Reports Server (NTRS)

    Neugebauer, M.

    1998-01-01

    In late 1997, the Ulysses spacecraft completed its first orbit around the Sun, observing the properties of the heliosphere at all latitudes between 80 degrees South and 80 degrees North. Because the mission occurred during a period of near-minimum solar activity, the configuration of the solar wind and interplanetary magnetic field were particularly simple, thus allowing confident comparisons between the properties of the polar corona observed by instruments of the Spartan and SOHO spacecraft and the resulting properties of the solar wind.

  13. Titan's interaction with the supersonic solar wind

    NASA Astrophysics Data System (ADS)

    Bertucci, C.; Hamilton, D. C.; Kurth, W. S.; Hospodarsky, G.; Mitchell, D.; Sergis, N.; Edberg, N. J. T.; Dougherty, M. K.

    2015-01-01

    9 years in the Saturn system, the Cassini spacecraft finally observed Titan in the supersonic and super-Alfvnic solar wind. These unique observations reveal that Titan's interaction with the solar wind is in many ways similar to unmagnetized planets Mars and Venus and active comets in spite of the differences in the properties of the solar plasma in the outer solar system. In particular, Cassini detected a collisionless, supercritical bow shock and a well-defined induced magnetosphere filled with mass-loaded interplanetary magnetic field lines, which drape around Titan's ionosphere. Although the flyby altitude may not allow the detection of an ionopause, Cassini reports enhancements of plasma density compatible with plasma clouds or streamers in the flanks of its induced magnetosphere or due to an expansion of the induced magnetosphere. Because of the upstream conditions, these observations may be also relevant to other bodies in the outer solar system such as Pluto, where kinetic processes are expected to dominate.

  14. Clouds blown by the solar wind

    NASA Astrophysics Data System (ADS)

    Voiculescu, M.; Usoskin, I.; Condurache-Bota, S.

    2013-12-01

    In this letter we investigate possible relationships between the cloud cover (CC) and the interplanetary electric field (IEF), which is modulated by the solar wind speed and the interplanetary magnetic field. We show that CC at mid-high latitudes systematically correlates with positive IEF, which has a clear energetic input into the atmosphere, but not with negative IEF, in general agreement with predictions of the global electric circuit (GEC)-related mechanism. Thus, our results suggest that mid-high latitude clouds might be affected by the solar wind via the GEC. Since IEF responds differently to solar activity than, for instance, cosmic ray flux or solar irradiance, we also show that such a study allows distinguishing one solar-driven mechanism of cloud evolution, via the GEC, from others.

  15. Laboratory Facility for Simulating Solar Wind Sails

    SciTech Connect

    Funaki, Ikkoh; Ayabe, Tomohiro; Horisawa, Hideyuki; Yamakawa, Hiroshi

    2008-12-31

    Magnetic sail (MagSail) is a deep space propulsion system, in which an artificial magnetic cavity captures the energy of the solar wind to propel a spacecraft in the direction leaving the sun. For a scale-model experiment of the plasma flow of MagSail, we employed a magnetoplasmadynamic arcjet as a solar wind simulator. It is observed that a plasma flow from the solar wind simulator reaches a quasi-steady state of about 0.8 ms duration after a transient phase when initiating the discharge. During this initial phase of the discharge, a blast-wave was observed to develop radially in a vacuum chamber. When a solenoidal coil (MagSail scale model) is immersed into the quasi-steady flow where the velocity is 45 km/s, and the number density is 10{sup 19} m-3, a bow shock as well as a magnetic cavity were formed in front of the coil. As a result of the interaction between the plasma flow and the magnetic cavity, the momentum of the simulated solar wind is decreased, and it is found from the thrust measurement that the solar wind momentum is transferred to the coil simulating MagSail.

  16. The Solar Wind Ion Analyzer for MAVEN

    NASA Astrophysics Data System (ADS)

    Halekas, J. S.; Taylor, E. R.; Dalton, G.; Johnson, G.; Curtis, D. W.; McFadden, J. P.; Mitchell, D. L.; Lin, R. P.; Jakosky, B. M.

    2015-12-01

    The Solar Wind Ion Analyzer (SWIA) on the MAVEN mission will measure the solar wind ion flows around Mars, both in the upstream solar wind and in the magneto-sheath and tail regions inside the bow shock. The solar wind flux provides one of the key energy inputs that can drive atmospheric escape from the Martian system, as well as in part controlling the structure of the magnetosphere through which non-thermal ion escape must take place. SWIA measurements contribute to the top level MAVEN goals of characterizing the upper atmosphere and the processes that operate there, and parameterizing the escape of atmospheric gases to extrapolate the total loss to space throughout Mars' history. To accomplish these goals, SWIA utilizes a toroidal energy analyzer with electrostatic deflectors to provide a broad 360∘×90∘ field of view on a 3-axis spacecraft, with a mechanical attenuator to enable a very high dynamic range. SWIA provides high cadence measurements of ion velocity distributions with high energy resolution (14.5 %) and angular resolution (3.75∘×4.5∘ in the sunward direction, 22.5∘×22.5∘ elsewhere), and a broad energy range of 5 eV to 25 keV. Onboard computation of bulk moments and energy spectra enable measurements of the basic properties of the solar wind at 0.25 Hz.

  17. Solar wind ion composition and charge states

    SciTech Connect

    Vonsteiger, R.

    1995-06-01

    The solar wind, a highly tenuous plasma streaming from the Sun into interplanetary space at supersonic speed, is roughly composed of 95% hydrogen and 5% helium by number. All other, heavy elements contribute less than 0.1% by number and thus are truly test particles Nevertheless, these particles provide valuable information not present in the main components. The authors first discuss the importance of the heavy ions as tracers for processes in the solar atmosphere. Specifically, their relative abundances are found to be different in the solar wind as compared to the photosphere. This fractionation, which is best organized as a function of the first ionization time (FIT) of the elements under solar surface conditions, provides information on the structure of the chromosphere, where it is imparted on the partially ionized material by an atom-ion separation mechanism. Moreover, the charge states of the heavy ions can be used to infer the coronal temperature, since they are frozen-in near the altitude where the expansion time scale overcomes the ionization/recombination time scales. Next, the authors review the published values of ion abundances in the solar wind, concentrating on the recent results of the SWICS instrument on Ulysses. About 8 elements and more than 20 charge states can be routinely analyzed by this sensor. There is clear evidence that both the composition and the charge state distribution is significantly different in the fast solar wind from the south polar coronal hole, traversed by Ulysses in 1993/94, as compared to the solar wind normally encountered near the ecliptic plane. The fractionation between low- and high-FIT elements is reduced, and the charge states indicate a lower, more uniform coronal temperature in the hole. Finally, the authors discuss these results in the framework of existing theoretical models of the chromosphere and corona, attempting to identify differences between the low- and high-latitude regions of the solar atmosphere.

  18. Energy Dissipation Processes in Solar Wind Turbulence

    NASA Astrophysics Data System (ADS)

    Wang, Y.; Wei, F. S.; Feng, X. S.; Xu, X. J.; Zhang, J.; Sun, T. R.; Zuo, P. B.

    2015-12-01

    Turbulence is a chaotic flow regime filled by irregular flows. The dissipation of turbulence is a fundamental problem in the realm of physics. Theoretically, dissipation ultimately cannot be achieved without collisions, and so how turbulent kinetic energy is dissipated in the nearly collisionless solar wind is a challenging problem. Wave particle interactions and magnetic reconnection (MR) are two possible dissipation mechanisms, but which mechanism dominates is still a controversial topic. Here we analyze the dissipation region scaling around a solar wind MR region. We find that the MR region shows unique multifractal scaling in the dissipation range, while the ambient solar wind turbulence reveals a monofractal dissipation process for most of the time. These results provide the first observational evidences for intermittent multifractal dissipation region scaling around a MR site, and they also have significant implications for the fundamental energy dissipation process.

  19. Magnetofluid Turbulence in the Solar Wind

    NASA Technical Reports Server (NTRS)

    Goldstein, Melvyn L.

    2008-01-01

    The solar wind shows striking characteristics that suggest that it is a turbulent magnetofluid, but the picture is not altogether simple. From the earliest observations, a strong correlation between magnetic fluctuations and plasma velocity fluctuations was noted. The high corrections suggest that the fluctuations are Alfven waves. In addition, the power spectrum of the magnetic fluctuation showed evidence of an inertial range that resembled that seen in fully-developed fluid turbulence. Alfven waves, however, are exact solutions of the equations of incompressible magnetohydrodynamics. Thus, there was a puzzle: how can a magnetofluid consisting of Alfven waves be turbulent? The answer lay in the role of velocity shears in the solar wind that could drive turbulent evolution. Puzzles remain: for example, the power spectrum of the velocity fluctuations is less steep than the slope of the magnetic fluctuations, nor do we understand even now why the solar wind appears to be nearly incompressible with a -5/3 power-spectral index.

  20. Solar cycle evolution of the solar wind in three dimensions

    NASA Technical Reports Server (NTRS)

    Rickett, B. J.; Coles, W. A.

    1983-01-01

    Measurements of the solar wind speed both in and out of the ecliptic are presented for 1971-82. The speed estimates, which were made with the interplanetary scintillation system at UC San Diego, have been compared to in situ for large, slowly evolving structures, and thus such structures can be studied up to 60 degrees north and south heliographic latitude. Annual average wind speeds are presented versus latitude for an entire solar cycle. Fast wind streams from the poles persisted through declining and low solar activity, but were closed off during four years of high activity. This evolution follows that of the polar coronal holes, as displayed by comparing averaged speed and coronal density over latitude and longitude. The most recent data (1982) show the reestablishment of large tilted polar holes and associated fast streams. Coronal magnetic field data show that the neutral sheet is confined to low latitudes at solar minimum and extends to high latitudes at solar maximum; thus the slow solar wind comes from the same latitude range as that of the neutral sheet.

  1. Standing shocks in the inner solar wind

    NASA Technical Reports Server (NTRS)

    Leer, Egil; Holzer, Thomas E.

    1990-01-01

    It has been pointed out by several authors that the equations describing rapidly diverging flow in the solar wind and in related astrophysical systems allow for solutions with standing shocks in the acceleration region of the flow. The range of plasma and flow-geometry parameters that allow for such solutions are investigated. It is shown that, for reasonable geometries, shocks can occur only for a very narrow range of flow parameters in the case of the solar wind. Similar results can be expected for related astrophysical systems.

  2. Solar Wind Change Exchange from the Magnetosheath

    NASA Technical Reports Server (NTRS)

    Snowden, Steve

    2008-01-01

    We report the results of a long (approximately 100 ks) XMM-Newton observation designed to observe solar wind charge exchange emission (SWCX) from Earth's magnetosheath. By luck, the observation took place during a period of minimal solar wind flux so the SWCX emission was also minimal. Never-the-less, there is a significant if not stunning correlation between the observed O VIII count rate and our model for magnetosheath emission. We also report on the observed O VII and O VII emission.

  3. Workshop on Solar Activity, Solar Wind, Terrestrial Effects, and Solar Acceleration

    NASA Technical Reports Server (NTRS)

    1992-01-01

    A summary of the proceedings from the workshop are presented. The areas covered were solar activity, solar wind, terrestrial effects, and solar acceleration. Specific topics addressed include: (1) solar cycle manifestations, both large and small scale, as well as long-term and short-term changes, including transients such as flares; (2) sources of solar wind, as identified by interplanetary observations including coronal mass ejections (CME's) or x-ray bright points, and the theory for and evolution of large-scale and small-scale structures; (3) magnetosphere responses, as observed by spacecraft, to variable solar wind and transient energetic particle emissions; and (4) origin and propagation of solar cosmic rays as related to solar activity and terrestrial effects, and solar wind coronal-hole relationships and dynamics.

  4. Adiabatic cooling of solar wind electrons

    NASA Technical Reports Server (NTRS)

    Sandbaek, Ornulf; Leer, Egil

    1992-01-01

    In thermally driven winds emanating from regions in the solar corona with base electron densities of n0 not less than 10 exp 8/cu cm, a substantial fraction of the heat conductive flux from the base is transfered into flow energy by the pressure gradient force. The adiabatic cooling of the electrons causes the electron temperature profile to fall off more rapidly than in heat conduction dominated flows. Alfven waves of solar origin, accelerating the basically thermally driven solar wind, lead to an increased mass flux and enhanced adiabatic cooling. The reduction in electron temperature may be significant also in the subsonic region of the flow and lead to a moderate increase of solar wind mass flux with increasing Alfven wave amplitude. In the solar wind model presented here the Alfven wave energy flux per unit mass is larger than that in models where the temperature in the subsonic flow is not reduced by the wave, and consequently the asymptotic flow speed is higher.

  5. Electrons In The Low Density Solar Wind

    NASA Technical Reports Server (NTRS)

    Ogilvie, Keith W.; Desch, Michael; Fitzenreiter, Richard; Vondrak, Richard R. (Technical Monitor)

    2000-01-01

    The recent occurrence of an interval (May 9th to May 12th, 1999) of abnormally low density solar wind has drawn attention to such events. The SWE instrument on the Wind spacecraft observed nine similar events between launch (November 1994) and August 1999: one in 1997, three in 1998, and five in January-August 1999. No such events were observed in 1996, the year of solar minimum. This already suggests a strong dependence upon solar activity. In this paper we discuss observations of the electron strahl, a strong anisotropy in the solar wind electrons above 60 eV directed along the magnetic field and observed continuously during the periods of low density in 1998 and 1999. When the solar wind density was less than 2/cc, the angular width of the strahl was below 3.5 degrees and the temperature deduced from the slope of the electron strahl phase density (as a function of energy in the energy range 200 to 800 eV) was 100 to 150 eV, equivalent to a typical coronal electron temperature. Three examples of this phenomenon, observed on Feb. 20- 22, April 26-27 and May 9-12, 1999, are discussed to show their similarity to one another. These electron observations are interpreted to show that the strahl occurs as a result of the conservation of the first adiabatic invariant, combined with the lack of coulomb collisions as suggested by Fairfield and Scudder, 1985.

  6. Solar wind composition from the Moon;

    NASA Astrophysics Data System (ADS)

    Bochsler, P.

    1994-06-01

    The lunar regolith contains the best accessible record of the solar wind composition of the past few billion years. Interpreting this record crucially depends on our understanding of the implantation mechanisms, potential alternative sources other than the solar wind, storage and degradation processes, and transport- and loss-mechanisms of trapped particles in the regolith. We therefore suggest that a future mission to the Moon should contain the following objectives: (1) A thorough in-situ investigation of the contemporary solar wind composition by means of long-duration exposure experiments with various techniques as baseline for investigation of the historic and ancient solar wind. (2) A multidisciplinary program, involving an experimental investigation of implantation-, storage- and loss-processes of solar particles at the conditions of the lunar environment. This program is complementary to an elaborated systematic sampling of all layers of the lunar regolith, based on the experience from the Apollo- and the Luna-missions. Difficulties with the interpretation of the lunar record are illuminated in the case of surface correlated nitrogen. (3) A complementary goal for the extensive sampling of the lunar surface is the documentation of the lunar regolith for future generations, prior to extended human activites which could have detrimental effects to the lunar environment.

  7. Effects of Dayside Ionospheric Conductivity on the Solar Wind-Magnetosphere-Ionosphere Coupling: Solar Cycle Dependence of Night-side Field-aligned Currents

    NASA Astrophysics Data System (ADS)

    Ohtani, S.; Higuchi, T.; Wing, S.; Merkin, V. G.

    2014-12-01

    In the present study we observationally address the role of ionospheric conductivity in the solar wind-magnetosphere coupling in terms of global field-aligned currents (FACs). Solar EUV irradiance changes during a solar cycle, and so does its contribution to the ionospheric conductivity. We statistically examine how, under fixed external conditions, the intensities of the R1 and R2 currents and their demarcation latitude depend on solar activity (F10.7). An emphasis is placed on nightside FACs in the dark hemisphere. The result shows that for fixed ranges of interplanetary electric field, the nightside FACs are more intense for higher solar activity irrespective of their polarities or local times. It is also found that the R1-R2 pair, therefore the auroral oval, moves equatorward as the solar activity increases. For both current intensity and latitude, the dependence on F10.7 is more sensitive at smaller F10.7 and it levels off with increasing F10.7. The intensities of dayside FACs reveal similar F10.7 dependence as expected from the enhancement of the local ionospheric conductance. Interestingly, they also move equatorward with increasing solar activity. It is expected from force balance that as the dayside R1 current becomes more intense with increasing solar activity, the magnetosphere shrinks on the day side and expands on the night side. This configurational change of the magnetosphere presumably affects the energy transport from the solar wind to the magnetosphere, although its details still remain to be understood. We conclude that the ionospheric conductivity actively affects the solar wind-magnetosphere-ionosphere coupling.

  8. Solar Wind Forecasting with Coronal Holes

    NASA Astrophysics Data System (ADS)

    Robbins, S. J.; Henney, C. J.; Harvey, J. W.

    2004-12-01

    An empirical model for forecasting solar wind speed related geomagnetic events is presented. The model is based on the location and size of solar coronal holes determined with Kitt Peak Vacuum Telescope \\ion{He}{1} 1083.0 nm spectroheliograms and photospheric magnetograms. This method differs from the Wang-Sheeley model that is based on photospheric magnetograms to estimate the open field line configuration. Solar wind and coronal hole data for the period between May 1992 and September 2003 are investigated. The new model is found to be accurate to within 4.5-5.7% (the range depends upon the number of days ahead forecast) of observed solar wind measurements for the best one-month periods within the time frame studied; the overall 11-year correlation is as high as 0.382. Using coronal hole maps, the model can predict the solar wind velocity up to 8.5 days in advance with an average fractional deviation as low as 9.4-10.0% for a given one-month period. This is further in advance forecasting and up to a factor of 2 improvement over the Wang-Sheeley model. Its main features are a strong southern hemisphere bias, sunspot cycle dependence, and that a complete forecast of up to 9 days can be made from a single solar image, as opposed to a full synoptic map required by the Wang-Sheeley model. This work is carried out through the National Solar Observatory Research Experiences for Undergraduate (REU) site program, which is co-funded by the Department of Defense in partnership with the National Science Foundation REU Program. This research was supported in part by the Office of Naval Research Grant N00014-91-J-1040. The National Solar Observatory is operated by AURA, Inc. under a cooperative agreement with the National Science Foundation.

  9. Solar Wind MHD Turbulence in Coronal Hole and Streamer Belt wind

    NASA Astrophysics Data System (ADS)

    Hu, J.; Li, G.; Miao, B.

    2014-12-01

    Solar wind MHD turbulence depends on solar wind type and can be quite different in coronal hole (fast) wind from streamer belt (slow) wind. In this work we identify the origins of solar wind using the O7+/O6+ ratio and proton specific entropy etc, and then study the differences of the MHD turbulence properties of these two winds. We first investigate the dependence of the occurrence rate of current sheets on solar wind type. We also examine how the residual energy and cross helicity behave in different periods of solar wind that are characterized by the occurrence rate of current sheets and solar wind type. The results will help us to get a better understanding of solar wind turbulence as well as the physical mechanisms of the dissipation process associated with current sheets.

  10. Solar Wind Interaction with Dusty Cometary Coma

    NASA Astrophysics Data System (ADS)

    Popel, S. I.; Gisko, A. A.; Losseva, T. V.; Vladimirov, S. V.

    Interaction of Solar wind with dusty cometary coma is considered. In contrast to previous descriptions of this interaction we take into account the influence of charged dust of cometary coma on bow shock formation. Our description is performed on the basis of a self-consistent model which takes into account solar radiation; dust particle charging; evaporation and formation of neutral particles; photoionization; electric fields; the evolution of solar wind ions, cometary ions and dust particles; as well as the dust charge variation. It is shown that the presence of dust in cometary coma can modify shock wave formed as a result of Solar wind interaction with a comet. The outer shock wave (bow shock) can be considered as an ion acoustic shock wave modified by dust particle charging process. Possible formation of dust structures in the region of the interaction of Solar wind with cometary coma is discussed. The developed model allows us to determine the shock front structure. The calculations are performed for a comet situated at the distance of 1 AU from the Sun. For typical cometary nucleus size of about 1 km and rather dense dusty coma (exceeding million of cubic centimeters near the comet nucleus) the bow shock formed as a result of the interaction of Solar wind with the coma is expected to be related to the anomalous dissipation due to the dust particle charging. The bow shock is similar, by its origin, to the shocks observed by Nakamura et al. (Phys. Rev. Lett. 83, 1602 (1999)) and Luo et al. (Phys. Plasmas 6, 3455 (1999)) and those predicted theoretically (Popel et al., Phys. Plasmas 3, 4313 (1996); Popel et al., Phys. Plasmas 7, 2410 (2000)).

  11. Coronal Plumes in the Fast Solar Wind

    NASA Technical Reports Server (NTRS)

    Velli, Marco; Lionello, Roberto; Linker, Jon A.; Mikic, Zoran

    2011-01-01

    The expansion of a coronal hole filled with a discrete number of higher density coronal plumes is simulated using a time-dependent two-dimensional code. A solar wind model including an exponential coronal heating function and a flux of Alfven waves propagating both inside and outside the structures is taken as a basic state. Different plasma plume profiles are obtained by using different scale heights for the heating rates. Remote sensing and solar wind in situ observations are used to constrain the parameter range of the study. Time dependence due to plume ignition and disappearance is also discussed. Velocity differences of the order of approximately 50 km/s, such as those found in microstreams in the high-speed solar wind, may be easily explained by slightly different heat deposition profiles in different plumes. Statistical pressure balance in the fast wind data may be masked by the large variety of body and surface waves which the higher density filaments may carry, so the absence of pressure balance in the microstreams should not rule out their interpretation as the extension of coronal plumes into interplanetary space. Mixing of plume-interplume material via the Kelvin-Helmholtz instability seems to be possible within the parameter ranges of the models defined here, only at large di stances from the Sun, beyond 0.2-0.3 AU. Plasma and composition measurements in the inner heliosphere, such as those which will become available with Solar Orbiter and Solar Probe Plus, should therefore definitely be able to identify plume remnants in the solar wind.

  12. Solar cycle changes in the polar solar wind

    NASA Technical Reports Server (NTRS)

    Coles, W. A.; Rickett, B. J.; Rumsey, V. H.; Kaufman, J. J.; Turley, D. G.; Ananthakrishnan, S.; Armstrong, J. W.; Harmons, J. K.; Scott, S. L.; Sime, D. G.

    1980-01-01

    It is noted that although the 11 year solar cycle was first recognized in 1843, it is still only poorly understood. Further, while there are satisfactory models for the magnetic variations, the underlying physics is still obscure. New observations on the changing three-dimensional form of the solar wind are presented which help relate some of the modulations observed in geomagnetic activity, the ionosphere, and the flux of galactic cosmic rays.

  13. Apollo 11 solar wind composition experiment: first results.

    PubMed

    Bhler, F; Eberhardt, P; Geiss, J; Meister, J; Signer, P

    1969-12-19

    The helium-4 solar wind flux during the Apollo 11 lunar surface excursion was (6.3 +/- 1.2) x 10(6) atoms per square centimeter per second. The solar wind direction and energy are essentially not perturbed by the moon. Evidence for a lunar solar wind albedo was found. PMID:17742848

  14. Electrodynamic sailing - Beating into the solar wind.

    NASA Technical Reports Server (NTRS)

    Sonett, C. P.; Fahleson, U.; Alfven, H.

    1972-01-01

    The recent suggestion by Alfven (1972) of a novel means of spacecraft propulsion based upon energy extraction from the electromagnetic field of the solar wind is critically reviewed. In response to this review, the original suggestion is somewhat amplified and clarified by its author.

  15. Modeling Multifractality of the Solar Wind

    NASA Astrophysics Data System (ADS)

    Macek, Wiesław M.

    2006-02-01

    The question of multifractality is of great importance because it allows us to investigate interplanetary hydromagnetic turbulence. The multifractal spectrum has been investigated with Voyager (magnetic field) data in the outer heliosphere and with Helios (plasma) data in the inner heliosphere. We use the Grassberger and Procaccia method that allows calculation of the generalized dimensions of the solar wind attractor in the phase space directly from the cleaned experimental signal. We analyze time series of plasma parameters of the low-speed streams of the solar wind measured in situ by Helios in the inner heliosphere. The resulting spectrum of dimensions shows a multifractal structure of the solar wind attractor. In order to quantify that multifractality, we use a simple analytical model of the dynamical system. Namely, we consider the generalized self-similar baker’s map with two parameters describing uniform compression and natural invariant measure on the attractor of the system. The action of this map exhibits stretching and folding properties leading to sensitive dependence on initial conditions. The obtained solar wind singularity spectrum is consistent with that for the multifractal measure on the weighted baker’s map.

  16. Hemispheric differences in solar wind - magnetosphere interactions

    NASA Astrophysics Data System (ADS)

    Reistad, J. P.; Ostgaard, N.; Laundal, K.; Snekvik, K.; Tenfjord, P.; Oksavik, K.

    2014-12-01

    Although the aurora to a large degree behave similar in the two hemispheres, recent simultaneous observations of the global aurora from space have revealed that sometimes rather large intensity and location asymmetries are present in the global aurora. From event studies using e.g. conjugate imaging, multiple mechanisms have been proposed to be responsible for the asymmetric aurora. However, we know very little about their general importance. We have investigated the general importance of an asymmetric solar wind dynamo. It has been suggested that the radial component of the IMF can modify the energy conversion between the solar wind and magnetosphere differently in the two hemispheres in a general sense. By looking at the global aurora using IMAGE WIC during carefully selected events minimally contaminated by other mechanisms affecting the two hemispheres differently, we find that the dusk side aurora depend oppositely on the radial IMF direction in the two hemispheres. These results are consistent with an asymmetric solar wind dynamo where the hemispheric preference is controlled by the radial IMF. This is the first study indicating the importance of the asymmetric solar wind dynamo in a general sense. A different mechanism, the asymmetric loading of magnetic flux during IMF By conditions is also expected to account for North-South asymmetries in the nightside global aurora. This will be investigated using a similar approach to establish the general importance of of this IMF By mechanism on the global aurora in the two hemispheres.

  17. Energy Primer: Solar, Water, Wind, and Biofuels.

    ERIC Educational Resources Information Center

    Portola Inst., Inc., Menlo Park, CA.

    This is a comprehensive, fairly technical book about renewable forms of energy--solar, water, wind, and biofuels. The biofuels section covers biomass energy, agriculture, aquaculture, alcohol, methane, and wood. The focus is on small-scale systems which can be applied to the needs of the individual, small group, or community. More than one-fourth…

  18. Identifying Wind and Solar Ramping Events: Preprint

    SciTech Connect

    Florita, A.; Hodge, B. M.; Orwig, K.

    2013-01-01

    Wind and solar power are playing an increasing role in the electrical grid, but their inherent power variability can augment uncertainties in power system operations. One solution to help mitigate the impacts and provide more flexibility is enhanced wind and solar power forecasting; however, its relative utility is also uncertain. Within the variability of solar and wind power, repercussions from large ramping events are of primary concern. At the same time, there is no clear definition of what constitutes a ramping event, with various criteria used in different operational areas. Here the Swinging Door Algorithm, originally used for data compression in trend logging, is applied to identify variable generation ramping events from historic operational data. The identification of ramps in a simple and automated fashion is a critical task that feeds into a larger work of 1) defining novel metrics for wind and solar power forecasting that attempt to capture the true impact of forecast errors on system operations and economics, and 2) informing various power system models in a data-driven manner for superior exploratory simulation research. Both allow inference on sensitivities and meaningful correlations, as well as the ability to quantify the value of probabilistic approaches for future use in practice.

  19. Energy Primer: Solar, Water, Wind, and Biofuels.

    ERIC Educational Resources Information Center

    Portola Inst., Inc., Menlo Park, CA.

    This is a comprehensive, fairly technical book about renewable forms of energy--solar, water, wind, and biofuels. The biofuels section covers biomass energy, agriculture, aquaculture, alcohol, methane, and wood. The focus is on small-scale systems which can be applied to the needs of the individual, small group, or community. More than one-fourth

  20. Solar Wind Drivers for Steady Magnetospheric Convection

    NASA Technical Reports Server (NTRS)

    McPherron, Robert L.; O'Brien, T. Paul; Thompson, Scott; Lui, A. T. Y. (Editor)

    2005-01-01

    Steady magnetospheric convection (SMC) also known as convection bays, is a particular mode of response of the magnetosphere to solar wind coupling. It is characterized by convection lasting for times longer than a typical substorm recovery during which no substorms expansions can be identified. It is generally believed that the solar wind must be unusually steady for the magnetosphere to enter this state. However, most previous studies have assumed this is true and have used such conditions to identify events. In a preliminary investigation using only the AE and AL indices to select events we have shown that these expectations are generally correct. SMC events seem to be associated with slow speed solar wind and moderate, stable IMF Bz. In this report we extend our previous study including additional parameters and the time variations in various statistical quantities. For the intervals identified as SMCs we perform a detailed statistical analysis of the properties of different solar wind variables. We compare these statistics to those determined from all data, and from intervals in which substorms but not SMCs are present. We also consider the question of whether substorms are required to initiate and terminate an SMC. We conclude that the intervals we have identified as SMC are likely to be examples of the original Dungey concept of balanced reconnection at a pair of x-lines on the day and night side of the Earth.

  1. Recent insights in solar wind MHD turbulence

    SciTech Connect

    Bruno, R.; D'Amicis, R.; Bavassano, B.; Carbone, V.; Marino, R.; Sorriso-Valvo, L.; Noullez, A.; Pietropaolo, E.

    2008-08-25

    In this short review we report about recent findings related to two fundamental points in the study of solar wind turbulence: a) the verification of the equivalent of the -4/5 law in the solar wind and b) the estimate of the energy cascade along the spectrum and its comparison with the heating rate necessary to heat the solar wind during its expansion as deduced from in-situ measurements. As a matter of fact, a Yaglom-like scaling relation has recently been found in both high-latitude and in-ecliptic data samples. However, analogous scaling law, suitably modified to take into account compressible fluctuations, has been observed in a much more extended fraction of the same data set recorded at high latitude. Thus, it seems that large scale density fluctuations, despite their low amplitude, play a major role in the basic scaling properties of turbulence. The compressive turbulent cascade, moreover, seems to be able to supply the energy needed to account for the local heating of the non-adiabatic solar wind.

  2. Material Interactions with Solar Wind Ion Environments

    NASA Technical Reports Server (NTRS)

    Minow, Joseph I.; McWilliams, Brett

    2006-01-01

    Solar wind composition is dominated by hydrogen (approx.96%) and helium (approx.3 to 4%) with a minor fraction (less than or equal to 1%) of heavy ions. Hydrogen (helium) ions impact spacecraft surfaces with energies from 0.5 to 5 keV (1.8 to 21 keV) due to variations in solar wind velocity from 300 km/s to 1000 km/sec with extremes of a few 10 s keV during periods of extremely high solar wind velocity exceeding 1000 km/sec. Mean impact energies are typically on the order of approximately 1 keV and 4 keV for hydrogen ions and helium ions, respectively. These energies are typically of the peak of the energy dependent light ion sputter yields for hydrogen and helium on many metals. In addition, light ions with kilovolt energies have been shown to produce blister (or exfoliation) damage to metal surfaces due to formation of high pressure gas bubbles within the materials when exposed to ion fluences on the order of 10(exp 16 to (10(exp 17 ions/sq cm. A number of spacecraft designs for current and future missions include gossamer polymer structures with thin metallic reflection coatings to shield instruments from the Sun or solar sail propulsion systems for use in a variety of locations in the inner solar system from 0.5 to 1 AU. In addition, there is interest in designing spacecraft for solar physics missions requiring operations as close to the Sun as 0.16 to 0.2 AU. Integrity of the metallic coatings is critical in many of these applications since degradation will result in modification of material thermal properties or exposure of polymers to solar UV photons which can compromise mission requirements. This paper will evaluate the relative contributions of sputtering and blister formation to material degradation in solar wind environments over a range of radial distances from the Sun to demonstrate where solar wind environments become important for materials selection. We will first review the physics and results from laboratory measurements of light ion sputtering, blistering, and exfoliation of metallic surfaces to establish the order of magnitude ion fluence required for significant surface damage. Solar wind ion fluence environments will then be evaluated due to variations in solar wind conditions as a function of solar cycle for varying distances from the Sun using models for radial variations in solar wind ion number density, temperature, and velocity to determine where sputtering and blistering is most likely to be an issue. Finally, ion fluence statistics for varying radial distances from the Sun will be shown to establish the mission duration and radial distances from the Sun where missions will encounter sufficient ion fluence to exhibit damage to metallic surfaces.

  3. The Genesis Solar-Wind Collector Materials

    NASA Astrophysics Data System (ADS)

    Jurewicz, A. J. G.; Burnett, D. S.; Wiens, R. C.; Friedmann, T. A.; Hays, C. C.; Hohlfelder, R. J.; Nishiizumi, K.; Stone, J. A.; Woolum, D. S.; Becker, R.; Butterworth, A. L.; Campbell, A. J.; Ebihara, M.; Franchi, I. A.; Heber, V.; Hohenberg, C. M.; Humayun, M.; McKeegan, K. D.; McNamara, K.; Meshik, A.; Pepin, R. O.; Schlutter, D.; Wieler, R.

    2003-01-01

    Genesis (NASA Discovery Mission #5) is a sample return mission. Collectors comprised of ultra-high purity materials will be exposed to the solar wind and then returned to Earth for laboratory analysis. There is a suite of fifteen types of ultra-pure materials distributed among several locations. Most of the materials are mounted on deployable panels (collector arrays), with some as targets in the focal spot of an electrostatic mirror (the concentrator). Other materials are strategically placed on the spacecraft as additional targets of opportunity to maximize the area for solar-wind collection. Most of the collection area consists of hexagonal collectors in the arrays; approximately half are silicon, the rest are for solar-wind components not retained and/or not easily measured in silicon. There are a variety of materials both in collector arrays and elsewhere targeted for the analyses of specific solar-wind components. Engineering and science factors drove the selection process. Engineering required testing of physical properties such as the ability to withstand shaking on launch and thermal cycling during deployment. Science constraints included bulk purity, surface and interface cleanliness, retentiveness with respect to individual solar-wind components, and availability. A detailed report of material parameters planned as a resource for choosing materials for study will be published on a Genesis website, and will be updated as additional information is obtained. Some material is already linked to the Genesis plasma data website (genesis.lanl.gov). Genesis should provide a reservoir of materials for allocation to the scientific community throughout the 21st Century.

  4. Numerical simulations to study solar wind turbulence

    SciTech Connect

    Sharma, R. P.; Sharma, Nidhi; Kumar, Sanjay; Kumar, Sachin; Singh, H. D.

    2011-02-15

    Numerical simulation of coupled equations of kinetic Alfven wave (KAW) and ion acoustic wave is presented in the solar wind. The nonlinear dynamical equations satisfy the modified Zakharov system of equations by taking the nonadiabatic response of the background density. The ponderomotive nonlinearity is incorporated in the wave dynamics. The effect of Landau damping of KAW is taken into account. Localization of magnetic field intensity and the wavenumber spectra (perpendicular and parallel) of magnetic fluctuations are studied in solar plasmas around 1 a.u. Our results reveal the formation of damped localized structures and the steeper spectra that are in good agreement with the observations. These damped structures and steeper turbulent spectra can be responsible for plasma heating and particle acceleration in solar wind.

  5. Ion Cyclotron Waves in the Solar Wind

    NASA Astrophysics Data System (ADS)

    Wei, H. Y.; Jian, L. K.; Russell, C. T.; Omidi, N.

    The ion cyclotron waves (ICWs) refer to electromagnetic transverse waves with nearly field-aligned propagation, circular polarization, and frequencies near the proton gyro-frequency. This chapter presents the ICW studies observed in the solar wind over a wide range of heliocentric distances, at all solar longitudes, and at locations far from planets or comets. To better understand the wave source region, case studies have been performed on a special group of ICW storm events, in which the left-handed (LH) and right-handed (RH) waves were observed simultaneously in the spacecraft frame. The study in the chapter assumes the waves are generated through one possible mechanism (i.e., the temperature anisotropy instability). The variations of the wave properties with heliocentric distances may also provide information on the possible wave generation sources and the effects of the wave to the solar wind plasma.

  6. Solar and solar wind sources of geomagnetic activity during grand solar maximum

    NASA Astrophysics Data System (ADS)

    Hynnen, Reko; Tanskanen, Eija

    2014-05-01

    We have studied solar activity for over entire grand solar maximum from solar cycle 12 to 23. We have analyzed different solar activity proxies in detail and furthermore the solar originated disturbances and their geomagnetic effects. We compared the occurrence rate of the coronal mass ejections, high-speed streams and co-rotating interaction regions and the occurrence of geomagnetic storms and substorms. We identified and analyzed solar wind ULF waves in details. ULF fluctuations were identified from the solar wind using the Fourier method developed in this work. The solar wind ULFs were identified from ACE and Wind data and ground-based ULFs from Oulujrvi, Kilpisjrvi and Kevo magnetic observations. We found out that solar wind ULF occurrence peaks during the declining solar cycle phase in a same solar cycle phase where high-speed streams and substorms are found to peak. Our analysis furthermore shows that the trend of ULF waves detected from ground-based instruments is similar to the trend of solar wind ULFs.

  7. Heliomagnetic latitude dependence of the heliospheric magnetic field

    NASA Astrophysics Data System (ADS)

    Burton, M. E.; Smith, E. J.; Balogh, A.

    1995-06-01

    Previous studies have revealed systematic variations of the interplanetary magnetic field with heliographic latitude. Luhmann et al. (1987) modeled Pioneer Venus (PVO) and ISEE-3 observations by assuming an asymmetric dependence on heliolatitude with stronger fields in the northern hemisphere. In a subsequent study, using data from ISEE-3/ICE and IMP-8, Burton et al. (1990) found evidence for a similar asymmetry. However, neither model has been completely successful. The model derived from PVO/ICE observations agrees quite well near solar maximum but shows significant discrepancies during the descending phase of the solar cycle. The model derived from the ICE/IMP-8 comparison suffers from significant phase delays between the difference in field magnitude at the two spacecraft and their latitude difference. In an attempt to account for these phase shifts, the IMP-8 and ICE data have been reexamined in heliomagnetic coordinates which are defined by the orientation of the solar magnetic dipole. The latitude and longitude of the dipole inferred from the data have then been compared with those implicit in source surface calculations. The IMP/ICE correlations have been extended into the recent solar maximum and descending phase. Comparisons have also been carried out between IMP-8 and Ulysses as it traveled to -30 deg south heliographic latitude.

  8. The Genesis Mission: Solar Wind Conditions, and Implications for the FIP Fractionation of the Solar Wind.

    SciTech Connect

    Reisenfeld, D. B.; Wiens, R. C.; Barraclough, B. L.; Steinberg, J. T; Dekoning, C. A.; Zurbuchen, T. H.; Burnett, D. S.

    2005-01-01

    The NASA Genesis mission collected solar wind on ultrapure materials between November 30, 2001 and April 1, 2004. The samples were returned to Earth September 8, 2004. Despite the hard landing that resulted from a failure of the avionics to deploy the parachute, many samples were returned in a condition that will permit analyses. Sample analyses of these samples should give a far better understanding of the solar elemental and isotopic composition (Burnett et al. 2003). Further, the photospheric composition is thought to be representative of the solar nebula, so that the Genesis mission will provide a new baseline for the average solar nebula composition with which to compare present-day compositions of planets, meteorites, and asteroids. Sample analysis is currently underway. The Genesis samples must be placed in the context of the solar and solar wind conditions under which they were collected. Solar wind is fractionated from the photosphere by the forces that accelerate the ions off of the Sun. This fractionation appears to be ordered by the first ionization potential (FIP) of the elements, with the tendency for low-FIP elements to be over-abundant in the solar wind relative to the photosphere, and high-FIP elements to be under-abundant (e.g. Geiss, 1982; von Steiger et al., 2000). In addition, the extent of elemental fractionation differs across different solarwind regimes. Therefore, Genesis collected solar wind samples sorted into three regimes: 'fast wind' or 'coronal hole' (CH), 'slow wind' or 'interstream' (IS), and 'coronal mass ejection' (CME). To carry this out, plasma ion and electron spectrometers (Barraclough et al., 2003) continuously monitored the solar wind proton density, velocity, temperature, the alpha/proton ratio, and angular distribution of suprathermal electrons, and those parameters were in turn used in a rule-based algorithm that assigned the most probable solar wind regime (Neugebauer et al., 2003). At any given time, only one of three regime-specific collectors (CH, IS, or CME) was exposed to the solar wind. Here we report on the regime-specific solar wind conditions from in-situ instruments over the course of the collection period. Further, we use composition data from the SWICS (Solar Wind Ion Composition Spectrometer) instrument on ACE (McComas et al., 1998) to examine the FIP fractionation between solar wind regimes, and make a preliminary comparison of these to the FIP analysis of Ulysses/SWICS composition data (von Steiger et al. 2000). Our elemental fractionation study includes a reevaluation of the Ulysses FIP analysis in light of newly reported photospheric abundance data (Asplund, Grevesse & Sauval, 2005). The new abundance data indicate a metallicity (Z/X) for the Sun almost a factor of two lower than that reported in the widely used compilation of Anders & Grevesse (1989). The new photospheric abundances suggest a lower degree of solar wind fractionation than previously reported by von Steiger et al. (2000) for the first Ulysses polar orbit (1991-1998).

  9. Wind and IMP 8 Solar Wind, Magnetosheath and Shock Data

    NASA Technical Reports Server (NTRS)

    2004-01-01

    The purpose of this project was to provide the community access to magnetosheath data near Earth. We provided 27 years of IMP 8 magnetosheath proton velocities, densities, and temperatures with our best (usually 1-min.) time resolution. IMP 8 crosses the magnetosheath twice each 125 day orbit, and we provided magnetosheath data for the roughly 27 years of data for which magnetometer data are also available (which are needed to reliably pick boundaries). We provided this 27 years of IMP 8 magnetosheath data to the NSSDC; this data is now integrated with the IMP 8 solar wind data with flags indicating whether each data point is in the solar wind, magnetosheath, or at the boundary between the two regions. The plasma speed, density, and temperature are provided for each magnetosheath point. These data are also available on the MIT web site ftp://space .mit.edu/pub/plasma/imp/www/imp.html. We provide ASCII time-ordered rows of data giving the observation time, the spacecraft position in GSE, the velocity is GSE, the density and temperature for protons. We also have analyzed and archived on our web site the Wind magnetosheath plasma parameters. These consist of ascii files of the proton and alpha densities, speeds, and thermal speeds. These data are available at ftp://space.mit.edu/pub/plasma/wind/sheath These are the two products promised in the work statement and they have been completed in full.

  10. Solar Wind Ablation of Terrestrial Planet Atmospheres

    NASA Technical Reports Server (NTRS)

    Moore, Thomas Earle; Fok, Mei-Ching H.; Delcourt, Dominique C.

    2009-01-01

    Internal plasma sources usually arise in planetary magnetospheres as a product of stellar ablation processes. With the ignition of a new star and the onset of its ultraviolet and stellar wind emissions, much of the volatiles in the stellar system undergo a phase transition from gas to plasma. Condensation and accretion into a disk is replaced by radiation and stellar wind ablation of volatile materials from the system- Planets or smaller bodies that harbor intrinsic magnetic fields develop an apparent shield against direct stellar wind impact, but UV radiation still ionizes their gas phases, and the resulting internal plasmas serve to conduct currents to and from the central body along reconnected magnetic field linkages. Photoionization and thermalization of electrons warms the ionospheric topside, enhancing Jeans' escape of super-thermal particles, with ambipolar diffusion and acceleration. Moreover, observations and simulations of auroral processes at Earth indicate that solar wind energy dissipation is concentrated by the geomagnetic field by a factor of 10-100, enhancing heavy species plasma and gas escape from gravity, and providing more current carrying capacity. Thus internal plasmas enable coupling with the plasma, neutral gas and by extension, the entire body. The stellar wind is locally loaded and slowed to develop the required power. The internal source plasma is accelerated and heated, inflating the magnetosphere as it seeks escape, and is ultimately blown away in the stellar wind. Bodies with little sensible atmosphere may still produce an exosphere of sputtered matter when exposed to direct solar wind impact. Bodies with a magnetosphere and internal sources of plasma interact more strongly with the stellar wind owing to the magnetic linkage between the two created by reconnection.

  11. Elemental building blocks of the slow solar wind

    NASA Astrophysics Data System (ADS)

    Kepko, L.; Viall, N. M.; Lepri, S. T.

    2014-12-01

    While the source of the fast solar wind is well understood to be linked to coronal holes, the source of the slow solar wind has remained elusive. A distinguishing characteristic of the slow solar wind is the high variability of the plasma parameters, such as magnetic field, velocity, density, composition, and charge state. Many previous studies of the slow solar wind have examined trends in the composition and charge states over long time scales and using data with comparatively low temporal resolution. In this study, we take advantage of high time resolution (12 min) measurements of the charge-state abundances recently reprocessed by the ACE SWICS science team to probe the timescales of solar wind variability of coherent structures at relatively small scales (<2000 Mm, or ~ 90 minutes at slow wind speeds). We use an interval of slow solar wind containing quasi pressure-balanced, periodic number density structures previously studied by Kepko et al and shown to be important in solar wind-magnetospheric coupling. The combination of high temporal resolution composition measurements and the clearly identified boundaries of the periodic structures allows us to probe the elemental slow solar wind flux tubes/structures. We use this train of 2000Mm periodic density structures as tracers of solar wind origin and/or acceleration. We find that each 2000 Mm parcel of slow solar wind, though its speed is steady, exhibits the complete range of charge state and composition variations expected for the entire range of slow solar wind, in a repeated sequence. Each parcel cycles through three states: 1) 'normal' slow wind, 2) compositionally slow wind with very high density, and 3) compositionally fast but typical slow solar wind density. We conclude by suggesting these structures form elemental building blocks of the slow solar wind, and discuss whether it is necessary to decouple separately the process(es) responsible for the release and acceleration.

  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. Pluto's solar wind interaction: Collisional effects

    NASA Astrophysics Data System (ADS)

    Cravens, T. E.; Strobel, D. F.

    2015-01-01

    Exospheric neutral atoms and molecules (primarily N2, with trace amounts of CH4 and CO according to our current understanding of Pluto's atmosphere) escape from Pluto and travel into interplanetary space for millions of kilometers. Eventually, the neutrals are ionized by solar EUV photons and/or by collisions with solar wind electrons. The mass-loading associated with this ion pick-up is thought to produce a comet-like interaction of the solar wind with Pluto. Within a few thousand kilometers of Pluto the solar wind interaction should lead to a magnetic field pile-up and draping, as it does around other "non-magnetic" bodies such as Venus and comets. The structure of plasma regions and boundaries will be greatly affected by large gyroradii effects and the extensive exosphere. Energetic plasma should disappear from the flow within radial distances of a few thousand kilometers due to charge exchange collisions. An ionosphere should be present close to Pluto with a composition that is determined both by the primary ion production and ion-neutral chemistry. One question discussed in the paper is whether or not the ionosphere has a Venus-like sharply defined ionopause boundary or a diamagnetic cavity such as that found around comet Halley. Simple physical estimates of plasma processes and structures in the collision-dominated region are made in this paper and predictions are made for the New Horizons mission.

  14. Properties of Minor Ions in the Solar Wind and Implications for the Background Solar Wind Plasma

    NASA Technical Reports Server (NTRS)

    Wagner, William (Technical Monitor); Esser, Ruth

    2004-01-01

    The scope of the investigation is to extract information on the properties of the bulk solar wind from the minor ion observations that are provided by instruments on board NASA space craft and theoretical model studies. Ion charge states measured in situ in interplanetary space are formed in the inner coronal regions below 5 solar radii, hence they carry information on the properties of the solar wind plasma in that region. The plasma parameters that are important in the ion forming processes are the electron density, the electron temperature and the flow speeds of the individual ion species. In addition, if the electron distribution function deviates from a Maxwellian already in the inner corona, then the enhanced tail of that distribution function, also called halo, greatly effects the ion composition. This study is carried out using solar wind models, coronal observations, and ion calculations in conjunction with the in situ observations.

  15. Characteristics of solar wind density depletions during solar cycles 23 and 24

    NASA Astrophysics Data System (ADS)

    Park, K.; Lee, J.; Oh, S.; Yi, Y.

    2014-12-01

    Solar wind density depletions are generally believed to be caused by the interplanetary (IP) shocks. However, there are other cases that are hardly associated with IP shocks. To better understand the cause of the density depletions, we investigate the solar wind parameters and interplanetary magnetic field (IMF) data related to the solar wind density depletion events during the period from 1996 to 2013 that are obtained with the Advanced Composition Explorer (ACE) and the WIND satellite. As a result, we found that the solar wind density has an anti-correlation with IMF strength during all events of solar wind density depletion, regardless of the presence of IP shocks. We thus argue that IMF strength is an important factor in understanding the nature of solar wind density depletion. Since IMF strength varies with solar cycle, we also investigate the characteristics of solar wind density depletion events in different phases of solar cycle as an attempt to find its connection to the sun.

  16. Role of solar wind turbulence in the coupling of the solar wind to the Earth's magnetosphere

    NASA Astrophysics Data System (ADS)

    Borovsky, Joseph E.; Funsten, Herbert O.

    2003-06-01

    The correlation between the amplitude of the MHD turbulence in the upstream solar wind and the amplitude of the Earth's geomagnetic activity indices AE, AU, AL, Kp, ap, Dst, and PCI is explored. The amplitude of the MHD turbulence is determined by the fluctuation amplitude of the solar wind magnetic field. This "turbulence effect" in solar wind/magnetosphere coupling is more easily discerned when the interplanetary magnetic field (IMF) is northward, but the effect is also present when the IMF is southward. The magnitude of the effect is the same for northward and southward IMF, accounting for about 150 nT of the variability of the AE index. Tests are performed that conclude (1) that the turbulence effect is not caused by the turbulence amplitude acting as a proxy for ∣B∣ in the solar wind and (2) that reversals of the IMF from northward to southward in the turbulent fluctuations is not the cause of the correlations. An expression is derived for the total viscous-shear force on the surface of the magnetosphere; improved solar wind/magnetosphere correlations result when this expression is used. With insight from fluid-flow experiments, the turbulence effect is interpreted as an enhanced viscous coupling of the solar wind flow to the Earth's magnetosphere caused by an eddy viscosity that is controlled by the amplitude of MHD turbulence in the upstream solar wind: more upstream turbulence means more momentum transfer from the magnetosheath into the magnetosphere, resulting in more stirring of the magnetosphere, which produces enhanced geomagnetic activity indices.

  17. Interpreting the solar wind ionization state

    NASA Technical Reports Server (NTRS)

    Owocki, S. P.

    1983-01-01

    The ionization state of the solar coronal expansion is frozen within a few solar radii of the solar photosphere, and spacecraft measurements of the solar wind heavy ion charge state can therefore yield information about coronal conditions (e.g., electron temperature). Previous interpretations of the frozen-in ionization state have always assumed that in the coronal freezing-in region, (1) all heavy ions flow at the same bulk speed as protons, (2) the electron velocity distribution function is Maxwellian, and (3) conditions vary in space but not in time. The consequences of relaxing these assumptions for the interpretation of solar wind charge state measurements are examined. It is found that: (1) the temperature inferred by traditional interpretation of the interplanetary ionization state overestimates (underestimate) the actual coronal electron temperature if higher ion charge stages flow systematically faster (slower) than lower stages at the coronal freezing radius; (2) temperatures inferred from relative abundance measurements of ion-charge-stages with high ionization potentials moderately overestimate the actual coronal electron temperature if the high-energy tail of the coronal electron velocity distribution is enhanced relative to a Maxwellian distribution; (3) the propagation of a disturbance, e.g., a shock wave, through the corona can strongly affect the frozen-in charge state, but only over a time (a few times ten minutes) corresponding to the coronal transit time for the disturbance.

  18. Solar wind plasma interaction with Gerasimovich lunar magnetic anomaly

    NASA Astrophysics Data System (ADS)

    Fatemi, Shahab; Lue, Charles; Holmstrm, Mats; Poppe, Andrew R.; Wieser, Martin; Barabash, Stas; Delory, Gregory T.

    2015-06-01

    We present the results of the first local hybrid simulations (particle ions and fluid electrons) for the solar wind plasma interaction with realistic lunar crustal fields. We use a three-dimensional hybrid model of plasma and an empirical model of the Gerasimovich magnetic anomaly based on Lunar Prospector observations. We examine the effects of low and high solar wind dynamic pressures on this interaction when the Gerasimovich magnetic anomaly is located at nearly 20 solar zenith angle. We find that for low solar wind dynamic pressure, the crustal fields mostly deflect the solar wind plasma, form a plasma void at very close distances to the Moon (below 20 km above the surface), and reflect nearly 5% of the solar wind in charged form. In contrast, during high solar wind dynamic pressure, the crustal fields are more compressed, the solar wind is less deflected, and the lunar surface is less shielded from impinging solar wind flux, but the solar wind ion reflection is more locally intensified (up to 25%) compared to low dynamic pressures. The difference is associated with an electrostatic potential that forms over the Gerasimovich magnetic anomaly as well as the effects of solar wind plasma on the crustal fields during low and high dynamic pressures. Finally, we show that an antimoonward Hall electric field is the dominant electric field for 3 km altitude and higher, and an ambipolar electric field has a noticeable contribution to the electric field at close distances (<3 km) to the Moon.

  19. The solar wind and magnetospheric dynamics

    NASA Technical Reports Server (NTRS)

    Russell, C. T.

    1974-01-01

    The dynamic processes involved in the interaction between the solar wind and the earth's magnetosphere are reviewed. The evolution of models of the magnetosphere is first surveyed. The existence of the auroral substorm and the cyclical polar magnetic substorm is evidence that the magnetosphere is a dynamic system. The dynamic changes occurring in the magnetosphere, including erosion of the magnetopause, changes in the size of the polar cap, variations in the flaring angle of the tail, neutral point formation, plasma sheet motions, and the inward collapse of the midnight magnetosphere, are discussed. The cyclical variations of geomagnetic activity are explained in terms of the control of the solar wind-magnetosphere interaction by the north-south component of the interplanetary magnetic field. Present phenomenological models allow prediction of geomagnetic activity from interplanetary measurements, but modeling of detailed magnetospheric processes is still in its infancy.

  20. Surface Waves on solar wind tangential discontinuities

    SciTech Connect

    Hollweg, J.V.

    1982-10-01

    We demonstrate that (tangential) discontinuities in the magnetic field direction can support MHD surface waves. The surface waves resemble the usual Alfven wave, but there are some important differences: (1) The surface waves exhibit a low-frequency cutoff. (2) The velocity and magnetic field fluctuations are elliptically, and sometimes circularly, polarized. They may account for the solar wind helicity spectrum. (3) The surface waves are compressive, but there are special cases where they are noncompressive. (4) The wave vector k, the local normals to the surfaces of constant phase, and the magnetic minimum variance direction (mvd) do not all coincide. (5) There is a tendency for the mvd to align itself with the mean magnetic field direction. (6) The waves can be intrinsically nonplanar. (7) Equipartition between magnetic and kinetic energies is not obeyed locally. These properties of the surface waves lead us to believe that surface waves may be common in the solar wind.

  1. Solar wind thermally induced magnetic fluctuations.

    PubMed

    Navarro, R E; Moya, P S; Muoz, V; Araneda, J A; F-Vias, A; Valdivia, J A

    2014-06-20

    A kinetic description of Alfvn-cyclotron magnetic fluctuations for anisotropic electron-proton quasistable plasmas is studied. An analytical treatment, based on the fluctuation-dissipation theorem, consistently shows that spontaneous fluctuations in plasmas with stable distributions significantly contribute to the observed magnetic fluctuations in the solar wind, as seen, for example, in [S.?D. Bale et al., Phys. Rev. Lett. 103, 211101 (2009)], even far below from the instability thresholds. Furthermore, these results, which do not require any adjustable parameters or wave excitations, are consistent with the results provided by hybrid simulations. It is expected that this analysis contributes to our understanding of the nature of magnetic fluctuations in the solar wind. PMID:24996092

  2. Deimos: an obstacle to the solar wind.

    PubMed

    Sauer, K; Dubinin, E; Baumgrtel, K; Bogdanov, A

    1995-08-25

    Two isolated solar wind disturbances about 5 minutes in duration were detected aboard the Russian spacecraft Phobos-2 upon its crossing the wake of the martian moon Deimos about 15,000 kilometers downstream from the moon on 1 February 1989. These plasma and magnetic events are interpreted as the inbound and outbound crossings of a Mach cone that is formed as a result of an effective interaction of the solar wind with Deimos. Possible mechanisms such as remanent magnetization, cometary type interaction caused by heavy ion or charged dust production, and unipolar induction resulting from the finite conductivity of the body are discussed. Although none of the present models is fully satisfactory, neutral gas emission through water loss by Deimos at a rate of about 10(23) molecules per second, combined with a charged dust coma, is favored. PMID:17755527

  3. Turbulence and waves in the solar wind

    SciTech Connect

    Roberts, D.A.; Goldstein, M.L. )

    1991-01-01

    Studies of turbulence and waves in the solar wind is discussed. Consideration is given to the observations and theory concerning the origin and evolution of interplanetary MHD fluctuations and to the observations, theory, and simulations of compressive fluctuations. Particular attention is given to extrapolations to near-sun and polar fields regions. Results obtained on turbulence at comets and magnetic turbulence of low-frequency waves excited by unstable distributions of ions are discussed. 230 refs.

  4. Cometary ion instabilities in the solar wind

    NASA Astrophysics Data System (ADS)

    Matteini, L.; Schwartz, S. J.; Hellinger, P.

    2015-12-01

    We review some of the processes that characterize the interaction of the solar wind with newborn cometary ions. Instabilities generated by the typical ring-beam velocity-space configuration of the pick-up ions in the solar wind frame are studied by means of one- and two-dimensional hybrid numerical simulations. In agreement with previous studies, we find that instabilities generated by the cometary ions play an important role in shaping the properties of the plasma. The resulting ion distributions are in good agreement with observations, showing the presence of energy shells in velocity space. Bi-spherical shells for the heavy oxygen ions are also observed in the late phase of the simulations. Moreover, we also investigate some new aspects of the dynamics, such as the generation of turbulent cascade from the initial spectra of unstable waves, and the related heating and back reaction of the solar wind plasma. We also consider the case of initial non-gyrotropic pick-up ion distributions, and we focus on the polarization of the associated waves, suggesting that linear polarization can be a signature of this configuration, possibly observed by the Rosetta spacecraft in orbit around comet 67P/CG.

  5. The MAVEN Solar Wind Electron Analyzer

    NASA Astrophysics Data System (ADS)

    Mitchell, D. L.; Mazelle, C.; Sauvaud, J.-A.; Thocaven, J.-J.; Rouzaud, J.; Fedorov, A.; Rouger, P.; Toublanc, D.; Taylor, E.; Gordon, D.; Robinson, M.; Heavner, S.; Turin, P.; Diaz-Aguado, M.; Curtis, D. W.; Lin, R. P.; Jakosky, B. M.

    2016-02-01

    The MAVEN Solar Wind Electron Analyzer (SWEA) is a symmetric hemispheric electrostatic analyzer with deflectors that is designed to measure the energy and angular distributions of 3-4600-eV electrons in the Mars environment. This energy range is important for impact ionization of planetary atmospheric species, and encompasses the solar wind core and halo populations, shock-energized electrons, auroral electrons, and ionospheric primary photoelectrons. The instrument is mounted at the end of a 1.5-meter boom to provide a clear field of view that spans nearly 80 % of the sky with ˜20° resolution. With an energy resolution of 17 % ( Δ E/E), SWEA readily distinguishes electrons of solar wind and ionospheric origin. Combined with a 2-second measurement cadence and on-board real-time pitch angle mapping, SWEA determines magnetic topology with high (˜8-km) spatial resolution, so that local measurements of the plasma and magnetic field can be placed into global context.

  6. Western Wind and Solar Integration Study (Fact Sheet)

    SciTech Connect

    Not Available

    2012-09-01

    Initiated in 2007 to examine the operational impact of up to 35% penetration of wind, photovoltaic (PV), and concentrating solar power (CSP) energy on the electric power system, the Western Wind and Solar Integration Study (WWSIS) is one of the largest regional wind and solar integration studies to date. The goal is to understand the effects of variability and uncertainty of wind, PV, and CSP on the grid. In the Western Wind and Solar Integration Study Phase 1, solar penetration was limited to 5%. Utility-scale PV was not included because of limited capability to model sub-hourly, utility-scale PV output . New techniques allow the Western Wind and Solar Integration Study Phase 2 to include high penetrations of solar - not only CSP and rooftop PV but also utility-scale PV plants.

  7. CHARGE STATE EVOLUTION IN THE SOLAR WIND. RADIATIVE LOSSES IN FAST SOLAR WIND PLASMAS

    SciTech Connect

    Landi, E.; Gruesbeck, J. R.; Lepri, S. T.; Zurbuchen, T. H.; Fisk, L. A.

    2012-10-10

    We study the effects of departures from equilibrium on the radiative losses of the accelerating fast, coronal hole-associated solar wind plasma. We calculate the evolution of the ionic charge states in the solar wind with the Michigan Ionization Code and use them to determine the radiative losses along the wind trajectory. We use the velocity, electron temperature, and electron density predicted by Cranmer et al. as a benchmark case even though our approach and conclusions are more broadly valid. We compare non-equilibrium radiative losses to values calculated assuming ionization equilibrium at the local temperature, and we find that differences are smaller than 20% in the corona but reach a factor of three in the upper chromosphere and transition region. Non-equilibrium radiative losses are systematically larger than the equilibrium values, so that non-equilibrium wind plasma radiates more efficiently in the transition region. Comparing the magnitude of the dominant energy terms in the Cranmer et al. model, we find that wind-induced departures from equilibrium are of the same magnitude as the differences between radiative losses and conduction in the energy equation. We investigate which ions are most responsible for such effects, finding that carbon and oxygen are the main source of departures from equilibrium. We conclude that non-equilibrium effects on the wind energy equation are significant and recommend that they are included in theoretical models of the solar wind, at least for carbon and oxygen.

  8. Solar wind effects on atmosphere evolution at Venus and Mars

    NASA Technical Reports Server (NTRS)

    Luhmann, Janet G.; Bauer, S. J.

    1992-01-01

    The weak intrinsic magnetism of Venus and Mars leaves these planets subject to some unique atmospheric loss processes. This paper reviews the ways in which material seems to be removed by the solar wind interaction, including atmospheric ion pickup by the solar wind, bulk removal and outflow of ionospheric plasma, and atmospheric sputtering by pickup ions. The factors in the planets' and sun's histories, such as planetary magnetism, solar luminosity, and past solar wind properties, that must ultimately be folded into considerations of the effects of the solar wind interaction on atmosphere evolution are discussed.

  9. Equatorwards Expansion of Unperturbed, High-Latitude Fast Solar Wind

    NASA Astrophysics Data System (ADS)

    Dorrian, G. D.; Breen, A. R.; Fallows, R. A.; Bisi, M. M.

    2013-07-01

    We use dual-site radio observations of interplanetary scintillation (IPS) with extremely long baselines (ELB) to examine meridional flow characteristics of the ambient fast solar wind at plane-of-sky heliocentric distances of 24 - 85 solar radii ( R ⊙). Our results demonstrate an equatorwards deviation of 3 - 4∘ in the bulk fast solar wind flow direction over both northern and southern solar hemispheres during different times in the declining phase of Solar Cycle 23.

  10. Electron energy flux in the solar wind.

    NASA Technical Reports Server (NTRS)

    Ogilvie, K. W.; Scudder, J. D.; Sugiura, M.

    1971-01-01

    Description of studies of electrons between 10 eV and 9.9 keV in the solar wind. The transport of energy in the rest frame of the plasma is evaluated and shown to be parallel to the interplanetary magnetic field. The presence of electrons from solar events causes this energy-flux density to exceed the heat flow due to thermal electrons. In one such event, the observations are shown to be consistent with the solar-electron observations made at higher energies. When observations are made at a point connected to the earth's bow shock by an interplanetary-field line, a comparatively large energy flux along the field toward the sun is observed, but the heat flow remains outwardly directed during this time interval. In either situation the heat flow is found to be consistent with measurements made on Vela satellites by a different method. These values, less than .01 ergs/sq cm/sec, are sufficiently low to require modifications to the Spitzer-Harm conductivity formula for use in solar-wind theories.

  11. The acceleration of the solar wind

    SciTech Connect

    Axford, W. I.; McKenzie, J. F.

    1996-07-20

    We review the observed properties of the solar wind with the aim of finding a simple and straightforward understanding of its origin and acceleration. A theory is developed for the high speed solar wind based on a simple dissipation length assumption for hydromagnetic wave heating of the coronal plasma close to the Sun. Solutions with the correct particle and energy fluxes and with a realistic magnetic field, match the requirements on the density at the base of the corona provided the dissipation length is relatively small ({approx}0.25-0.5 solar radii). The significant features are that the acceleration is rapid, with the sonic point within {approx}2 solar radii, and the proton temperatures are high, namely 8-10x10{sup 6} K. Such efficient dissipation requires any Alfven waves responsible to have frequencies in the range 0.01 Hz-10 kHz. This has implications for the nature of the plasma and energy source in the supergranular network.

  12. Solar wind interaction with the terrestrial planets

    NASA Astrophysics Data System (ADS)

    Garnier, Philippe; Milillo, Anna; Radioti, Aikaterini

    2015-09-01

    This issue entitled "Solar wind interaction with the terrestrial planets" follows the recurrent session PS5.1 (Planetary Plasma Physics and Interactions in the Solar System) held at the European Geophysical Union conference. The EGU session hosts original studies on all aspects of planetary plasma physics and interactions in the Solar System. This issue more specifically includes studies presented at several international meetings during the recent years on the physics of magnetospheres, ionospheres, auroras, and also the surface-plasma or atmosphere-plasma interactions, at inner planets such as Mercury, Earth (and Moon), Mars and Venus. The following papers, in fact, cover all of these aspects, and are based on a variety of techniques: space and ground-based observations, numerical modeling and even laboratory measurements.

  13. Dust in the Solar Wind

    NASA Astrophysics Data System (ADS)

    Kramer, Emily; Bauer, James; Mainzer, Amy; Grav, Tommy; Nugent, Carolyn; Sonnett, Sarah; Stevenson, Rachel

    2015-08-01

    As some of the most pristine objects in the Solar System, comets present an excellent opportunity to understand the mechanics and chemistry of the planetary formation era. By studying a large number of comets in different dynamical classes, we can better understand their ensemble properties.NEOWISE is the planetary-funded mission that uses data from the Wide-field Infrared Survey Explorer (WISE) spacecraft to detect and characterize moving objects. The WISE mission surveyed the sky in four infrared wavelength bands (3.4, 4.6, 12 and 22-microns) between January 2010 and February 2011, during which time over 160 comets were detected. Since the restart of the mission as NEOWISE in December 2013, over 60 additional comets have been observed in the shorter two wavelength channels. In both phases of the mission, a mix of both long-period comets and short-period comets were detected. Over half of the comets in the prime mission displayed a significant dust tail in the 12 and 22-micron (thermal emission) bands, showing a wide range of activity levels and dust morphology. In both the prime and restarted phases of the mission, extended dust structures were also detected for many of the comets in the 3.4 and 4.6-micron bands. For the comets that displayed a significant dust tail, we have estimated the sizes and ages of the particles using dynamical models based on the Finson-Probstein method. We will present updated modeling results, comparing the different comet populations.

  14. The Rising Phase of Solar Cycle 24: General Solar Wind, Large-Scale Solar Wind Structures, and Sector Asymmetry

    NASA Astrophysics Data System (ADS)

    Jian, L.; Russell, C. T.; Luhmann, J. G.; Riley, P.; Hoeksema, J. T.; Odstrcil, D.; Petrie, G. J.

    2011-12-01

    The solar polar field is presently nearing its reversal, suggesting the approach of solar maximum. However, the sunspot number, solar wind dynamic pressure, and IMF are still weak, similar to conditions in 1998 (the middle of last rising phase), suggesting a peculiar rising phase for Solar Cycle 24. In this presentation, following the study of solar minimum 23/24 in Jian et al. (2011), we first report the variations of solar wind parameters from the beginning of space era to present and compare the current rising phase with that of previous cycles. Secondly, based on our long-term study of large-scale solar wind structures, including interplanetary CMEs (ICMEs), stream interaction regions (SIRs), and their associated shocks at 1 AU from 1995 to present, we compare their properties in this rising phase with those of Cycle 23 and study their possible influence on geomagnetic activity. Thirdly, dividing the solar wind into positive (anti-sunward) and negative (sunward) sectors depending on the IMF polarity, we compare the solar wind parameters of the two polarity sectors from the beginning of Solar Cycle 21 to present. We note that an asymmetry between the two sectors exists for past cycles as reported by Hiltula and Mursula (2007) as well as Erdos and Balogh (2010). The sector asymmetry is more pronounced during the last solar minimum 23/24. Positive polarity solar wind is observed more often at 1 AU than negative polarity in Cycles 21 and 23 and less often in Cycle 22 and likely in this Cycle 24. Using the PFSS and MHD models, we can calculate the polarity distributions closer to the Sun, and they do not always agree with the observations. We closely examine several representative Carrington rotations to find out the reason. From 1-AU observations, the solar wind from the negative polarity sector (currently from northern hemisphere of the Sun) is found to be faster, hotter, and have a smaller proton density than the wind from the positive sector since 2009. This can affect the geomagnetic activity systematically. Comparing with the solar and coronal observations, we look for interpretations of the asymmetry.

  15. Variations of the solar wind and solar cycle in the last 300 years

    NASA Technical Reports Server (NTRS)

    Feynman, J.; Silverman, S.

    1980-01-01

    The past history of the solar wind and solar cycle, inferred from records of geomagnetics and aurora, is examined. Records show that the solar wind apparently varied in a systematic manner throughout the period from 1770 to 1857 and that the period around 1810 resembled the 1901 minimum geomagnetic disturbance. Results show that the solar wind and hence the Sun changes on a time scale long compared to a solar cycle and short compared to the Maunder minimum. The inclusion of a study on the solar wind and solar cycle variations for the SCADM mission is discussed.

  16. ISOTOPIC MASS FRACTIONATION OF SOLAR WIND: EVIDENCE FROM FAST AND SLOW SOLAR WIND COLLECTED BY THE GENESIS MISSION

    SciTech Connect

    Heber, Veronika S.; Baur, Heinrich; Wieler, Rainer; Bochsler, Peter; McKeegan, Kevin D.; Neugebauer, Marcia; Reisenfeld, Daniel B.; Wiens, Roger C.

    2012-11-10

    NASA's Genesis space mission returned samples of solar wind collected over {approx}2.3 years. We present elemental and isotopic compositions of He, Ne, and Ar analyzed in diamond-like carbon targets from the slow and fast solar wind collectors to investigate isotopic fractionation processes during solar wind formation. The solar wind provides information on the isotopic composition for most volatile elements for the solar atmosphere, the bulk Sun and hence, on the solar nebula from which it formed 4.6 Ga ago. Our data reveal a heavy isotope depletion in the slow solar wind compared to the fast wind composition by 63.1 {+-} 2.1 per mille for He, 4.2 {+-} 0.5 per mille amu{sup -1} for Ne and 2.6 {+-} 0.5 per mille amu{sup -1} for Ar. The three Ne isotopes suggest that isotopic fractionation processes between fast and slow solar wind are mass dependent. The He/H ratios of the collected slow and fast solar wind samples are 0.0344 and 0.0406, respectively. The inefficient Coulomb drag model reproduces the measured isotopic fractionation between fast and slow wind. Therefore, we apply this model to infer the photospheric isotopic composition of He, Ne, and Ar from our solar wind data. We also compare the isotopic composition of oxygen and nitrogen measured in the solar wind with values of early solar system condensates, probably representing solar nebula composition. We interpret the differences between these samples as being due to isotopic fractionation during solar wind formation. For both elements, the magnitude and sign of the observed differences are in good agreement with the values predicted by the inefficient Coulomb drag model.

  17. Solar wind rare gas analysis: Trapped solar wind helium and neon in Surveyor 3 material

    NASA Technical Reports Server (NTRS)

    Buehler, F.; Eberhardt, P.; Geiss, J.; Schwarzmueller, J.

    1972-01-01

    The He-4 and Ne-20 contents in sections of the Surveyor 3 support strut samples were determined by optical and scanning electron microscopy and are compared to the results of the Apollo solar wind composition (SWC) experiments. The He-4/Ne-20 ratio in the samples from the sunlit side of the strut was approximately 300; the ratios determined in Apollo 12 lunar fines and SWC foil were below 100. The He-4/He-3 ratios were also determined, and the ratio obtained from Surveyor 3 material is higher than those found with Apollo 11 and 12 SWC experiments. The effects of spallation by cosmic rays or solar protons, stripping by cosmic ray or energetic solar alpha particles, recycling of solar wind He and radiogenic Ne, He from terrestrial atmosphere, mass discrimination near the moon, mass dependence of trapping probability, diffusion, and contamination by lunar dust are considered.

  18. Interpretation of Solar Wind Ion Composition Measurements from Ulysses

    NASA Technical Reports Server (NTRS)

    Esser, Ruth

    1998-01-01

    The ion compositions measured in situ in the solar wind are important since the ion fractions carry information on the plasma conditions in the inner corona. The conditions in the inner corona define the properties of the solar wind plasma flow. Thus, if the ion fraction measurements can be used to unravel some of the plasma parameters in the inner corona, they will provide a valuable contribution to solving the heating and acceleration problem of the solar wind. The ion charge states in the solar wind carry information on electron temperature, electron density and ion flow speed. They are also sensitive to the shape of the electron distribution function. Through carefully modeling the solar wind and calculating the ion fractions predicted for different solar wind conditions, constraints on the electron temperature and ion flow speeds can be placed if the electron density is measured using polarization brightness measurements.

  19. Variations of Strahl Properties with Fast and Slow Solar Wind

    NASA Technical Reports Server (NTRS)

    Figueroa-Vinas, Adolfo; Goldstein, Melvyn L.; Gurgiolo, Chris

    2008-01-01

    The interplanetary solar wind electron velocity distribution function generally shows three different populations. Two of the components, the core and halo, have been the most intensively analyzed and modeled populations using different theoretical models. The third component, the strahl, is usually seen at higher energies, is confined in pitch-angle, is highly field-aligned and skew. This population has been more difficult to identify and to model in the solar wind. In this work we make use of the high angular, energy and time resolution and three-dimensional data of the Cluster/PEACE electron spectrometer to identify and analyze this component in the ambient solar wind during high and slow speed solar wind. The moment density and fluid velocity have been computed by a semi-numerical integration method. The variations of solar wind density and drift velocity with the general build solar wind speed could provide some insight into the source, origin, and evolution of the strahl.

  20. Nitrogen in solar energetic particles: isotopically distinct from solar wind.

    PubMed

    Mathew, K J; Kerridge, J F; Marti, K

    1998-12-01

    Stepwise etching of lunar soil ilmenite grains reveals that the 15N/14N ratio of implanted nitrogen decreases with increasing implantation depth within the ilmenite grains, i.e., with increasing energy of implantation. These results show that N derived from solar energetic particles, NSEP, is enriched in the light isotope, 14N, relative to solar-wind nitrogen, NSW. This is in striking contrast to the neon isotopic record: NeSEP is depleted in the light isotope, 20Ne, relative to NeSW. These data suggest either distinct signatures in the respective solar source regions, or fractionation in the acceleration mechanism(s). However, the observed opposite fractionation trends for light N and Ne isotopes do not agree with model predictions. PMID:11542821

  1. Radial evolution of the energy density of solar wind fluctuations

    NASA Technical Reports Server (NTRS)

    Zank, G. P.; Matthaeus, W. H.; Smith, C. W.

    1995-01-01

    On the basis of transport theories appropriate to a radially expanding solar wind, we describe new results for the radial evolution of the energy density in solar wind fluctuations at MHD scales. These models include the effects of 'mixing' and driving as well as the possibility of non-isotropic MHD turbulence. Implications of these results for solar wind heating, cosmic ray diffusion and interstellar pick-up ions will also be addressed.

  2. Elemental and charge state composition of the fast solar wind observed with SMS instruments on WIND

    NASA Technical Reports Server (NTRS)

    Gloeckler, G.; Galvin, A. B.; Ipavich, F. M.; Hamilton, D. C.; Bochsler, P.; Geiss, J.; Fisk, L. A.; Wilken, B.

    1995-01-01

    The elemental composition and charge state distributions of heavy ions of the solar wind provide essential information about: (1) atom-ion separation processes in the solar atmosphere leading to the 'FIP effect' (the overabundance of low First Ionization potential (FIP) elements in the solar wind compared to the photosphere); and (2) coronal temperature profiles, as well as mechanisms which heat the corona and accelerate the solar wind. This information is required for solar wind acceleration models. The SWICS instrument on Ulysses measures for all solar wind flow conditions the relative abundance of about 8 elements and 20 charge states of the solar wind. Furthermore, the Ulysses high-latitude orbit provides an unprecedented look at the solar wind from the polar coronal holes near solar minimum conditions. The MASS instrument on the WIND spacecraft is a high-mass resolution solar wind ion mass spectrometer that will provide routinely not only the abundances and charge state of all elements easily measured with SWICS, but also of N, Mg, S. The MASS sensor was fully operational at the end of 1994 and has sampled the in-ecliptic solar wind composition in both the slow and the corotating fast streams. This unique combination of SWICS on Ulysses and MASS on WIND allows us to view for the first time the solar wind from two regions of the large coronal hole. Observations with SWICS in the coronal hole wind: (1) indicate that the FIP effect is small; and (2) allow us determine the altitude of the maximum in the electron temperature profile, and indicate a maximum temperature of approximately 1.5 MK. New results from the SMS instruments on Wind will be compared with results from SWICS on Ulysses.

  3. The solar wind during current and past solar minima and maxima

    NASA Astrophysics Data System (ADS)

    Zerbo, J.-L.; Richardson, J. D.

    2015-12-01

    This paper presents solar wind data from the last five solar cycles. We review solar wind parameters over the four solar minima and five maxima for which spacecraft data are available and show the recovery from the last very weak minimum to the current solar maximum. The solar wind magnetic field, speed, and density have remained anomalously low in this time period. However, the distributions of these parameters about the (lower than normal) average are similar to those from previous solar minima and maxima. This result suggests that the acceleration mechanism for the recent weak solar wind is probably not significantly different from earlier solar cycles. The He++/H+ ratio variation with solar cycle continues to be a function of speed, but the most recent solar minimum has significantly lower ratios than in the previous solar cycle.

  4. Reception of real-time solar wind data at NICT

    NASA Astrophysics Data System (ADS)

    Watari, Shinichi; Ishii, Mamoru; Kubo, Yuki

    National Institute of Information and Communications Technology (NICT) has contributed reception of real-time solar wind data from Advanced Composition Explorer (ACE) since 1997. ACE has made in-situ solar wind observations at L1 point and has provided the data in real-time. The data is useful for warnings of geomagnetic storms up to one hour in advance. We renewed our antenna system for real-time solar wind data considering Deep Space Climate Observatory (DSCOVR), which follows on mission of ACE. In our presentation, we will report on our new antenna system and our application of solar wind data in Japanese space weather center.

  5. Solar wind turbulence: anisotropy, anisotropy, anisotropy!

    NASA Astrophysics Data System (ADS)

    Wicks, R.; Forman, M. A.; Summerlin, E. J.; Roberts, D. A.; Salem, C. S.

    2014-12-01

    Turbulence heats the solar wind as it expands away from the Sun, but where and how does heating of ions and electrons occur? In order to understand this we must first look at the fluctuations making up the cascade, the properties and anisotropies of which will determine whether ions or electrons are heated and whether field-parallel or -perpendicular heating will occur, all of which amounts to a lot of different anisotropies! With this in mind, we present a review of recent advances in the observation of plasma turbulence in the solar wind and comparison with simulations; which features of solar wind turbulence are well reproduced and which need to be captured better? The first anisotropy is that of the fluctuations making up the turbulent cascade itself, fluctuations are known to be highly transverse, meaning that the perpendicular magnetic field components are dominant over the field-parallel component. The second anisotropy is that of the scaling of amplitude towards smaller scales with steeper spectra parallel to the local magnetic field direction. Observations of the anisotropy of the full power spectral tensor will be discussed, in particular with reference to Alfvenic and pseudo-Alfvenic fluctuations (effectively two different polarizations of Alfven waves), the next step beyond the traditional "slab + 2D" approach to incompressible MHD turbulence. The third anisotropy is that of the ion and electron distributions. Both sets of charged particles frequently show non-Maxwellian distributions with higher temperatures found either perpendicular to or parallel to the magnetic field direction. Proton distributions often show beams and the heavier alpha particles are often hotter than the protons. Localized structures such as current sheets and magnetic discontinuities are shown to be sites of intense and anisotropic heating. Small scale fluctuations filling the space between such discontinuities may also dissipate energy into ions and electrons, either through electric fields intrinsic to the modes generated by the turbulence or through resonant or stochastic processes. Observations show that kinetic Alfven waves are the dominant mode.

  6. Gaseous isotope separation using solar wind phenomena

    PubMed Central

    Wang, Chia-Gee

    1980-01-01

    A large evacuated drum-like chamber fitted with supersonic nozzles in the center, with the chamber and the nozzles corotating, can separate gaseous fluids according to their molecular weights. The principle of separation is essentially the same as that of the solar wind propagation, in which components of the plasma fluid are separated due to their difference in the time-of-flight. The process can inherently be very efficient, serving as a pump as well as a separator, and producing well over 105 separative work units (kg/year) for the hydrogen/deuterium mixture at high-velocity flows. PMID:16592924

  7. Coulomb collisions in the solar wind

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

    A major improvement of the present investigation over previous studies of the subject is related to the use of helium temperatures obtained from helium ion measurements uncontaminated by the high-velocity tail of the proton distribution. More observations, covering a large parameter range, were employed, and the effects of interspecies drift were taken into account. It is shown in a more definite way than has been done previously, that Coulomb collisions provide the most important mechanism bringing about equilibrium between helium and protons in the solar wind. Other mechanisms may play some part in restricted regions, but Coulomb collisions are dominant on the macroscale.

  8. Genesis Solar Wind Samples: Update of Availability

    NASA Technical Reports Server (NTRS)

    Gonzalez, C. P.; Allums, K. K.; Allton, J. H.

    2015-01-01

    The Genesis mission collected solar wind atoms for 28 months with a variety of collectors. The array wafer collector availability is displayed in the online catalog. The purpose of this report is to update the community on availability of array wafer samples and to preview other collectors which are in the process of being added to the online catalog. A total of fifteen pure materials were selected based on engineering and science requirements. Most of the materials were semiconductor wafers which were mounted on the arrays.

  9. Genesis Solar Wind Science Canister Components Curated as Potential Solar Wind Collectors and Reference Contamination Sources

    NASA Technical Reports Server (NTRS)

    Allton, J. H.; Gonzalez, C. P.; Allums, K. K.

    2016-01-01

    The Genesis mission collected solar wind for 27 months at Earth-Sun L1 on both passive and active collectors carried inside of a Science Canister, which was cleaned and assembled in an ISO Class 4 cleanroom prior to launch. The primary passive collectors, 271 individual hexagons and 30 half-hexagons of semiconductor materials, are described in. Since the hard landing reduced the 301 passive collectors to many thousand smaller fragments, characterization and posting in the online catalog remains a work in progress, with about 19% of the total area characterized to date. Other passive collectors, surfaces of opportunity, have been added to the online catalog. For species needing to be concentrated for precise measurement (e.g. oxygen and nitrogen isotopes) an energy-independent parabolic ion mirror focused ions onto a 6.2 cm diameter target. The target materials, as recovered after landing, are described in. The online catalog of these solar wind collectors, a work in progress, can be found at: http://curator.jsc.nasa.gov/gencatalog/index.cfm This paper describes the next step, the cataloging of pieces of the Science Canister, which were surfaces exposed to the solar wind or component materials adjacent to solar wind collectors which may have contributed contamination.

  10. ELECTRON TRANSPORT IN THE FAST SOLAR WIND

    SciTech Connect

    Smith, H. M.; Marsch, E.; Helander, P.

    2012-07-01

    The electron velocity distribution function is studied in the extended solar corona above coronal holes (i.e., the inner part of the fast solar wind) from the highly collisional corona close to the Sun to the weakly collisional regions farther out. The electron kinetic equation is solved with a finite-element method in velocity space using a linearized Fokker-Planck collision operator. The ion density and temperature profiles are assumed to be known and the electric field and electron temperature are determined self-consistently. The results show quantitatively how much lower the electron heat flux and the thermal force are than predicted by high-collisionality theory. The sensitivity of the particle and heat fluxes to the assumed ion temperature profile and the applied boundary condition at the boundary far from the Sun is also studied.

  11. On rotational forces in the solar wind

    NASA Technical Reports Server (NTRS)

    Hollweg, J. V.; Isenberg, P. A.

    1981-01-01

    Solar rotational forces affecting the flow of minor ions in the solar wind are considered as corotating with the sun. Cold, noninteracting charged particles in the magnetic and gravitational fields of the sun rotate with the angular velocity of the sun, and calculations of lowest bulk order velocities show that differences in particle velocities decrease with increasing distance from the sun. A centrifugal potential in the corotating frame implies that ion motion is independent of protons, with velocities determined by the potential, which monotonically decreases without limit. The potential dominates the initial kinetic energy of the particles, and the equality of velocities within the potential is not due to interactions between particles as claimed by Mackenzie et al. (1979).

  12. A numerical study of transient, thermally-conductive solar wind

    NASA Technical Reports Server (NTRS)

    Han, S. M.; Wu, S. T.; Dryer, M.

    1987-01-01

    A numerical analysis of transient solar wind starting at the solar surface and arriving at 1 AU is performed by an implicit numerical method. The model hydrodynamic equations include thermal conduction terms for both steady and unsteady simulations. Simulation results show significant influence of thermal conduction on both steady and time-dependent solar wind. Higher thermal conduction results in higher solar wind speed, higher temperature, but lower plasma density at 1 AU. Higher base temperature at the solar surface gives lower plasma speed, lower temperature, but higher density at 1 AU. Higher base density, on the other hand, gives lower velocity, lower temperature, but higher density at 1 AU.

  13. Magnetic Influences on the Solar Wind

    NASA Astrophysics Data System (ADS)

    Woolsey, Lauren N.

    2016-01-01

    The Sun is our closest star, and even with the ability to resolve fine structure, there are several large mysteries that remain unsolved. One of these unanswered questions is how the supersonic outflow from the Sun, the solar wind, is generated and accelerated. In this dissertation, I have investigated the role of Alfvén waves in heating the corona and accelerating the wind. I focus on modeling of flux tubes that are open to the heliosphere, i.e. bundles of magnetic field that stretch beyond a few solar radii into the heliosphere. In these flux tubes, Alfvén waves are launched by the shaking of the footpoints from the convective motions of granulation on the solar photosphere. I present results of modeling efforts in one dimension that investigate how this process changes for a variety of different magnetic field structures over a solar cycle and three-dimensional modeling of time-dependent processes that unlock a connection between pico- and nanoflare-scale events and the turbulent heating generated by counter-propagating Alfvén waves. In addition to computational modeling, I also present efforts to find magnetic thresholds in observations of small-scale network jets seen with the Interface Region Imaging Spectrograph (IRIS). These jets were first discovered by IRIS due to their short lifetimes (10s of seconds) and small size (widths of 100s of kilometers). The findings for this project suggest that the modeled Alfvén-wave-driven turbulence is consistent with these network jets.

  14. Latitudinal Dependence of Coronal Hole-Associated Fast Solar Wind

    NASA Astrophysics Data System (ADS)

    Zhao, L.; Landi, E.

    2014-05-01

    The fast solar wind can have at least two different coronal sources: high-latitude, polar coronal holes (PCH) and low-latitude, equatorial coronal holes (ECH). The in-situ differences in the PCH and ECH winds have not been well studied, nor have the differences in their evolution over the solar cycles. Ulysses' 19 years of observations from 1990 to 2009, combined with ACE observations from 1998 to the present, provide us with measurements of solar wind properties that span two entire solar cycles, which allow us to study the in-situ properties and evolution of the coronal hole-associated solar wind at different latitudes. In this work, we focus on the PCH and ECH solar winds during the minima between solar cycles 22-23 and 23-24. We use data from SWICS, SWOOPS, and VHM/FGM on board Ulysses, and SWICS, SWEPAM, and MAG on board ACE to analyze the proton dynamics, heavy ion composition, elemental abundance, and magnetic field properties of the PCH wind and ECH wind, with a special focus on their differences during the recent two solar minima. We also include the slow and hot, streamer-associated (ST) wind as a reference in the comparison. The comparison of PCH and ECH wind shows that: 1) the in-situ properties of ECH and PCH winds are significantly different during the two solar minima, and 2) the two types of coronal hole-associated solar wind respond differently to changes in solar activity strength from cycle 23 to cycle 24.

  15. The floor in the solar wind: status report

    NASA Astrophysics Data System (ADS)

    Cliver, E. W.

    2012-07-01

    Cliver & Ling (2010) recently suggested that the solar wind had a floor or ground-state magnetic field strength at Earth of ~2.8 nT and that the source of the field was the slow solar wind. This picture has recently been given impetus by the evidence presented by Schrijver et al. (2011) that the Sun has a minimal magnetic state that was approached globally in 2009, a year in which Earth was imbedded in slow solar wind ~70% of the time. A precursor relation between the solar dipole field strength at solar minimum and the peak sunspot number (SSN MAX ) of the subsequent 11-yr cycle suggests that during Maunder-type minima (when SSN MAX was ~0), the solar polar field strength approaches zero - indicating weak or absent polar coronal holes and an increase to nearly ~100% in the time that Earth spends in slow solar wind.

  16. Surface waves on solar wind tangential discontinuities

    NASA Technical Reports Server (NTRS)

    Hollweg, J. V.

    1982-01-01

    It is demonstrated that (tangential) discontinuities in the magnetic field direction can support MHD surface waves. The surface waves are similar to the usual Alfven wave, but there are seven important differences. The first is that the surface waves exhibit a low-frequency cutoff; the second is that the velocity and magnetic field fluctuations are elliptically, and sometimes circularly, polarized. It is noted that they may account for the solar wind helicity spectrum. The third difference is that the surface waves are compressive, although there are special cases where they are noncompressive. The fourth is that the wave vector k, the local normals to the surfaces of constant phase, and the magnetic minimum variance direction do not all coincide. The fifth is that there is a tendency for the minimum variance direction to align itself with the mean magnetic field direction. The sixth difference is that the waves can be intrinsically nonplanar, and the seventh is that equipartition between magnetic and kinetic energies is not obeyed locally. These properties of the surface waves are interpreted to mean that surface waves may be common in the solar wind.

  17. An asymmetric solar wind termination shock.

    PubMed

    Stone, Edward C; Cummings, Alan C; McDonald, Frank B; Heikkila, Bryant C; Lal, Nand; Webber, William R

    2008-07-01

    Voyager 2 crossed the solar wind termination shock at 83.7 au in the southern hemisphere, approximately 10 au closer to the Sun than found by Voyager 1 in the north. This asymmetry could indicate an asymmetric pressure from an interstellar magnetic field, from transient-induced shock motion, or from the solar wind dynamic pressure. Here we report that the intensity of 4-5 MeV protons accelerated by the shock near Voyager 2 was three times that observed concurrently by Voyager 1, indicating differences in the shock at the two locations. (Companion papers report on the plasma, magnetic field, plasma-wave and lower energy particle observations at the shock.) Voyager 2 did not find the source of anomalous cosmic rays at the shock, suggesting that the source is elsewhere on the shock or in the heliosheath. The small intensity gradient of Galactic cosmic ray helium indicates that either the gradient is further out in the heliosheath or the local interstellar Galactic cosmic ray intensity is lower than expected. PMID:18596802

  18. Velocity shear generation of solar wind turbulence

    SciTech Connect

    Roberts, D.A.; Goldstein, M.L.; Ghosh, S.; Matthaeus, W.H.

    1992-11-01

    The authors use a two-dimensional, incompressible MHD spectral code to establish that shear-driven turbulence is a possible means for producing many observed properties of the evolution of the magnetic and velocity fluctuations in the solar wind and, in particular, the evolution of the cross helicity ({open_quotes}Alfvenicity{close_quotes}) at small scales. They find that large-scale shear can nonlinearly produce a cascade to smaller scale fluctuations even when the linear Kelvin-Helmholtz mode is stable and that a roughly power law inertial range is established by this process. While the fluctuations thus produced are not Alfvenic, they are nearly equipartitioned between magnetic and kinetic energy. The authors report simulations with Alfvenic fluctuations at high wave numbers, both with and without shear layers and find that it is the low cross helicity at low wave numbers that is critical to the cross helicity evolution, rather than the geometry of the flow or the dominance of kinetic energy at large scales. The fluctuations produced by shear effects are shown to evolve similarly but more slowly in the presence of a larger mean field and to be anisotropic with a preferred direction of spectral transfer perpendicular to the mean field. The evolution found is similar to that seen in some other simulations of HMD turbulence, and thus seems in many respects to be an instance of a more generic turbulent evolution rather than due to specific conditions in the solar wind. 75 refs., 18 figs.

  19. Anisotropy in solar wind plasma turbulence.

    PubMed

    Oughton, S; Matthaeus, W H; Wan, M; Osman, K T

    2015-05-13

    A review of spectral anisotropy and variance anisotropy for solar wind fluctuations is given, with the discussion covering inertial range and dissipation range scales. For the inertial range, theory, simulations and observations are more or less in accord, in that fluctuation energy is found to be primarily in modes with quasi-perpendicular wavevectors (relative to a suitably defined mean magnetic field), and also that most of the fluctuation energy is in the vector components transverse to the mean field. Energy transfer in the parallel direction and the energy levels in the parallel components are both relatively weak. In the dissipation range, observations indicate that variance anisotropy tends to decrease towards isotropic levels as the electron gyroradius is approached; spectral anisotropy results are mixed. Evidence for and against wave interpretations and turbulence interpretations of these features will be discussed. We also present new simulation results concerning evolution of variance anisotropy for different classes of initial conditions, each with typical background solar wind parameters. PMID:25848082

  20. Variance Anisotropy of Solar Wind fluctuations

    NASA Astrophysics Data System (ADS)

    Oughton, S.; Matthaeus, W. H.; Wan, M.; Osman, K.

    2013-12-01

    Solar wind observations at MHD scales indicate that the energy associated with velocity and magnetic field fluctuations transverse to the mean magnetic field is typically much larger than that associated with parallel fluctuations [eg, 1]. This is often referred to as variance anisotropy. Various explanations for it have been suggested, including that the fluctuations are predominantly shear Alfven waves [1] and that turbulent dynamics leads to such states [eg, 2]. Here we investigate the origin and strength of such variance anisotropies, using spectral method simulations of the compressible (polytropic) 3D MHD equations. We report on results from runs with initial conditions that are either (i) broadband turbulence or (ii) fluctuations polarized in the same sense as shear Alfven waves. The dependence of the variance anisotropy on the plasma beta and Mach number is examined [3], along with the timescale for any variance anisotropy to develop. Implications for solar wind fluctuations will be discussed. References: [1] Belcher, J. W. and Davis Jr., L. (1971), J. Geophys. Res., 76, 3534. [2] Matthaeus, W. H., Ghosh, S., Oughton, S. and Roberts, D. A. (1996), J. Geophys. Res., 101, 7619. [3] Smith, C. W., B. J. Vasquez and K. Hamilton (2006), J. Geophys. Res., 111, A09111.

  1. Electric conductivity of plasma in solar wind

    NASA Technical Reports Server (NTRS)

    Chertkov, A. D.

    1995-01-01

    One of the most important parameters in MHD description of the solar wind is the electric conductivity of plasma. There exist now two quite different approaches to the evaluation of this parameter. In the first one a value of conductivity taken from the most elaborated current theory of plasma should be used in calculations. The second one deals with the empirical, phenomenological value of conductivity. E.g.: configuration of interplanetary magnetic field, stretched by the expanding corona, depends on the magnitude of electrical conductivity of plasma in the solar wind. Knowing the main empirical features of the field configuration, one may estimate the apparent phenomenological value of resistance. The estimations show that the electrical conductivity should be approximately 10(exp 13) times smaller than that calculated by Spitzer. It must be noted that the empirical value should be treated with caution. Due to the method of its obtaining it may be used only for 'large-scale' description of slow processes like coronal expansion. It cannot be valid for 'quick' processes, changing the state of plasma, like collisions with obstacles, e.g., planets and vehicles. The second approach is well known in large-scale planetary hydrodynamics, stemming from the ideas of phenomenological thermodynamics. It could formulate real problems which should be solved by modern plasma physics, oriented to be adequate for complicated processes in space.

  2. The solar wind effect on cosmic rays and solar activity

    NASA Technical Reports Server (NTRS)

    Fujimoto, K.; Kojima, H.; Murakami, K.

    1985-01-01

    The relation of cosmic ray intensity to solar wind velocity is investigated, using neutron monitor data from Kiel and Deep River. The analysis shows that the regression coefficient of the average intensity for a time interval to the corresponding average velocity is negative and that the absolute effect increases monotonously with the interval of averaging, tau, that is, from -0.5% per 100km/s for tau = 1 day to -1.1% per 100km/s for tau = 27 days. For tau 27 days the coefficient becomes almost constant independently of the value of tau. The analysis also shows that this tau-dependence of the regression coefficiently is varying with the solar activity.

  3. Ulysses Composition, Plasma and Magnetic Field Observations of High Speed Solar wind Streams

    NASA Technical Reports Server (NTRS)

    Smith, E. J.

    1997-01-01

    During 1992-3 as the Ulysses spacecraft passed in and out of the southern high speed solar wind stream, the Solar Wind Ion Spectrometer, SWICS made continuous composition and temperature measurements of all major solar wind ions.

  4. Solar wind velocity and temperature in the outer heliosphere

    NASA Technical Reports Server (NTRS)

    Gazis, P. R.; Barnes, A.; Mihalov, J. D.; Lazarus, A. J.

    1994-01-01

    At the end of 1992, the Pioneer 10, Pioneer 11, and Voyager 2 spacecraft were at heliocentric distances of 56.0, 37.3, and 39.0 AU and heliographic latitudes of 3.3 deg N, 17.4 deg N, and 8.6 deg S, respectively. Pioneer 11 and Voyager 2 are at similar celestial longitudes, while Pioneer 10 is on the opposite side of the Sun. All three spacecraft have working plasma analyzers, so intercomparison of data from these spacecraft provides important information about the global character of the solar wind in the outer heliosphere. The averaged solar wind speed continued to exhibit its well-known variation with solar cycle: Even at heliocentric distances greater than 50 AU, the average speed is highest during the declining phase of the solar cycle and lowest near solar minimum. There was a strong latitudinal gradient in solar wind speed between 3 deg and 17 deg N during the last solar minimum, but this gradient has since disappeared. The solar wind temperature declined with increasing heliocentric distance out to a heliocentric distance of at least 20 AU; this decline appeared to continue at larger heliocentric distances, but temperatures in the outer heliosphere were suprisingly high. While Pioneer 10 and Voyager 2 observed comparable solar wind temperatures, the temperature at Pioneer 11 was significantly higher, which suggests the existence of a large-scale variation of temperature with heliographic longitude. There was also some suggestion that solar wind temperatures were higher near solar minimum.

  5. The solar wind in the third dimension

    SciTech Connect

    Neugebauer, M.

    1996-07-20

    For many years, solar-wind physicists have been using plasma and field data acquired near the ecliptic plane together with data on the scintillation of radio sources and remote sensing of structures in the solar corona to estimate the properties of the high-latitude solar wind. Because of the highly successful Ulysses mission, the moment of truth is now here. This paper summarizes the principal agreements and differences between the Ulysses observations and expectations. The speed of the high-latitude solar wind was even greater than anticipated. The strength of the radial component of the interplanetary magnetic field was found to be independent of latitude. The tilt of the heliospheric current sheet caused reverse corotating shocks to be observed to higher latitudes than forward corotating shocks. The energetic particles accelerated in these shocks were detected well poleward of the latitudes at which Ulysses observed the interaction regions themselves. As anticipated, there was a strong flux of outward propagating Alfven waves throughout the polar flow. Those waves were probably largely responsible for the smaller-than-anticipated increase of galactic cosmic rays with increasing latitude. As expected, the charge state or ionization temperature of heavy ions was lower in the polar flow than in low-latitude interstream flows. What was not anticipated was the correlation of elemental abundances with ionization temperatures; the Ulysses data revealed a connection between the first ionization time in the upper chromosphere and the final ionization state in the corona. As expected, transient events were detected to {approx}60 deg. latitude, but the properties of those high latitude transient flows held some surprises. At high latitudes, the speeds of the transient interplanetary plasma clouds were approximately the same as the speed of the ambient plasma and the expansion of the clouds drove forward and reverse shock pairs that had never been seen at low latitudes. At high latitudes, the plasma in interplanetary clouds differed from low-latitude events in that it was not enriched in helium and did not have high ionization temperatures.

  6. A two-fluid model of the solar wind

    NASA Technical Reports Server (NTRS)

    Sandbaek, O.; Leer, E.; Holzer, T. E.

    1992-01-01

    A method is presented for the integration of the two-fluid solar-wind equations which is applicable to a wide variety of coronal base densities and temperatures. The method involves proton heat conduction, and may be applied to coronal base conditions for which subsonic-supersonic solar wind solutions exist.

  7. On WKB expansions for Alfven waves in the solar wind

    NASA Astrophysics Data System (ADS)

    Hollweg, Joseph V.

    1990-09-01

    The WKB expansion for 'toroidal' Alfven waves in solar wind, which is described by equations of Heinemann and Olbert (1980), is examined. In this case, the multiple scales method (Nayfeh, 1981) is used to obtain a uniform expansion. It is shown that the WKB expansion used by Belcher (1971) and Hollweg (1973) for Alfven waves in the solar wind is nonuniformly convergent.

  8. Solar and Wind Technologies for Hydrogen Production Report to Congress

    SciTech Connect

    None, None

    2005-12-01

    DOE's Solar and Wind Technologies for Hydrogen Production Report to Congress summarizes the technology roadmaps for solar- and wind-based hydrogen production. Published in December 2005, it fulfills the requirement under section 812 of the Energy Policy Act of 2005.

  9. Correlations between solar wind parameters and auroral kilometric radiation intensity

    NASA Technical Reports Server (NTRS)

    Gallagher, D. L.; Dangelo, N.

    1981-01-01

    The relationship between solar wind properties and the influx of energy into the nightside auroral region as indicated by the intensity of auroral kilometric radiation is investigated. Smoothed Hawkeye satellite observations of auroral radiation at 178, 100 and 56.2 kHz for days 160 through 365 of 1974 are compared with solar wind data from the composite Solar Wind Plasma Data Set, most of which was supplied by the IMP-8 spacecraft. Correlations are made between smoothed daily averages of solar wind ion density, bulk flow speed, total IMF strength, electric field, solar wind speed in the southward direction, solar wind speed multiplied by total IMF strength, the substorm parameter epsilon and the Kp index. The greatest correlation is found between solar wind bulk flow speed and auroral radiation intensity, with a linear correlation coefficient of 0.78 for the 203 daily averages examined. A possible mechanism for the relationship may be related to the propagation into the nightside magnetosphere of low-frequency long-wavelength electrostatic waves produced in the magnetosheath by the solar wind.

  10. Western Wind and Solar Integration Study Phase 3: Technical Overview

    SciTech Connect

    2015-11-01

    Technical fact sheet outlining the key findings of Phase 3 of the Western Wind and Solar Integration Study (WWSIS-3). NREL and GE find that with good system planning, sound engineering practices, and commercially available technologies, the Western grid can maintain reliability and stability during the crucial first minute after grid disturbances with high penetrations of wind and solar power.

  11. Turbulence in the solar wind: Kinetic effects

    NASA Technical Reports Server (NTRS)

    Goldstein, M. L.

    1995-01-01

    Although a casual look at the fluctuating magnetic and velocity fields in the solar wind may be reminiscent of a chaotic and disordered flow, there is, nonetheless. considerable organization and structure in the temporal and spatial evolution of those fluctuations. Much of that evolution is controlled by processes operating on rather large scales for example, in the inner heliosphere, the fluctuations in magnetic and velocity are highly correlated in the sense of outward propagating Alfven waves. This correlation can be destroyed both in time and distance by the velocity gradients present between fast and slow streams and by other nonlinear processes which stir the medium, producing a turbulent cascade of energy from large to small scales. Many aspects of this turbulent evolution can be described using fluid models; however, at some scale the fluid approximation breaks down and a more detailed paradigm is necessary. The breakdown is evident in the power spectrum of magnetic fluctuations at scales approaching the wavelength of ion cyclotron waves. At those scales, as evident in Mariner 10 and other magnetometer data, the spectrum bends over and the fluctuations damp, possibly heating the ambient plasma. Some evidence for heating of the solar wind is present in the Voyager data. Fluid models can be modified to some extent to incorporate aspects of a kinetic treatment. This is done by modifying the dissipation terms in the fluid equations and by including extra terms, such as the Hall term. As the scale lengths of phenomena shrink further and approach the spatial and temporal scales characteristic of electron phenomena, the fluid description must be abandoned altogether and a fully kinetic treatment is required. One example is the generation of Langmuir solitons produced by the electron beams that generate type 3 solar radio bursts.

  12. Venus Ionosphere and Solar Wind Interaction

    NASA Astrophysics Data System (ADS)

    Russell, C. T.; Luhmann, Janet G.; Ma, Yingjuan; Zhang, Tielong; Villarreal, M.

    Venus Express, which was inserted into orbit in mid-2006, has added significantly to the knowledge gained from Pioneer Venus from 1978 to 1992. This observational database interpreted in terms of modern multi-fluid codes and hybrid simulations has deepened our understanding of Earth’s very different twin sister planet. Furthermore, the very different orbits of VEX and PVO has allowed the more complete mapping of the volume of space around the planet. Now the bow shock has been probed over its full surface, the ionosphere mapped everywhere, and the tail studied from the ionosphere to 12 Venus radii. Some unexpected discoveries have been made. The exospheric hydrogen at Venus, unlike that at Mars, does not produce ion-cyclotron waves, perhaps because the stronger gravity of Venus produces a smaller geocorona. The solar wind interaction drapes the magnetic field around the planet, and a strong layer of magnetic field builds up at low altitudes. While the layer does not appear to penetrate into the dayside atmosphere (perhaps diffusing only slowly through the low atmosphere), it does appear to dip into the atmosphere at night. Surprisingly, over the poles, this layer is most strongly seen when the IMF BY component has a positive Y-component in Venus-Solar-Orbital coordinates. Multi-fluid simulations show that this result is consistent with the pressure of significant ion densities of ions with quite different mass which causes magnetic polarity control of the ion flow over the terminators. Reconnection is found in the tail close to the planet, and the structure of the outer tail found by PVO is confirmed to exist in the inner tail by VEX. When combined, the VEX and PVO Data provide a very comprehensive picture of the physics of the solar wind interaction with the ionosphere of Venus.

  13. Jupiter's Main Auroral Emission for Different Solar Wind Conditions

    NASA Astrophysics Data System (ADS)

    Chan, E.; Saur, J.; Poedts, S.

    2014-12-01

    We study the temporal change of Jupiter's magnetosphere and aurora due to changing solar wind conditions. In particular, we examine how the the main auroral emission is affected by the solar wind density. Using three dimensional global MHD simulations, we perform three different runs, with: 1) quiet solar wind conditions (ram pressure of 0.05 nPa), 2) disturbed solar wind conditions (ram pressure of 0.17 nPa), and 3) very disturbed solar wind conditions (ram pressure of 0.34 nPa). We show that the response of the main auroral emission depends on local time: at noon, the main oval is only weakly affected by the variations in the solar wind; whereas on the night side, the main emission becomes brighter when the solar wind ram pressure increases. For instance, 10 hours after the high density solar wind reached the magnetosphere, the peak in parallel electrical current on the night side is 20% and 40% stronger for the disturbed and very disturbed solar wind conditions, respectively. The main auroral emission begins to change three hours after the solar wind density enhancement strikes the bow-shock and it takes approximately three days for the magnetosphere to adjust to the new solar wind conditions. The total electrical current flowing out of the ionosphere is then 30% (50%) higher for the (very) disturbed solar wind conditions than for the quiet solar wind conditions. In addition, for the three simulations, a localized enhancement of the main oval emission is periodically observed around noon local time (inside the main oval discontinuity). A very similar enhancement has already been observed with the Hubble Space Telescope in Far-UV images by Palmaerts et al. (JGR, under review). In our simulations, the localized peak is not caused by fluctuations in the solar wind, but is always associated with a region of negative radial velocity in the equatorial plane at the position where the corotation breaks down. The shearing motions associated with this negative radial velocity region produce strong gradients for Bz in the azimuthal direction, which causes an enhancement of the electrical current.

  14. Heliospheric Solar-Wind Charge Exchange

    NASA Astrophysics Data System (ADS)

    Wargelin, Bradford J.

    2011-05-01

    X-ray emission from solar wind charge exchange (SWCX) arises in the Earth's exosphere and throughout the solar system in the heliosphere. The intensity of SXCW emission observed by X-ray telescopes from within these emission regions varies a great deal, both as a function of viewing geometry and solar activity. SWCX accounts for much or most of the soft X-ray background (SXRB) but distinguishing it from Galactic emission is a tricky problem. One approach is to measure the SXRB at a given point on the sky at different times and with different lines of sight through the heliosphere. The Chandra Deep Field-South, comprising 52 observations and 4 Msec of data collected between 2000 and 2010, is uniquely suited for such studies. This talk will also discuss the potential of high-spectral-resolution observations and prospects for measuring mass-loss rates around other stars from their charge exchange emission. Support for this work was provided by NASA through Chandra Award Number SP1-12001X issued by the Chandra X-ray Observatory Center (CXC), which is operated by the Smithsonian Astrophysical Observatory for and on behalf of NASA under contract NAS8-03060.

  15. The Western Wind and Solar Integration Study Phase 2

    SciTech Connect

    Lew, D.; Brinkman, G.; Ibanez, E.; Hodge, B. M.; Hummon, M.; Florita, A.; Heaney, M.

    2013-09-01

    The electric grid is a highly complex, interconnected machine, and changing one part of the grid can have consequences elsewhere. Adding wind and solar affects the operation of the other power plants and adding high penetrations can induce cycling of fossil-fueled generators. Cycling leads to wear-and-tear costs and changes in emissions. Phase 2 of the Western Wind and Solar Integration Study (WWSIS-2) evaluated these costs and emissions and simulated grid operations for a year to investigate the detailed impact of wind and solar on the fossil-fueled fleet. This built on Phase 1, one of the largest wind and solar integration studies ever conducted, which examined operational impacts of high wind and solar penetrations in the West.

  16. Plasma Properties of Pseudostreamers and Associated Solar Wind Streams

    NASA Astrophysics Data System (ADS)

    Miralles, M. P.; Cranmer, S. R.; Stenborg, G.

    2014-12-01

    We study pseudostreamers (i.e., open-field extensions of plasma from unipolar footpoints in the corona; distinct from classical helmet streamers that have opposite-polarity footpoints) that are believed to be sources of slow to intermediate speed wind streams. We make use of multi-spacecraft and ground-based observations that extend from the solar corona to the solar wind at 1 AU. We compare the physical properties of selected pseudostreamers and helmet streamers to characterize how the differences in magnetic topology affect the plasma properties of the coronal structures and their wind. Due to the large number of pseudostreamers and their long persistence over multiple solar rotations, their contribution to the solar wind is likely to be substantial. In order to investigate solar wind heating and acceleration, we also compare our measurements with predictions from pseudostreamer and streamer theoretical models. This work is supported by NASA grant NNX10AQ58G to the Smithsonian Astrophysical Observatory.

  17. The Western Wind and Solar Integration Study Phase 2

    SciTech Connect

    Lew, Debra; Brinkman, Greg; Ibanez, E.; Florita, A.; Heaney, M.; Hodge, B. -M.; Hummon, M.; Stark, G.; King, J.; Lefton, S. A.; Kumar, N.; Agan, D.; Jordan, G.; Venkataraman, S.

    2013-09-01

    The electric grid is a highly complex, interconnected machine, and changing one part of the grid can have consequences elsewhere. Adding wind and solar affects the operation of the other power plants and adding high penetrations can induce cycling of fossil-fueled generators. Cycling leads to wear-and-tear costs and changes in emissions. Phase 2 of the Western Wind and Solar Integration Study (WWSIS-2) evaluated these costs and emissions and simulated grid operations for a year to investigate the detailed impact of wind and solar on the fossil-fueled fleet. This built on Phase 1, one of the largest wind and solar integration studies ever conducted, which examined operational impacts of high wind and solar penetrations in the West(GE Energy 2010).

  18. Solar wind control of auroral zone geomagnetic activity

    NASA Technical Reports Server (NTRS)

    Clauer, C. R.; Mcpherron, R. L.; Searls, C.; Kivelson, M. G.

    1981-01-01

    Solar wind magnetosphere energy coupling functions are analyzed using linear prediction filtering with 2.5 minute data. The relationship of auroral zone geomagnetic activity to solar wind power input functions are examined, and a least squares prediction filter, or impulse response function is designed from the data. Computed impulse response functions are observed to have characteristics of a low pass filter with time delay. The AL index is found well related to solar wind energy functions, although the AU index shows a poor relationship. High frequency variations of auroral indices and substorm expansions are not predictable with solar wind information alone, suggesting influence by internal magnetospheric processes. Finally, the epsilon parameter shows a poorer relationship with auroral geomagnetic activity than a power parameter, having a VBs solar wind dependency.

  19. Solar wind iron charge states preceding a driver plasma

    NASA Technical Reports Server (NTRS)

    Galvin, A. B.; Ipavich, F. M.; Gloeckler, G.; Hovestadt, D.; Tsurutani, B. T.

    1987-01-01

    Iron and silicon/sulfur charge state and velocity measurements and iron density measurements in the shocked solar wind which preceded the flare-related driver plasma observed on September 29, 1978 by ISEE 3 are reported. Given the assumption that the driver plasma is magnetically isolated from the ambient solar wind, the contact surface separating these two plasma regimes is expected to form an distinct boundary in the charge state composition. Instead, an apparent transition in the ionization state of the shocked solar wind from ambient solar wind values to those typical of the driver plasma is observed. This result may reflect X-ray ionization of the solar wind plasma near the flare site.

  20. OBSERVATION OF FLUX-TUBE CROSSINGS IN THE SOLAR WIND

    SciTech Connect

    Arnold, L.; Li, G.; Li, X.; Yan, Y.

    2013-03-20

    Current sheets are ubiquitous in the solar wind. They are a major source of the solar wind MHD turbulence intermittency. They may result from nonlinear interactions of the solar wind MHD turbulence or are the boundaries of flux tubes that originate from the solar surface. Some current sheets appear in pairs and are the boundaries of transient structures such as magnetic holes and reconnection exhausts or the edges of pulsed Alfven waves. For an individual current sheet, discerning whether it is a flux-tube boundary or due to nonlinear interactions or the boundary of a transient structure is difficult. In this work, using data from the Wind spacecraft, we identify two three-current-sheet events. Detailed examination of these two events suggests that they are best explained by the flux-tube-crossing scenario. Our study provides convincing evidence supporting the scenario that the solar wind consists of flux tubes where distinct plasmas reside.

  1. Short-scale variations of the solar wind helium abundance

    SciTech Connect

    afrnkov, J.; N?me?ek, Z.; Caga, P.; P?ech, L.; Pavl?, J.; Zastenker, G. N.; Riazantseva, M. O.; Koloskova, I. V.

    2013-11-20

    Abrupt changes of the relative He abundance in the solar wind are usually attributed to encounters with boundaries dividing solar wind streams from different sources in the solar corona. This paper presents a systematic study of fast variations of the He abundance that supports the idea that a majority of these variations on short timescales (3-30 s) are generated by in-transit turbulence that is probably driven by the speed difference between the ion species. This turbulence contributes to the solar wind heating and leads to a correlation of the temperature with He abundance.

  2. Solar-wind tritium limit and nuclear processes in the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Fireman, E. L.; Damico, J.; Defelice, J.

    1975-01-01

    Tritium in Surveyor 3 material is measured, and the resulting H-3/H-1 ratio for the solar wind is applied in a solar flare-solar wind relation to investigate the mixing requirements for the solar atmosphere. The flare-wind relation is derived. None of the tritium can be attributed to solar-wind implantation. The upper limit for the H-3/He ratio in the solar wind is 4 times 10 to the minus tenth power and corresponds to a H-3/H-1 limit of 2 times 10 to the minus eleventh power. This limit imposes a requirement on the mixing rate in the solar atmosphere if the H-3 production rate in solar-surface nuclear reactions is greater than 160/sq cm per sec.

  3. Solar wind fluctuations and solar activity long-term swing: 1963-2012

    NASA Astrophysics Data System (ADS)

    Zerbo, J. L.; Amory-Mazaudier, C.; Ouattara, F.

    2014-01-01

    In this study we investigate the time variation of several solar activity, geomagnetic indices, and solar wind parameters (B, V). It is well known that solar wind is one of the main contributing factors to geomagnetic activity and his topology is strongly affect by solar events such as CMEs and coronals. For these two solar events, we study the correlation between PCI and BV during solar cycle phases and point out the close link between PCI and the occurring of CMEs and high wind speed flowing from coronal holes.

  4. Measurements of the solar wind using spacecraft radio scattering observations

    NASA Technical Reports Server (NTRS)

    Woo, R.

    1977-01-01

    This paper reviews radio scattering measurements of the solar wind carried out with coherent, monochromatic, and point-source spacecraft signals. The observed phenomena which include spectral and angular broadening, and phase as well as intensity scintillations, have provided measurements of the solar wind previously not available from radio astronomical observations. These cover a wide range of heliocentric distances (as close as 1.7 solar radii), and large- as well as small-scale electron density fluctuations.

  5. Polar solar wind and interstellar wind properties from interplanetary Lyman-alpha radiation measurements

    NASA Technical Reports Server (NTRS)

    Witt, N.; Blum, P. W.; Ajello, J. M.

    1981-01-01

    The analysis of Mariner 10 observations of Lyman-alpha resonance radiation shows an increase of interplanetary neutral hydrogen densities above the solar poles. This increase is caused by a latitudinal variation of the solar wind velocity and/or flux. Using both the Mariner 10 results and other solar wind observations, the values of the solar wind flux and velocity with latitude are determined for several cases of interest. The latitudinal variation of interplanetary hydrogen gas, arising from the solar wind latitudinal variation, is shown to be most pronounced in the inner solar system. From this result it is shown that spacecraft Lyman-alpha observations are more sensitive to the latitudinal anisotropy for a spacecraft location in the inner solar system near the downwind axis.

  6. First Results from the Genesis Autonomous Solar Wind Regime Algorithm

    NASA Astrophysics Data System (ADS)

    Steinberg, J. T.; Barraclough, B.; Bremmer, R. R.; Dors, E. E.; Gosling, J. T.; Neugebauer, M.; Skoug, R. M.; Tokar, R. L.; Wiens, R. C.

    2001-12-01

    Launched on August 8, 2001, the NASA Genesis mission will collect samples of the solar wind in various materials for approximately two years, and return those samples to Earth for analysis. A primary science goal of Genesis is the determination of the elemental and isotopic composition of the solar atmosphere from the solar wind material returned. Because the solar wind itself is known to exhibit compositional variations across different types of solar wind flows, Genesis will expose different collectors to solar wind originating from three flow types: coronal hole (CH), coronal mass ejection (CME) and interstream (IS) flows. Flow types are identified using in situ measurements of solar wind ions and electrons from electrostatic analyzers carried by Genesis. The flow regime selection algorithm and subsequent array deployment on Genesis act autonomously, taking into account the proton speed, proton temperature, alpha particle abundance, and the presence of counter-streaming suprathermal electrons as determined onboard. Autonomous determination of counter-streaming electrons is novel, as is the simultaneous utilization of electron information and ion moments in logic that autonomously controls the science payload. We will report on the first four months of algorithm performance, comparing the onboard results to an assessment of regime based on post analysis of the in situ solar wind measurements. At the time of this writing, the regime algorithm has been active for eleven days, choosing regime IS for the first ten days, then transitioning to CH. In addition two interplanetary shocks have been correctly identified.

  7. Solar Energetic Particle Events in Different Types of Solar Wind

    NASA Astrophysics Data System (ADS)

    Kahler, Stephen W.; Vourlidas, Angelos

    2014-06-01

    We examine statistically some properties of 96 20 MeV gradual solar energetic proton (SEP) events as a function of three different types of solar winds (SWs) as classified by Richardson and Cane (2012). Gradual SEP (E > 10 MeV) events are produced in shocks driven by fast (V > 900 km/s) and wide (W > 60 deg) coronal mass ejections (CMEs). We find no differences between transient and fast or slow SW streams for SEP 20-MeV event timescales. It has recently been found that the peak intensities Ip of these SEP events scale with the ~ 2 MeV proton background intensities, which may be a proxy for the near-Sun shock seed particles. Both the intensities Ip and their 2 MeV backgrounds are significantly enhanced in transient SW compared to those of fast and slow SW streams, and the values of Ip normalized to the 2 MeV backgrounds only weakly correlate with CME V for all SW types. This result implies that forecasts of SEP events could be improved by monitoring both the Sun and the local SW stream properties and that the well known power-law size distributions of Ip may differ between transient and long-lived SW streams. We interpret an observed correlation between CME V and the 2 MeV background for SEP events in transient SW as a manifestation of enhanced solar activity.

  8. Solar Energetic Particle Events in Different Types of Solar Wind

    NASA Astrophysics Data System (ADS)

    Kahler, S. W.; Vourlidas, A.

    2014-08-01

    We examine statistically some properties of 96 20 MeV gradual solar energetic proton (SEP) events as a function of three different types of solar wind (SW) as classified by Richardson and Cane. Gradual SEP (E > 10 MeV) events are produced in shocks driven by fast (V >~ 900 km s-1) and wide (W > 60) coronal mass ejections (CMEs). We find no differences among the transient, fast, and slow SW streams for SEP 20 MeV proton event timescales. It has recently been found that the peak intensities Ip of these SEP events scale with the ~2 MeV proton background intensities, which may be a proxy for the near-Sun shock seed particles. Both the intensities Ip and their 2 MeV backgrounds are significantly enhanced in transient SW compared to those of fast and slow SW streams, and the values of Ip normalized to the 2 MeV backgrounds only weakly correlate with CME V for all SW types. This result implies that forecasts of SEP events could be improved by monitoring both the Sun and the local SW stream properties and that the well known power-law size distributions of Ip may differ between transient and long-lived SW streams. We interpret an observed correlation between CME V and the 2 MeV background for SEP events in transient SW as a manifestation of enhanced solar activity.

  9. Solar Coronal Plumes and the Fast Solar Wind

    NASA Astrophysics Data System (ADS)

    Dwivedi, Bhola N.; Wilhelm, Klaus

    2015-03-01

    The spectral profiles of the coronal Ne viii line at 77 nm have different shapes in quiet-Sun regions and Coronal Holes (CHs). A single Gaussian fit of the line profile provides an adequate approximation in quiet-Sun areas, whereas, a strong shoulder on the long-wavelength side is a systematic feature in CHs. Although this has been noticed since 1999, no physical reason for the peculiar shape could be given. In an attempt to identify the cause of this peculiarity, we address three problems that could not be conclusively resolved, in a review article by a study team of the International Space Science Institute (ISSI) (Wilhelm et al. 2011): (1) The physical processes operating at the base and inside of plumes, as well as their interaction with the Solar Wind (SW). (2) The possible contribution of plume plasma to the fast SW streams. (3) The signature of the First-Ionization Potential (FIP) effect between plumes and inter-plume regions (IPRs). Before the spectroscopic peculiarities in IPRs and plumes in Polar Coronal Holes (PCHs) can be further investigated with the instrument Solar Ultraviolet Measurements of Emitted Radiation (SUMER) aboard the Solar and Heliospheric Observatory (SOHO), it is mandatory to summarize the results of the review to place the spectroscopic observations into context. Finally, a plume model is proposed that satisfactorily explains the plasma flows up and down the plume field lines and leads to the shape of the neon line in PCHs.

  10. Solar energetic particle events in different types of solar wind

    SciTech Connect

    Kahler, S. W.; Vourlidas, A.

    2014-08-10

    We examine statistically some properties of 96 20 MeV gradual solar energetic proton (SEP) events as a function of three different types of solar wind (SW) as classified by Richardson and Cane. Gradual SEP (E > 10 MeV) events are produced in shocks driven by fast (V ? 900 km s{sup 1}) and wide (W > 60) coronal mass ejections (CMEs). We find no differences among the transient, fast, and slow SW streams for SEP 20 MeV proton event timescales. It has recently been found that the peak intensities Ip of these SEP events scale with the ?2 MeV proton background intensities, which may be a proxy for the near-Sun shock seed particles. Both the intensities Ip and their 2 MeV backgrounds are significantly enhanced in transient SW compared to those of fast and slow SW streams, and the values of Ip normalized to the 2 MeV backgrounds only weakly correlate with CME V for all SW types. This result implies that forecasts of SEP events could be improved by monitoring both the Sun and the local SW stream properties and that the well known power-law size distributions of Ip may differ between transient and long-lived SW streams. We interpret an observed correlation between CME V and the 2 MeV background for SEP events in transient SW as a manifestation of enhanced solar activity.

  11. Intermittent turbulence in the solar wind

    NASA Technical Reports Server (NTRS)

    Burlaga, L. F.

    1991-01-01

    This paper demonstrates the existence of intermittent turbulence in the solar wind at 8.5 AU. The pth-order velocity structure functions show scaling behavior in the range of periods from 0.85 hour to 13.6 hours for p of less than 20. The exponent of the scaling law s(p) is a quadratic function of p. These observations of s(p) for compressible MHD turbulence on a scale of the order of about 1 AU are consistent with laboratory measurements of s(p) for gasdynamic turbulence on a scale of the order of 1 m, indicating the universal character of intermittent turbulence. The observations are not described by the 'constant beta' model of intermittent turbulence. They are marginally consistent with the lognormal model. The observations are consistent with a random beta model prediction which assumes that the turbulence is a mixture of sheets and space-filling eddies.

  12. Microstructures in the Polar Solar Wind: Ulysses

    NASA Technical Reports Server (NTRS)

    Tsuruyani, Bruce T.; Arballo, J. K.; Galvan, C.; Goldstein, B. E.; Lakhina, G. S.; Sakurai, R.; Smith, E. J.; Neugebauer, M.

    1999-01-01

    We find that small (10-200 rP) magnetic decreases comprise a dominant part of the polar solar wind microstructure at Ulysses distances (2.2 AU). These magnetic field dips are almost always bounded by tangential discontinuities, a feature which is not well understood at this time. Hundreds of these events have been examined in detail and a variety of types have been found. These will be described. It is speculated that these structures have been generated by perpendicular heating of ions closer to the Sun and have then been convected to distances of Ulysses. Such structures may be very important for the rapid cross- field diffusion of ions in the polar regions of the heliosphere.

  13. Bidirectional solar wind electron heat flux events

    NASA Technical Reports Server (NTRS)

    Gosling, J. T.; Baker, D. N.; Bame, S. J.; Feldman, W. C.; Zwickl, R. D.; Smith, E. J.

    1987-01-01

    ISEE 3 plasma and magnetic field data are used here to document the general characteristics of bidirectional electron heat flux events (BEHFEs). Significant field rotations often occur at the beginning and/or end of such events and, at times, the large-field rotations characteristic of 'magnetic clouds' are present. Approximately half of all BEHFEs are associated with and follow interplanetary shocks, while the other events have no obvious shock associations. When shock-associated, the delay from shock passage typically is about 13 hours, corresponding to a radial separation of about 0.16 AU. When independent of any shock association, BEHFEs typically are about 0.13 AU thick in the radial direction. It is suggested that BEHFEs are one of the more prominent signatures of coronal mass ejection events in the solar wind at 1 AU.

  14. Suprathermal protons in the interplanetary solar wind

    NASA Technical Reports Server (NTRS)

    Goodrich, C. C.; Lazarus, A. J.

    1976-01-01

    Using the Mariner 5 solar wind plasma and magnetic field data, we present observations of field-aligned suprathermal proton velocity distributions having pronounced high-energy shoulders. These observations, similar to the interpenetrating stream observations of Feldman et al. (1974), are clear evidence that such proton distributions are interplanetary rather than bow shock associated phenomena. Large Alfven speed is found to be a requirement for the occurrence of suprathermal proton distribution; further, we find the proportion of particles in the shoulder to be limited by the magnitude of the Alfven speed. It is suggested that this last result could indicate that the proton thermal anisotropy is limited at times by wave-particle interactions

  15. ASYMMETRIC ELECTRON DISTRIBUTIONS IN THE SOLAR WIND

    SciTech Connect

    Rha, Kicheol; Ryu, Chang-Mo; Yoon, Peter H.

    2013-09-20

    A plausible mechanism responsible for producing asymmetric electron velocity distribution functions in the solar wind is investigated by means of one-dimensional electrostatic particle-in-cell (PIC) simulation. A recent paper suggests that the variation in the ion-to-electron temperature ratio influences the nonlinear wave-particle dynamics such that it results in the formation of asymmetric distributions. The present PIC code simulation largely confirms this finding, but quantitative differences between the weak turbulence formalism and the present PIC simulation are also found, suggesting the limitation of the analytical method. The inter-relationship between the asymmetric electron distribution and the ion-to-electron temperature ratio may be a new useful concept for the observation.

  16. Genesis Solar Wind Array Collector Cataloging Status

    NASA Technical Reports Server (NTRS)

    Burkett, P.J.; Rodriguez, M.C.; Calaway, M.C.; Allton, J.H.

    2009-01-01

    Genesis solar wind array collectors were fractured upon landing hard in Utah in 2004. The fragments were retrieved from the damaged canister, imaged, repackaged and shipped to the Johnson Space Center curatorial facility [1]. As of January 2009, the collection consists of 3460 samples. Of these, 442 are comprised into "multiple" sample groupings, either affixed to adhesive paper (177) or collected in jars (17), culture trays (87), or sets of polystyrene vials (161). A focused characterization task was initiated in May 2008 to document the largest samples in the collection. The task consisted of two goals: to document sapphire based fragments greater than 2 cm in one dimension, and to document silicon based fragments greater than 1 cm in one direction.

  17. KOLMOGOROV VECTORIAL LAW FOR SOLAR WIND TURBULENCE

    SciTech Connect

    Galtier, Sebastien

    2012-02-20

    We investigate a class of axisymmetric magnetohydrodynamic turbulence which satisfies the exact relation for third-order Elsaesser structure functions. Following the critical balance conjecture, we assume the existence of a power-law relation between correlation length scales along and transverse to the local mean magnetic field direction. The flow direction of the vector third-order moments F{sup {+-}} is then along axisymmetric concave/convex surfaces, the axis of symmetry being given by the mean magnetic field. Under this consideration, the vector F{sup {+-}} satisfies a simple Kolmogorov law which depends on the anisotropic parameter a{sup {+-}}, which measures the concavity of the surfaces. A comparison with recent in situ multispacecraft solar wind observations is made; it is concluded that the underlying turbulence is very likely convex. A discussion is given about the physical meaning of such an anisotropy.

  18. Innovations in Wind and Solar PV Financing

    SciTech Connect

    Cory, K.; Coughlin, J.; Jenkin, T.; Pater, J.; Swezey, B.

    2008-02-01

    There is growing national interest in renewable energy development based on the economic, environmental, and security benefits that these resources provide. Historically, greater development of our domestic renewable energy resources has faced a number of hurdles, primarily related to cost, regulation, and financing. With the recent sustained increase in the costs and associated volatility of fossil fuels, the economics of renewable energy technologies have become increasingly attractive to investors, both large and small. As a result, new entrants are investing in renewable energy and new business models are emerging. This study surveys some of the current issues related to wind and solar photovoltaic (PV) energy project financing in the electric power industry, and identifies both barriers to and opportunities for increased investment.

  19. RELAXATION PROCESSES IN SOLAR WIND TURBULENCE

    SciTech Connect

    Servidio, S.; Carbone, V.; Gurgiolo, C.; Goldstein, M. L.

    2014-07-10

    Based on global conservation principles, magnetohydrodynamic (MHD) relaxation theory predicts the existence of several equilibria, such as the Taylor state or global dynamic alignment. These states are generally viewed as very long-time and large-scale equilibria, which emerge only after the termination of the turbulent cascade. As suggested by hydrodynamics and by recent MHD numerical simulations, relaxation processes can occur during the turbulent cascade that will manifest themselves as local patches of equilibrium-like configurations. Using multi-spacecraft analysis techniques in conjunction with Cluster data, we compute the current density and flow vorticity and for the first time demonstrate that these localized relaxation events are observed in the solar wind. Such events have important consequences for the statistics of plasma turbulence.

  20. Synthetic four-solar-cycle solar wind at 1 AU generated from the OMNI data set

    NASA Astrophysics Data System (ADS)

    Thatcher, L. J.; Mller, H.-R.

    2013-02-01

    Abstract Numerical modeling provides key insights into the physics of the outer heliosphere. The <span class="hlt">solar</span> <span class="hlt">wind</span> data utilized by these models impact their accuracy and should be as close as possible to the actual <span class="hlt">solar</span> <span class="hlt">wind</span>. Because of the time scales involved, such a data set should also span several <span class="hlt">solar</span> cycles. Yet the bulk of <span class="hlt">solar</span> <span class="hlt">wind</span> measurements in such a time frame was obtained near Earth. A method to infer the <span class="hlt">solar</span> <span class="hlt">wind</span> at points not directly observed is developed such that a 1 AU ring in the ecliptic plane is filled with four <span class="hlt">solar</span> cycles of <span class="hlt">solar</span> <span class="hlt">wind</span> data. Hourly OMNI data are used as the seed data. The OMNI data are separated into four separate categories, and those categories are first extrapolated, generating a continuous 2-D category map of the <span class="hlt">solar</span> <span class="hlt">wind</span> for the full four <span class="hlt">solar</span> cycles covered by OMNI. The category map is used to determine <span class="hlt">solar</span> <span class="hlt">wind</span> characteristics. The <span class="hlt">solar</span> <span class="hlt">wind</span> values are determined by local running averages coupled with a random walk technique. The averages provide baseline values and the random walk adds short-duration deviations from this baseline. The statistics from the extrapolated data are compared to the statistics of the original OMNI data set. Category durations, relative coverage, variable distributions, and correlations are similar to those of the OMNI data, although with some discrepancies.</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://www.osti.gov/scitech/biblio/22039134','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22039134"><span id="translatedtitle">CONDITIONED ANALYSIS OF HIGH-LATITUDE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> INTERMITTENCY</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>D'Amicis, R.; Consolini, G.; Bavassano, B.; Bruno, R.</p> <p>2012-08-10</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> is a turbulent medium displaying intermittency. Its intermittent features have been widely documented and studied, showing how the intermittent character is different in fast and slow <span class="hlt">wind</span>. In this paper, a statistical conditioned analysis of the <span class="hlt">solar</span> <span class="hlt">wind</span> intermittency for a period of high-latitude fast <span class="hlt">solar</span> <span class="hlt">wind</span> is presented. In particular, the intermittent features are investigated as a function of the Alfvenic degree of fluctuations at a given scale. The results show that the main contribution to <span class="hlt">solar</span> <span class="hlt">wind</span> intermittency is due to non-Alfvenic structures, while Alfvenic increments are found to be characterized by a smaller level of intermittency than the previous ones. Furthermore, the lifetime statistics of Alfvenic periods are discussed in terms of a multiscale texture of randomly oriented flux tubes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011APS..MARV31015P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011APS..MARV31015P"><span id="translatedtitle">Analysis of <span class="hlt">Wind</span> Forces on Roof-Top <span class="hlt">Solar</span> Panel</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Panta, Yogendra; Kudav, Ganesh</p> <p>2011-03-01</p> <p>Structural loads on <span class="hlt">solar</span> panels include forces due to high <span class="hlt">wind</span>, gravity, thermal expansion, and earthquakes. International Building Code (IBC) and the American Society of Civil Engineers are two commonly used approaches in <span class="hlt">solar</span> industries to address <span class="hlt">wind</span> loads. Minimum Design Loads for Buildings and Other Structures (ASCE 7-02) can be used to calculate <span class="hlt">wind</span> uplift loads on roof-mounted <span class="hlt">solar</span> panels. The present study is primarily focused on 2D and 3D modeling with steady, and turbulent flow over an inclined <span class="hlt">solar</span> panel on the flat based roof to predict the <span class="hlt">wind</span> forces for designing <span class="hlt">wind</span> management system. For the numerical simulation, 3-D incompressible flow with the standard k- ? was adopted and commercial CFD software ANSYS FLUENT was used. Results were then validated with <span class="hlt">wind</span> tunnel experiments with a good agreement. <span class="hlt">Solar</span> panels with various aspect ratios for various high <span class="hlt">wind</span> speeds and angle of attacks were modeled and simulated in order to predict the <span class="hlt">wind</span> loads in various scenarios. The present study concluded to reduce the strong <span class="hlt">wind</span> uplift by designing a guide plate or a deflector before the panel. Acknowledgments to Northern States Metal Inc., OH (GK & YP) and School of Graduate Studies of YSU for RP & URC 2009-2010 (YP).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5601625','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5601625"><span id="translatedtitle"><span class="hlt">Wind</span> and radiant <span class="hlt">solar</span> energy for drying fruits and vegetables</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wagner, C.J. Jr.; Coleman, R.L.; Berry, R.E.</p> <p>1981-01-01</p> <p>The combination of <span class="hlt">wind</span> with radiant <span class="hlt">solar</span> energy for drying fruits and vegetables can help promote conservation of food and nonrenewable energy resources. Low-cost, small-scale <span class="hlt">solar</span> dryers have been developed with the potential for developing larger dryers. These dryers depend on natural air convection to remove moisture. Designing the dryers to incorporate natural <span class="hlt">wind</span> currents, providing forced air circulation, could increase drying rates. Preliminary studies to provide information for such designs included: (1) comparing drying tests with and without forced air circulation, (2) monitoring <span class="hlt">wind</span> speeds on-site, and (3) testing <span class="hlt">wind</span> collecting devices. Average <span class="hlt">wind</span> speeds during <span class="hlt">solar</span> periods were higher than air velocities from unassisted air convection in these small food dryers. Drying rates were increased by 6 to 11% when the natural convection dryer was provided with a small electric fan. Either of two <span class="hlt">wind</span> collecting devices also could increase drying rates.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820012230','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820012230"><span id="translatedtitle">Evidence for <span class="hlt">solar</span> <span class="hlt">wind</span> control of Saturn radio emission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Desch, M. D.</p> <p>1982-01-01</p> <p>Using data collected by the Voyager 1 and 2 spacecraft in 1980 and 1981, strong evidence is presented for a direct correlation between variations in the <span class="hlt">solar</span> <span class="hlt">wind</span> at Saturn and the level of activity of Saturn's nonthermal radio emission. Correlation coefficients of 57 to 58% are reached at lag times of 0 to 1 days between the arrival at Saturn of high pressure <span class="hlt">solar</span> <span class="hlt">wind</span> streams and the onset of increased radio emission. The radio emission exhibits a long-term periodicity of 25 days, identical to the periodicity seen in the <span class="hlt">solar</span> <span class="hlt">wind</span> at this time and consistent with the <span class="hlt">solar</span> rotation period. The energy coupling efficiency between the <span class="hlt">solar</span> <span class="hlt">wind</span> with the Saturn radio emission is estimated and compared with that for Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JPhCS.642a2016M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JPhCS.642a2016M"><span id="translatedtitle">Modeling <span class="hlt">solar</span> <span class="hlt">wind</span> with boundary conditions from interplanetary scintillations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Manoharan, P.; Kim, T.; Pogorelov, N. V.; Arge, C. N.; Manoharan, P. K.</p> <p>2015-09-01</p> <p>Interplanetary scintillations make it possible to create three-dimensional, time- dependent distributions of the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity. Combined with the magnetic field observations in the <span class="hlt">solar</span> photosphere, they help perform <span class="hlt">solar</span> <span class="hlt">wind</span> simulations in a genuinely time-dependent way. Interplanetary scintillation measurements from the Ooty Radio Astronomical Observatory in India provide directions to multiple stars and may assure better resolution of transient processes in the <span class="hlt">solar</span> <span class="hlt">wind</span>. In this paper, we present velocity distributions derived from Ooty observations and compare them with those obtained with the Wang-Sheeley-Arge (WSA) model. We also present our simulations of the <span class="hlt">solar</span> <span class="hlt">wind</span> flow from 0.1 AU to 1 AU with the boundary conditions based on both Ooty and WSA data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18046399','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18046399"><span id="translatedtitle">Little or no <span class="hlt">solar</span> <span class="hlt">wind</span> enters Venus' atmosphere at <span class="hlt">solar</span> minimum.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zhang, T L; Delva, M; Baumjohann, W; Auster, H-U; Carr, C; Russell, C T; Barabash, S; Balikhin, M; Kudela, K; Berghofer, G; Biernat, H K; Lammer, H; Lichtenegger, H; Magnes, W; Nakamura, R; Schwingenschuh, K; Volwerk, M; Vrs, Z; Zambelli, W; Fornacon, K-H; Glassmeier, K-H; Richter, I; Balogh, A; Schwarzl, H; Pope, S A; Shi, J K; Wang, C; Motschmann, U; Lebreton, J-P</p> <p>2007-11-29</p> <p>Venus has no significant internal magnetic field, which allows the <span class="hlt">solar</span> <span class="hlt">wind</span> to interact directly with its atmosphere. A field is induced in this interaction, which partially shields the atmosphere, but we have no knowledge of how effective that shield is at <span class="hlt">solar</span> minimum. (Our current knowledge of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with Venus is derived from measurements at <span class="hlt">solar</span> maximum.) The bow shock is close to the planet, meaning that it is possible that some <span class="hlt">solar</span> <span class="hlt">wind</span> could be absorbed by the atmosphere and contribute to the evolution of the atmosphere. Here we report magnetic field measurements from the Venus Express spacecraft in the plasma environment surrounding Venus. The bow shock under low <span class="hlt">solar</span> activity conditions seems to be in the position that would be expected from a complete deflection by a magnetized ionosphere. Therefore little <span class="hlt">solar</span> <span class="hlt">wind</span> enters the Venus ionosphere even at <span class="hlt">solar</span> minimum. PMID:18046399</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AIPC.1539..364J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AIPC.1539..364J"><span id="translatedtitle">Using comet plasma tails to study the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jackson, B. V.; Buffington, A.; Clover, J. M.; Hick, P. P.; Yu, H.-S.; Bisi, M. M.</p> <p>2013-06-01</p> <p>The plasma tails of comets have been used as probes of the <span class="hlt">solar</span> <span class="hlt">wind</span> for many years, and well before direct <span class="hlt">solar</span> <span class="hlt">wind</span> measurements. Now, analyses utilizing the much greater regularity and extent of comet tails imaged from space detail outward <span class="hlt">solar</span> <span class="hlt">wind</span> flow much better than was previously possible. These analyses mark the location of the <span class="hlt">solar</span> <span class="hlt">wind</span> flow in three-dimensions over time much as do in-situ measurements. Data from comet plasma tails using coronagraphs and heliospheric white-light imagers provide a view closer to the Sun than where spacecraft have ventured to date. These views show that this flow is chaotic and highly variable, and not the benign regular outward motion of a quiescent plasma. While this is no surprise to those who study and characterize the <span class="hlt">solar</span> <span class="hlt">wind</span> in situ or use remotely-sensed interplanetary scintillation (IPS) techniques, these spacecraft images provide a visualization of this as never-before possible. Here we summarize the results of an analysis that determines <span class="hlt">solar</span> <span class="hlt">wind</span> velocity from multiple comet tails that were observed by the <span class="hlt">Solar</span> Mass Ejection Imager (SMEI) and also by the inner Heliospheric Imager (HI) on board the <span class="hlt">Solar</span> Terrestrial Relations Observatory Ahead (STEREOA) spacecraft. Finally, we present results using a similar analysis that measures this same behavior using coronagraph observations in the low corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1996A%26AT...11...65O','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1996A%26AT...11...65O"><span id="translatedtitle">On calculating the <span class="hlt">solar</span> <span class="hlt">wind</span> parameters from the <span class="hlt">solar</span> magnetic 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>Obridko, V. N.; Kharshiladze, A. F.; Shelting, B. D.</p> <p></p> <p>It is shown that the expansion factor of the <span class="hlt">solar</span> magnetic field is insufficient to calculate the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity. Moreover, the magnetic field structure cannot unambiguously determine the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity field in therms of the source surface concept and the potential magnetic field approximation in the corona. It is shown that characteristics relating the <span class="hlt">solar</span> and near-Earth interplanetary magnetic field undergo cyclic variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920048629&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dluhmann','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920048629&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dluhmann"><span id="translatedtitle">The <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with unmagnetized planets - A tutorial</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>1990-01-01</p> <p>The interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with the Venus ionosphere induces currents which can substantially exclude the <span class="hlt">solar</span> <span class="hlt">wind</span> and IMF from the dayside ionosphere beneath the 'ionopause', where ionosphere thermal pressure equals incident <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure. The field then diffuses through the ionopause with increasing speed at decreasing altitudes, and is weakest in the subpolar region. Once within the ionopause, the magnetic field is redistributed by ionospheric convection, and then decays at low altitudes via collisional dissipation of the associated currents. The maximum ionospheric field magnitudes observed, of about 150 nT, furnish magnetic pressures exceeding the ionospheric thermal pressure by a factor of about 3.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830016174','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830016174"><span id="translatedtitle">The relationship between Saturn kilometric radiation and the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Desch, M. D.; Rucker, H. O.</p> <p>1983-01-01</p> <p>Voyager spacecraft radio, interplanetary plasma, and interplanetary magnetic field data are used to show that large amplitude fluctuations in the power generated by the Saturn kilometric radio emission are best correlated with <span class="hlt">solar</span> <span class="hlt">wind</span> ram pressure variation. In all, thirteen <span class="hlt">solar</span> <span class="hlt">wind</span> quantities previously found important in driving terrestrial magnetospheric substorms and other auroral processes were examined for evidence of correlations with the Saturn radio emission. The results are consistent with hydromagnetic wave or eddy diffusion processes driven by large scale <span class="hlt">solar</span> <span class="hlt">wind</span> pressure changes at Saturn's dayside magnetopause.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008EOSTr..89..212C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008EOSTr..89..212C"><span id="translatedtitle">Mars: A Richly Complicated Obstacle to the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Crider, Dana H.; Brain, David A.; Lundin, Rickard</p> <p>2008-06-01</p> <p>Chapman Conference on the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Interaction With Mars; San Diego, California, 22-25 January 2008; Although studies of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with Mars (SWIM) date back to the mid-1960s, whether Mars possessed a global magnetic field remained uncertain until 1997. We now know that Mars lacks a measurable dynamo; however, it has intense, localized regions of magnetization tied to its crust. With this patchy magnetic field, the <span class="hlt">solar</span> <span class="hlt">wind</span> interacts directly with the upper atmosphere of Mars, driving structural and compositional variations and providing energy for atmospheric escape to space. These processes may have played an important role in the long-term evolution of the Martian climate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21394380','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21394380"><span id="translatedtitle">MEASUREMENTS OF RAPID DENSITY FLUCTUATIONS IN THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Malaspina, D. M.; Ergun, R. E.; Kellogg, P. J.; Bale, S. D.</p> <p>2010-03-01</p> <p>The power spectrum of density fluctuations in the <span class="hlt">solar</span> <span class="hlt">wind</span> is inferred by tracking small timescale changes in the electron plasma frequency during periods of strong Langmuir wave activity. STEREO electric field waveform data are used to produce time profiles of plasma density from which the density power spectrum is derived. The power spectra obtained by this method extend the observed frequency range by an order of magnitude while remaining consistent with previous results near a few Hertz. Density power spectral indices are found to be organized by the angle between the local magnetic field and the <span class="hlt">solar</span> <span class="hlt">wind</span> direction, indicating significant anisotropy in <span class="hlt">solar</span> <span class="hlt">wind</span> high-frequency density turbulence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890052693&hterms=amd&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Damd','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890052693&hterms=amd&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Damd"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> control of Jupiter's hectometric radio emission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Barrow, C. H.; Desch, M. D.</p> <p>1989-01-01</p> <p>Radio, plasma, and magnetic field data obtained by Voyager 1 and Voyager 2 were used to examine the manner in which the Jovian hectometric radio emission (HOM) is controlled by the <span class="hlt">solar</span> <span class="hlt">wind</span>. Using the method of superposed epochs, it was found that the higher energy HOM is correlated with the IMF as well as with the <span class="hlt">solar</span> <span class="hlt">wind</span> density and pressure. However, unlike the Io-independent decametric radio emission (Non-Io DAM), the HOM displayed no correlation with the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity, although this radio component appear to be also influenced by the IMF. The results suggest separate HOM amd Non-Io DAM sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021391&hterms=sms&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsms','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021391&hterms=sms&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsms"><span id="translatedtitle">Iron charge states in the <span class="hlt">solar</span> <span class="hlt">wind</span> as measured by SMS on <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Galvin, A. B.; Cohen, C. M. S.; Ipavich, F. M.; Gloeckler, G.; Hamilton, D. C.; Chotoo, K.; Balsiger, H.; Sheldon, R.</p> <p>1995-01-01</p> <p>The <span class="hlt">Wind</span> spacecraft was launched in November 1994. In the first half of 1995 it was in the interplanetary medium upstream of the Earth. The <span class="hlt">Solar</span> <span class="hlt">Wind</span> and Suprathermal Ion Composition Experiment (SMS) on <span class="hlt">Wind</span> consists of three sensors, the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Composition Spectrometer (SWICS), the Suprathermal Ion Composition Spectrometer (STICS), and the high mass resolution spectrometer (MASS). All three instruments utilize electrostatic deflection combined with time-of-flight measurement. The data from these three sensors allows the determination of the ionic composition of the <span class="hlt">solar</span> <span class="hlt">wind</span> in a variety of <span class="hlt">solar</span> <span class="hlt">wind</span> conditions over a large energy/charge range (0.5 to 230 keV/e). We have examined the <span class="hlt">Wind</span> database for time periods conducive to observing <span class="hlt">solar</span> <span class="hlt">wind</span> iron. With the high mass resolution of the MASS spectrometer (M/Delta-M greater than 100) iron is easily identified while the electrostatic deflection provides information concerning the mass/charge distribution. We present here the relative abundance of iron charge states in the <span class="hlt">solar</span> <span class="hlt">wind</span> near 1 AU.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/6517833','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/6517833"><span id="translatedtitle"><span class="hlt">Wind</span> loading on <span class="hlt">solar</span> concentrators: some general considerations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Roschke, E. J.</p> <p>1984-05-01</p> <p>A survey has been completed to examine the problems and complications arising from <span class="hlt">wind</span> loading on <span class="hlt">solar</span> concentrators. <span class="hlt">Wind</span> loading is site specific and has an important bearing on the design, cost, performance, operation and maintenance, safety, survival, and replacement of <span class="hlt">solar</span> collecting systems. Emphasis herein is on paraboloidal, two-axis tracking systems. Thermal receiver problems also are discussed. <span class="hlt">Wind</span> characteristics are discussed from a general point of view; current methods for determining design <span class="hlt">wind</span> speed are reviewed. Aerodynamic coefficients are defined and illustrative examples are presented. <span class="hlt">Wind</span> tunnel testing is discussed, and environmental <span class="hlt">wind</span> tunnels are reviewed; recent results on heliostat arrays are reviewed as well. Aeroelasticity in relation to structural design is discussed briefly. <span class="hlt">Wind</span> loads, i.e., forces and moments, are proportional to the square of the mean <span class="hlt">wind</span> velocity. Forces are proportional to the square of concentrator diameter, and moments are proportional to the cube of diameter. Thus, <span class="hlt">wind</span> loads have an important bearing on size selection from both cost and performance standpoints. It is concluded that sufficient information exists so that reasonably accurate predictions of <span class="hlt">wind</span> loading are possible for a given paraboloidal concentrator configuration, provided that reliable and relevant <span class="hlt">wind</span> conditions are specified. Such predictions will be useful to the design engineer and to the systems engineer as well. Information is lacking, however, on <span class="hlt">wind</span> effects in field arrays of paraboloidal concentrators. <span class="hlt">Wind</span> tunnel tests have been performed on model heliostat arrays, but there are important aerodynamic differences between heliostats and paraboloidal dishes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AnGeo..33..845M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AnGeo..33..845M"><span id="translatedtitle"><span class="hlt">Solar-wind</span> control of plasma sheet dynamics</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Myllys, M.; Kilpua, E.; Pulkkinen, T.</p> <p>2015-07-01</p> <p>The purpose of this study is to quantify how <span class="hlt">solar-wind</span> conditions affect the energy and plasma transport in the geomagnetic tail and its large-scale configuration. To identify the role of various effects, the magnetospheric data were sorted according to different <span class="hlt">solar-wind</span> plasma and interplanetary magnetic field (IMF) parameters: speed, dynamic pressure, IMF north-south component, epsilon parameter, Auroral Electrojet (AE) index and IMF ultra low-frequency (ULF) fluctuation power. We study variations in the average flow speed pattern and the occurrence rate of fast flow bursts in the magnetotail during different <span class="hlt">solar-wind</span> conditions using magnetospheric data from five Time History of Events and Macroscale Interactions during Substorms (THEMIS) mission spacecraft and <span class="hlt">solar-wind</span> data from NASA's OMNIWeb. The time interval covers the years from 2008 to 2011 during the deep <span class="hlt">solar</span> minimum between cycles 23 and 24 and the relatively quiet rising phase of cycle 24. Hence, we investigate magnetospheric processes and <span class="hlt">solar-wind</span>-magnetospheric coupling during a relatively quiet state of the magnetosphere. We show that the occurrence rate of the fast (|Vtail| > 100 km s-1) sunward flows varies under different <span class="hlt">solar-wind</span> conditions more than the occurrence of the fast tailward flows. The occurrence frequency of the fast tailward flows does not change much with the <span class="hlt">solar-wind</span> conditions. We also note that the sign of the IMF BZ has the most visible effect on the occurrence rate and pattern of the fast sunward flows. High-speed flow bursts are more common during the slow than fast <span class="hlt">solar-wind</span> conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840004997','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840004997"><span id="translatedtitle">Interpretation of 3He variations in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Coplan, M. A.; Ogilvie, K. W.; Geiss, J.; Bochsler, P.</p> <p>1983-01-01</p> <p>The ion composition instrument (ICI) on ISEE-3 observed the isotopes of helium of mass 3 and 4 in the <span class="hlt">solar</span> <span class="hlt">wind</span> almost continuously between August 1978 and July 1982. This period included the increase towards the maximum of <span class="hlt">solar</span> activity cycle 21, the maximum period, and the beginning of the descent towards <span class="hlt">solar</span> minimum. Observations were made when the <span class="hlt">solar</span> <span class="hlt">wind</span> speed was between 300 and 620 km/s. For part of the period evidence for regular interplanetary magnetic sector structure was clear and a number of 3He flares occurred during this time.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MNRAS.454.3697M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MNRAS.454.3697M"><span id="translatedtitle">Alfvn wave <span class="hlt">solar</span> model (AWSoM): proton temperature anisotropy and <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Meng, X.; van der Holst, B.; Tth, G.; Gombosi, T. I.</p> <p>2015-12-01</p> <p>Temperature anisotropy has been frequently observed in the <span class="hlt">solar</span> corona and the <span class="hlt">solar</span> <span class="hlt">wind</span>, yet poorly represented in computational models of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Therefore, we have included proton temperature anisotropy in our Alfvn wave <span class="hlt">solar</span> model (AWSoM). This model solves the magnetohydrodynamic equations augmented with low-frequency Alfvn wave turbulence. The wave reflection due to Alfvn speed gradient and field-aligned vorticity results in turbulent cascade. At the gyroradius scales, the apportioning of the turbulence dissipation into coronal heating of the protons and electrons is through stochastic heating. This paper focuses on the impacts of the proton temperature anisotropy on the <span class="hlt">solar</span> <span class="hlt">wind</span>. We apply AWSoM to simulate the steady <span class="hlt">solar</span> <span class="hlt">wind</span> from the corona to 1 AU using synoptic magnetograms. The Alfvn wave energy density at the inner boundary is prescribed with a uniform Poynting flux per field strength. We present the proton temperature anisotropy distribution, and investigate the firehose instability in the heliosphere from our simulations. In particular, the comparisons between the simulated and observed <span class="hlt">solar</span> <span class="hlt">wind</span> properties at 1 AU during the ramping-up phase and the maximum of <span class="hlt">solar</span> cycle 24 imply the importance of addressing the proton temperature anisotropy in <span class="hlt">solar</span> <span class="hlt">wind</span> modelling to capture the fast <span class="hlt">solar</span> <span class="hlt">wind</span> speed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870007250&hterms=cloud+technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcloud%2Btechnologie','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870007250&hterms=cloud+technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dcloud%2Btechnologie"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span>-plasma interaction: The AMPTE <span class="hlt">solar</span> <span class="hlt">wind</span> plasma releases</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>1986-01-01</p> <p>In situ measurements during AMPTE <span class="hlt">solar</span> <span class="hlt">wind</span> ion releases are described. The creation of a diamagnetic cavity, compression and draping of magnetic field lines, recoil of the entire artificial comet, and ion beam and tail formation are discussed. The wave measurements were used to determine the time variation of the plasma density from the measurement of the electron plasma frequency and to determine the state of cloud expansion and cavity formation. Features found include absence of strong turbulence and anomalous diffusion in the cavity boundary, and the appearance of very intense shock-like emission in front of the plasma clouds. The first effect suggests partially unknowm processes leading to magnetic field penetration into the region of the clouds. The direct observation of the interaction processes between the fast streaming <span class="hlt">solar</span> <span class="hlt">wind</span> plasma and the expanding cloud plasma of the Li and artificial comet releases may have relevance to astrophysical situations as, for instance, encountered in <span class="hlt">solar</span> flares, interstellar clouds, or during accretion of matter onto compact objects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910047213&hterms=witold&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dwitold','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910047213&hterms=witold&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dwitold"><span id="translatedtitle">Erosion of carbon/carbon by <span class="hlt">solar</span> <span class="hlt">wind</span> charged particle radiation during a <span class="hlt">solar</span> probe mission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sokolowski, Witold; O'Donnell, Tim; Millard, Jerry</p> <p>1991-01-01</p> <p>The possible erosion of a carbon/carbon thermal shield by <span class="hlt">solar</span> <span class="hlt">wind</span>-charged particle radiation is reviewed. The present knowledge of erosion data for carbon and/or graphite is surveyed, and an explanation of erosion mechanisms under different charged particle environments is discussed. The highest erosion is expected at four <span class="hlt">solar</span> radii. Erosion rates are analytically estimated under several conservative assumptions for a normal quiet and worst case <span class="hlt">solar</span> <span class="hlt">wind</span> storm conditions. Mass loss analyses and comparison studies surprisingly indicate that the predicted erosion rate by <span class="hlt">solar</span> <span class="hlt">wind</span> could be greater than by nominal free sublimation during <span class="hlt">solar</span> <span class="hlt">wind</span> storm conditions at four <span class="hlt">solar</span> radii. The predicted overall mass loss of a carbon/carbon shield material during the critical four <span class="hlt">solar</span> radii flyby can still meet the mass loss mission requirement of less than 0.0025 g/sec.</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/2009JASS...26..425P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009JASS...26..425P"><span id="translatedtitle">Dst Prediction Based on <span class="hlt">Solar</span> <span class="hlt">Wind</span> Parameters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Park, Yoon-Kyung; Ahn, Byung-Ho</p> <p>2009-12-01</p> <p>We reevaluate the Burton equation (Burton et al. 1975) of predicting Dst index using high quality hourly <span class="hlt">solar</span> <span class="hlt">wind</span> data supplied by the ACE satellite for the period from 1998 to 2006. Sixty magnetic storms with monotonously decreasing main phase are selected. In order to determine the injection term (Q) and the decay time (tau) of the equation, we examine the relationships between Dst^ast and VB_s, Delta Dst^ast and VB_s, and Delta Dst^ast and Dst^ast during the magnetic storms. For this analysis, we take into account one hour of the propagation time from the ACE satellite to the magnetopause, and a half hour of the response time of the magnetosphere/ring current to the <span class="hlt">solar</span> <span class="hlt">wind</span> forcing. The injection term is found to be Q({nT}/h)=-3.56VB_s for VB_s>0.5mV/m and Q({nT}/h)=0 for VB_s leq0.5mV/m. The tau (hour) is estimated as 0.060 Dst^ast + 16.65 for Dst^ast>-175nT and 6.15 hours for Dst^ast leq -175nT. Based on these empirical relationships, we predict the 60 magnetic storms and find that the correlation coefficient between the observed and predicted Dst^ast is 0.88. To evaluate the performance of our prediction scheme, the 60 magnetic storms are predicted again using the models by Burton et al. (1975) and O'Brien & McPherron (2000a). The correlation coefficients thus obtained are 0.85, the same value for both of the two models. In this respect, our model is slightly improved over the other two models as far as the correlation coefficients is concerned. Particularly our model does a better job than the other two models in predicting intense magnetic storms (Dst^ast lesssim -200nT).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E3124S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E3124S"><span id="translatedtitle">Transient flows of the <span class="hlt">solar</span> <span class="hlt">wind</span> associated with small-scale <span class="hlt">solar</span> activity in <span class="hlt">solar</span> minimum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Slemzin, Vladimir; Veselovsky, Igor; Kuzin, Sergey; Gburek, Szymon; Ulyanov, Artyom; Kirichenko, Alexey; Shugay, Yulia; Goryaev, Farid</p> <p></p> <p>The data obtained by the modern high sensitive EUV-XUV telescopes and photometers such as CORONAS-Photon/TESIS and SPHINX, STEREO/EUVI, PROBA2/SWAP, SDO/AIA provide good possibilities for studying small-scale <span class="hlt">solar</span> activity (SSA), which is supposed to play an important role in heating of the corona and producing transient flows of the <span class="hlt">solar</span> <span class="hlt">wind</span>. During the recent unusually weak <span class="hlt">solar</span> minimum, a large number of SSA events, such as week <span class="hlt">solar</span> flares, small CMEs and CME-like flows were observed and recorded in the databases of flares (STEREO, SWAP, SPHINX) and CMEs (LASCO, CACTUS). On the other hand, the <span class="hlt">solar</span> <span class="hlt">wind</span> data obtained in this period by ACE, <span class="hlt">Wind</span>, STEREO contain signatures of transient ICME-like structures which have shorter duration (<10h), weaker magnetic field strength (<10 nT) and lower proton temperature than usual ICMEs. To verify the assumption that ICME-like transients may be associated with the SSA events we investigated the number of weak flares of C-class and lower detected by SPHINX in 2009 and STEREO/EUVI in 2010. The flares were classified on temperature and emission measure using the diagnostic means of SPHINX and Hinode/EIS and were confronted with the parameters of the <span class="hlt">solar</span> <span class="hlt">wind</span> (velocity, density, ion composition and temperature, magnetic field, pitch angle distribution of the suprathermal electrons). The outflows of plasma associated with the flares were identified by their coronal signatures - CMEs (only in few cases) and dimmings. It was found that the mean parameters of the <span class="hlt">solar</span> <span class="hlt">wind</span> projected to the source surface for the times of the studied flares were typical for the ICME-like transients. The results support the suggestion that weak flares can be indicators of sources of transient plasma flows contributing to the slow <span class="hlt">solar</span> <span class="hlt">wind</span> at <span class="hlt">solar</span> minimum, although these flows may be too weak to be considered as separate CMEs and ICMEs. The research leading to these results has received funding from the European Unions Seventh Programme for Research, Technological Development and Demonstration under Grant Agreement eHeroes (project n 284461, www.eheroes.eu).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/112936','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/112936"><span id="translatedtitle">He abundance variations in the <span class="hlt">solar</span> <span class="hlt">wind</span>: Observations from Ulysses</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Barraclough, B.L.; Gosling, J.T.; Phillips, J.L.; McComas, D.J.; Feldman, W.C.; Goldstein, B.E.</p> <p>1995-09-01</p> <p>The Ulysses mission is providing the first opportunity to observe variations in <span class="hlt">solar</span> <span class="hlt">wind</span> plasma parameters at heliographic latitudes far removed from the ecliptic plane. We present an overview of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed and the variability in helium abundance, [He] data on [He] in six high latitude coronal mass ejections (CMEs), and a superposed epoch analysis of [He] variations at the seven heliospheric current sheet (HCS) crossings made during the rapid-latitude-scan portion of the mission. The differences in the variability of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed and [He] in high latitude and equatorial regions are quite striking. <span class="hlt">Solar</span> <span class="hlt">wind</span> speed is generally low but highly variable near the <span class="hlt">solar</span> equator, while at higher latitudes the average speed is quite high with little variability. [He] can vary over nearly two decades at low <span class="hlt">solar</span> latitudes, while at high latitudes it varies only slightly. In contrast to the high [He] that is commonly associated with CMEs observed in the ecliptic, none of the six high-speed CMEs encountered at high southern heliographic latitudes showed any significant variation in helium content. A superposed epoch analysis of the [He] during all seven HCS crossings made as Ulysses passed from the southern to northern <span class="hlt">solar</span> hemisphere shows the expected [He] minimum near the crossing and a broad region of low [He] around the crossing time. We discuss how our <span class="hlt">solar</span> <span class="hlt">wind</span> [He] observations may provide an accurate measure of the helium composition for the entire convective zone of the Sun.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890057117&hterms=appearance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dappearance','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890057117&hterms=appearance&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dappearance"><span id="translatedtitle">The visual appearance of comets under varying <span class="hlt">solar</span> <span class="hlt">wind</span> conditions</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.; Guan, L.; Luhmann, J. G.; Fedder, J. A.</p> <p>1989-01-01</p> <p>Three-dimensional MHD simulations have been performed for four different sets of <span class="hlt">solar</span> <span class="hlt">wind</span> conditions and cometary outgassing rates appropriate to the Halley encounters. Even though the simulations are single fluid calculations, it is possible to separate the <span class="hlt">solar</span> <span class="hlt">wind</span> and cometary ions using the divergenceless nature of the <span class="hlt">solar</span> <span class="hlt">wind</span> ions. The cometary ion density is then integrated along the line-of-sight from the observer through the comet to determine how the comet would look to a distant observer under these different conditions. In general, comet tails appear longer when the interplanetary magnetic field lies in the plane of the sky rather than along the line-of-sight. Also, the tail shrinks as the speed of the <span class="hlt">solar</span> <span class="hlt">wind</span> increases and/or the mass loading rate decreases.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH13C4131Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH13C4131Y"><span id="translatedtitle">On the Dynamic Character of the Polar <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, H. S.; Jackson, B. V.; Hick, P. P.; Buffington, A.</p> <p>2014-12-01</p> <p>SOHO LASCO C2 and STEREO SECCHI COR 2 coronagraph images, when analyzed using correlation tracking techniques, show a surprising result in polar coronal hole regions ordinarily thought of as "quiet" <span class="hlt">solar</span> <span class="hlt">wind</span>. Here what we observe is not the static well-ordered flow and gradual acceleration expected of quiescent regions. Rather, the coronagraph images show outflow in polar coronal holes as intermittent, highly-variable <span class="hlt">solar</span> <span class="hlt">wind</span> speed structures. We compare measurements of these structures in different simultaneously-measured coronagraph images, and with coronal brightness. The distribution of structure speeds shows a gradual decrease with speed in the overlap regions of the two coronagraphs. Measurements of the mean speed derived versus height shows the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration with position angle, and are compared with mass flux and other determinations of <span class="hlt">solar</span> <span class="hlt">wind</span> outflow over the large polar coronal hole regions. In this presentation we give the most recent work on this ongoing analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19890054328&hterms=supplies+wind+energy&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsupplies%2Bwind%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19890054328&hterms=supplies+wind+energy&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dsupplies%2Bwind%2Benergy"><span id="translatedtitle">Electrodynamics of <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere-ionosphere interactions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Kan, Joseph R.; Akasofu, Syun-Ichi</p> <p>1989-01-01</p> <p>The paper presents a coherent picture of fundamental physical processes in three basic elements of the <span class="hlt">solar-wind</span>/magnetosphere/ionosphere coupling system: (1) the field-aligned potential structure which leads to the formation of auroral arcs, (2) the magnetosphere-ionosphere coupling which leads to the onset of magnetospheric substorms, and (3) the <span class="hlt">solar-wind</span>/magnetosphere dynamo which supplies the power driving various magnetospheric processes. Process (1) is forced into existence by the loss-cone constriction effect when the upward field-aligned current density exceeds the loss-cone thermal flux limit. Substorm onset occurs when the ionosphere responds fully to the enhanced magnetospheric convection driven by the <span class="hlt">solar</span> <span class="hlt">wind</span>. Energy is transferred from the <span class="hlt">solar</span> <span class="hlt">wind</span> to the magnetosphere by a dynamo process, primarily on open field lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19920027384&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dluhmann','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19920027384&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dluhmann"><span id="translatedtitle">A parametric study of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with comets</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.; Le, G.; Luhmann, J. G.; Fedder, J. A.</p> <p>1991-01-01</p> <p>The Naval Research Laboratory's magnetohydrodynamic simulation code is used to simulate the <span class="hlt">solar</span> <span class="hlt">wind</span> interction with comet Halley for two different outgassing rates and several different <span class="hlt">solar</span> <span class="hlt">wind</span> states. The magnetic field is more strongly draped for fast <span class="hlt">solar</span> <span class="hlt">wind</span> conditions than slow. For higher mass loading rates, the tail becomes wider and contains more magnetic flux. The visual appearance of the comet differs for the case in which the interplanetary magnetic field lies in the plane of the sky from the case when it lies along the line of sight. The ion tail appears shorter in the latter case. Thus variation in the IMF direction can cause significant changes in the appearance of comets. The comet also creates a large momentum flux deficit in the <span class="hlt">solar</span> <span class="hlt">wind</span> with a narrow enhanced region within it corresponding to the ion tail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6020000','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6020000"><span id="translatedtitle">Saturn radio emission and the <span class="hlt">solar</span> <span class="hlt">wind</span> - Voyager-2 studies</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Desch, M.D.; Rucker, H.O.</p> <p>1985-01-01</p> <p>Voyager 2 data from the Plasma Science experiment, the Magnetometer experiment and the Planetary Radio Astronomy experiment were used to analyze the relationship between parameters of the <span class="hlt">solar</span> <span class="hlt">wind</span>/interplanetary medium and the nonthermal Saturn radiation. <span class="hlt">Solar</span> <span class="hlt">wind</span> and interplanetary magnetic field properties were combined to form quantities known to be important in controlling terrestrial magnetospheric processes. The Voyager 2 data set used in this investigation consists of 237 days of Saturn preencounter measurements. However, due to the immersion of Saturn and the Voyager 2 spacecraft into the extended Jupiter magnetic tail, substantial periods of the time series were lacking <span class="hlt">solar</span> <span class="hlt">wind</span> data. To cope with this problem a superposed epoch method (CHREE analysis) was used. The results indicate the superiority of the quantities containing the <span class="hlt">solar</span> <span class="hlt">wind</span> density in stimulating the radio emission of Saturn - a result found earlier using Voyager 1 data - and the minor importance of quantities incorporating the interplanetary magnetic field. 10 references.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080026012','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080026012"><span id="translatedtitle">Genesis <span class="hlt">Solar</span> <span class="hlt">Wind</span> Sample Curation: A Progress Report</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Allton, Judith H.; Calaway, M. J.; Rodriquez, M. C.; Hittle, J. D.; Wentworth, S. J.; Stansbery, E. K.; McNamara, K. M.</p> <p>2006-01-01</p> <p>In the year since the Genesis <span class="hlt">solar</span> <span class="hlt">wind</span> collector fragments were returned, early science samples, specimens for cleaning experiments, and science allocations have been distributed. <span class="hlt">Solar</span> <span class="hlt">wind</span> samples are stored under nitrogen and handled in an ISO Class 4 (Class 10) laboratory. For array collector fragments, a basic characterization process has been established. This characterization consists of identification of <span class="hlt">solar</span> <span class="hlt">wind</span> regime, whole fragment image for identification and surface quality, higher magnification images for contaminant particle density, and assessment of molecular film contaminant thickness via ellipsometry modeling. Compilations of this characterization data for AuOS (gold film on sapphire), and sapphire from the bulk <span class="hlt">solar</span> <span class="hlt">wind</span> for fragments greater than 2 cm are available. Removal of contaminant particles using flowing ultrapure water (UPW) energized megasonically is provided as requested.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1094889','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1094889"><span id="translatedtitle">Western <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Integration Study Phase 2 (Fact Sheet)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Not Available</p> <p>2013-09-01</p> <p>This is one-page, two-sided fact sheet presents high-level summary results of the Western <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Integration Study Phase 2, which examined operational impacts of high penetrations of variable renewable generation in the West.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1094881','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1094881"><span id="translatedtitle">Western <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Integration Study: Phase 2 (Presentation)</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lew, D.; Brinkman, G.; Ibanez, E.; Lefton, S.; Kumar, N.; Venkataraman, S.; Jordan, G.</p> <p>2013-09-01</p> <p>This presentation summarizes the scope and results of the Western <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Integration Study Phase 2, which examined operational impacts of high penetrations of variable renewable generation in the West.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.8177A','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.8177A"><span id="translatedtitle">Electron energetics in the expanding <span class="hlt">solar</span> <span class="hlt">wind</span> via Helios observations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Å tverák, Å. těpán.; Trávníček, Pavel M.; Hellinger, Petr</p> <p>2015-10-01</p> <p>We present an observational analysis of electron cooling/heating rates in the fast and slow <span class="hlt">solar</span> <span class="hlt">wind</span> between 0.3 and 1 AU. We fit electron velocity distribution functions acquired in situ by Helios 1 and 2 spacecraft by a three-component (core-halo-strahl) analytical model. The resulting radial profiles of macroscopic characteristics (density, temperatures, and heat fluxes) are employed to examine properties of theoretical energy balance equations and to estimate external cooling/heating terms. Our analysis indicates that in contrast to <span class="hlt">solar</span> <span class="hlt">wind</span> protons the electrons do not require important heating mechanisms to explain the observed temperature gradients. The electron heating rates are actually found to be negative for both the slow and fast <span class="hlt">solar</span> <span class="hlt">wind</span>, namely, due to the significant degradation of the electron heat flux with increasing radial distance from the Sun. Cooling mechanisms acting on electrons are found to be significantly stronger in the slow <span class="hlt">wind</span> than in the fast <span class="hlt">wind</span> streams.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840065464&hterms=collective+modes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dcollective%2Bmodes','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840065464&hterms=collective+modes&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dcollective%2Bmodes"><span id="translatedtitle">Collective capture of released lithium ions in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Winske, D.; Wu, C. S.; Li, Y. Y.; Zhou, G. C.</p> <p>1984-01-01</p> <p>The capture of newly ionized lithium ions in the <span class="hlt">solar</span> <span class="hlt">wind</span> by means of electromagnetic instabilities is investigated through linear analysis and computer simulation. Three instabilities, driven by a lithium velocity ring perpendicular to and drifting along the magnetic field, are considered. The capture time of the lithium by the <span class="hlt">solar</span> <span class="hlt">wind</span> is roughly 10 linear growth times, regardless of whether resonant or nonresonant modes dominate initially. Possible implications of the results for the Active Magnetosphere Particle Tracer Explorer (AMPTE) mission are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19820024368','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19820024368"><span id="translatedtitle">Calculation of <span class="hlt">solar</span> <span class="hlt">wind</span> flows about terrestrial planets</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stahara, S. S.; Spreiter, J. R.</p> <p>1982-01-01</p> <p>A computational model was developed for the determination of the plasma and magnetic field properties of the global interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with terrestrial planetary magneto/ionospheres. The theoretical method is based on an established single fluid, steady, dissipationless, magnetohydrodynamic continuum model, and is appropriate for the calculation of supersonic, super Alfvenic <span class="hlt">solar</span> <span class="hlt">wind</span> flow past terrestrial planets. A summary is provided of the important research results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900054427&hterms=leer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dleer','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900054427&hterms=leer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dleer"><span id="translatedtitle">Flow of oxygen ions in the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration region</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Esser, Ruth; Leer, Egil</p> <p>1990-01-01</p> <p>A <span class="hlt">solar</span> <span class="hlt">wind</span> model with protons, electrons, O VII and O VI ions is studied. It is found that ionization and recombination processes lead to an approximately constant density ratio of the oxygen states in the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration region. Although ionization and recombination have a significant effect on the flow speed of the O VI ions, these processes are not fast enough to bring the speed of O VI up to the flow speed of the O VII ions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930049630&hterms=hsieh&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhsieh','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930049630&hterms=hsieh&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dhsieh"><span id="translatedtitle">Sensing the <span class="hlt">solar-wind</span> termination shock from Earth's orbit</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hsieh, K. C.; Shih, K. L.; Jokipii, J. R.; Gruntman, M. A.</p> <p>1992-01-01</p> <p>The <span class="hlt">solar-wind</span> termination shock is inaccessible for repeated in situ investigation. We examine, therefore, the possibility of remote sensing the entire heliopause from Earth's orbit using the energetic neutral atoms (ENA) produced by charge exchange between energetic ions and the neutral atoms of the interstellar medium at and beyond the termination shock. We estimate the ENA fluxes at Earth's orbit coming from the thermalized <span class="hlt">solar-wind</span> ions and the shock-accelerated anomalous cosmic rays (ACR) at the heliospheric boundary.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19750011027','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19750011027"><span id="translatedtitle">Interplanetary stream magnetism: Kinematic effects. [<span class="hlt">solar</span> magnetic fields and <span class="hlt">wind</span></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.; Barouch, E.</p> <p>1974-01-01</p> <p>The particle density, and the magnetic field intensity and direction are calculated in corotating streams of the <span class="hlt">solar</span> <span class="hlt">wind</span>, assuming that the <span class="hlt">solar</span> <span class="hlt">wind</span> 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.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EPSC....9..529V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EPSC....9..529V"><span id="translatedtitle">Jupiter's Magnetospheric Dynamics: Evidence of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Driving?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vogt, M. F.; Bunce, E. J.; Kronberg, E. A.</p> <p>2014-04-01</p> <p>Jupiter's magnetosphere is a highly dynamic environment. Analysis of magnetic field and particle measurements collected by the Galileo spacecraft in Jupiter's magnetotail has shown evidence of hundreds of reconnection events [3,7]. It has long been suggested that Jupiter's magnetospheric dynamics are controlled primarily by rotational stresses, rather than by the <span class="hlt">solar</span> <span class="hlt">wind</span>, due to the rapid planetary rotation period and large spatial scales [6]. Such an internally-driven mass loading and release process is expected to occur with a typical 2-4 day recurrence period. Quasi-periodic behavior, suggestive of reconnection, has been observed on a similar time scale intermittently in several data sets, including magnetic field dipolarizations, flow bursts, and the hectometric radio emissions [4,5]. However, several questions remain unanswered, including why some specific spacecraft orbits were particularly dynamic (such as Galileo orbits G2 and G8), why the periodicity is not always observed, and why the characteristic time scale varies from ~1 to 7 days when the periodicity is present. One possible explanation is that the periodic magnetospheric reconfigurations may be modulated by the <span class="hlt">solar</span> <span class="hlt">wind</span>, as seen in global MHD simulations of plasmoid release and other dynamics in the magnetospheres of both Jupiter and Saturn [1,2]. In this study we use the Michigan mSWiM propagated <span class="hlt">solar</span> <span class="hlt">wind</span> MHD model to estimate the <span class="hlt">solar</span> <span class="hlt">wind</span> conditions upstream of Jupiter. We make use of event association tests to determine whether there is a statistical link between Jovian reconnection events and <span class="hlt">solar</span> <span class="hlt">wind</span> compressions or other disturbed <span class="hlt">solar</span> <span class="hlt">wind</span> conditions. We also consider the possibility that varying <span class="hlt">solar</span> <span class="hlt">wind</span> conditions may alter the characteristic periodicity in Jupiter's magnetosphere. For example, we perform a Lomb periodogram analysis on the <span class="hlt">solar</span> <span class="hlt">wind</span> model data during both quiet intervals and intervals when quasi-periodic behavior is observed in the in situ magnetospheric data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/964607','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/964607"><span id="translatedtitle">Potential for Development of <span class="hlt">Solar</span> and <span class="hlt">Wind</span> Resource in Bhutan</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gilman, P.; Cowlin, S.; Heimiller, D.</p> <p>2009-09-01</p> <p>With support from the U.S. Agency for International Development (USAID), the U.S. Department of Energy's National Renewable Energy Laboratory (NREL) produced maps and data of the <span class="hlt">wind</span> and <span class="hlt">solar</span> resources in Bhutan. The <span class="hlt">solar</span> resource data show that Bhutan has an adequate resource for flat-plate collectors, with annual average values of global horizontal <span class="hlt">solar</span> radiation ranging from 4.0 to 5.5 kWh/m2-day (4.0 to 5.5 peak sun hours per day). The information provided in this report may be of use to energy planners in Bhutan involved in developing energy policy or planning <span class="hlt">wind</span> and <span class="hlt">solar</span> projects, and to energy analysts around the world interested in gaining an understanding of Bhutan's <span class="hlt">wind</span> and <span class="hlt">solar</span> energy potential.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22364988','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22364988"><span id="translatedtitle">The dynamic character of the polar <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Jackson, B. V.; Yu, H.-S.; Buffington, A.; Hick, P. P. E-mail: hsyu@ucsd.edu E-mail: pphick@ucsd.edu</p> <p>2014-09-20</p> <p>The <span class="hlt">Solar</span> and Heliospheric Observatory (SOHO) Large Angle and Spectrometric Coronagraph C2 and <span class="hlt">Solar</span> Terrestrial Relations Observatory (STEREO) COR2A coronagraph images, when analyzed using correlation tracking techniques, show a surprising result in places ordinarily thought of as 'quiet' <span class="hlt">solar</span> <span class="hlt">wind</span> above the poles in coronal hole regions. Instead of the static well-ordered flow and gradual acceleration normally expected, coronagraph images show outflow in polar coronal holes consisting of a mixture of intermittent slow and fast patches of material. We compare measurements of this highly variable <span class="hlt">solar</span> <span class="hlt">wind</span> from C2 and COR2A images and show that both coronagraphs measure essentially the same structures. Measurements of the mean velocity as a function of height of these structures are compared with mass flux determinations of the <span class="hlt">solar</span> <span class="hlt">wind</span> outflow in the large polar coronal hole regions and give similar results.</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://hdl.handle.net/2060/20110013339','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110013339"><span id="translatedtitle">The Character of the <span class="hlt">Solar</span> <span class="hlt">Wind</span>, Surface Interactions, and Water</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Farrell, William M.</p> <p>2011-01-01</p> <p>We discuss the key characteristics of the proton-rich <span class="hlt">solar</span> <span class="hlt">wind</span> and describe how it may interact with the lunar surface. We suggest that <span class="hlt">solar</span> <span class="hlt">wind</span> can be both a source and loss of water/OH related volatiles, and review models showing both possibilities. Energy from the Sun in the form of radiation and <span class="hlt">solar</span> <span class="hlt">wind</span> plasma are in constant interaction with the lunar surface. As such, there is a <span class="hlt">solar</span>-lunar energy connection, where <span class="hlt">solar</span> energy and matter are continually bombarding the lunar surface, acting at the largest scale to erode the surface at 0.2 Angstroms per year via ion sputtering [1]. Figure 1 illustrates this dynamically Sun-Moon system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5502783','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5502783"><span id="translatedtitle">Off-disk penetration of ancient <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Sasaki, SHO )</p> <p>1991-05-01</p> <p>Following a suggestion by Wetherill (1981), an estimation is made of the capture of an ancient, intense <span class="hlt">solar</span> <span class="hlt">wind</span> by primordial dust. Because the mutual collision of planetesimals would generate additional dust grains in interplanetary space after the <span class="hlt">solar</span> nebula's dissipation, the vertical distribution of the dust is taken into account. The <span class="hlt">solar</span> <span class="hlt">wind</span> penetrates the dust swarm through the less opaque off-disk portions, explaining both the trapping of a substantial quantity of <span class="hlt">solar</span> <span class="hlt">wind</span> species and the high abundances of <span class="hlt">solar</span>-type noble gases in gas-rich meteorites and on Venus. The off-disk trap is efficient when the disk is opaque and its relative thickness does not diminish with increasing heliocentric distance. 34 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110005629','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110005629"><span id="translatedtitle">Dissipation of Turbulence in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Goldstein, Melvyn L.</p> <p>2010-01-01</p> <p>I will describe the first three-dimensional (3-D) dispersion relations and wavenumber spectra of magnetic turbulence in the <span class="hlt">solar</span> <span class="hlt">wind</span> at sub-proton scales. The analysis takes advantage of the short separations of the Cluster spacecraft (d/sim approx.200 km) to apply the {it k}-filtering technique to the frequency range where the transition to sub-proton scales occurs. The dispersion diagrams show unambiguously that the cascade is carried by highly oblique Kinetic Alfven Wave with \\omega\\leq 0.1\\omega_{ci} in the plasma rest frame down to k_\\perp\\rho_i \\sim 2. The wavenumber spectra in the direction perpendicular to the mean magnetic field consists of two ranges of scales separated by a breakpoint in the interval [0.4,1] k_\\perp \\rho_i. Above the breakpoint, the spectra follow the Kolmogorov scaling k_\\perp^{-1.7}, consistent with existing theoretical predictions. Below the breakpoint, the spectra steepen to \\sim k_\\perp^{-4.5}. We conjecture that the turbulence undergoes a {\\it transition-range}, where part of energy is dissipated into proton heating via Landau damping, and the remaining energy cascades down to electron scales where electron Landau damping may predominate.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040182379','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040182379"><span id="translatedtitle">Interaction of Comets and the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wagner, William (Technical Monitor); Raymond, John C.</p> <p>2004-01-01</p> <p>The analysis of Comet Kudo-Fujikawa at perihelion was published and picked up by Der Spiegel. Besides a large and rapidly increasing water outgassing rate, we detected a bright tail in doubly ionized carbon. The amount of carbon was greater than could be accounted for by CO photodissociation, and we attribute it to evaporation of organics from dust. A spectacular disconnection event was apparent in the C III tail, and it coincides within the uncertainties to the position of the heliospheric current sheet. The analysis of the sungrazing comet C2001 C2 is in press. It showed evidence for subfragments and for a very long lasting source of neutrals, which we identify as evaporation of pyroxene dust grains. Results were also presented at COSPAR. We are working on observations of another sungrazer, comet C2002 S2, which shows a sudden 2 magnitude drop in optical brightness and an equally sudden recovery. UVCS observations during that time show a steadily increasing outgassing rate. We have derived <span class="hlt">solar</span> <span class="hlt">wind</span> densities for both comets, but we are still sorting out the ambiguities involving the fragmentation and optical behavior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040000671&hterms=Raymond+Williams&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DRaymond%2BWilliams','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040000671&hterms=Raymond+Williams&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DRaymond%2BWilliams"><span id="translatedtitle">Interaction of Comets and the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wagner, William (Technical Monitor); Raymond, John C.</p> <p>2003-01-01</p> <p>We had originally planned to analyze UVCS observations of Comet Machholz, but we obtained higher quality observations of Comet Kudo-Fujikawa in January 2003 at its 0.19 AU perihelion. Besides a large and rapidly increasing water outgassing rate, we detected a bright tail in doubly ionized carbon. The amount of carbon was greater than could be accounted for by GO photodissociation, and we attribute the carbon to evaporation of organics from dust. A spectacular disconnection event was apparent in the C III tail, and it coincides within the uncertainties with the position of the heliospheric current sheet. A paper is in press in Science, and it will be the subject of a press release. We are also analyzing two sungrazing comets. Comet C/2001 C2 shows evidence for sub-fragments and for a very long lasting source of neutrals, which we tentatively identify as evaporation of pyroxene dust grains. Comet C/2002 S2 shows a sudden 2 magnitude drop in optical brightness and an equally sudden recovery. UVCS observations during that time show a steadily increasing outgassing rate. We have derived <span class="hlt">solar</span> <span class="hlt">wind</span> densities for both comets, but we are still sorting out the ambiguities involving the fragmentation and optical behavior. We are collaborating with Philippe Lamy on the LASCO measurements.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19840024844','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19840024844"><span id="translatedtitle"><span class="hlt">Wind</span> loading on <span class="hlt">solar</span> concentrators: Some general considerations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Roschke, E. J.</p> <p>1984-01-01</p> <p>A survey was completed to examine the problems and complications arising from <span class="hlt">wind</span> loading on <span class="hlt">solar</span> concentrators. <span class="hlt">Wind</span> loading is site specific and has an important bearing on the design, cost, performance, operation and maintenance, safety, survival, and replacement of <span class="hlt">solar</span> collecting systems. Emphasis herein is on paraboloidal, two-axis tracking systems. Thermal receiver problems also are discussed. <span class="hlt">Wind</span> characteristics are discussed from a general point of view. Current methods for determining design <span class="hlt">wind</span> speed are reviewed. Aerodynamic coefficients are defined and illustrative examples are presented. <span class="hlt">Wind</span> tunnel testing is discussed, and environmental <span class="hlt">wind</span> tunnels are reviewed. Recent results on heliostat arrays are reviewed as well. Aeroelasticity in relation to structural design is discussed briefly.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1051165','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1051165"><span id="translatedtitle">Western <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Integration Study Phase 2: Preprint</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lew, D.; Brinkman, G.; Ibanez, E.; Hodge, B.-M.; King, J.</p> <p>2012-09-01</p> <p>The Western <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Integration Study (WWSIS) investigates the impacts of high penetrations of <span class="hlt">wind</span> and <span class="hlt">solar</span> power into the Western Interconnection of the United States. WWSIS2 builds on the Phase 1 study but with far greater refinement in the level of data inputs and production simulation. It considers the differences between <span class="hlt">wind</span> and <span class="hlt">solar</span> power on systems operations. It considers mitigation options to accommodate <span class="hlt">wind</span> and <span class="hlt">solar</span> when full costs of wear-and-tear and full impacts of emissions rates are taken into account. It determines wear-and-tear costs and emissions impacts. New data sets were created for WWSIS2, and WWSIS1 data sets were refined to improve realism of plant output and forecasts. Four scenarios were defined for WWSIS2 that examine the differences between <span class="hlt">wind</span> and <span class="hlt">solar</span> and penetration level. Transmission was built out to bring resources to load. Statistical analysis was conducted to investigate <span class="hlt">wind</span> and <span class="hlt">solar</span> impacts at timescales ranging from seasonal down to 5 minutes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110015175','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110015175"><span id="translatedtitle">Sputtering by the <span class="hlt">Solar</span> <span class="hlt">Wind</span>: Effects of Variable Composition</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Killen, R. M.; Arrell, W. M.; Sarantos, M.; Delory, G. T.</p> <p>2011-01-01</p> <p>It has long been recognized that <span class="hlt">solar</span> <span class="hlt">wind</span> bombardment onto exposed surfaces in the <span class="hlt">solar</span> system will produce an energetic component to the exospheres about those bodies. Laboratory experiments have shown that there is no increase in the sputtering yield caused by highly charged heavy ions for metallic and for semiconducting surfaces, but the sputter yield can be noticeably increased in the case of a good insulating surface. Recently measurements of the <span class="hlt">solar</span> <span class="hlt">wind</span> composition have become available. It is now known that the <span class="hlt">solar</span> <span class="hlt">wind</span> composition is highly dependent on the origin of the particular plasma. Using the measured composition of the slow <span class="hlt">wind</span>, fast <span class="hlt">wind</span>, <span class="hlt">solar</span> energetic particle (SEP) population, and coronal mass ejection (CME), broken down into its various components, we have estimated the total sputter yield for each type of <span class="hlt">solar</span> <span class="hlt">wind</span>. Whereas many previous calculations of sputtering were limited to the effects of proton bombardment. we show that the heavy ion component. especially the He++ component. can greatly enhance the total sputter yield during times when the heavy ion population is enhanced. We will discuss sputtering of both neutrals and ions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH51D4183K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH51D4183K"><span id="translatedtitle">Asymptotic Theory of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Electron Halo Distribution</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, S.; Yoon, P. H.</p> <p>2014-12-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> electrons are conveniently divided into core Maxwellian background, isotropic halo, and super-halo components (and some times, highly field-aligned strahl component, which can be considered as a fourth element). Recently, a theory was proposed that explains the origin of super-halo distribution. It was assumed that the super-halo distribution forms as a result of wave-particle interaction between the super-halo electron and steady-state Langmuir fluctuation known as the quasi-thermal noise. In the present paper, we discuss a theory of <span class="hlt">solar</span> <span class="hlt">wind</span> halo electron distribution. It is assumed that the <span class="hlt">solar</span> <span class="hlt">wind</span> electrons whose energy is intermediate to the Gaussian cold core and super-halo components can interact efficiently with the whistler turbulence, which is pervasively detected in the <span class="hlt">solar</span> <span class="hlt">wind</span> near 1 AU. By making use of Fokker-Planck particle kinetic equations for the electrons and the wave kinetic equation for the whistler waves, it is shown that the <span class="hlt">solar</span> <span class="hlt">wind</span> halo distribution emerges as an asymptotic steady-state solution. The figure shown below summarizes the theoretical reconstruction of the total <span class="hlt">solar</span> <span class="hlt">wind</span> electron velocity distribution.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20020086296','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20020086296"><span id="translatedtitle">Investigation of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Correlations and <span class="hlt">Solar</span> <span class="hlt">Wind</span> Modifications Near Earth by Multi-Spacecraft Observations: IMP 8, <span class="hlt">WIND</span> and INTERBALL-1</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Paularena, Karolen I.; Richardson, John D.; Zastenker, Georgy N.</p> <p>2002-01-01</p> <p>The foundation of this Project is use of the opportunity available during the ISTP (International <span class="hlt">Solar</span>-Terrestrial Physics) era to compare <span class="hlt">solar</span> <span class="hlt">wind</span> measurements obtained simultaneously by three spacecraft - IMP 8, <span class="hlt">WIND</span> and INTERBALL-1 at wide-separated points. Using these data allows us to study three important topics: (1) the size and dynamics of near-Earth mid-scale (with dimension about 1-10 million km) and small-scale (with dimension about 10-100 thousand km) <span class="hlt">solar</span> <span class="hlt">wind</span> structures; (2) the reliability of the common assumption that <span class="hlt">solar</span> <span class="hlt">wind</span> conditions at the upstream Lagrangian (L1) point accurately predict the conditions affecting Earth's magnetosphere; (3) modification of the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma and magnetic field in the regions near the Earth magnetosphere, the foreshock and the magnetosheath. Our Project was dedicated to these problems. Our research has made substantial contributions to the field and has lead others to undertake similar work.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015TESS....110802K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015TESS....110802K"><span id="translatedtitle">Using the fingerprints of <span class="hlt">solar</span> magnetic reconnection to identify the elemental building blocks of the slow <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kepko, Larry; Viall, Nicholeen M.; Kasper, Justin; Lepri, Sue</p> <p>2015-04-01</p> <p>While the source of the fast <span class="hlt">solar</span> <span class="hlt">wind</span> is well understood to be linked to coronal holes, the source of the slow <span class="hlt">solar</span> <span class="hlt">wind</span> has remained elusive. Many previous studies of the slow <span class="hlt">solar</span> <span class="hlt">wind</span> have examined trends in the composition and charge states over long time scales and found strong relationships between the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity and these plasma parameters. These relationships have been used to constrain models of <span class="hlt">solar</span> <span class="hlt">wind</span> source and acceleration. In this study, we take advantage of high time resolution (12 min) measurements of <span class="hlt">solar</span> <span class="hlt">wind</span> composition and charge-state abundances recently reprocessed by the ACE <span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Composition Spectrometer (SWICS) science team to probe the timescales of <span class="hlt">solar</span> <span class="hlt">wind</span> variability at relatively small scales. We study an interval of slow <span class="hlt">solar</span> <span class="hlt">wind</span> containing quasi-periodic 90 minute structures and show that they are remnants of <span class="hlt">solar</span> magnetic reconnection. Each 90-minute parcel of slow <span class="hlt">solar</span> <span class="hlt">wind</span>, though the speed remains steady, exhibits the complete range of charge state and composition variations expected for the entire range of slow <span class="hlt">solar</span> <span class="hlt">wind</span>, which is repeated again in the next 90-minute interval. These observations show that previous statistical results break down on these shorter timescales, and impose new and important constraints on models of slow <span class="hlt">solar</span> <span class="hlt">wind</span> creation. We conclude by suggesting these structures were created through interchange magnetic reconnection and form elemental building blocks of the slow <span class="hlt">solar</span> <span class="hlt">wind</span>. We also discuss the necessity of decoupling separately the process(es) responsible for the release and acceleration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4604519','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4604519"><span id="translatedtitle">Impacts of <span class="hlt">wind</span> stilling on <span class="hlt">solar</span> radiation variability in China</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Lin, Changgui; Yang, Kun; Huang, Jianping; Tang, Wenjun; Qin, Jun; Niu, Xiaolei; Chen, Yingying; Chen, Deliang; Lu, Ning; Fu, Rong</p> <p>2015-01-01</p> <p><span class="hlt">Solar</span> dimming and <span class="hlt">wind</span> stilling (slowdown) are two outstanding climate changes occurred in China over the last four decades. The <span class="hlt">wind</span> stilling may have suppressed the dispersion of aerosols and amplified the impact of aerosol emission on <span class="hlt">solar</span> dimming. However, there is a lack of long-term aerosol monitoring and associated study in China to confirm this hypothesis. Here, long-term meteorological data at weather stations combined with short-term aerosol data were used to assess this hypothesis. It was found that surface <span class="hlt">solar</span> radiation (SSR) decreased considerably with <span class="hlt">wind</span> stilling in heavily polluted regions at a daily scale, indicating that <span class="hlt">wind</span> stilling can considerably amplify the aerosol extinction effect on SSR. A threshold value of 3.5 m/s for <span class="hlt">wind</span> speed is required to effectively reduce aerosols concentration. From this SSR dependence on <span class="hlt">wind</span> speed, we further derived proxies to quantify aerosol emission and <span class="hlt">wind</span> stilling amplification effects on SSR variations at a decadal scale. The results show that aerosol emission accounted for approximately 20% of the typical <span class="hlt">solar</span> dimming in China, which was amplified by approximately 20% by <span class="hlt">wind</span> stilling. PMID:26463748</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015NatSR...515135L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015NatSR...515135L"><span id="translatedtitle">Impacts of <span class="hlt">wind</span> stilling on <span class="hlt">solar</span> radiation variability in China</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lin, Changgui; Yang, Kun; Huang, Jianping; Tang, Wenjun; Qin, Jun; Niu, Xiaolei; Chen, Yingying; Chen, Deliang; Lu, Ning; Fu, Rong</p> <p>2015-10-01</p> <p><span class="hlt">Solar</span> dimming and <span class="hlt">wind</span> stilling (slowdown) are two outstanding climate changes occurred in China over the last four decades. The <span class="hlt">wind</span> stilling may have suppressed the dispersion of aerosols and amplified the impact of aerosol emission on <span class="hlt">solar</span> dimming. However, there is a lack of long-term aerosol monitoring and associated study in China to confirm this hypothesis. Here, long-term meteorological data at weather stations combined with short-term aerosol data were used to assess this hypothesis. It was found that surface <span class="hlt">solar</span> radiation (SSR) decreased considerably with <span class="hlt">wind</span> stilling in heavily polluted regions at a daily scale, indicating that <span class="hlt">wind</span> stilling can considerably amplify the aerosol extinction effect on SSR. A threshold value of 3.5?m/s for <span class="hlt">wind</span> speed is required to effectively reduce aerosols concentration. From this SSR dependence on <span class="hlt">wind</span> speed, we further derived proxies to quantify aerosol emission and <span class="hlt">wind</span> stilling amplification effects on SSR variations at a decadal scale. The results show that aerosol emission accounted for approximately 20% of the typical <span class="hlt">solar</span> dimming in China, which was amplified by approximately 20% by <span class="hlt">wind</span> stilling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990028031&hterms=leer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dleer','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990028031&hterms=leer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dleer"><span id="translatedtitle">Coronal hole structure and the high speed <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Holzer, Thomas E.; Leer, Egil</p> <p>1997-01-01</p> <p>The basic physical processes which are important in the acceleration of high speed <span class="hlt">wind</span> from coronal holes are reviewed. The early works of Birkeland and Parker are discussed. The extension of Parker's work is included. It is shown that the greatest area of uncertainty is that of coronal heating. It is demonstrated that in modeling <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration, it is important to carry out a study on the chromosphere-corona-<span class="hlt">wind</span> system analysis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20080022945','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20080022945"><span id="translatedtitle">On the Relationship Between <span class="hlt">Solar</span> <span class="hlt">Wind</span> Speed, Geomagnetic Activity, and the <span class="hlt">Solar</span> Cycle Using Annual Values</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wilson, Robert M.; Hathaway, David H.</p> <p>2008-01-01</p> <p>The aa index can be decomposed into two separate components: the leading sporadic component due to <span class="hlt">solar</span> activity as measured by sunspot number and the residual or recurrent component due to interplanetary disturbances, such as coronal holes. For the interval 1964-2006, a highly statistically important correlation (r = 0.749) is found between annual averages of the aa index and the <span class="hlt">solar</span> <span class="hlt">wind</span> speed (especially between the residual component of aa and the <span class="hlt">solar</span> <span class="hlt">wind</span> speed, r = 0.865). Because cyclic averages of aa (and the residual component) have trended upward during cycles 11-23, cyclic averages of <span class="hlt">solar</span> <span class="hlt">wind</span> speed are inferred to have also trended upward.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950063967&hterms=Importance+Exercise&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DImportance%2BExercise','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950063967&hterms=Importance+Exercise&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DImportance%2BExercise"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> eddies and the heliospheric current sheet</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.; Mccomas, D. J.; Bame, S. J.; Goldstein, B. E.</p> <p>1995-01-01</p> <p>Ulysses has collected data between 1 and 5 AU during, and just following <span class="hlt">solar</span> maximum, when the heliospheric current sheet (HCS) can be thought of as reaching its maximum tilt and being subject to the maximum amount of turbulence in the <span class="hlt">solar</span> <span class="hlt">wind</span>. The Ulysses <span class="hlt">solar</span> <span class="hlt">wind</span> plasma instrument measures the vector velocity and can be used to estimate the flow speed and direction in turbulent 'eddies' in the <span class="hlt">solar</span> <span class="hlt">wind</span> that are a fraction of an astronomical unit in size and last (have either a turnover or dynamical interaction time of) several hours to more than a day. Here, in a simple exercise, these <span class="hlt">solar</span> <span class="hlt">wind</span> eddies at the HCS are characterized using Ulysses data. This character is then used to define a model flow field with eddies that is imposed on an ideal HCS to estimate how the HCS will be deformed by the flow. This model inherently results in the complexity of the HCS increasing with heliocentric distance, but the result is a measure of the degree to which the observed change in complexity is a measure of the importance of <span class="hlt">solar</span> <span class="hlt">wind</span> flows in deforming the HCS. By comparison with randomly selected intervals not located on the HCS, it appears that eddies on the HCS are similar to those elsewhere at this time during the <span class="hlt">solar</span> cycle, as is the resultant deformation of the interplanetary magnetic field (IMF). The IMF deformation is analogous to what is often termed the 'random walk' of interplanetary magnetic field lines.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930049592&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930049592&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dlazarus"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> temperature observations in the outer heliosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gazis, P. R.; Barnes, A.; Mihalov, J. D.; Lazarus, A. J.</p> <p>1992-01-01</p> <p>The Pioneer 10, Pioneer 11, and Voyager 2 spacecraft are now at heliocentric distances of 50, 32 and 33 AU, and heliographic latitudes of 3.5 deg N, 17 deg N, and 0 deg N, respectively. Pioneer 11 and Voyager 2 are at similar celestial longitudes, while Pioneer l0 is on the opposite side of the sun. The baselines defined by these spacecraft make it possible to resolve radial, longitudinal, and latitudinal variations of <span class="hlt">solar</span> <span class="hlt">wind</span> parameters. The <span class="hlt">solar</span> <span class="hlt">wind</span> temperature decreases with increasing heliocentric distance out to a distance of 10-15 AU. At larger heliocentric distances, this gradient disappears. These high <span class="hlt">solar</span> <span class="hlt">wind</span> temperatures in the outer heliosphere have persisted for at least 10 years, which suggests that they are not a <span class="hlt">solar</span> cycle effect. The <span class="hlt">solar</span> <span class="hlt">wind</span> temperature varied with heliographic latitude during the most recent <span class="hlt">solar</span> minimum. The <span class="hlt">solar</span> <span class="hlt">wind</span> temperature at Pioneer 11 and Voyager 2 was higher than that seen at Pioneer 10 for an extended period of time, which suggests the existence of a large-scale variation of temperature with celestial longitude, but the contribution of transient phenomena is yet to be clarified.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021284&hterms=wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwind%2Benergy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021284&hterms=wind+energy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dwind%2Benergy"><span id="translatedtitle">Electron energy transport in the <span class="hlt">solar</span> <span class="hlt">wind</span>: Ulysses observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Scime, Earl; Gary, S. Peter; Phillips, J. L.; Corniileau-Wehrlin, N.; Solomon, J.</p> <p>1995-01-01</p> <p>The electron heat flux in the <span class="hlt">solar</span> <span class="hlt">wind</span> has been measured by the Ulysses <span class="hlt">solar</span> <span class="hlt">wind</span> plasma experiment in the ecliptic from 1 to 5 AU and out of the ecliptic during the recently completed pass over the <span class="hlt">solar</span> south pole and the ongoing pass over the <span class="hlt">solar</span> north pole. Although the electron heat flux contains only a fraction of the kinetic energy of the <span class="hlt">solar</span> <span class="hlt">wind</span>. the available energy is sufficient to account for the non-adiabatic expansion of the <span class="hlt">solar</span> <span class="hlt">wind</span> electrons. The Ulysses measurements indicate that the electron heat flux is actively dissipated in the <span class="hlt">solar</span> <span class="hlt">wind</span>. The exact mechanism or mechanisms is unknown. but a model based on the whistler heat flux instability predicts radial gradients for the electron heat flux in good agreement with the data. We will present measurements of the correlation between wave activity measured by the unified radio and plasma experiment (URAP) and the electron heat flux throughout the Ulysses mission. The goal is to determine if whistler waves are a good candidate for the observed electron heat flux dissipation. The latitudinal gradients of the electron heat flux. wave activity. and electron pressure will be discussed in light of the changes in the magnetic field geometry from equator to poles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014FrASS...1....4E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014FrASS...1....4E"><span id="translatedtitle">A survey of <span class="hlt">solar</span> <span class="hlt">wind</span> conditions at 5 AU: A tool for interpreting <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere interactions at Jupiter</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ebert, Robert; Bagenal, Fran; McComas, David; Fowler, Christopher</p> <p>2014-09-01</p> <p>We examine Ulysses <span class="hlt">solar</span> <span class="hlt">wind</span> and interplanetary magnetic field (IMF) observations at 5 AU for two ~13 month intervals during the rising and declining phases of <span class="hlt">solar</span> cycle 23 and the predicted response of the Jovian magnetosphere during these times. The declining phase <span class="hlt">solar</span> <span class="hlt">wind</span>, composed primarily of corotating interaction regions and high-speed streams, was, on average, faster, hotter, less dense, and more Alfvnic relative to the rising phase <span class="hlt">solar</span> <span class="hlt">wind</span>, composed mainly of slow <span class="hlt">wind</span> and interplanetary coronal mass ejections. Interestingly, none of <span class="hlt">solar</span> <span class="hlt">wind</span> and IMF distributions reported here were bimodal, a feature used to explain the bimodal distribution of bow shock and magnetopause standoff distances observed at Jupiter. Instead, many of these distributions had extended, non-Gaussian tails that resulted in large standard deviations and much larger mean over median values. The distribution of predicted Jupiter bow shock and magnetopause standoff distances during these intervals were also not bimodal, the mean/median values being larger during the declining phase by ~1 - 4%. These results provide data-derived <span class="hlt">solar</span> <span class="hlt">wind</span> and IMF boundary conditions at 5 AU for models aimed at studying <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere interactions at Jupiter and can support the science investigations of upcoming Jupiter system missions. Here, we provide expectations for Juno, which is scheduled to arrive at Jupiter in July 2016. Accounting for the long-term decline in <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure reported by McComas et al. (2013), Jupiters bow shock and magnetopause is expected to be at least 8 - 12% further from Jupiter, if these trends continue.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015TESS....110805L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015TESS....110805L"><span id="translatedtitle">Element Abundances in the Sun and <span class="hlt">Solar</span> <span class="hlt">Wind</span> Along the <span class="hlt">Solar</span> Cycle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Landi, Enrico</p> <p>2015-04-01</p> <p>Element abundances are a critical parameter in almost every aspect of <span class="hlt">solar</span> physics, from regulating the energy flow and the structure of the <span class="hlt">solar</span> interior, to shaping the energy losses of the <span class="hlt">solar</span> atmosphere, ruling the radiative output of the UV, EUV and X-rays <span class="hlt">solar</span> radiation which impacts the Earth's upper atmosphere, and determining the composition of the <span class="hlt">solar</span> <span class="hlt">wind</span>.In this work we study the evolution of the element abundances in the <span class="hlt">solar</span> corona and in the <span class="hlt">solar</span> <span class="hlt">wind</span> from 1996 to date using data from SoHO, Hinode, Ulysses and ACE satellites, in order to determine their variability along the <span class="hlt">solar</span> cycle, and the relationship between <span class="hlt">solar</span> abundance variations in the <span class="hlt">solar</span> <span class="hlt">wind</span> and in its source regions in the <span class="hlt">solar</span> atmosphere. We study all the most abundant elements, with a special emphasis on Ne and O. We discuss our results in light of the source region of the <span class="hlt">solar</span> <span class="hlt">wind</span>, and of the radiative output of the <span class="hlt">solar</span> corona.</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://www.osti.gov/scitech/biblio/21371703','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21371703"><span id="translatedtitle">Velocity Distributions and Proton Beam Production in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pierrard, Viviane; Voitenko, Yuriy</p> <p>2010-03-25</p> <p>Helios, Ulysses, and <span class="hlt">Wind</span> spacecraft have observed the velocity distribution functions (VDFs) of <span class="hlt">solar</span> <span class="hlt">wind</span> particles deviating significantly from Maxwellians. We review recent models using different approximations and mechanisms that determine various observed characteristics of the VDFs for the electrons, protons and minor ions. A new generation mechanism is proposed for super-Alfvenic proton beams and tails that are often observed in the fast <span class="hlt">solar</span> <span class="hlt">wind</span>. The mechanism is based on the proton trapping and acceleration by kinetic Alfven waves (KAWs), which carry a field-aligned potential well propagating with super-Alfven velocities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.4825F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.4825F"><span id="translatedtitle">Small Scale Magnetic Reconnection in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Foster, Alice; Owen, Christopher; Forsyth, Colin; Rae, Jonathan; Fazakerley, Andrew; Carr, Christopher; Dandouras, Iannis</p> <p>2015-04-01</p> <p>Previous studies of magnetic reconnection in the <span class="hlt">solar</span> <span class="hlt">wind</span> have suggested that a single reconnection X-line can extend and be active over millions of kilometres. We present a case study of an event observed in the <span class="hlt">solar</span> <span class="hlt">wind</span> on the 2nd March 2006 by the four Cluster spacecraft. We utilised the four point measurement capability to study the event at sub-second resolution over separation distances of 10,000 km as well as over the larger scales separating Cluster from ACE and <span class="hlt">WIND</span>. We thus test the consistency of the temporal and spatial structure of magnetic reconnection from large scales to small scales. This reconnection event showed significant differences between the Cluster spacecraft, particularly in the magnetic field data, suggesting reconnection in the <span class="hlt">solar</span> <span class="hlt">wind</span> can be variable over relatively small temporal and or spatial scales (< 60 s and/or ~ 10,000 km). This leads to the conclusion that magnetic reconnection in the <span class="hlt">solar</span> <span class="hlt">wind</span> is not necessarily large scale and may be patchy in nature. This result raises questions about our current understanding of magnetic reconnection in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19730054131&hterms=wind+moon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwind%2Bmoon','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19730054131&hterms=wind+moon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwind%2Bmoon"><span id="translatedtitle">Electric potential of the moon in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Freeman, J. W., Jr.; Fenner, M. A.; Hills, H. K.</p> <p>1973-01-01</p> <p>Acceleration and detection of the lunar thermal ionosphere in the presence of the lunar electric field yields a value of at least +10 V for the lunar electric potential for <span class="hlt">solar</span> zenith angles between approximately 20 and 45 deg and in the magnetosheath or <span class="hlt">solar</span> <span class="hlt">wind</span>. An enhanced positive ion flux is observed with the Apollo Lunar Surface Experiments Package Suprathermal Ion Detector Experiment when a preacceleration voltage attains certain values. This enhancement is greater when the moon is in the <span class="hlt">solar</span> <span class="hlt">wind</span> as opposed to the magnetosheath.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...807...86S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...807...86S"><span id="translatedtitle">Self-consistent Castaing Distribution of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Turbulent Fluctuations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sorriso-Valvo, L.; Marino, R.; Lijoi, L.; Perri, S.; Carbone, V.</p> <p>2015-07-01</p> <p>The intermittent behavior of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulent fluctuations has often been investigated through the modeling of their probability distribution functions (PDFs). Among others, the Castaing model has successfully been used in the past. In this paper, the energy dissipation field of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence has been studied for fast, slow, and polar <span class="hlt">wind</span> samples recorded by Helios 2 and Ulysses spacecraft. The statistical description of the dissipation rate has then been used to remove intermittency through conditioning of the PDFs. Based on such observation, a self-consistent, parameter-free Castaing model is presented. The self-consistent model is tested against experimental PDFs, showing good agreement and supporting the picture of a multifractal energy cascade at the origin of <span class="hlt">solar</span> <span class="hlt">wind</span> intermittency.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22342072','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22342072"><span id="translatedtitle">The Yaglom law in the expanding <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gogoberidze, G.; Perri, S.; Carbone, V.</p> <p>2013-06-01</p> <p>We study the Yaglom law, which relates the mixed third-order structure function to the average dissipation rate of turbulence, in a uniformly expanding <span class="hlt">solar</span> <span class="hlt">wind</span> by using the two-scale expansion model of magnetohydrodynamic (MHD) turbulence. We show that due to the expansion of the <span class="hlt">solar</span> <span class="hlt">wind</span>, two new terms appear in the Yaglom law. The first term is related to the decay of the turbulent energy by nonlinear interactions, whereas the second term is related to the non-zero cross-correlation of the Elsässer fields. Using magnetic field and plasma data from <span class="hlt">WIND</span> and Helios 2 spacecrafts, we show that at lower frequencies in the inertial range of MHD turbulence the new terms become comparable to Yaglom's third-order mixed moment, and therefore they cannot be neglected in the evaluation of the energy cascade rate in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5990417','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5990417"><span id="translatedtitle">The interaction of active comets with the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Neugebauer, M. )</p> <p>1990-11-01</p> <p>The interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with active comets is investigated based on observations of cometary plasma processes and studies of comets using telescopes and photographic plates. Data were also collected when a spacecraft flew through the tail of Comet Giacobini-Zinner in 1985 and five spacecraft encountered Comet Halley in 1986. The <span class="hlt">solar</span> <span class="hlt">wind</span> is considered to be supersonic (thermal Mach number 2-10) and to carry a magnetic field twisted into an Archimedean spiral by the rotation of the sun. Since the <span class="hlt">wind</span> can change its properties during the time a spacecraft is inside the ionosphere or magnetosphere of the body being studied, it is difficult to separate spatial from temporal effects. Photoionization results in addition of plasma to the <span class="hlt">solar</span> <span class="hlt">wind</span>. Between the outer and inner edges of the cometosheath, the increasing rate of ion pickup causes the flow to slow down until it stagnates, while the plasma density and the magnetic field strength increase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22004277','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22004277"><span id="translatedtitle">CARBON IONIZATION STAGES AS A DIAGNOSTIC OF THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Landi, E.; Alexander, R. L.; Gruesbeck, J. R.; Gilbert, J. A.; Lepri, S. T.; Manchester, W. B.; Zurbuchen, T. H.</p> <p>2012-01-10</p> <p>Oxygen charge states measured by in situ instrumentation have long been used as a powerful diagnostic of the <span class="hlt">solar</span> corona and to discriminate between different <span class="hlt">solar</span> <span class="hlt">wind</span> regimes, both because they freeze in very close to the Sun, and because the oxygen element abundance is comparatively high, allowing for statistically relevant measures. Like oxygen, carbon is also rather abundant and freezes in very close to the Sun. Here, we show an analysis of carbon and oxygen ionic charge states. First, through auditory and Fourier analysis of in situ measurements of <span class="hlt">solar</span> <span class="hlt">wind</span> ion composition by ACE/SWICS we show that some carbon ion ratios are very sensitive to <span class="hlt">solar</span> <span class="hlt">wind</span> type, even more sensitive than the commonly used oxygen ion ratios. Then we study the evolution of the ionization states of carbon and oxygen by means of a freeze-in code, and find that carbon ions, commonly found in the <span class="hlt">solar</span> <span class="hlt">wind</span>, freeze in at comparable coronal distances, while oxygen ions evolve over a much larger range of coronal distances. Finally, we show that carbon and oxygen ion abundance ratios have similar sensitivity to the electron plasma temperature, but the carbon ratios are more robust against atomic physics uncertainties and a better indicator of the temperature of the <span class="hlt">solar</span> <span class="hlt">wind</span> source regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/419263','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/419263"><span id="translatedtitle">Ulysses <span class="hlt">solar</span> <span class="hlt">wind</span> plasma observations at high latitudes</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Riley, P.; Bame, S.J.; Barraclough, B.L.</p> <p>1996-10-01</p> <p>Ulysses reached its peak northerly heliolatitude of 80.2{degrees}N on July 31, 1995, and now is moving towards aphelion at 5.41 AU which it will reach in May, 1998. We summarize measurements from the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma experiment, SWOOPS, emphasizing northern hemispheric observations but also providing southern and equatorial results for comparison. The <span class="hlt">solar</span> <span class="hlt">wind</span> momentum flux during Ulysses` fast pole-to- pole transit at <span class="hlt">solar</span> minimum was significantly higher over the poles than at near-equatorial latitudes, suggesting a non-circular cross section for the heliosphere. Furthermore, modest asymmetries in the <span class="hlt">wind</span> speed, density, and mass flux were observed between the two hemispheres during the fast latitude scan. The <span class="hlt">solar</span> <span class="hlt">wind</span> was faster and less dense in the north than in the south. These asymmetries persist in the most recent high- and mid-latitude data but are less pronounced. As of July 1, 1996 the northern fast <span class="hlt">solar</span> <span class="hlt">wind</span> has lacked any strong stream interactions or shocks and, although a comprehensive search has not yet been made, no CMEs have yet been identified during this interval. On the other hand, Alfv{acute e}nic, compressional, and pressure balanced features are abundant at high latitudes. The most recent data, at 4 AU and 32{degrees}N, has begun to show the effects of <span class="hlt">solar</span> rotation modulated features in the form of recurrent compressed regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFM.P21C3918D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFM.P21C3918D"><span id="translatedtitle">Improving <span class="hlt">solar</span> <span class="hlt">wind</span> modeling at Mercury: Incorporating transient <span class="hlt">solar</span> phenomena into the WSA-ENLIL model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Dewey, R. M.; Baker, D. N.; Anderson, B. J.; Benna, M.; Johnson, C. L.; Korth, H.; Gershman, D. J.; Ho, G. C.; McClintock, W. E.; Odstrcil, D.; Philpott, L. C.; Raines, J. M.; Schriver, D.; Slavin, J. A.; Solomon, S. C.; Winslow, R. M.; Zurbuchen, T.</p> <p>2014-12-01</p> <p>Coronal mass ejections (CMEs) and other transient <span class="hlt">solar</span> phenomena play important roles in magnetospheric and exospheric dynamics. Although a planet may only occasionally interact with the products of these events, such transient phenomena can result in departures from the background <span class="hlt">solar</span> <span class="hlt">wind</span> that often involve more than an order of magnitude greater ram pressure and interplanetary electric field applied to the magnetosphere. For Mercury, an order of magnitude greater ram pressure can push the magnetopause to the planet's surface, exposing the surface directly to the <span class="hlt">solar</span> <span class="hlt">wind</span>. In order to understand how the <span class="hlt">solar</span> <span class="hlt">wind</span> interacts with Mercury's magnetosphere and exosphere, previous studies have used the Wang-Sheeley-Arge (WSA)-ENLIL <span class="hlt">solar</span> <span class="hlt">wind</span> modeling tool to calculate basic and composite <span class="hlt">solar</span> <span class="hlt">wind</span> parameters, such as <span class="hlt">solar</span> <span class="hlt">wind</span> velocity (V) and Alfvén Mach number (MA) at Mercury's orbital location. This model forecasts only the background <span class="hlt">solar</span> <span class="hlt">wind</span>, however, and does not include these transient events. The Cone extension permits the inclusion of CMEs and other phenomena, and thus enables characterization of the effect of strong <span class="hlt">solar</span> <span class="hlt">wind</span> perturbations on the Mercury system. The Cone extension is predicated on the assumption of constant angular and radial velocities of ejecta to integrate them into the WSA-ENLIL coupled model. Comparisons of the model results with the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft observations indicate that the WSA-ENLIL-Cone model more accurately forecasts total <span class="hlt">solar</span> <span class="hlt">wind</span> conditions at Mercury and has greater predictive power for magnetospheric and exospheric processes than the WSA-ENLIL model alone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740044930&hterms=heinemann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dheinemann','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740044930&hterms=heinemann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dheinemann"><span id="translatedtitle">Shapes of strong shock fronts in an inhomogeneous <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Heinemann, M. A.; Siscoe, G. L.</p> <p>1974-01-01</p> <p>The shapes expected for <span class="hlt">solar</span>-flare-produced strong shock fronts in the <span class="hlt">solar</span> <span class="hlt">wind</span> have been calculated, large-scale variations in the ambient medium being taken into account. It has been shown that for reasonable ambient <span class="hlt">solar</span> <span class="hlt">wind</span> conditions the mean and the standard deviation of the east-west shock normal angle are in agreement with experimental observations including shocks of all strengths. The results further suggest that near a high-speed stream it is difficult to distinguish between corotating shocks and flare-associated shocks on the basis of the shock normal alone. Although the calculated shapes are outside the range of validity of the linear approximation, these results indicate that the variations in the ambient <span class="hlt">solar</span> <span class="hlt">wind</span> may account for large deviations of shock normals from the radial direction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.2004S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.2004S"><span id="translatedtitle">Results From The Genesis Autonomous <span class="hlt">Solar</span> <span class="hlt">Wind</span> Regime Algorithm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Steinberg, J. T.; Barraclough, B. L.; Dors, E. E.; Neugebauer, M.; Wiens, R. C.</p> <p></p> <p>Launched on August 8, 2001, the NASA Genesis mission is now collecting samples of the <span class="hlt">solar</span> <span class="hlt">wind</span> in various materials, and will return those samples to Earth for analysis in 2004. A primary science goal of Genesis is the determination of the elemental and isotopic composition of the <span class="hlt">solar</span> atmosphere from the <span class="hlt">solar</span> <span class="hlt">wind</span> material returned. Because the <span class="hlt">solar</span> <span class="hlt">wind</span> itself is known to exhibit compositional variations across dif- ferent types of <span class="hlt">solar</span> <span class="hlt">wind</span> flows, Genesis exposes different collectors to <span class="hlt">solar</span> <span class="hlt">wind</span> originating from three flow types: coronal hole (CH), coronal mass ejection (CME), and interstream (IS) flows. Flow types are identified using in situ measurements of so- lar <span class="hlt">wind</span> ions and electrons from electrostatic analyzers carried by Genesis. The flow regime selection algorithm and subsequent collector deployment on Genesis act au- tonomously. The algorithm takes into account the proton speed, proton temperature, alpha particle abundance, and the presence of counter-streaming suprathermal elec- trons as determined onboard. Autonomous determination of counter-streaming elec- trons is novel, as is the simultaneous utilization of electron information and ion mo- ments in logic that autonomously controls the science payload. Results to date show that <span class="hlt">solar</span> <span class="hlt">wind</span> has recently been dominated by IS flow with frequent CMEs. Between 24 August 2001 and 31 December 2001, the Genesis algo- rithm categorized the flow to be 67 % IS, 26% CME, and 7% CH. Counter-streaming electrons signatures were identified for 23% of that total time interval. The Genesis onboard shock detector was set seventeen times, and nearly all were verified to be ac- tual CME-associated shocks. We will present the results of the autonomous algorithm obtained up to the time of the EGS meeting, as well as our assessment of the validity of those onboard results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22126793','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22126793"><span id="translatedtitle"><span class="hlt">SOLAR</span> <span class="hlt">WIND</span> HEAVY IONS OVER <span class="hlt">SOLAR</span> CYCLE 23: ACE/SWICS MEASUREMENTS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lepri, S. T.; Landi, E.; Zurbuchen, T. H.</p> <p>2013-05-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> plasma and compositional properties reflect the physical properties of the corona and its evolution over time. Studies comparing the previous <span class="hlt">solar</span> minimum with the most recent, unusual <span class="hlt">solar</span> minimum indicate that significant environmental changes are occurring globally on the Sun. For example, the magnetic field decreased 30% between the last two <span class="hlt">solar</span> minima, and the ionic charge states of O have been reported to change toward lower values in the fast <span class="hlt">wind</span>. In this work, we systematically and comprehensively analyze the compositional changes of the <span class="hlt">solar</span> <span class="hlt">wind</span> during cycle 23 from 2000 to 2010 while the Sun moved from <span class="hlt">solar</span> maximum to <span class="hlt">solar</span> minimum. We find a systematic change of C, O, Si, and Fe ionic charge states toward lower ionization distributions. We also discuss long-term changes in elemental abundances and show that there is a {approx}50% decrease of heavy ion abundances (He, C, O, Si, and Fe) relative to H as the Sun went from <span class="hlt">solar</span> maximum to <span class="hlt">solar</span> minimum. During this time, the relative abundances in the slow <span class="hlt">wind</span> remain organized by their first ionization potential. We discuss these results and their implications for models of the evolution of the <span class="hlt">solar</span> atmosphere, and for the identification of the fast and slow <span class="hlt">wind</span> themselves.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21320551','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21320551"><span id="translatedtitle"><span class="hlt">Wind</span> heat transfer coefficient in <span class="hlt">solar</span> collectors in outdoor conditions</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kumar, Suresh; Mullick, S.C.</p> <p>2010-06-15</p> <p>Knowledge of <span class="hlt">wind</span> heat transfer coefficient, h{sub w}, is required for estimation of upward losses from the outer surface of flat plate <span class="hlt">solar</span> collectors/<span class="hlt">solar</span> cookers. In present study, an attempt has been made to estimate the <span class="hlt">wind</span> induced convective heat transfer coefficient by employing unglazed test plate (of size about 0.9 m square) in outdoor conditions. Experiments, for measurement of h{sub w}, have been conducted on rooftop of a building in the Institute campus in summer season for 2 years. The estimated <span class="hlt">wind</span> heat transfer coefficient has been correlated against <span class="hlt">wind</span> speed by linear regression and power regression. Experimental values of <span class="hlt">wind</span> heat transfer coefficient estimated in present work have been compared with studies of other researchers after normalizing for plate length. (author)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/6150252','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/6150252"><span id="translatedtitle">Meteoric ions in the corona and <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lemaire, J. )</p> <p>1990-09-01</p> <p>The total mass of refractory material of interplanetary origin penetrating and evaporated in the meltosphere surrounding the sun has been inferred from observations of meteoroids and fireballs falling in earth's atmosphere. The amount of iron atoms deposited this way in the <span class="hlt">solar</span> corona is of the order of 3000 t/s or larger. The measured flux of outflowing <span class="hlt">solar</span> <span class="hlt">wind</span> iron ions is equal to 2200 t/s. The close agreement of both fluxes is evidence that a significant fraction of iron ions observed in the <span class="hlt">solar</span> <span class="hlt">wind</span> and in the corona must be of meteoric origin. A similar accord is also obtained for silicon ions. The mean velocity of meteoroid ions formed in the <span class="hlt">solar</span> corona is equal to the free-fall velocity: i.e., independent of their atomic mass as the thermal speed of heavy ion measured in low-density <span class="hlt">solar</span> <span class="hlt">wind</span> streams at 1 AU. Furthermore, the heavy ions of meteoric origin escape out of the corona with a larger bulk velocity than the protons which are mainly of <span class="hlt">solar</span> origin. These differences of heavy ion and proton bulk velocities are also observed in the <span class="hlt">solar</span> <span class="hlt">wind</span>. 52 refs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AGUSMSP51B..01R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AGUSMSP51B..01R"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Forecasting with the SOLIS-VSM</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robbins, S. J.; Henney, C. J.; Harvey, J. W.</p> <p>2005-05-01</p> <p>A web based <span class="hlt">solar</span> <span class="hlt">wind</span> forecasting resource applying a simple empirical model with SOLIS-VSM (Vector Spectromagnetograph) data is presented here. The <span class="hlt">solar</span> <span class="hlt">wind</span> empirical model uses the locations of coronal holes on the observed <span class="hlt">solar</span> disk to forecast an estimated <span class="hlt">solar</span> <span class="hlt">wind</span> velocity at Earth. The model coefficients are estimated minimizing the difference between 10+ years of coronal hole images and the corresponding measured <span class="hlt">solar</span> <span class="hlt">wind</span> velocities. The coronal hole training data set was derived from Kitt Peak Vacuum Telescope (KPVT) He I 1083 nm images and photospheric magnetograms. The model can forecast up to 8.5 days in advance. The VSM estimated coronal hole images are derived from daily full-disk photospheric magnetograms and He I 1083 nm spectroheliograms using an automated coronal hole detection algorithm. Daily <span class="hlt">solar</span> <span class="hlt">wind</span> forecasts are planned to be automated using SOLIS-VSM data and made available publicly during the year 2005. The coronal hole data used here was compiled by K. Harvey and F. Recely using National <span class="hlt">Solar</span> Observatory (NSO) KPVT observations under a grant from the National Science Foundation (NSF). <span class="hlt">Solar</span> <span class="hlt">wind</span> data utilized for this project is provided on the Internet at http://nssdc.gsfc.nasa.gov/omniweb/. This work is carried out through the NSO Research Experiences for Undergraduate (REU) site program, which is co-funded by the Department of Defense in partnership with the National Science Foundation REU Program. This research was supported in part by the Office of Naval Research Grant N00014-91-J-1040. The NSO is operated by AURA, Inc. under a cooperative agreement with the NSF.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EPSC....9..528B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EPSC....9..528B"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> interaction with Venus and impact on its atmosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Barabash, S.; Futaana, Y.; Wieser, G. S.; Luhmann, J.</p> <p>2014-04-01</p> <p>We present a review of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with Venus and how the interaction affects the Venusian atmosphere. The Venus Express observations for more than 8 years (2005-present) and quantitatively new simulation codes substantially advanced physical understanding of the plasma processes in the near-Venus space since the Pioneer Venus Orbiter (PVO) mission (1978-1992). The near-Venus space can be divided into several plasma domains: the magnetotail with the plasmasheet, induced magnetosphere, and magnetosheath. The bow shock separates the undisturbed <span class="hlt">solar</span> <span class="hlt">wind</span> from the Venus-affected environment. We review the shapes and positions of the boundaries enveloping the main domains and discuss how they are formed by the current systems and pressure balance. In particular, we discuss the morphology and dynamics of the near-Venus magnetotail that was not accessible by PVO. Using the unique Venus Express measurements we discuss the ion acceleration processes and their links to the ionosphere. The focus is given to the Venus' atmosphere erosion associated with the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction, both through the energy (ion acceleration) and momentum (atmospheric sputtering) transfer. We review the measurements of the escape rates, their variability with the upstream <span class="hlt">solar</span> <span class="hlt">wind</span> conditions and the <span class="hlt">solar</span> cycle. We emphasize the measurements duirng extreme <span class="hlt">solar</span> <span class="hlt">wind</span> conditions as an analogue with nominal conditions for the young Sun. The modeling efforts in this area are also reviewed as they provide a quantitatively approach to understand the impact of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction on the atmospheric evolution. Finally, we compare Venus with other planets of the terrestrial planet group, the Earth and Mars. The Earth, a twin planet of the similar size, is magnetized. Mars, an unmagnetized planet like Venus, possesses by far weaker gravitation to hold its atmospheric gasses. This comparative magnetosphere approach based on the natural <span class="hlt">solar</span> system laboratory of experiments gives a clearer perspective on physics and processes, which forms the near-Venus space.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37..621D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37..621D"><span id="translatedtitle">Numerical studies on neutral <span class="hlt">solar</span> <span class="hlt">wind</span> flux at <span class="hlt">Solar</span> Orbiter's perihelion</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>D'Amicis, Raffaella; Mura, Alessandro; Orsini, Stefano; Hilchenbach, Martin; Hsieh, K. C.; Telloni, Daniele; Bruno, Roberto; Antonucci, Ester</p> <p></p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> neutral hydrogen, flowing together with the ionized component, has basically a different phase-space distribution function. As a matter of fact, contrary to the ionized component, neutrals can cover long distances on ballistic trajectories, unmodified by magnetic and electric fields. As a consequence, once decoupled from protons, neutral hydrogen atoms retain information on the three-dimensional distribution of protons at the location where they are generated. In the present study, we perform numerical simulations of neutral hydrogen flux distribution to be measured by <span class="hlt">Solar</span> Orbiter at a perihelion distance of 48 <span class="hlt">solar</span> radii (RS ), using different models of <span class="hlt">solar</span> <span class="hlt">wind</span> expansion and considering neutral hydrogen coming from fast and slow <span class="hlt">solar</span> <span class="hlt">wind</span>. By analysing flux distributions as a function of energy and heliocentric distance, we find that the generation region of neutral hydrogen is at approximately 10 RS for fast <span class="hlt">wind</span> and at about 20 RS for slow <span class="hlt">wind</span>. Moreover, the differential flux in angle shows that the signal is concentrated in a small region around the Sun direction. The width of this region depends on the <span class="hlt">solar</span> <span class="hlt">wind</span> model applied, and may be up to 10° for fast <span class="hlt">wind</span> and up to 20° for slow <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006cosp...36.1178V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006cosp...36.1178V"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> RAM pressure and the geomagnetic activity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vats, H. O.; Sawant, H. S.; Sharma, S.</p> <p></p> <p>The <span class="hlt">solar</span> flares coronal holes and the coronal mass ejections are the main source of geomagnetic activity The main role is attributed mainly to coronal mass ejections -CMEs There is no simple association between CMEs and flares there are large CMEs without flares and big flares without CMEs Flares and CMEs seem to be part of a single phenomenon a <span class="hlt">solar</span> eruption and neither one is the cause of the other There have been a number of detailed analyses of geomagnetic contributions due to different <span class="hlt">solar</span> <span class="hlt">wind</span> sources and also on the classification of geomagnetic activity according to each <span class="hlt">solar</span> <span class="hlt">wind</span> structure Observations from Skylab Helios Ulysses ACE and SOHO have been very useful for the understanding of the Sun - Earth system A set of recent <span class="hlt">solar</span> events were selected and using the ACE data and geomagnetic observation in the form of Ap Kp and Dst we performed a detailed study of the control of IMF and <span class="hlt">solar</span> <span class="hlt">wind</span> parameters on the enhancements of geomagnetic activity It is found that there are three types of events for the enhancement in geomagnetic activity associated with 1 negative or southward Bz 2 oscillatory variation in Bz and 3 positive or northward Bz Here these observations and their implications will be discussed The <span class="hlt">solar</span> <span class="hlt">wind</span> RAM pressure on logarithmic scale show almost linear relationship with Kp and not so with other geomagnetic indices The slope of the line is found to be different from event to event Kp enhancement varies from 2 to 6 for a tenfold increase in the <span class="hlt">solar</span> <span class="hlt">wind</span> RAM pressure during different <span class="hlt">solar</span> events</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930049627&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtechnologie','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930049627&hterms=technologie&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dtechnologie"><span id="translatedtitle">Ions with low charges in the <span class="hlt">solar</span> <span class="hlt">wind</span> as measured by SWICS on board Ulysses. [<span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Composition Spectrometer</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Geiss, J.; Ogilvie, K. W.; Von Steiger, R.; Mall, U.; Gloeckler, G.; Galvin, A. B.; Ipavich, F.; Wilken, B.; Gliem, F.</p> <p>1992-01-01</p> <p>We present new data on rare ions in the <span class="hlt">solar</span> <span class="hlt">wind</span>. Using the Ulysses-SWICS instrument with its very low background we have searched for low-charge ions during a 6-d period of low-speed <span class="hlt">solar</span> <span class="hlt">wind</span> and established sensitive upper limits for many species. In the <span class="hlt">solar</span> <span class="hlt">wind</span>, we found He(1+)/He(2+) of less than 5 x 10 exp -4. This result and the charge state distributions of heavier elements indicate that all components of the investigated ion population went through a regular coronal expansion and experienced the typical electron temperatures of 1 to 2 million Kelvin. We argue that the virtual absence of low-charge ions demonstrates a very low level of nonsolar contamination in the source region of the <span class="hlt">solar</span> <span class="hlt">wind</span> sample we studied. Since this sample showed the FlP effect typical for low-speed <span class="hlt">solar</span> <span class="hlt">wind</span>, i.e., an enhancement in the abundances of elements with low first ionization potential, we conclude that this enhancement was caused by an ion-atom separation mechanism operating near the <span class="hlt">solar</span> surface and not by foreign material in the corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/18063784','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/18063784"><span id="translatedtitle">Chromospheric alfvenic waves strong enough to power the <span class="hlt">solar</span> <span class="hlt">wind</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>De Pontieu, B; McIntosh, S W; Carlsson, M; Hansteen, V H; Tarbell, T D; Schrijver, C J; Title, A M; Shine, R A; Tsuneta, S; Katsukawa, Y; Ichimoto, K; Suematsu, Y; Shimizu, T; Nagata, S</p> <p>2007-12-01</p> <p>Alfvén waves have been invoked as a possible mechanism for the heating of the Sun's outer atmosphere, or corona, to millions of degrees and for the acceleration of the <span class="hlt">solar</span> <span class="hlt">wind</span> to hundreds of kilometers per second. However, Alfvén waves of sufficient strength have not been unambiguously observed in the <span class="hlt">solar</span> atmosphere. We used images of high temporal and spatial resolution obtained with the <span class="hlt">Solar</span> Optical Telescope onboard the Japanese Hinode satellite to reveal that the chromosphere, the region sandwiched between the <span class="hlt">solar</span> surface and the corona, is permeated by Alfvén waves with strong amplitudes on the order of 10 to 25 kilometers per second and periods of 100 to 500 seconds. Estimates of the energy flux carried by these waves and comparisons with advanced radiative magnetohydrodynamic simulations indicate that such Alfvén waves are energetic enough to accelerate the <span class="hlt">solar</span> <span class="hlt">wind</span> and possibly to heat the quiet corona. PMID:18063784</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_13");'>13</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li class="active"><span>15</span></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_15 --> <div id="page_16" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_14");'>14</a></li> <li><a href="#" onclick='return showDiv("page_15");'>15</a></li> <li class="active"><span>16</span></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="301"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.7577B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.7577B"><span id="translatedtitle">Rosetta observations of <span class="hlt">solar</span> <span class="hlt">wind</span> deflection in the coma</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Broiles, Thomas; Burch, James; Clark, George; Goldstein, Raymond; Koenders, Christoph; Mandt, Kathleen; Mokashi, Prachet; Samara, Marilia</p> <p>2015-04-01</p> <p>Until recently, study of the <span class="hlt">solar</span> <span class="hlt">wind</span> around comets was limited to remote observations and brief in-situ encounters. With the arrival of Rosetta at the comet Churyumov-Gerasimenko (CG), we have had near constant <span class="hlt">solar</span> <span class="hlt">wind</span> observations at the comet for over 6 months. This is an unprecedented opportunity to study this dynamic interaction over time. Neutral atoms produced by the comet become ionized through photoionization or charge-exchange with the <span class="hlt">solar</span> <span class="hlt">wind</span>. The freshly ionized particles experience v x B electric field and begin to gyrate around the interplanetary magnetic field. Currently, CG is ~2.6 AU from the Sun, and as of this writing, neutral production is still relatively low. Consequently, most pickup ions are produced locally (< few hundred kilometers), and a diamagnetic cavity may not exist. Moreover, neutral production is variable and changes over the comet's rotational period. We find the following: 1) The <span class="hlt">solar</span> <span class="hlt">wind</span> is heavily deflected near the comet (in some cases >45 away from the anti-sunward direction). 2) The <span class="hlt">solar</span> <span class="hlt">wind</span> helium experiences less deflection than the protons. 3) The periodicity of the deflection is highly variable, and can vary over minutes or hours. From these results, we conclude that the <span class="hlt">solar</span> <span class="hlt">wind</span> is deflected by a mechanism very close to the comet. We suggest the following possibilities: 1) The <span class="hlt">solar</span> <span class="hlt">wind</span> could be deflected by a Lorenz force in the opposite direction to that experienced by the pickup ions, which would also conserve the momentum of the two fluid system. This would explain why <span class="hlt">solar</span> <span class="hlt">wind</span> protons are more strongly deflected than the heavier alpha particles. Additionally, this would explain the periodicity of the deflections, which would react to changes in the interplanetary magnetic field. 2) The <span class="hlt">solar</span> <span class="hlt">wind</span> deflection might occur from strong charging of comet's nucleus. In which case, the nucleus may charge both positively or negatively. The nucleus could charge positively due photoionization of the surface, but could also charge negatively due to the high electron fluxes that are regularly observed. This mechanism might also explain the preferential deflection of lighter ions and the variable periodicity of the deflection.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990056503&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=19990056503&hterms=Ulysses&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DUlysses"><span id="translatedtitle">Charge state composition in coronal hole and CME related <span class="hlt">solar</span> <span class="hlt">wind</span>: Latitudinal variations observed by Ulysses and <span class="hlt">WIND</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Galvin, A. B.; Gloeckler, G.</p> <p>1997-01-01</p> <p>Iron charge states in recurrent coronal hole-associated <span class="hlt">solar</span> <span class="hlt">wind</span> flows are obtained in the ecliptic by <span class="hlt">WIND</span>/SMS, while measurements of iron and silicon from the polar coronal holes are available from Ulysses/SWICS. Ulysses/SWICS also provides ion composition of coronal mass ejection (CME)-related <span class="hlt">solar</span> <span class="hlt">wind</span>. Both coronal hole-associated and CME-related <span class="hlt">solar</span> <span class="hlt">wind</span> charge charges show heliographic latitudinal variations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1215020','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1215020"><span id="translatedtitle">Role of Concentrating <span class="hlt">Solar</span> Power in Integrating <span class="hlt">Solar</span> and <span class="hlt">Wind</span> Energy: Preprint</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Denholm, P.; Mehos, M.</p> <p>2015-06-03</p> <p>As <span class="hlt">wind</span> and <span class="hlt">solar</span> photovoltaics (PV) increase in penetration it is increasingly important to examine enabling technologies that can help integrate these resources at large scale. Concentrating <span class="hlt">solar</span> power (CSP) when deployed with thermal energy storage (TES) can provide multiple services that can help integrate variable generation (VG) resources such as <span class="hlt">wind</span> and PV. CSP with TES can provide firm, highly flexible capacity, reducing minimum generation constraints which limit penetration and results in curtailment. By acting as an enabling technology, CSP can complement PV and <span class="hlt">wind</span>, substantially increasing their penetration in locations with adequate <span class="hlt">solar</span> resource.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950057086&hterms=solar+activity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dsolar%2Bactivity','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950057086&hterms=solar+activity&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dsolar%2Bactivity"><span id="translatedtitle"><span class="hlt">Solar</span> activity variations in midlatitude thermospheric meridional <span class="hlt">winds</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hedin, A. E.; Buonsanto, M. J.; Codrescu, M.; Duboin, M.-L.; Fesen, C. G.; Hagan, M. E.; Miller, K. L.; Sipler, D. P.</p> <p>1994-01-01</p> <p>Upper thermospheric meridional <span class="hlt">wind</span> data at midlatitudes and for low magnetic activity are examined for <span class="hlt">solar</span> activity variations following an analysis scheme suggested by a Coordinated Analysis of the Thermosphere workshop. <span class="hlt">Wind</span> data from incoherent scatter, Fabry-Perot, and F2 peak heights show decreasing diurnal amplitudes with increasing <span class="hlt">solar</span> activity during all seasons, except for Saint Santin data, which show a slight increase in summer. Equivalent <span class="hlt">winds</span> from F2 peak height data have strong decreases in diurnal amplitude in all seasons. The coupled thermosphere ionosphere model and thermosphere ionosphere global circulation model predictions of diurnal amplitude, while differing considerably in magnitude, also show decreasing amplitudes during all seasons except summer, while the HWM90 empirical model amplitudes increase slightly with <span class="hlt">solar</span> activity during all seasons. The diurnal mean <span class="hlt">wind</span> trends with <span class="hlt">solar</span> activity are fairly weak, except for Millstone Hill incoherent scatter radar, which shows a shift from strong southward to near zero or northward <span class="hlt">wind</span> with increasing activity. Model results for the mean generally fall within the band of measurements. Near midnight, most of the data also show that the typically southward <span class="hlt">winds</span> weaken with increasing solart activity in all seasons except summer, when results are mixed. There are significant differences between the trends and between absolute values for the various data sets and models which need further investigation.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002AGUFMSM11B0436B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002AGUFMSM11B0436B"><span id="translatedtitle"><span class="hlt">Solar-Wind</span>/Magnetosphere Coupling: The Turbulence Effect</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Borovsky, J. E.; Funsten, H. O.</p> <p>2002-12-01</p> <p>The correlation between the amplitude of the MHD turbulence in the upstream <span class="hlt">solar</span> <span class="hlt">wind</span> and the amplitude of the Earth's geomagnetic-activity indices AE, AU, AL, Kp, ap, Dst, and PCI is explored. Increased amplitudes of the turbulence results in elevated geomagnetic indices. It is found that this "turbulence effect" accounts for about 100 nT of the variability of the AE index. The magnitude of the effect is the same for northward and for southward IMF. Tests are performed that conclude (1) that the turbulence effect is not caused by the turbulence amplitude acting as a proxy for |B| in the <span class="hlt">solar</span> <span class="hlt">wind</span> and (2) that reversals of the IMF from northward to southward in the turbulent fluctuations is not the cause of the correlations. An expression is derived for the total viscous-shear force on the surface of the magnetosphere; improved <span class="hlt">solar-wind</span>/magnetosphere correlations result when this expression is used. The turbulence effect is interpreted as an enhanced viscous coupling of the <span class="hlt">solar-wind</span> flow to the Earth's magnetosphere caused by an eddy viscosity that is controlled by the amplitude of MHD turbulence in the upstream <span class="hlt">solar</span> <span class="hlt">wind</span>: more upstream turbulence means more momentum transfer from the magnetosheath into the magnetosphere, resulting in more stirring of the magnetosphere, which produces enhanced geomagnetic-activity indices. The total energy input to the magnetosphere by this eddy-viscous coupling is theoretically estimated and compared with the data.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950029146&hterms=leer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dleer','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950029146&hterms=leer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dleer"><span id="translatedtitle">Coupling of the coronal helium abundance to the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hansteen, Viggo H.; Leer, Egil; Holzer, Thomas E.</p> <p>1994-01-01</p> <p>Models of the transition region-corona-<span class="hlt">solar</span> <span class="hlt">wind</span> system are investigated in order to find the coronal helium abundance and to study the role played by coronal helium in controlling the <span class="hlt">solar</span> <span class="hlt">wind</span> proton flux. The thermal force on alpha-particles in the transition region sets the flow of helium into the corona. The frictional coupling between alpha-particles and protons and/or the electric polarization field determines the proton flux in the <span class="hlt">solar</span> <span class="hlt">wind</span> as well as the fate of the coronal helium content. The models are constructed by solving the time-dependent population and momentum equations for all species of hydrogen and helium in an atmosphere with a given temperature profile. Several temperature profiles are considered in order to very the roles of frictional coupling and electric polarization field in the <span class="hlt">solar</span> <span class="hlt">wind</span>, and the thermal force in the transition region. Steady-state solutions are found for coronae with a hydrogen flux at 1 AU of 1.0 x 10(exp 9)/cm(exp 2)/sec or larger. For coronae with lower hydrogen fluxes, the helium flux into the corona is larger than the flux 'pulled out' by the <span class="hlt">solar</span> <span class="hlt">wind</span> protons, and solutions with increasing coronal helium content are found. The timescale for forming a helium-filled corona, that may allow for a steady outflow, is long compared to the mixing time for the corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...812..170T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...812..170T"><span id="translatedtitle">Thermalization of Heavy Ions in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Tracy, Patrick J.; Kasper, Justin C.; Zurbuchen, Thomas H.; Raines, Jim M.; Shearer, Paul; Gilbert, Jason</p> <p>2015-10-01</p> <p>Observations of velocity distribution functions from the Advanced Composition Explorer/<span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Composition Spectrometer heavy ion composition instrument are used to calculate ratios of kinetic temperature and Coulomb collisional interactions of an unprecedented 50 ion species in the <span class="hlt">solar</span> <span class="hlt">wind</span>. These ions cover a mass per charge range of 1-5.5 amu/e and were collected in the time range of 1998-2011. We report the first calculation of the Coulomb thermalization rate between each of the heavy ion (A > 4 amu) species present in the <span class="hlt">solar</span> <span class="hlt">wind</span> along with protons (H+) and alpha particles (He2+). From these rates, we find that protons are the dominant source of Coulomb collisional thermalization for heavy ions in the <span class="hlt">solar</span> <span class="hlt">wind</span> and use this fact to calculate a collisional age for those heavy ion populations. The heavy ion thermal properties are well organized by this collisional age, but we find that the temperature of all heavy ions does not simply approach that of protons as Coulomb collisions become more important. We show that He2+ and C6+ follow a monotonic decay toward equal temperatures with protons with increasing collisional age, but O6+ shows a noted deviation from this monotonic decay. Furthermore, we show that the deviation from monotonic decay for O6+ occurs in <span class="hlt">solar</span> <span class="hlt">wind</span> of all origins, as determined by its Fe/O ratio. The observed differences in heavy ion temperature behavior point toward a local heating mechanism that favors ions depending on their charge and mass.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4308709','PMC'); return false;" href="http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=4308709"><span id="translatedtitle">Direct evidence for kinetic effects associated with <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pmc">PubMed Central</a></p> <p>Xu, Xiaojun; Wang, Yi; Wei, Fengsi; Feng, Xueshang; Deng, Xiaohua; Ma, Yonghui; Zhou, Meng; Pang, Ye; Wong, Hon-Cheng</p> <p>2015-01-01</p> <p>Kinetic effects resulting from the two-fluid physics play a crucial role in the fast collisionless reconnection, which is a process to explosively release massive energy stored in magnetic fields in space and astrophysical plasmas. In-situ observations in the Earth's magnetosphere provide solid consistence with theoretical models on the point that kinetic effects are required in the collisionless reconnection. However, all the observations associated with <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection have been analyzed in the context of magnetohydrodynamics (MHD) although a lot of <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection exhausts have been reported. Because of the absence of kinetic effects and substantial heating, whether the reconnections are still ongoing when they are detected in the <span class="hlt">solar</span> <span class="hlt">wind</span> remains unknown. Here, by dual-spacecraft observations, we report a <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection with clear Hall magnetic fields. Its corresponding Alfvenic electron outflow jet, derived from the decouple between ions and electrons, is identified, showing direct evidence for kinetic effects that dominate the collisionless reconnection. The turbulence associated with the exhaust is a kind of background <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence, implying that the reconnection generated turbulence has not much developed. PMID:25628139</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/25628139','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/25628139"><span id="translatedtitle">Direct evidence for kinetic effects associated with <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Xu, Xiaojun; Wang, Yi; Wei, Fengsi; Feng, Xueshang; Deng, Xiaohua; Ma, Yonghui; Zhou, Meng; Pang, Ye; Wong, Hon-Cheng</p> <p>2015-01-01</p> <p>Kinetic effects resulting from the two-fluid physics play a crucial role in the fast collisionless reconnection, which is a process to explosively release massive energy stored in magnetic fields in space and astrophysical plasmas. In-situ observations in the Earth's magnetosphere provide solid consistence with theoretical models on the point that kinetic effects are required in the collisionless reconnection. However, all the observations associated with <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection have been analyzed in the context of magnetohydrodynamics (MHD) although a lot of <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection exhausts have been reported. Because of the absence of kinetic effects and substantial heating, whether the reconnections are still ongoing when they are detected in the <span class="hlt">solar</span> <span class="hlt">wind</span> remains unknown. Here, by dual-spacecraft observations, we report a <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection with clear Hall magnetic fields. Its corresponding Alfvenic electron outflow jet, derived from the decouple between ions and electrons, is identified, showing direct evidence for kinetic effects that dominate the collisionless reconnection. The turbulence associated with the exhaust is a kind of background <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence, implying that the reconnection generated turbulence has not much developed. PMID:25628139</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22133859','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22133859"><span id="translatedtitle">COLLISIONLESS DAMPING AT ELECTRON SCALES IN <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> TURBULENCE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>TenBarge, J. M.; Howes, G. G.; Dorland, W.</p> <p>2013-09-10</p> <p>The dissipation of turbulence in the weakly collisional <span class="hlt">solar</span> <span class="hlt">wind</span> plasma is governed by unknown kinetic mechanisms. Two candidates have been suggested to play an important role in the dissipation, collisionless damping via wave-particle interactions and dissipation in small-scale current sheets. High resolution spacecraft measurements of the turbulent magnetic energy spectrum provide important constraints on the dissipation mechanism. The limitations of popular fluid and hybrid numerical schemes for simulation of the dissipation of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence are discussed, and instead a three-dimensional kinetic approach is recommended. We present a three-dimensional nonlinear gyrokinetic simulation of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence at electron scales that quantitatively reproduces the exponential form of the turbulent magnetic energy spectrum measured in the <span class="hlt">solar</span> <span class="hlt">wind</span>. A weakened cascade model that accounts for nonlocal interactions and collisionless Landau damping also quantitatively agrees with the observed exponential form. These results establish that a turbulent cascade of kinetic Alfven waves that is terminated by collisionless Landau damping is sufficient to explain the observed magnetic energy spectrum in the dissipation range of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AIPC.1539..466S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AIPC.1539..466S"><span id="translatedtitle">Fast <span class="hlt">solar</span> <span class="hlt">wind</span> monitoring available: BMSW in operation</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>afrnkov, J.; N?me?ek, Z.; P?ech, L.; Zastenker, G.</p> <p>2013-06-01</p> <p>The Spektr-R spacecraft was launched on a Zenit-3F rocket into an orbit with a perigee of 10.000 kilometers and apogee of 390.000 km on July 18, 2011. The spacecraft operational lifetime would exceed five years. The main task of the mission is investigations of distant sources of electromagnetic emissions but, as a supporting measurement, the spacecraft carries a complex of instruments for <span class="hlt">solar</span> <span class="hlt">wind</span> monitoring because it will spend there ~ 8 days out of the 9-day orbit. The main task of the <span class="hlt">solar</span> <span class="hlt">wind</span> monitor (BMSW) is to provide fast measurements of the <span class="hlt">solar</span> <span class="hlt">wind</span> density, velocity, and temperature with a maximum time resolution of 31 ms. Such time resolution was obtained using simultaneous measurements of several Faraday cups oriented permanently nearly in the <span class="hlt">solar</span> <span class="hlt">wind</span> direction. In this paper, we describe briefly basic principles of the BMSWoperation, and show a few examples its observations. We present frequency spectra of the <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence at the kinetic scale and an example of high-frequency waves associated with an IP shock.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21567559','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21567559"><span id="translatedtitle"><span class="hlt">SOLAR</span> <span class="hlt">WIND</span> MODELING WITH TURBULENCE TRANSPORT AND HEATING</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Usmanov, Arcadi V.; Goldstein, Melvyn L.; Matthaeus, William H.; Breech, Benjamin A.</p> <p>2011-02-01</p> <p>We have developed an axisymmetric steady-state <span class="hlt">solar</span> <span class="hlt">wind</span> model that describes properties of the large-scale <span class="hlt">solar</span> <span class="hlt">wind</span>, interplanetary magnetic field, and turbulence throughout the heliosphere from 0.3 AU to 100 AU. The model is based on numerical solutions of large-scale Reynolds-averaged magnetohydrodynamic equations coupled with a set of small-scale transport equations for the turbulence energy, normalized cross helicity, and correlation scale. The combined set of time-dependent equations is solved in the frame of reference corotating with the Sun using a time-relaxation method. We use the model to study the self-consistent interaction between the large-scale <span class="hlt">solar</span> <span class="hlt">wind</span> and smaller-scale turbulence and the role of the turbulence in the large-scale structure and temperature distribution in the <span class="hlt">solar</span> <span class="hlt">wind</span>. To illuminate the roles of the turbulent cascade and the pickup protons in heating the <span class="hlt">solar</span> <span class="hlt">wind</span> depending on the heliocentric distance, we compare the model results with and without turbulence/pickup protons. The variations of plasma temperature in the outer heliosphere are compared with Ulysses and Voyager 2 observations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19720036359&hterms=wind+moon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwind%2Bmoon','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19720036359&hterms=wind+moon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwind%2Bmoon"><span id="translatedtitle">Interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with the moon.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Ness, N. F.</p> <p>1972-01-01</p> <p>During its orbit about the earth, the moon is located in the interplanetary medium or in the geomagnetosheath-geomagnetotail formed by the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with earth. In the tail, no evidence is found for a lunar magnetic field. In the interplanetary medium, no evidence exists for a bow shock or a trailing shock, although a well defined plasma wake region is observed in the anti-<span class="hlt">solar</span> <span class="hlt">wind</span> direction. The moon absorbs the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma that strikes its surface and creates a void region or cavity in the flow. The observed lunar Mach cone gives evidence for the anisotropic propagation of waves in the magnetized collisionless warm plasma of the <span class="hlt">solar</span> <span class="hlt">wind</span>. The transmission of microstructural discontinuities in the interplanetary medium past the moon shows little distortion, indicating a low effective electrical conductivity of the lunar body. Fluctuations of the interplanetary magnetic field upstream from the plasma wake are stimulated by the disturbed conditions in that region. The moon behaves like a cold, nonmagnetic, fully absorbing dielectric sphere in the <span class="hlt">solar</span> <span class="hlt">wind</span> flow.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM44A..02L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM44A..02L"><span id="translatedtitle">The Importance of Suprathermal Electrons in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>LE CHAT, G.; Meyer-Vernet, N.; Pantellini, F. G. E.; Issautier, K.; Moncuquet, M.</p> <p>2014-12-01</p> <p>Non-Gaussian distributions are ubiquitous in systems having long-range interactions, from real-world networks to astrophysical plasmas. The corona and <span class="hlt">solar</span> <span class="hlt">wind</span> are no exception. In this review, we concentrate on the corona and <span class="hlt">solar</span> <span class="hlt">wind</span> electrons, whose suprathermal tail governs heat transport and plays a crucial role in the temperature structure and <span class="hlt">wind</span> production, as first suggested thirty years ago by Olbert and confirmed by a large number of subsequent studies. These non-thermal electrons have been measured in both the corona and <span class="hlt">solar</span> <span class="hlt">wind</span>, and are a direct consequence of the fast increase with speed of the Coulomb free-path, compared to the pressure scale-height. This situation has four important consequences: (1) the fluid description, on which the vast majority of <span class="hlt">solar</span> <span class="hlt">wind</span> models are based is inadequate; (2) the heat flux is NOT given by the classical Spitzer-Hrm expression in the corona and <span class="hlt">solar</span> <span class="hlt">wind</span>; (3) for most non-thermal distributions (except the convenient and fashionable Kappa distribution), the fraction of supra-thermal electrons increases with altitude in the corona because of velocity filtration; for example, with a sum of Maxwellians, the hotter the population, the larger the increase with altitude of its fractional contribution; (4) ad-hoc heat addition - assumed in most models, is not necessarily required to produce the observed variation in temperature and the <span class="hlt">wind</span> acceleration. We will shortly review the observed electron velocity distributions together with the theoretical expectations, the major role of the electric field and the consequences on the heat flux, the temperature structure and the <span class="hlt">wind</span> acceleration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011JASTP..73..290L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011JASTP..73..290L"><span id="translatedtitle">Change of <span class="hlt">solar</span> <span class="hlt">wind</span> quasi-invariant in <span class="hlt">solar</span> cycle 23Analysis of PDFs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Leitner, M.; Farrugia, C. J.; Vrs, Z.</p> <p>2011-02-01</p> <p>An in situ <span class="hlt">solar</span> <span class="hlt">wind</span> measurement which is a very good proxy for <span class="hlt">solar</span> activity, correlating well with the sunspot number, is the <span class="hlt">solar</span> <span class="hlt">wind</span> quasi-invariant (QI), which is defined as the ratio between magnetic and kinetic energy densities. Here we use 1-min OMNI data to determine yearly probability density functions (PDFs) for QI. We distinguish between fast and slow <span class="hlt">solar</span> <span class="hlt">winds</span>, and exclude interplanetary coronal mass ejections (ICMEs) from the data, since the latter have a different distribution. Fitting the PDFs by a log-kappa distribution, we discuss the variation of QI in the period 1995-2009, encompassing <span class="hlt">solar</span> cycle 23 and the long, very quiet minimum in 2007-2009. The additional value of kappa allows us to obtain a better description for the tails of the distribution than the log-normal approach. Here we describe for the first time how parameter kappa changes over one <span class="hlt">solar</span> cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22039263','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22039263"><span id="translatedtitle">THE TURBULENT CASCADE AND PROTON HEATING IN THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> DURING <span class="hlt">SOLAR</span> MINIMUM</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Coburn, Jesse T.; Smith, Charles W.; Vasquez, Bernard J.; Stawarz, Joshua E.; Forman, Miriam A. E-mail: Charles.Smith@unh.edu E-mail: Joshua.Stawarz@Colorado.edu</p> <p>2012-08-01</p> <p>The recently protracted <span class="hlt">solar</span> minimum provided years of interplanetary data that were largely absent in any association with observed large-scale transient behavior on the Sun. With large-scale shear at 1 AU generally isolated to corotating interaction regions, it is reasonable to ask whether the <span class="hlt">solar</span> <span class="hlt">wind</span> is significantly turbulent at this time. We perform a series of third-moment analyses using data from the Advanced Composition Explorer. We show that the <span class="hlt">solar</span> <span class="hlt">wind</span> at 1 AU is just as turbulent as at any other time in the <span class="hlt">solar</span> cycle. Specifically, the turbulent cascade of energy scales in the same manner proportional to the product of <span class="hlt">wind</span> speed and temperature. Energy cascade rates during <span class="hlt">solar</span> minimum average a factor of 2-4 higher than during <span class="hlt">solar</span> maximum, but we contend that this is likely the result of having a different admixture of high-latitude sources.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..17.6705K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..17.6705K"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Drivers of Storm-Time Radiation Belt Variations</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; Hietala, Heli; Turner, Drew; Koskinen, Hannu; Pulkkinen, Tuija; Rodriguez, Juan; Reeves, Geoffrey; Claudepierre, Seth; Spence, Harlan</p> <p>2015-04-01</p> <p>It is an outstanding question why some storms result in an increase of the outer radiation belt electron fluxes, while others deplete them or produce no change. One approach to this problem is to look at differences in the large-scale <span class="hlt">solar</span> <span class="hlt">wind</span> storm drivers. The drivers have traditionally been classified to Stream Interaction Regions (SIRs) and Interplanetary Coronal Mass Ejections (ICMEs). However, ICMEs and SIRs are complex structures: SIRs consist of a slow stream followed by a turbulent, higher pressure interface region and then a faster stream. The core of the ICME is an ejecta. If the mass ejection is fast enough, it can drive a shock in front of it. This leads to the formation of a sheath region between the interplanetary shock and the leading edge of the ejecta. Fast streams that are integral part of SIR may or may not follow the ICME. The <span class="hlt">solar</span> <span class="hlt">wind</span> properties, and hence, the magnetospheric driving of different substructures in SIRs and ICMEs are very distinct. In this work we will investigate the radiation belt response to different storm drivers by combining near-Earth <span class="hlt">solar</span> <span class="hlt">wind</span> observations, long-term geosynchronous observations from GOES spanning over 1.5 <span class="hlt">solar</span> cycles (1995-2013) and the state-of-the art Van Allen Probe data. Our study uses superposed epoch analysis with multiple reference times and we expand/contract each <span class="hlt">solar</span> <span class="hlt">wind</span> substructure to the population mean. This novel approach allows us to determine the typical evolution of the electron fluxes during each <span class="hlt">solar</span> <span class="hlt">wind</span> structure. Our results show that the separation of the effects from different parts of the ICME and SIRs will be crucial for understanding how radiation belt electrons react to different <span class="hlt">solar</span> <span class="hlt">wind</span> driving conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM31C4218H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM31C4218H"><span id="translatedtitle">The Storm-Substorm Relationship during Different <span class="hlt">Solar</span> <span class="hlt">Wind</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>Hsu, T. S.; McPherron, R. L.; Chu, X.</p> <p>2014-12-01</p> <p><span class="hlt">Solar</span>-terrestrial coupling is the study of processes which transfer <span class="hlt">solar</span> <span class="hlt">wind</span> energy to the magnetosphere creating geomagnetic activity. This coupling depends on properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> and particularly on the discrete structures present in the <span class="hlt">solar</span> <span class="hlt">wind</span>. These include CMEs, CIRs, and HSS (high speed streams) which have very different characteristics causing different modes of response of the magnetosphere such as magnetic storm, substorms, steady magnetospheric convection (SMC) and others. Among these different modes of response, magnetic storms and substorms are two of the primary ones because they occur frequently and because they can cause considerable problems in technological systems. The differences in <span class="hlt">solar</span> <span class="hlt">wind</span> driving conditions during CME, CIR, and HSS provide a good opportunity to examine how the properties of substorms change with <span class="hlt">solar</span> <span class="hlt">wind</span> structures and the activity they create. Since the probability of observing these structures is a function of <span class="hlt">solar</span> cycle phase, the storm-substorm relationship changes with <span class="hlt">solar</span> cycle phase. It is possible that the nature of <span class="hlt">solar</span> <span class="hlt">wind</span> coupling changes with the type of storm, storm intensity, and/or the phase of the storms. The original hypothesis was that a magnetic storm is simply a superposition of substorms. However, some evidences have been found that storms begin to develop before substorms occur. Is substorm occurrence independent of storm development? This would suggest that substorms can be seen in any phase of a storm and even a storm without substorms. There are some recent studies suggest this is possible. However, most of the studies did not take into consideration different <span class="hlt">solar</span> <span class="hlt">wind</span> driving conditions. In this study, we will investigate several aspects of the relation of substorms to storms such as: Does the frequency and intensity of substorms change with phase of the <span class="hlt">solar</span> cycle? Are there differences in these properties between cycles? Are the characteristics of substorms different if they occur within a storm or outside of a storm? Are CME storm time substorms different from CIR storm substorms? Do substorm properties change with phase of the storm?</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014cosp...40E2551P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014cosp...40E2551P"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> and coronal rotation during an activity cycle</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pinto, Rui; Brun, Allan Sacha</p> <p></p> <p>The properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> flow are strongly affected by the time-varying strength and geometry of the global background magnetic field. The <span class="hlt">wind</span> velocity and mass flux depend directly on the size and position of the <span class="hlt">wind</span> sources at the surface, and on the geometry of the magnetic flux-tubes along which the <span class="hlt">wind</span> flows. We address these problems by performing numerical simulations coupling a kinematic dynamo code (STELEM) evolve in a 2.5D axisymmetric coronal MHD code (DIP) covering an 11 yr activity cycle. The latitudinal distribution of the calculated <span class="hlt">wind</span> velocities agrees with in-situ (ULYSSES, HELIO) and radio measurements (IPS). The transition from fast to slow <span class="hlt">wind</span> flows can be explained in terms of the high overall flux-tube superradial expansion factors in the vicinities of coronal streamer boundaries. We found that the Alfvén radii and the global Sun's mass loss rate vary considerably throughout the cycle (by a factor 4.5 and 1.6, respectively), leading to strong temporal modulations of the global angular momentum flux and magnetic braking torque. The slowly varying magnetic topology introduces strong non-uniformities in the coronal rotation rate in the first few <span class="hlt">solar</span> radii. Finally, we point out directions to assess the effects of surface transient phenomena on the global properties of the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AAS...22440801D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AAS...22440801D"><span id="translatedtitle">Observing MHD Waves in the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Acceleration Region</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>DeForest, Craig; McComas, Dave; Howard, Tim A.</p> <p>2014-06-01</p> <p>We have, for the first time, observed and characterized compressive waves propagating both outward and inward in the outer <span class="hlt">solar</span> corona above 4 Rs. In addition to detecting the waves, we have used them to measure outflow in the all-important <span class="hlt">wind</span> acceleration region. Because the corona is an MHD system, any disturbance in the corona launches low-frequency waves that propagate at the familiar MHD speeds and serve to communicate that disturbance to other parts of the system. Through careful filtration of synoptic STEREO-A/COR-2 data, we have been able to measure both inbound and outbound waves at all locations in the <span class="hlt">solar</span> corona. By measuring in/out asymmetries in the wave characteristics we have been able to estimate the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration profile. Further, we are able to estimate the location of the Alfvn surface - the hard-to-measure transition between the corona and the superalfvnic <span class="hlt">solar</span> <span class="hlt">wind</span>, and the boundary at which <span class="hlt">solar</span> magnetic field lines transition from "closed" to "open". There is a great deal of work to be done beyond these preliminary results, which - it is hoped - open a new avenue for understanding coronal dynamics and the origin of the <span class="hlt">solar</span> <span class="hlt">wind</span>.</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/2015P%26SS..115..110K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015P%26SS..115..110K"><span id="translatedtitle">Simulation of <span class="hlt">solar</span> <span class="hlt">wind</span> space weathering in orthopyroxene</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kuhlman, Kimberly R.; Sridharan, Kumar; Kvit, Alexander</p> <p>2015-09-01</p> <p>We have simulated <span class="hlt">solar</span> <span class="hlt">wind</span>-based space weathering on airless bodies in our <span class="hlt">Solar</span> System by implanting hydrogen and helium into orthopyroxene at <span class="hlt">solar</span> <span class="hlt">wind</span> energies (~1 keV/amu). Here we present the results of the first scanning transmission electron microscope (STEM) study of one of these simulants. It has been demonstrated that the visible/near infrared (VNIR) reflectance spectra of airless bodies are dependent on the size and abundance of nanophase iron (npFe0) particles in the outer rims of regolith grains. However, the mechanism of formation of npFe0 in the patina on lunar regolith grains and in lunar agglutinates remains debated. As the lattice is disrupted by hydrogen and helium implantation, broken bonds are created. These dangling bonds are free to react with hydrogen, creating OH and/or H2O molecules within the grain. These molecules may diffuse out through the damaged lattice and migrate toward the cold traps identified at the lunar poles. This mechanism would leave the iron in a reduced state and able to form npFe0. This work illustrates that npFe0 can be nucleated in orthopyroxene under implantation of <span class="hlt">solar</span> <span class="hlt">wind</span> hydrogen and helium. Our data suggest that the <span class="hlt">solar</span> <span class="hlt">wind</span> provides a mechanism by which iron is reduced in the grain and npFe0 is nucleated in the outer surfaces of regolith grains. This formation mechanism should also operate on other airless bodies in the <span class="hlt">Solar</span> System.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21370889','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21370889"><span id="translatedtitle">Generalized Similarity in Finite Range <span class="hlt">Solar</span> <span class="hlt">Wind</span> Magnetohydrodynamic Turbulence</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Chapman, S. C.; Nicol, R. M.</p> <p>2009-12-11</p> <p>Extended or generalized similarity is a ubiquitous but not well understood feature of turbulence that is realized over a finite range of scales. The ULYSSES spacecraft <span class="hlt">solar</span> polar passes at <span class="hlt">solar</span> minimum provide in situ observations of evolving anisotropic magnetohydrodynamic turbulence in the <span class="hlt">solar</span> <span class="hlt">wind</span> under ideal conditions of fast quiet flow. We find a single generalized scaling function characterizes this finite range turbulence and is insensitive to plasma conditions. The recent unusually inactive <span class="hlt">solar</span> minimum - with turbulent fluctuations down by a factor of approx2 in power - provides a test of this invariance.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/20366193','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/20366193"><span id="translatedtitle">Generalized similarity in finite range <span class="hlt">solar</span> <span class="hlt">wind</span> magnetohydrodynamic turbulence.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Chapman, S C; Nicol, R M</p> <p>2009-12-11</p> <p>Extended or generalized similarity is a ubiquitous but not well understood feature of turbulence that is realized over a finite range of scales. The ULYSSES spacecraft <span class="hlt">solar</span> polar passes at <span class="hlt">solar</span> minimum provide in situ observations of evolving anisotropic magnetohydrodynamic turbulence in the <span class="hlt">solar</span> <span class="hlt">wind</span> under ideal conditions of fast quiet flow. We find a single generalized scaling function characterizes this finite range turbulence and is insensitive to plasma conditions. The recent unusually inactive <span class="hlt">solar</span> minimum--with turbulent fluctuations down by a factor of approximately 2 in power--provides a test of this invariance. PMID:20366193</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22348569','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22348569"><span id="translatedtitle">Weakest <span class="hlt">solar</span> <span class="hlt">wind</span> of the space age and the current 'MINI' <span class="hlt">solar</span> maximum</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>McComas, D. J.; Angold, N.; Elliott, H. A.; Livadiotis, G.; Schwadron, N. A.; Smith, C. W.; Skoug, R. M.</p> <p>2013-12-10</p> <p>The last <span class="hlt">solar</span> minimum, which extended into 2009, was especially deep and prolonged. Since then, sunspot activity has gone through a very small peak while the heliospheric current sheet achieved large tilt angles similar to prior <span class="hlt">solar</span> maxima. The <span class="hlt">solar</span> <span class="hlt">wind</span> fluid properties and interplanetary magnetic field (IMF) have declined through the prolonged <span class="hlt">solar</span> minimum and continued to be low through the current mini <span class="hlt">solar</span> maximum. Compared to values typically observed from the mid-1970s through the mid-1990s, the following proton parameters are lower on average from 2009 through day 79 of 2013: <span class="hlt">solar</span> <span class="hlt">wind</span> speed and beta (?11%), temperature (?40%), thermal pressure (?55%), mass flux (?34%), momentum flux or dynamic pressure (?41%), energy flux (?48%), IMF magnitude (?31%), and radial component of the IMF (?38%). These results have important implications for the <span class="hlt">solar</span> <span class="hlt">wind</span>'s interaction with planetary magnetospheres and the heliosphere's interaction with the local interstellar medium, with the proton dynamic pressure remaining near the lowest values observed in the space age: ?1.4 nPa, compared to ?2.4 nPa typically observed from the mid-1970s through the mid-1990s. The combination of lower magnetic flux emergence from the Sun (carried out in the <span class="hlt">solar</span> <span class="hlt">wind</span> as the IMF) and associated low power in the <span class="hlt">solar</span> <span class="hlt">wind</span> points to the causal relationship between them. Our results indicate that the low <span class="hlt">solar</span> <span class="hlt">wind</span> output is driven by an internal trend in the Sun that is longer than the ?11 yr <span class="hlt">solar</span> cycle, and they suggest that this current weak <span class="hlt">solar</span> maximum is driven by the same trend.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010AGUFMSH11B1620K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010AGUFMSH11B1620K"><span id="translatedtitle">The <span class="hlt">Solar</span> <span class="hlt">Wind</span> Electrons Alphas and Protons (SWEAP) Investigation for <span class="hlt">Solar</span> Probe Plus</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kasper, J. C.; SWEAP Investigation Team</p> <p>2010-12-01</p> <p>The NASA <span class="hlt">Solar</span> Probe Plus mission will be humanity’s first direct visit to the atmosphere of our Sun. The spacecraft will close to within nine <span class="hlt">solar</span> radii (about four million miles) of the <span class="hlt">solar</span> surface in order to observe the heating of the corona and the acceleration of the <span class="hlt">solar</span> <span class="hlt">wind</span> first hand. A key requirement for <span class="hlt">Solar</span> Probe Plus is the ability to make continuous, accurate, and fast measurements of the electrons and ionized helium (alpha-particles) and hydrogen (protons) that constitute the bulk of the <span class="hlt">solar</span> <span class="hlt">wind</span>. The <span class="hlt">Solar</span> <span class="hlt">Wind</span> Electrons Alphas and Protons (SWEAP) Investigation is a two-instrument suite that provides these observations. The purpose of this talk is to describe the science motivation for SWEAP, the instrument designs, and the expected data products. SWEAP consists of the <span class="hlt">Solar</span> Probe Cup (SPC) and the <span class="hlt">Solar</span> Probe Analyzers (SPAN). SWEAP measurements enable discovery and understanding of <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration and formation, coronal and <span class="hlt">solar</span> <span class="hlt">wind</span> heating, high-energy particle acceleration, and the interaction between <span class="hlt">solar</span> <span class="hlt">wind</span> and the dust environment of the inner heliosphere. SPC is a Faraday Cup (FC) that looks at the Sun and measures ion and electron fluxes and flow angles as a function of energy. SPAN consists of an ion and electron electrostatic analyzer (ESA) on the ram side of SPP (SPAN-A) and an electron ESA on the anti-ram side (SPAN-B). SPAN-A and -B are rotated 90 degrees relative to one another so their broad FOV combine like the seams on a baseball to view the entire sky except for the region obscured by the heat shield. SWEAP data products include ion and electron velocity distribution functions with high energy and angular resolution at 0.5-16 Hz and flow angles and fluxes at 128 Hz. Continuous buffering provides triggered burst observations during shocks, reconnection events, and other transient structures with no changes to the instrument operating mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/574652','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/574652"><span id="translatedtitle">He abundance variations in the <span class="hlt">solar</span> <span class="hlt">wind</span>: Observations from Ulysses</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Barraclough, B.L.; Feldman, W.C.; Gosling, J.T.; McComas, D.J.; Phillips, J.L.; Goldstein, B.E.</p> <p>1996-07-01</p> <p>The Ulysses mission is providing the first opportunity to observe variations in <span class="hlt">solar</span> <span class="hlt">wind</span> plasma parameters at heliographic latitudes far removed from the ecliptic plane. We present here an overview of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed and the variability in helium abundance, [He], for the entire mission to date, data on [He] in six high-latitude coronal mass ejections (CMEs), and a superposed epoch analysis of [He] variations at the seven heliospheric current sheet (HCS) crossings made during the rapid-latitude-scan portion of the mission. The differences in the variability of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed and [He] in high-latitude and equatorial regions are quite striking. <span class="hlt">Solar</span> <span class="hlt">wind</span> speed is generally low but highly variable near the <span class="hlt">solar</span> equator, while at higher latitudes the average speed is quite high (average speed around 760 km/s) with little variability. [He] can vary over nearly two decades at low <span class="hlt">solar</span> latitudes, while at high latitudes it varies only slightly around an average value of {approximately}4.3{percent}. In contrast to the high [He] that is often associated with CMEs observed near the ecliptic, none of the six high-speed CMEs encountered at high southern heliographic latitudes showed any significant variation in helium content from average values. Reasons for this difference between high and low latitude CME observations are not yet understood. A superposed epoch analysis of the [He] during all seven HCS crossings made as Ulysses passed from the southern to northern <span class="hlt">solar</span> hemisphere shows the expected [He] minimum near the crossing and a broad ({plus_minus}3day) period of low [He] around the crossing time. We briefly discuss how our <span class="hlt">solar</span> <span class="hlt">wind</span> [He] observations may provide an accurate measure of the helium composition for all regions of the sun lying above the helium ionization zone. {copyright} {ital 1996 American Institute of Physics.}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21190105','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21190105"><span id="translatedtitle">Application of grazing incidence x-ray fluorescence technique to discriminate and quantify implanted <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kitts, K.; Choi, Y.; Eng, P. J.; Ghose, S. K.; Sutton, S. R.; Rout, B.</p> <p>2009-03-15</p> <p>NASA launched the Genesis return mission to obtain pristine <span class="hlt">solar</span> <span class="hlt">wind</span> samples in order to better understand <span class="hlt">solar</span> <span class="hlt">wind</span> mechanics, <span class="hlt">solar</span> physics, and <span class="hlt">solar</span> system evolution. Unfortunately, the probe crash-landed shattering the collector plates necessitating the application of a grazing incidence x-ray fluorescence technique. This nondestructive methodology differentiates the terrestrial contamination from the low concentration implanted <span class="hlt">solar</span> <span class="hlt">wind</span>. Using this technique, the elemental depth distribution is obtained resulting in the determination of absolute <span class="hlt">solar</span> <span class="hlt">wind</span> elemental abundance. We describe this application and present the <span class="hlt">solar</span> <span class="hlt">wind</span> Fe concentration determination as an example.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20040082015','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20040082015"><span id="translatedtitle">XMM-Newton Observations of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Charge Exchange Emission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Snowden, S. L.; Collier, M. R.; Kuntz, K. D.</p> <p>2004-01-01</p> <p>We present an XMM-Newton spectrum of diffuse X-ray emission from within the <span class="hlt">solar</span> system. The spectrum is dominated by O VII and O VIII lines at 0.57 keV and 0.65 keV, O VIII (and possibly Fe XVII) lines at approximately 0.8 keV, Ne IX lines at approximately 0.92 keV, and Mg XI lines at approximately 1.35 keV. This spectrum is consistent with what is expected from charge exchange emission between the highly ionized <span class="hlt">solar</span> <span class="hlt">wind</span> and either interstellar neutrals in the heliosphere or material from Earth's exosphere. The emission is clearly seen as a low-energy ( E less than 1.5 keV) spectral enhancement in one of a series of observations of the Hubble Deep Field North. The X-ray enhancement is concurrent with an enhancement in the <span class="hlt">solar</span> <span class="hlt">wind</span> measured by the ACE satellite. The <span class="hlt">solar</span> <span class="hlt">wind</span> enhancement reaches a flux level an order of magnitude more intense than typical fluxes at 1 AU, and has ion ratios with significantly enhanced higher ionization states. Whereas observations of the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma made at a single point reflect only local conditions which may only be representative of <span class="hlt">solar</span> <span class="hlt">wind</span> properties with spatial scales ranging from less than half of an Earth radii (approximately 10 s) to 100 Earth radii, X-ray observations of <span class="hlt">solar</span> <span class="hlt">wind</span> charge exchange are remote sensing measurements which may provide observations which are significantly more global in character. Besides being of interest in its own right for studies of the <span class="hlt">solar</span> system, this emission can have significant consequences for observations of more cosmological objects. It can provide emission lines at zero redshift which are of particular interest (e.g., O VII and O VIII) in studies of diffuse thermal emission, and which can therefore act as contamination in objects which cover the entire detector field of view. We propose the use of <span class="hlt">solar</span> <span class="hlt">wind</span> monitoring data, such as from the ACE and <span class="hlt">Wind</span> spacecraft, as a diagnostic to screen for such possibilities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008PhDT.........9C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT.........9C"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> driving of magnetospheric ultra-low frequency pulsations</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Claudepierre, Seth G.</p> <p></p> <p>Two <span class="hlt">solar</span> <span class="hlt">wind</span> parameters in particular are thought to be responsible for the majority of <span class="hlt">solar</span> <span class="hlt">wind</span>-driven ULF waves. These two parameters, <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure and <span class="hlt">solar</span> <span class="hlt">wind</span> velocity, are studied in this work through the use of global magnetohydrodynamic (MHD) simulations of the <span class="hlt">solar</span> <span class="hlt">wind</span>- magnetosphere interaction. We drive the global MHD simulations with idealized <span class="hlt">solar</span> <span class="hlt">wind</span> input conditions, chosen to mimic each of the above mechanisms. This allows us to study, in isolation, both of the <span class="hlt">solar</span> <span class="hlt">wind</span> parameters and to compare and contrast their effectiveness in the generation of magnetospheric ULF waves. Moreover, the global, three-dimensional nature of the MHD simulations allows us to fully characterize the spectral properties and global distribution of the ULF waves generated. These wave properties are known from a theoretical standpoint to be important for the interaction of ULF waves with radiation belt electrons. From these considerations, we are able to quantify the effect that the simulated ULF waves could have on radiation belt electrons, and thus, how the <span class="hlt">solar</span> <span class="hlt">wind</span> ultimately couples its energy into the radiation belts. Though this is the primary goal of our work, these investigations have uncovered two magnetospheric phenomenon, the MHD Kelvin-Helmholtz instability and magnetospheric cavity modes, that have never before been studied in the realistic magnetospheric configuration provided by global MHD simulations. The MHD Kelvin-Helmholtz instability has long been predicted to occur at the boundary interface between the <span class="hlt">solar</span> <span class="hlt">wind</span> and the magnetosphere and is often invoked as an explanation for various magnetospheric phenomenon. For example, several theoretical studies have suggested that the Kelvin-Helmholtz instability at the magnetospheric boundary drives magnetospheric field-line resonances, resonant oscillations of geomagnetic field lines analogous to standing waves on a string. In addition, the nonlinear evolution of the MHD Kelvin-Helmholtz instability leads to large-scale (several times the size of the Earth) vortices in the plasma flow. A number of studies have suggested that these vortical structures are responsible for the entry of <span class="hlt">solar</span> <span class="hlt">wind</span> plasma into the magnetosphere. This is an important process in the magnetosphere as <span class="hlt">solar</span> <span class="hlt">wind</span> plasma ultimately fuels geomagnetic storms and the auroras. Though the magnetospheric Kelvin-Helmholtz interaction has been studied from a theoretical standpoint in simple flow configurations for many years, it has received little attention in modern, global MHD simulations. Moreover, while many studies have presented surface wave observations that can be easily explained in terms of the Kelvin-Helmholtz theory, others argue that the observations can just as easily be explained by fluctuating upstream <span class="hlt">solar</span> <span class="hlt">wind</span> plasma parameters. We circumvent these ambiguities by driving global MHD simulations with idealized <span class="hlt">solar</span> <span class="hlt">wind</span> input conditions, where all of the upstream <span class="hlt">solar</span> <span class="hlt">wind</span> plasma parameters are held constant. Thus, any surface waves generated at the magnetospheric boundary cannot be due to fluctuations in the upstream <span class="hlt">solar</span> <span class="hlt">wind</span>. We show that the Kelvin-Helmholtz instability is excited at both edges of the magnetospheric boundary layer and over a wide range of <span class="hlt">solar</span> <span class="hlt">wind</span> speeds (400-800 km/s). The results presented in the first half of this work are the first comprehensive study of the MHD Kelvin-Helmholtz instability in a realistic magnetospheric configuration. Magnetospheric cavity modes have been studied for many years, both theoretically and through simple numerical simulations. The concept of magnetospheric cavity modes is physically quite appealing; however, such oscillations have proved elusive in magnetospheric observations. Moreover, global MHD simulations have yet to reproduce cavity mode oscillations, further calling into question their existence. The results presented in the second half of this work show the excitation of magnetospheric cavity modes in global MHD simulations of the <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere interaction. These resonant cavity modes are excited when the frequency of upstream <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure fluctuations matches one of the natural frequencies of the magnetospheric cavity. Furthermore, the results from this study suggest that only even mode number cavity resonances can be excited within the magnetosphere. We also show that monochromatic fluctuations in the upstream <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure directly drive magnetospheric pulsations at the same frequency, regardless of whether or not these fluctuations simultaneously energize cavity mode resonances. These results provide substantial support for the existence of magnetospheric cavity modes, and also shed light on why cavity mode observations have thus far proved so elusive. (Abstract shortened by UMI.)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021350&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DA.i','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021350&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DA.i"><span id="translatedtitle">Features of <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration according to radio occultation data</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Efimov, A. I.</p> <p>1995-01-01</p> <p>In addressing one of the fundamental problems in <span class="hlt">solar</span> physics establishing the mechanism(s) responsible for the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration and the corona heating - it is essential to have a reliable knowledge of the heliocentric radial dependence of the <span class="hlt">solar</span> <span class="hlt">wind</span> properties. Adequate data are available for small <span class="hlt">solar</span> distances R less than 4 R(<span class="hlt">solar</span> mass) from coronal white light and EUV observations and at distances R greater than 60 R(<span class="hlt">solar</span> mass) from in situ measurements. One of the few methods available to fill in the gap between these boundaries is the radio scintillation technique. Taking the example of the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity, the most reliable such measurements are obtained when phase fluctuation observations of scattered radio waves, which are not susceptible to saturation effects, are recorded at two or more widely-spaced ground stations. Two extensive observation campaigns of this type were carried out with the Venus-orbiting satellites Venera 10 in 1976 and Venera 15/16 in 1984. The observations were performed over the course of three months near superior conjunction at <span class="hlt">solar</span> offset distances R approximately 6-80 R(<span class="hlt">solar</span> mass). The main results from the subsequent analysis of these data are: (1) velocities vary between 250 and 380 km s(exp -1) for R greater than 20 R(<span class="hlt">solar</span> mass), agreeing with similar measurements using natural sources (IPS); (2) velocities derived from two-station phase fluctuation observations varv between 70 and 120 km s(exp -1) for R less than 12 R(<span class="hlt">solar</span> mass), i.e. values substantially lower than those derived from conventional IPS data; and (3) it is suggested that the different velocity profiles derived from the two data sets at small R may be due to the effects of magnetosonic and Alfvenic waves on radio wave scattering. Further analysis of additional radio sounding data should help resolve the apparent discrepancy.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22364020','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22364020"><span id="translatedtitle">PROTON KINETIC EFFECTS IN VLASOV AND <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> TURBULENCE</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Servidio, S.; Valentini, F.; Perrone, D.; Veltri, P.; Osman, K. T.; Chapman, S.; Califano, F.; Matthaeus, W. H.</p> <p>2014-02-01</p> <p>Kinetic plasma processes are investigated in the framework of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence, employing hybrid Vlasov-Maxwell (HVM) simulations. Statistical analysis of spacecraft observation data relates proton temperature anisotropy T /T {sub ?} and parallel plasma beta ?{sub ?}, where subscripts refer to the ambient magnetic field direction. Here, this relationship is recovered using an ensemble of HVM simulations. By varying plasma parameters, such as plasma beta and fluctuation level, the simulations explore distinct regions of the parameter space given by T /T {sub ?} and ?{sub ?}, similar to <span class="hlt">solar</span> <span class="hlt">wind</span> sub-datasets. Moreover, both simulation and <span class="hlt">solar</span> <span class="hlt">wind</span> data suggest that temperature anisotropy is not only associated with magnetic intermittent events, but also with gradient-type structures in the flow and in the density. This connection between non-Maxwellian kinetic effects and various types of intermittency may be a key point for understanding the complex nature of plasma turbulence.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19810055592&hterms=energy+consumption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Denergy%2Bconsumption','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810055592&hterms=energy+consumption&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Denergy%2Bconsumption"><span id="translatedtitle">Energy coupling between the <span class="hlt">solar</span> <span class="hlt">wind</span> and the magnetosphere</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>1981-01-01</p> <p>A description is given of the path leading to the first approximation expression for the <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere energy coupling function (epsilon), which correlates well with the total energy consumption rate (U sub T) of the magnetosphere. It is shown that epsilon is the primary factor controlling the time development of magnetospheric substorms and storms. The finding of this particular expression epsilon indicates how the <span class="hlt">solar</span> <span class="hlt">wind</span> couples its energy to the magnetosphere; the <span class="hlt">solar</span> <span class="hlt">wind</span> and the magnetosphere make up a dynamo. In fact, the power generated by the dynamo can be identified as epsilon through the use of a dimensional analysis. In addition, the finding of epsilon suggests that the magnetosphere is closer to a directly driven system than to an unloading system which stores the generated energy before converting it to substorm and storm energies. The finding of epsilon and its implications is considered to have significantly advanced and improved the understanding of magnetospheric processes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2006AdSpR..37..461M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2006AdSpR..37..461M"><span id="translatedtitle">Testing for multifractality of the slow <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Macek, Wiesław M.; Bruno, Roberto; Consolini, Giuseppe</p> <p></p> <p>We analyse a time series of the radial component of the Elsässer variable for the low-speed stream of the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma representing Alfvénic fluctuations propagating downstream as measured in situ by the Helios spacecraft in the inner heliosphere. We demonstrate that the influence of noise in the data can be efficiently reduced by moving average and singular-value decomposition filters. We calculate the multifractal spectrum for the flow of the <span class="hlt">solar</span> <span class="hlt">wind</span> directly from the cleaned experimental signal. The resulting spectrum of dimensions shows a multifractal structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> in the inner heliosphere. The obtained multifractal spectrum is consistent with that for the multifractal measure on the self-similar weighted Cantor set with the degree of multifractality of ˜10 -1.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19810042382&hterms=self+determination+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dself%2Bdetermination%2Btheory','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19810042382&hterms=self+determination+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dself%2Bdetermination%2Btheory"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> flow past Venus - Theory and comparisons</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Spreiter, J. R.; Stahara, S. S.</p> <p>1980-01-01</p> <p>Advanced computational procedures are applied to an improved model of <span class="hlt">solar</span> <span class="hlt">wind</span> flow past Venus to calculate the locations of the ionopause and bow wave and the properties of the flowing ionosheath plasma in the intervening region. The theoretical method is based on a single-fluid, steady, dissipationless, magneto-hydrodynamic continuum model and is appropriate for the calculation of axisymmetric supersonic, super-Alfvenic <span class="hlt">solar</span> <span class="hlt">wind</span> flow past a nonmagnetic planet possessing a sufficiently dense ionosphere to stand off the flowing plasma above the subsolar point and elsewhere. Determination of time histories of plasma and magnetic field properties along an arbitrary spacecraft trajectory and provision for an arbitrary oncoming direction of the interplanetary <span class="hlt">solar</span> <span class="hlt">wind</span> have been incorporated in the model. An outline is provided of the underlying theory and computational procedures, and sample comparisons of the results are presented with observations from the Pioneer Venus orbiter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19720035478&hterms=Magnetism&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DMagnetism','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19720035478&hterms=Magnetism&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DMagnetism"><span id="translatedtitle">Lunar fossil magnetism and perturbations of the <span class="hlt">solar</span> <span class="hlt">wind</span>.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sonett, C. P.; Mihalov, J. D.</p> <p>1972-01-01</p> <p>Perturbations of the <span class="hlt">solar</span> <span class="hlt">wind</span> downstream of the moon and lying outside of the rarefaction wave that defines the diamagnetic cavity are used to define possible source regions comprised of intrinsically magnetized areas of the moon. A map of the moon is constructed showing that a model in which the sources are exposed to the grazing <span class="hlt">solar</span> <span class="hlt">wind</span> during the lunation yields a selenographically invariant set of regions strongly favoring the lunar highlands over the maria. An alternative model with the source due to electromagnetic induction is explored. The ages of the field sources should be consistent with those based on the basalt ages and possibly far older if the sources are connected with the formation of the highland rocks themselves. The perturbations are tentatively identified as weak shock waves, and a Mach angle in accord with nominal values for the <span class="hlt">solar</span> <span class="hlt">wind</span> is found.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22348150','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22348150"><span id="translatedtitle">Effects of electrons on the <span class="hlt">solar</span> <span class="hlt">wind</span> proton temperature anisotropy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Michno, M. J.; Lazar, M.; Schlickeiser, R.; Yoon, P. H. E-mail: mlazar@tp4.rub.de E-mail: yoonp@umd.edu</p> <p>2014-01-20</p> <p>Among the kinetic microinstabilities, the firehose instability is one of the most efficient mechanisms to restrict the unlimited increase of temperature anisotropy in the direction of an ambient magnetic field as predicted by adiabatic expansion of collision-poor <span class="hlt">solar</span> <span class="hlt">wind</span>. Indeed, the <span class="hlt">solar</span> <span class="hlt">wind</span> proton temperature anisotropy detected near 1 AU shows that it is constrained by the marginal firehose condition. Of the two types of firehose instabilities, namely, parallel and oblique, the literature suggests that the <span class="hlt">solar</span> <span class="hlt">wind</span> data conform more closely to the marginal oblique firehose condition. In the present work, however, it is shown that the parallel firehose instability threshold is markedly influenced by the presence of anisotropic electrons, such that under some circumstances, the cumulative effects of both electron and proton anisotropies could describe the observation without considering the oblique firehose mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840050402&hterms=entropy+symmetry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dentropy%2Bsymmetry','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840050402&hterms=entropy+symmetry&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dentropy%2Bsymmetry"><span id="translatedtitle">A hydromagnetic model of corotating conductive <span class="hlt">solar</span> <span class="hlt">wind</span> streams</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yeh, T.</p> <p>1984-01-01</p> <p>Under the assumption of quasi-azimuthal symmetry the governing equations of a steady hydromagnetic flow in a thermally conductive flux tube possess six invariants. Four of them represent constancy of mass efflux, energy efflux, angular momentum efflux and magnetic flux. Based on the entropy equation we obtain useful approximation in explicit expressions for the two remaining invariants. One of them provides the constraint which determines the compatible heat flux to ensure a vanishing pressure at infinity. Thus, the admissible solution that represents a corotating <span class="hlt">solar</span> <span class="hlt">wind</span> stream in terms of specified interplanetary condition can be calculated by an algebraic method, without the necessity of numerical integration. A two-point relationship is then derived, which correlates the <span class="hlt">solar</span> <span class="hlt">wind</span> properties at two separated interplanetary sites measured at two properly separated instants. This relationship may be applied to observational data from spacecraft and earth-bound satellites to discern the corotation feature in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740034914&hterms=magnetic+signature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmagnetic%2Bsignature','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740034914&hterms=magnetic+signature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmagnetic%2Bsignature"><span id="translatedtitle">Magnetic measurements of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with the moon</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lichtenstein, B. R.; Coleman, P. J., Jr.; Russell, C. T.</p> <p>1973-01-01</p> <p>The magnetic signature of the interaction between the moon and the <span class="hlt">solar</span> <span class="hlt">wind</span> (as observed by the Apollo 15 subsatellite) is an enhanced field directly behind the moon, bounded on either side by two dips in the field strength. On occasion, compressions of the field strength are observed external to either one or sometimes both of these dips. Theories of the interaction postulate either that these compressions are a general feature of the <span class="hlt">solar</span> <span class="hlt">wind</span>-moon interaction modulated by changes in the <span class="hlt">solar</span> <span class="hlt">wind</span> parameters or that they are associated with the appearance of specific lunar regions at the limbs. The measurements of the lunar magnetic field with the Apollo 15 and 16 subsatellites, the mapping of projected source positions of limb compressions onto the lunar surface, and the study of the persistence of limb compressions supports the hypothesis that limb compressions are formed when regions of high magnetization are at the lunar limbs.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH22B..06E','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH22B..06E"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Observations from 10 to 30 AU Measured With The New Horizons <span class="hlt">Solar</span> <span class="hlt">Wind</span> Around Pluto (SWAP) Instrument</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Elliott, H. A.; McComas, D. J.; Valek, P. W.; Nicolaou, G.; Bagenal, F.; Delamere, P. A.; Livadiotis, G.</p> <p>2014-12-01</p> <p>Beginning in 2012 the New Horizons mission to Pluto began collecting <span class="hlt">solar</span> <span class="hlt">wind</span> observations during the spacecraft hibernation greatly increasing the <span class="hlt">solar</span> <span class="hlt">wind</span> coverage. We have extensively analyzed both the laboratory and flight calibration measurements for the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Around Pluto (SWAP) instrument to produce a data set of <span class="hlt">solar</span> <span class="hlt">wind</span> observations at times when the New Horizons spacecraft is spinning. This full data set spans from 10 to 30 AU, and the improved coverage portion spans from 20- 30 AU. Coincidently, in 2012 and 2013 the ACE, STEREO A, and STEREO B were well separated in longitude. We compare the New Horizons speeds with propagated 1 AU speed measurements, and find many of the largest scale structures persist beyond 20 AU. The New Horizons <span class="hlt">solar</span> <span class="hlt">wind</span> coverage between 20 and 30 AU is now extensive enough to examine the temperature-speed relationship and compare that to the relationship found in the inner heliosphere and to that in the Voyager 2 observations. Upon initial examination we also find a temperature-speed relationship that persists in the 20-30 AU distance range.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021461&hterms=solar+power+works&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dsolar%2Bpower%2Bworks','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021461&hterms=solar+power+works&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dsolar%2Bpower%2Bworks"><span id="translatedtitle">Search for fine scale structures in high latitude <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Livi, S.; Parenti, S.; Poletto, G.</p> <p>1995-01-01</p> <p>About 25 years ago, E. Parker suggested that, as a consequence of the inhomogeneous structure of the corona, the <span class="hlt">solar</span> <span class="hlt">wind</span> might consist of adjacent structures with different physical conditions. Since that suggestion was made, the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma characteristics have been measured in situ through many experiments, but little has been done to check whether the <span class="hlt">solar</span> <span class="hlt">wind</span> shows any evidence for fine scale structures, and, in the affirmative, how far from the Sun these structures persist. A previous work on this subject, by Thieme, Marsch and Schwenn (1990), based on Helios data, lead these authors to claim that the <span class="hlt">solar</span> <span class="hlt">wind</span>, between 0.3 and 1 AU, is inhomogeneous on a scale consistent with the hypothesis that the plume-interplume plasmas, at those distances, still retain their identity. In this work we present preliminary results from an investigation of the <span class="hlt">solar</span> <span class="hlt">wind</span> fine structure from Ulysses high latitude observations. To this end, we have analyzed data over several months, during 1994, at times well after Ulysses's last encounter with the Heliospheric Current Sheet, when the spacecraft was at latitudes above 50 degrees. These data refer to high speed <span class="hlt">wind</span> coming from southern polar coronal holes and are best suited for plume-interplume identification. We have performed a power spectra analysis of typical plasma parameters, to test whether the <span class="hlt">wind</span> plasma consist of two distinct plasma populations. We also examined data to check whether there is any evidence for an horizontal pressure balance over the hypothesized distinct structures. Our results are discussed and compared with previous findings.</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://www.osti.gov/scitech/servlets/purl/1167251','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1167251"><span id="translatedtitle">Agua Caliente <span class="hlt">Wind/Solar</span> Project at Whitewater Ranch</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Hooks, Todd; Stewart, Royce</p> <p>2014-12-16</p> <p>Agua Caliente Band of Cahuilla Indians (ACBCI) was awarded a grant by the Department of Energy (DOE) to study the feasibility of a <span class="hlt">wind</span> and/or <span class="hlt">solar</span> renewable energy project at the Whitewater Ranch (WWR) property of ACBCI. Red Mountain Energy Partners (RMEP) was engaged to conduct the study. The ACBCI tribal lands in the Coachella Valley have very rich renewable energy resources. The tribe has undertaken several studies to more fully understand the options available to them if they were to move forward with one or more renewable energy projects. With respect to the resources, the WWR property clearly has excellent <span class="hlt">wind</span> and <span class="hlt">solar</span> resources. The DOE National Renewable Energy Laboratory (NREL) has continued to upgrade and refine their library of resource maps. The newer, more precise maps quantify the resources as among the best in the world. The <span class="hlt">wind</span> and <span class="hlt">solar</span> technology available for deployment is also being improved. Both are reducing their costs to the point of being at or below the costs of fossil fuels. Technologies for energy storage and microgrids are also improving quickly and present additional ways to increase the <span class="hlt">wind</span> and/or <span class="hlt">solar</span> energy retained for later use with the network management flexibility to provide power to the appropriate locations when needed. As a result, renewable resources continue to gain more market share. The transitioning to renewables as the major resources for power will take some time as the conversion is complex and can have negative impacts if not managed well. While the economics for <span class="hlt">wind</span> and <span class="hlt">solar</span> systems continue to improve, the robustness of the WWR site was validated by the repeated queries of developers to place <span class="hlt">wind</span> and/or <span class="hlt">solar</span> there. The robust resources and improving technologies portends toward WWR land as a renewable energy site. The business case, however, is not so clear, especially when the potential investment portfolio for ACBCI has several very beneficial and profitable alternatives.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSH43A..03W','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSH43A..03W"><span id="translatedtitle">Turbulent Heating and Wave Pressure in <span class="hlt">Solar</span> <span class="hlt">Wind</span> Acceleration Modeling: New Insights to Empirical Forecasting of the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Woolsey, L. N.; Cranmer, S. R.</p> <p>2013-12-01</p> <p>The study of <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration has made several important advances recently due to improvements in modeling techniques. Existing code and simulations test the competing theories for coronal heating, which include reconnection/loop-opening (RLO) models and wave/turbulence-driven (WTD) models. In order to compare and contrast the validity of these theories, we need flexible tools that predict the emergent <span class="hlt">solar</span> <span class="hlt">wind</span> properties from a wide range of coronal magnetic field structures such as coronal holes, pseudostreamers, and helmet streamers. ZEPHYR (Cranmer et al. 2007) is a one-dimensional magnetohydrodynamics code that includes Alfven wave generation and reflection and the resulting turbulent heating to accelerate <span class="hlt">solar</span> <span class="hlt">wind</span> in open flux tubes. We present the ZEPHYR output for a wide range of magnetic field geometries to show the effect of the magnetic field profiles on <span class="hlt">wind</span> properties. We also investigate the competing acceleration mechanisms found in ZEPHYR to determine the relative importance of increased gas pressure from turbulent heating and the separate pressure source from the Alfven waves. To do so, we developed a code that will become publicly available for <span class="hlt">solar</span> <span class="hlt">wind</span> prediction. This code, TEMPEST, provides an outflow solution based on only one input: the magnetic field strength as a function of height above the photosphere. It uses correlations found in ZEPHYR between the magnetic field strength at the source surface and the temperature profile of the outflow solution to compute the <span class="hlt">wind</span> speed profile based on the increased gas pressure from turbulent heating. With this initial solution, TEMPEST then adds in the Alfven wave pressure term to the modified Parker equation and iterates to find a stable solution for the <span class="hlt">wind</span> speed. This code, therefore, can make predictions of the <span class="hlt">wind</span> speeds that will be observed at 1 AU based on extrapolations from magnetogram data, providing a useful tool for empirical forecasting of the sol! ar <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22118611','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22118611"><span id="translatedtitle">The turbulent cascade and proton heating in the <span class="hlt">solar</span> <span class="hlt">wind</span> during <span class="hlt">solar</span> minimum</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Coburn, Jesse T.; Smith, Charles W.; Vasquez, Bernard J.; Stawarz, Joshua E.; Forman, Miriam A.</p> <p>2013-06-13</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> measurements at 1 AU during the recent <span class="hlt">solar</span> minimum and previous studies of <span class="hlt">solar</span> maximum provide an opportunity to study the effects of the changing <span class="hlt">solar</span> cycle on in situ heating. Our interest is to compare the levels of activity associated with turbulence and proton heating. Large-scale shears in the flow caused by transient activity are a source that drives turbulence that heats the <span class="hlt">solar</span> <span class="hlt">wind</span>, but as the <span class="hlt">solar</span> cycle progresses the dynamics that drive the turbulence and heat the medium are likely to change. The application of third-moment theory to Advanced Composition Explorer (ACE) data gives the turbulent energy cascade rate which is not seen to vary with the <span class="hlt">solar</span> cycle. Likewise, an empirical heating rate shows no significan changes in proton heating over the cycle.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21333812','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21333812"><span id="translatedtitle"><span class="hlt">SOLAR</span> <span class="hlt">WIND</span> MAGNETOHYDRODYNAMICS TURBULENCE: ANOMALOUS SCALING AND ROLE OF INTERMITTENCY</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Salem, C.; Bale, S. D.; Mangeney, A.; Veltri, P.</p> <p>2009-09-01</p> <p>In this paper, we present a study of the scaling properties and intermittency of <span class="hlt">solar</span> <span class="hlt">wind</span> MHD turbulence based on the use of wavelet transforms. More specifically, we use the Haar Wavelet transform on simultaneous 3 s resolution particle and magnetic field data from the <span class="hlt">Wind</span> spacecraft, to investigate anomalous scaling and intermittency effects of both magnetic field and <span class="hlt">solar</span> <span class="hlt">wind</span> velocity fluctuations in the inertial range. For this purpose, we calculated spectra, structure functions, and probability distribution functions. We show that this powerful wavelet technique allows for a systematic elimination of intermittency effects on spectra and structure functions and thus for a clear determination of the actual scaling properties in the inertial range. The scaling of the magnetic field and the velocity fluctuations are found to be fundamentally different. Moreover, when the most intermittent structures superposed to the standard fluctuations are removed, simple statistics are recovered. The magnetic field and the velocity fluctuations exhibit a well-defined, although different, monofractal behavior, following a Kolmogorov -5/3 scaling and a Iroshnikov-Kraichnan -3/2 scaling, respectively. The multifractal properties of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence appear to be determined by the presence of those most intermittent structures. Finally, our wavelet technique also allows for a direct and systematic identification of the most active, singular structures responsible for the intermittency in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/17994092','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/17994092"><span id="translatedtitle">Modulation of Saturn's radio clock by <span class="hlt">solar</span> <span class="hlt">wind</span> speed.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Zarka, Philippe; Lamy, Laurent; Cecconi, Baptiste; Prangé, Renée; Rucker, Helmut O</p> <p>2007-11-01</p> <p>The internal rotation rates of the giant planets can be estimated by cloud motions, but such an approach is not very precise because absolute <span class="hlt">wind</span> speeds are not known a priori and depend on latitude: periodicities in the radio emissions, thought to be tied to the internal planetary magnetic field, are used instead. Saturn, despite an apparently axisymmetric magnetic field, emits kilometre-wavelength (radio) photons from auroral sources. This emission is modulated at a period initially identified as 10 h 39 min 24 +/- 7 s, and this has been adopted as Saturn's rotation period. Subsequent observations, however, revealed that this period varies by +/-6 min on a timescale of several months to years. Here we report that the kilometric radiation period varies systematically by +/-1% with a characteristic timescale of 20-30 days. Here we show that these fluctuations are correlated with <span class="hlt">solar</span> <span class="hlt">wind</span> speed at Saturn, meaning that Saturn's radio clock is controlled, at least in part, by conditions external to the planet's magnetosphere. No correlation is found with the <span class="hlt">solar</span> <span class="hlt">wind</span> density, dynamic pressure or magnetic field; the <span class="hlt">solar</span> <span class="hlt">wind</span> speed therefore has a special function. We also show that the long-term fluctuations are simply an average of the short-term ones, and therefore the long-term variations are probably also driven by changes in the <span class="hlt">solar</span> <span class="hlt">wind</span>. PMID:17994092</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AIPC.1539..418R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AIPC.1539..418R"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> mass-loading due to dust</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rasca, A. P.; Hornyi, M.</p> <p>2013-06-01</p> <p>Collisionless mass-loading by interplanetary dust particles is expected to cause a significant disruption in the flow of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Dust particles near the Sun can become a source of ions and neutrals due to evaporation and sputtering. This mass-loading effect can lead to the formation of collisionless shocks, as it was first discussed in the case of <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with comets. This effect can also be compared with a de Laval nozzle, which behaves differently between subsonic and supersonic flows. We investigate the effects of mass-loading resulting from sun-grazing comets or collisions by larger bodies in the vicinity of the Sun, where the <span class="hlt">solar</span> <span class="hlt">wind</span> transitions from subsonic to supersonic speeds. We look at results obtained using a simple 1D hydrodynamic model to mass-load ionized dust into the the <span class="hlt">wind</span> near the sonic point, which are relevant for understanding the acceleration of the <span class="hlt">solar</span> <span class="hlt">wind</span> and possible changes in its composition due to dust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSH33B2061R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSH33B2061R"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Mass-Loading Due to Dust</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rasca, A.; Horanyi, M.</p> <p>2011-12-01</p> <p>Collisionless mass-loading by interplanetary dust particles is expected to cause a significant disruption in the flow of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Dust particles near the Sun can become a source of ions and neutrals due to evaporation and sputtering. This mass-loading effect can lead to the formation of collisionless shocks, as it was first discussed in the case of <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with comets. This effect can also be compared with a de Laval nozzle, which behaves differently between subsonic and supersonic flows. We investigate the effects of mass-loading resulting from sun-grazing comets or collisions in the vicinity of the Sun, where the <span class="hlt">solar</span> <span class="hlt">wind</span> transitions from subsonic to supersonic speeds. We implement a hydrodynamic numerical model to generate a steady <span class="hlt">wind</span> extending out to the inner heliosphere. Dust is introduced through a set of mass-loading source terms, and the model is evolved using a shock-capturing scheme. These results are relevant for understanding the acceleration of the <span class="hlt">solar</span> <span class="hlt">wind</span> and possible changes in its composition due to dust.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1983STIA...8334147T','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1983STIA...8334147T"><span id="translatedtitle">Source reliability in a combined <span class="hlt">wind-solar</span>-hydro system</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Traca de Almeida, A.; Martins, A.; Jesus, H.; Climaco, J.</p> <p>1983-06-01</p> <p>The results of an examination of the feasibility of using coupled <span class="hlt">wind-solar</span>-hydro power generation systems to provide all of Portugal's electricity by the year 2000 are reported. Portugal used 15.6 TWh of electricity in 1981, of which hydro supplied 10 TWh. Demand is expected to reach 34 TWh in 2000 AD. The full development of hydropower resource would furnish 18 TWh and a storage capacity of 4.5 TWh. The installed hydro system could meet the peak demand of 6 GW, while <span class="hlt">solar</span> cells and <span class="hlt">wind</span> turbines must produce 16 TWh annually plus a reserve. The Growian <span class="hlt">wind</span> turbine, 100 m tall, is considered for its 2.2 MW output. A coastal strip of <span class="hlt">wind</span> turbines 150 x 20 km, with 1 km spacing between the machines, would be needed to produce 5.4 GW of power. Partially tracking <span class="hlt">solar</span> cell arrays generating 9.4 GW of electricity would require an area of 100 sq km. Computer simulations of the annual rainfall, combined with projections of the variations in <span class="hlt">wind-solar</span> output, demonstrates that a reserve margin of 1.20 will be necessary. The costs of installation of the renewable energy converters are estimated at about three times that currently necessary for obtaining the same capacity from fission power plants, although the situation may change due to import and technical considerations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/22181719','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/22181719"><span id="translatedtitle">Modified temperature-anisotropy instability thresholds in the <span class="hlt">solar</span> <span class="hlt">wind</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Schlickeiser, R; Michno, M J; Ibscher, D; Lazar, M; Skoda, T</p> <p>2011-11-11</p> <p>The proton and electron temperature anisotropies in the <span class="hlt">solar</span> <span class="hlt">wind</span> are constrained by the instability thresholds for temperature-anisotropy-driven kinetic plasma instabilities. The modifications to the marginal instability conditions from accounting for the influence of damping connected with the collisional effects in the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma are calculated for right- and left-handed polarized parallel propagating Alfvn waves and mirror and firehose fluctuations. These modifications provide tighter threshold constraints compared to the marginal thresholds but do not fully explain the observations at small values of the parallel plasma beta. PMID:22181719</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22252082','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22252082"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> kinetic instabilities at small plasma betas</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ibscher, D. Schlickeiser, R.</p> <p>2014-02-15</p> <p>The ordinary perpendicular mode of drifting bi-Maxwellian plasma particle distributions with and without temperature anisotropy can provide aperiodic instabilities. These instabilities occur if the perpendicular thermal energy is much smaller than the streaming energy. This provides instabilities at small parallel plasma betas ?{sub ?}<1 and temperature anisotropies A?<?1. In this regime, the <span class="hlt">solar</span> <span class="hlt">wind</span> is unstable, which cannot be explained so far. To clarify if the ordinary perpendicular mode can be responsible for this instability, here we compare measurements in the <span class="hlt">solar</span> <span class="hlt">wind</span> with the instability provided by this mode.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999JNav...52...42S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999JNav...52...42S"><span id="translatedtitle">The Impact of <span class="hlt">Solar</span> <span class="hlt">Winds</span> on Navigation Aids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sandford, W. H.</p> <p></p> <p>Recent developments in remote imaging equipment carried on satellites have given the scientific community a vast amount of new information about the Sun and its atmosphere. Media coverage of the remarkable discoveries accompanied by impressive images of the Sun's atmosphere, and linkage to the loss of a television satellite over the United States, have focused public attention on the existence and effects of the <span class="hlt">Solar</span> <span class="hlt">Wind</span>. This paper sets out to illustrate the impact of the <span class="hlt">Solar</span> <span class="hlt">Wind</span> on radio aids to navigation, and to look at the possible effects on present and proposed systems.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21371710','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21371710"><span id="translatedtitle">Compressive turbulent cascade and heating in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Marino, R.; Sorriso-Valvo, L.; Noullez, A.; Bruno, R.</p> <p>2010-03-25</p> <p>A turbulent energy cascade has been recently identified in high-latitude <span class="hlt">solar</span> <span class="hlt">wind</span> data samples by using a Yaglom-like relation. However, analogous scaling law, suitably modified to take into account compressible fluctuations, has been observed in a much more extended fraction of the same data set recorded by the Ulysses spacecraft. Thus, it seems that large scale density fluctuations, despite their low amplitude, play a major role in the basic scaling properties of turbulence. The compressive turbulent cascade, moreover, seems to be able to supply the energy needed to account for the local heating of the non-adiabatic <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/574650','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/574650"><span id="translatedtitle">Electron energy transport in the <span class="hlt">solar</span> <span class="hlt">wind</span>: Ulysses observations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Scime, E.E.; Gary, S.P.; Phillips, J.L.; Balogh, A.; Lengyel-Frey, D.</p> <p>1996-07-01</p> <p>Previous analysis suggests that the whistler heat flux instability is responsible for the regulation of the electron heat flux of the <span class="hlt">solar</span> <span class="hlt">wind</span>. For an interval of quiescent <span class="hlt">solar</span> <span class="hlt">wind</span> during the in-ecliptic phase of the Ulysses mission, the plasma wave data in the whistler frequency regime are compared to the predictions of the whistler heat flux instability model. The data is well constrained by the predicted upper bound on the electron heat flux and a clear correlation between wave activity and electron heat flux dissipation is observed. {copyright} {ital 1996 American Institute of Physics.}</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21163474','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21163474"><span id="translatedtitle">Electron energy transport in the <span class="hlt">solar</span> <span class="hlt">wind</span>: Ulysses observations</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Scime, Earl E.; Gary, S. Peter; Phillips, John L.; Balogh, Andre; Lengyel-Frey, Denise</p> <p>1996-07-20</p> <p>Previous analysis suggests that the whistler heat flux instability is responsible for the regulation of the electron heat flux of the <span class="hlt">solar</span> <span class="hlt">wind</span>. For an interval of quiescent <span class="hlt">solar</span> <span class="hlt">wind</span> during the in-ecliptic phase of the Ulysses mission, the plasma wave data in the whistler frequency regime are compared to the predictions of the whistler heat flux instability model. The data is well constrained by the predicted upper bound on the electron heat flux and a clear correlation between wave activity and electron heat flux dissipation is observed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19990014460','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19990014460"><span id="translatedtitle">Interpretation of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Composition Measurements from Ulysses</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Esser, Ruth</p> <p>1999-01-01</p> <p>Ion charge states measured in situ in interplanetary space carry information on the properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma in the inner corona. This information is, however, not easy to extract from the in situ observations. The goal of the proposal was to determine <span class="hlt">solar</span> <span class="hlt">wind</span> models and coronal observations that are necessary tools for the interpretation of charge state observations. It has been shown that the interpretation of the in situ ion fractions are heavily dependent on the assumptions about conditions in the inner corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770067670&hterms=Bohr+Niels&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Bohr%2BNiels%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770067670&hterms=Bohr+Niels&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3D%2528Bohr%2BNiels%2529"><span id="translatedtitle">Mass fractionation of the lunar surface by <span class="hlt">solar</span> <span class="hlt">wind</span> sputtering</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Switkowski, Z. E.; Haff, P. K.; Tombrello, T. A.; Burnett, D. S.</p> <p>1977-01-01</p> <p>An investigation is conducted concerning the mass-fractionation effects produced in connection with the bombardment of the moon by the <span class="hlt">solar</span> <span class="hlt">wind</span>. Most of the material ejected by sputtering escapes the moon's gravity, but some returning matter settles back onto the lunar surface. This material, which is somewhat richer in heavier atoms than the starting surface, is incorporated into the heavily radiation-damaged outer surfaces of grains. The investigation indicates that sputtering of the lunar surface by the <span class="hlt">solar</span> <span class="hlt">wind</span> will give rise to significant surface heavy atom enrichments if the grain surfaces are allowed to come into sputtering equilibrium.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22365363','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22365363"><span id="translatedtitle">CORE ELECTRON HEATING IN <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> RECONNECTION EXHAUSTS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Pulupa, M. P.; Salem, C.; Phan, T. D.; Bale, S. D.; Gosling, J. T.</p> <p>2014-08-10</p> <p>We present observational evidence of core electron heating in <span class="hlt">solar</span> <span class="hlt">wind</span> reconnection exhausts. We show two example events, one which shows clear heating of the core electrons within the exhaust, and one which demonstrates no heating. The event with heating occurred during a period of high inflow Alfvén speed (V {sub AL}), while the event with no heating had a low V {sub AL}. This agrees with the results of a recent study of magnetopause exhausts, and suggests that similar core electron heating can occur in both symmetric (<span class="hlt">solar</span> <span class="hlt">wind</span>) and asymmetric (magnetopause) exhausts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EM%26P..116..159L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EM%26P..116..159L"><span id="translatedtitle">Interaction of Low-Activity Comets with the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lebedev, Michail G.; Baranov, Vladimir B.; Alexashov, Dmitry B.</p> <p>2015-12-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> flow around a cometary atmosphere is calculated using the three-dimensional magnetohydrodynamic model developed by the authors. Emphasis is placed on the case of low-activity comets in which some special features, both quantitative and qualitative, are inherent. The behavior of the flowfield and the magnetic field disturbed by the cometary outflow is analyzed. Some similarity laws that govern the pattern of the interaction between the <span class="hlt">solar</span> <span class="hlt">wind</span> and a cometary atmosphere are derived on the basis of the calculated results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20070021568&hterms=silicon+implants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsilicon%2Bimplants','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070021568&hterms=silicon+implants&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dsilicon%2Bimplants"><span id="translatedtitle">Measurement of Damage Profiles from <span class="hlt">Solar</span> <span class="hlt">Wind</span> Implantation</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>McNamara, K. M.; Synowicki, R. A.; Tiwald, T. E.</p> <p>2007-01-01</p> <p>NASA's Genesis Mission launched from Cape Canaveral in August of 2001 with the goal of collecting <span class="hlt">solar</span> <span class="hlt">wind</span> in ultra-pure materials. The samples were returned to Earth more than three years later for subsequent analysis. Although the <span class="hlt">solar</span> <span class="hlt">wind</span> is comprised primarily of protons, it also contains ionized species representing the entire periodic table. The Genesis mission took advantage of the natural momentum of these ionized species to implant themselves in specialized collectors including single crystal Si and SiC. The collectors trapped the <span class="hlt">solar</span> <span class="hlt">wind</span> species of interest and sustained significant damage to the surface crystal structure as a result of the ion bombardment. In this work, spectroscopic ellipsometry has been used to evaluate the extent of this damage in Si and SiC samples. These results and models are compared for artificially implanted samples and pristine non-flight material. In addition, the flown samples had accumulated a thin film of molecular contamination as a result of outgassing in flight, and we demonstrate that this layer can be differentiated from the material damage. In addition to collecting bulk <span class="hlt">solar</span> <span class="hlt">wind</span> samples (continuous exposure), the Genesis mission actually returned silicon exposed to four different <span class="hlt">solar</span> <span class="hlt">wind</span> regimes: bulk, high speed, low speed, and coronal mass ejections. Each of these <span class="hlt">solar</span> <span class="hlt">wind</span> regimes varies in energy, but may vary in composition as well. While determining the composition is a primary goal of the mission, we are also interested in the variation in depth and extent of the damage layer as a function of <span class="hlt">solar</span> <span class="hlt">wind</span> regime. Here, we examine flight Si from the bulk <span class="hlt">solar</span> <span class="hlt">wind</span> regime and compare the results to both pristine and artificially implanted Si. Finally, there were four samples which were mounted in an electrostatic "concentrator" designed to reject a large fraction (>85%) of incoming protons while enhancing the concentration of ions mass 4-28 amu by a factor of at least 20. Two of these samples were single crystal 6H silicon carbide. (The others were polycrystalline CVD diamond and amorphous carbon that were not examined in the work.) The ion damaged SiC samples from the concentrator were studied in comparison to the flight Si from the bulk array to understand differences in the extent of the damage.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19850041177&hterms=1055&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231055','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19850041177&hterms=1055&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3D%2526%25231055"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> control of magnetospheric pressure (CDAW 6)</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Fairfield, D. H.</p> <p>1985-01-01</p> <p>The CDAW 6 data base is used to compare <span class="hlt">solar</span> <span class="hlt">wind</span> and magnetospheric pressures. The flaring angle of the tail magnetopause is determined by assuming that the component of <span class="hlt">solar</span> <span class="hlt">wind</span> pressure normal to the tail boundary is equal to the total pressure within the tail. Results indicate an increase in the tail flaring angle from 18 deg to 32 deg prior to the 1055 substorm onset and a decrease to 25 deg after the onset. This behavior supports the concept of tail energy storage before the substorm and subsequent release after the onset.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_16");'>16</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li class="active"><span>18</span></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_18 --> <div id="page_19" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="361"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004APS..DPPHM2004B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004APS..DPPHM2004B"><span id="translatedtitle">Transport and Modulation of Cosmic Rays in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bieber, John</p> <p>2004-11-01</p> <p>Understanding the mechanism by which energetic charged particles scatter and diffuse in collisionless plasma is an enduring fundamental problem of astrophysics. The study of this process in the <span class="hlt">solar</span> <span class="hlt">wind</span> provides vital opportunities for confronting theoretical models with direct observation. This talk will review recent advances in this field resulting from (1) an improved understanding of magnetic turbulence in the <span class="hlt">solar</span> <span class="hlt">wind</span> (especially relating to turbulence geometry), (2) the use of nonlinear methods in particle scattering theory, (3) increasingly realistic models of turbulence evolution and transport, and (4) detailed observations at far flung locations through the heliosphere (especially from Pioneer, Voyager, and Ulysses). Supported by NSF grant ATM-0000315.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015DPS....4710006B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015DPS....4710006B"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> interaction with Pluto’s escaping atmosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bagenal, Fran; Stern, S. A.; Weaver, H. A.; Young, L. A.; Ennico, K.; Olkin, C.; McComas, D. J.; McNutt, R. L.; Horanyi, M.; Elliott, H. A.; Hill, M. E.; Zernstein, E.; Kollman, P.; Krimigis, S. M.; Lisse, C. M.; Strobel, D. F.; SzalAy, J.; Piquette, M.</p> <p>2015-11-01</p> <p>NASA’s New Horizons spacecraft carries two instruments, SWAP and PEPSSI, that measure low and high energy particles respectively. These particle instruments have been measuring the conditions in the <span class="hlt">solar</span> <span class="hlt">wind</span> for most of the trajectory from Earth to Pluto. The Venetia Burney Student Dust Counter measured impacts from micron-sixed dust particles. These particle instruments also made observations during the flyby of Pluto on July 14, 2015. We report on New Horizons measurements of the interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with Pluto’s extended atmosphere and discuss comparisons with theoretical expectations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21394447','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21394447"><span id="translatedtitle">CHARACTERIZATION OF TRANSITIONS IN THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> PARAMETERS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Perri, S.; Balogh, A. E-mail: a.balogh@imperial.ac.u</p> <p>2010-02-20</p> <p>The distinction between fast and slow <span class="hlt">solar</span> <span class="hlt">wind</span> streams and the dynamically evolved interaction regions is reflected in the characteristic fluctuations of both the <span class="hlt">solar</span> <span class="hlt">wind</span> and the embedded magnetic field. High-resolution magnetic field data from the Ulysses spacecraft have been analyzed. The observations show rapid variations in the magnetic field components and in the magnetic field strength, suggesting a structured nature of the <span class="hlt">solar</span> <span class="hlt">wind</span> at small scales. The typical sizes of fluctuations cover a broad range. If translated to the <span class="hlt">solar</span> surface, the scales span from the size of granules ({approx}10{sup 3} km) and supergranules ({approx}10{sup 4} km) on the Sun down to {approx}10{sup 2} km and less. The properties of the short time structures change in the different types of <span class="hlt">solar</span> <span class="hlt">wind</span>. While fluctuations in fast streams are more homogeneous, slow streams present a bursty behavior in the magnetic field variances, and the regions of transition are characterized by high levels of power in narrow structures around the transitions. The probability density functions of the magnetic field increments at several scales reveal a higher level of intermittency in the mixed streams, which is related to the presence of well localized features. It is concluded that, apart from the differences in the nature of fluctuations in flows of different coronal origin, there is a small-scale structuring that depends on the origin of streams themselves but it is also related to a bursty generation of the fluctuations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021388&hterms=wind+energy+negative&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dwind%2Benergy%2Bnegative','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021388&hterms=wind+energy+negative&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dwind%2Benergy%2Bnegative"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> helium observations on the Prognoz 7 satellite</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Yermolaev, Yu. I.</p> <p>1995-01-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> data obtained with ion mass-energy-spectrometer on the Prognoz 7 satellite are analyzed to study the alpha-particle and proton features in different types of <span class="hlt">solar</span> <span class="hlt">wind</span> streams. In the streams from coronal holes the abundance of helium relative to proton slightly increases with increasing <span class="hlt">solar</span> <span class="hlt">wind</span> flux and proton density while in the streams from coronal streamers it decreases. These results indicate that the mechanisms of <span class="hlt">solar</span> <span class="hlt">wind</span> formation in different regions of <span class="hlt">solar</span> corona differ. Preferential alpha-particle acceleration and heating are often observed in the streams from coronal holes. Minimum (as well as negative) values of alpha-proton velocity difference are recorded in the heliospheric current sheet, shocked plasma, and coronal mass ejections. Dependences of alpha-proton velocity difference and temperature ratio on several MHD parameters (Alfven velocity, number of Coulomb collisions. etc.) are compared for different types of streams. For velocity difference the dependences in streams from coronal holes and streamers are often similar to each other, and they differ from the ones in the heliospheric current sheet. For temperature ratio the dependences in heliospheric current sheet and streams from coronal streamers are similar, and they differ in streams from coronal holes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22167206','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22167206"><span id="translatedtitle">ACCELERATION OF THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> BY ALFVEN WAVE PACKETS</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Galinsky, V. L.; Shevchenko, V. I.</p> <p>2013-01-20</p> <p>A scale separation kinetic model of the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration is presented. The model assumes an isotropic Maxwellian distribution of protons and a constant influx of outward propagating Alfven waves with a single exponent Kolmogorov-type spectrum at the base of a coronal acceleration region ({approx}2 R {sub Sun }). Our results indicate that nonlinear cyclotron resonant interaction taking energy from Alfven waves and depositing it into mostly perpendicular heating of protons in initially weakly expanding plasma in a spherically non-uniform magnetic field is able to produce the typical fast <span class="hlt">solar</span> <span class="hlt">wind</span> velocities for the typical plasma and wave conditions after expansion to about 5-10 <span class="hlt">solar</span> radii R {sub Sun }. The acceleration model takes into account the gravity force and the ambipolar electric field, as well as the mirror force, which plays the most important role in driving the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration. Contrary to the recent claims of Isenberg, the cold plasma dispersion only slightly slows down the acceleration and actually helps in obtaining the more realistic fast <span class="hlt">solar</span> <span class="hlt">wind</span> speeds.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008ApJ...675..853S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008ApJ...675..853S"><span id="translatedtitle">Heliospheric Images of the <span class="hlt">Solar</span> <span class="hlt">Wind</span> at Earth</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sheeley, N. R., Jr.; Herbst, A. D.; Palatchi, C. A.; Wang, Y.-M.; Howard, R. A.; Moses, J. D.; Vourlidas, A.; Newmark, J. S.; Socker, D. G.; Plunkett, S. P.; Korendyke, C. M.; Burlaga, L. F.; Davila, J. M.; Thompson, W. T.; St Cyr, O. C.; Harrison, R. A.; Davis, C. J.; Eyles, C. J.; Halain, J. P.; Wang, D.; Rich, N. B.; Battams, K.; Esfandiari, E.; Stenborg, G.</p> <p>2008-03-01</p> <p>During relatively quiet <span class="hlt">solar</span> conditions throughout the spring and summer of 2007, the SECCHI HI2 white-light telescope on the STEREO B <span class="hlt">solar</span>-orbiting spacecraft observed a succession of wave fronts sweeping past Earth. We have compared these heliospheric images with in situ plasma and magnetic field measurements obtained by near-Earth spacecraft, and we have found a near perfect association between the occurrence of these waves and the arrival of density enhancements at the leading edges of high-speed <span class="hlt">solar</span> <span class="hlt">wind</span> streams. Virtually all of the strong corotating interaction regions are accompanied by large-scale waves, and the low-density regions between them lack such waves. Because the Sun was dominated by long-lived coronal holes and recurrent <span class="hlt">solar</span> <span class="hlt">wind</span> streams during this interval, there is little doubt that we have been observing the compression regions that are formed at low latitude as <span class="hlt">solar</span> rotation causes the high-speed <span class="hlt">wind</span> from coronal holes to run into lower speed <span class="hlt">wind</span> ahead of it.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AAS...22420302S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AAS...22420302S"><span id="translatedtitle">Origin of the Wang-Sheeley-Arge <span class="hlt">Solar</span> <span class="hlt">Wind</span> Model</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sheeley, Neil R.</p> <p>2014-06-01</p> <p>A correlation between <span class="hlt">solar</span> <span class="hlt">wind</span> speed at Earth and the amount of field line expansion in the corona was verified in 1989 using 22 years of <span class="hlt">solar</span> and interplanetary observations. This talk will trace the history of this discovery from its birth 15 years earlier in the Skylab era to its current use as a space weather forecasting technique. This research was supported by NASA and ONR.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740034906&hterms=wind+moon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwind%2Bmoon','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740034906&hterms=wind+moon&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dwind%2Bmoon"><span id="translatedtitle">The electric potential of the moon in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Freeman, J. W., Jr.; Fenner, M. A.; Hills, H. K.</p> <p>1973-01-01</p> <p>Acceleration and detection of the lunar thermal ionosphere in the presence of the lunar electric field yields a value of approximately +10 V for the lunar electric potential for <span class="hlt">solar</span> zenith angles between 20 and 45 deg and in the magnetosheath or <span class="hlt">solar</span> <span class="hlt">wind</span>. The ion number density of the thermal ionosphere observed is compatible with a surface neutral number density of about 100,000 atoms/cu cm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014EGUGA..16.9652R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014EGUGA..16.9652R"><span id="translatedtitle">Comparison of <span class="hlt">solar</span> <span class="hlt">wind</span> driving of the aurora in the two hemispheres due to the <span class="hlt">solar</span> <span class="hlt">wind</span> dynamo</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reistad, Jone Peter; stgaard, Nikolai; Magnus Laundal, Karl; Haaland, Stein; Tenfjord, Paul; Oksavik, Kjellmar</p> <p>2014-05-01</p> <p>Event studies of simultaneous global imaging of the aurora in both hemispheres have suggested that an asymmetry of the <span class="hlt">solar</span> <span class="hlt">wind</span> driving between the two hemispheres could explain observations of non-conjugate aurora during specific driving conditions. North-South asymmetries in energy transfer from the <span class="hlt">solar</span> <span class="hlt">wind</span> across the magnetopause is believed to depend upon the dipole tilt angle and the x-component of the interplanetary magnetic field (IMF). Both negative tilt (winter North) and negative IMF Bx is expected to enhance the efficiency of the <span class="hlt">solar</span> <span class="hlt">wind</span> dynamo in the Northern Hemisphere. By the same token, positive tilt and IMF Bx is expected to enhance the <span class="hlt">solar</span> <span class="hlt">wind</span> dynamo efficiency in the Southern Hemisphere. We show a statistical study of the auroral response from both hemispheres using global imaging where we compare results during both favourable and not favourable conditions in each hemisphere. By this study we will address the question of general impact on auroral hemispheric asymmetries by this mechanism - the asymmetric <span class="hlt">solar</span> <span class="hlt">wind</span> dynamo. We use data from the Wideband Imaging Camera on the IMAGE spacecraft which during its lifetime from 2000-2005 covered both hemispheres. To ease comparison of the two hemispheres, seasonal differences in auroral brightness is removed as far as data coverage allows by only using events having small dipole tilt angles. Hence, the IMF Bx is expected to be the controlling parameter for the hemispheric preference of strongest <span class="hlt">solar</span> <span class="hlt">wind</span> dynamo efficiency in our dataset. Preliminary statistical results indicate the expected opposite behaviour in the two hemispheres, however, the effect is believed to be weak.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/5275459','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/5275459"><span id="translatedtitle">Mean <span class="hlt">wind</span> forces on parabolic-trough <span class="hlt">solar</span> collectors</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Peterka, J.A.; Sinau, J.M.; Cermak, J.E.</p> <p>1980-05-01</p> <p>The purpose of this study was to investigate characteristics of mean <span class="hlt">wind</span> loads produced by airflow in and around several configurations of parabolic trough <span class="hlt">solar</span> collectors with and without a <span class="hlt">wind</span> fence. Four basic parabolic shapes were investigated as single units and one shape was studied as part of several array fields. One 1:25 scale model of each parabolic shape was constructed for mounting on a force balance to measure two forces and three moments. The effects of several dominant variables were investigated in this study: <span class="hlt">wind</span>-azimuth (or yaw), trough elevation (or pitch) angle, array field configuration, and protective <span class="hlt">wind</span> fence characteristics. All measurements were made in a boundary-layer flow developed by the meteorological <span class="hlt">wind</span> tunnel at the Fluid Dynamics and Diffusion Laboratory of Colorado State University. Results are presented and discussed. (WHK)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015ApJ...801..100S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015ApJ...801..100S"><span id="translatedtitle">On the Origin of Mid-latitude Fast <span class="hlt">Wind</span>: Challenging the Two-state <span class="hlt">Solar</span> <span class="hlt">Wind</span> Paradigm</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Stakhiv, Mark; Landi, Enrico; Lepri, Susan T.; Oran, Rona; Zurbuchen, Thomas H.</p> <p>2015-03-01</p> <p>The bimodal paradigm of <span class="hlt">solar</span> <span class="hlt">wind</span> describes a slow <span class="hlt">solar</span> <span class="hlt">wind</span> situated near the heliospheric current sheet while a fast <span class="hlt">wind</span> overexpands from the poles to fill in the remainder of the heliosphere. In this paper, we challenge this paradigm and focus here on mid-latitude <span class="hlt">wind</span> using three fast-latitude passes completed by the Ulysses spacecraft. Based on its composition and dynamic properties, we discuss how this <span class="hlt">wind</span> differs from both the fast, polar coronal hole <span class="hlt">wind</span> and the low latitude, streamer-associated slow <span class="hlt">solar</span> <span class="hlt">wind</span>. Using a detailed analysis of ionic and elemental abundances, as well as <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic properties, we conclude that there is a third quasi-stationary <span class="hlt">solar</span> <span class="hlt">wind</span> state, called the boundary <span class="hlt">wind</span>. This boundary <span class="hlt">wind</span> is characterized by a charge-state distribution that is similar to slow <span class="hlt">wind</span>, but with an elemental composition that is coronal hole like. Based on these data, we present arguments for the location of the origin of this <span class="hlt">wind</span>. We conclude that the boundary <span class="hlt">wind</span> is a subset of the fast <span class="hlt">wind</span> emanating from regions close to the boundaries of coronal holes and is accelerated by a similar process.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002PhDT........14K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002PhDT........14K"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> plasma: Kinetic properties and micro- instabilities</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kasper, Justin Christophe</p> <p>2002-11-01</p> <p>The kinetic properties of ions in the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma are studied. Observations of <span class="hlt">solar</span> <span class="hlt">wind</span> +H and +2He by the Faraday Cup instrument component of the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Experiment on the <span class="hlt">Wind</span> spacecraft show that these ions have magnetic field- aligned, convected, bi-Maxwellian velocity distribution functions. The analysis yields the best-fit values of the bulk velocity, U? , number density n, and parallel T ? and perpendicular T? temperatures of each of the ion species. The accuracy of each of these measurements is studied and an absolute calibration of the Faraday Cup is performed, demonstrating the accuracy of the densities to ?2%. The range of the proton temperature anisotropy Rp ? T?p/T ?p is explored, and it is demonstrated that thermodynamic concepts such as the double adiabatic equations of state are insufficient approximations for a kinetic description of the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma. It is shown that Rp is constrained on macroscopic timescales by Coulomb relaxation and the expansion of the <span class="hlt">solar</span> <span class="hlt">wind</span>, and on kinetic timescales by the mirror, cyclotron, and firehose plasma micro- instabilities. Electromagnetic fluctuations generated by growing mirror and cyclotron modes are detected in the <span class="hlt">solar</span> <span class="hlt">wind</span>. The first detailed observations of the firehose instability are presented. The limiting bounds to Rp imposed by each of these instabilities are measured and compared with the theoretical predictions of fluid magnetohydrodynamics, linear kinetic Vlasov theory, and numerical simulations. It is shown that the predictions of linear theory and the simulations are in agreement with the observations. A new proton temperature anisotropy driven instability in the regieme Rp < 1, ? ?p < 1 is discovered. The kinetic properties of +H and +2He are compared. For the first time a cyclotron resonant instability driven by the proton temperature anisotropy is demonstrated to limit the differential flow DU??U? a- Up attainable in the <span class="hlt">solar</span> <span class="hlt">wind</span>, in confirmation of recent theoretical predictions. It is shown that the +2He temperature anisotropy R? ? T??/T ?? is also constrained by micro- instabilities, and the first observations of the +2He cyclotron and firehose instabilities are presented. The parallel and perpendicular temperatures of +H and +2He are compared, and evidence of cyclotron-resonant heating of +2He preferentially to +H in the interplanetary medium is presented. (Copies available exclusively from MIT Libraries, Rm. 14-0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax 617-253-1690.)</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20110016219&hterms=open+source&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dopen%2Bsource','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110016219&hterms=open+source&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dopen%2Bsource"><span id="translatedtitle">A Model fot the Sources of the Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Antiochos, S. K.; Mikic, Z.; Titov, V. S.; Lionello, R.; Linker, J. A.</p> <p>2011-01-01</p> <p>Models for the origin of the slow <span class="hlt">solar</span> <span class="hlt">wind</span> must account for two seemingly contradictory observations: the slow <span class="hlt">wind</span> has the composition of the closed-field corona, implying that it originates from the continuous opening and closing of flux at the boundary between open and closed field. On the other hand, the slow <span class="hlt">wind</span> also has large angular width, up to approx.60deg, suggesting that its source extends far from the open-closed boundary. We propose a model that can explain both observations. The key idea is that the source of the slow <span class="hlt">wind</span> at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices and quasi-separatrix layers in the heliosphere. We compute analytically the topology of an open-field corridor and show that it produces a quasi-separatrix layer in the heliosphere that extends to angles far from the heliospheric current sheet. We then use an MHD code and MDI/SOHO observations of the photospheric magnetic field to calculate numerically, with high spatial resolution, the quasi-steady <span class="hlt">solar</span> <span class="hlt">wind</span>, and magnetic field for a time period preceding the 2008 August 1 total <span class="hlt">solar</span> eclipse. Our numerical results imply that, at least for this time period, a web of separatrices (which we term an S-web) forms with sufficient density and extent in the heliosphere to account for the observed properties of the slow <span class="hlt">wind</span>. We discuss the implications of our S-web model for the structure and dynamics of the corona and heliosphere and propose further tests of the model. Key words: <span class="hlt">solar</span> <span class="hlt">wind</span> - Sun: corona - Sun: magnetic topology</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20020069138&hterms=Ulysses&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DUlysses','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20020069138&hterms=Ulysses&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3DUlysses"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Characteristics from SOHO-Sun-Ulysses Quadrature Observations</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Poletto, Giannina; Suess, Steve T.; Six, N. Frank (Technical Monitor)</p> <p>2002-01-01</p> <p>Over the past few years, we have been running SOHO (<span class="hlt">Solar</span> and Heliospheric Observatory)-Sun-Ulysses quadrature campaigns, aimed at comparing the plasma properties at coronal altitudes with plasma properties at interplanetary distances. Coronal plasma has been observed by SOHO experiments: mainly, we used LASCO (Large Angle and Spectrometric Coronagraph Experiment) data to understand the overall coronal configuration at the time of quadratures and analyzed SUMER (<span class="hlt">Solar</span> Ultraviolet Measurements of Emitted Radiation), CDS (Coronal Diagnostic Spectrometer) and UVCS (Ultraviolet Coronagraph Spectrometer) data to derive its physical characteristics. At interplanetary distances, SWICS (<span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Composition Spectrometer) and SWOOPS (<span class="hlt">Solar</span> <span class="hlt">Wind</span> Observation over the Poles of the Sun) aboard Ulysses provided us with interplanetary plasma data. Here we report on results from some of the campaigns. We notice that, depending on the geometry of the quadrature, i.e. on whether the radial to Ulysses traverses the corona at high or low latitudes, we are able to study different kinds of <span class="hlt">solar</span> <span class="hlt">wind</span>. In particular, a comparison between low-latitude and high-latitude <span class="hlt">wind</span>, allowed us to provide evidence for differences in the acceleration of polar, fast plasma and equatorial, slow plasma: the latter occurring at higher levels and through a more extended region than fast <span class="hlt">wind</span>. These properties are shared by both the proton and heavy ions outflows. Quadrature observations may provide useful information also on coronal vs. in situ elemental composition. To this end, we analyzed spectra taken in the corona, at altitudes ranging between approx. 1.02 and 2.2 <span class="hlt">solar</span> radii, and derived the abundances of a number of ions, including oxygen and iron. Values of the O/Fe ratio, at coronal levels, have been compared with measurements of this ratio made by SWICS at interplanetary distances. Our results are compared with previous findings and predictions from modeling efforts.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/1045074','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/1045074"><span id="translatedtitle">Enabling Technologies for High Penetration of <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Energy</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Denholm, P.</p> <p>2011-01-01</p> <p>High penetration of variable <span class="hlt">wind</span> and <span class="hlt">solar</span> electricity generation will require modifications to the electric power system. This work examines the impacts of variable generation, including uncertainty, ramp rate, ramp range, and potentially excess generation. Time-series simulations were performed in the Texas (ERCOT) grid where different mixes of <span class="hlt">wind</span>, <span class="hlt">solar</span> photovoltaic and concentrating <span class="hlt">solar</span> power provide up to 80% of the electric demand. Different enabling technologies were examined, including conventional generator flexibility, demand response, load shifting, and energy storage. A variety of combinations of these technologies enabled low levels of surplus or curtailed <span class="hlt">wind</span> and <span class="hlt">solar</span> generation depending on the desired penetration of renewable sources. At lower levels of penetration (up to about 30% on an energy basis) increasing flexible generation, combined with demand response may be sufficient to accommodate variability and uncertainty. Introduction of load-shifting through real-time pricing or other market mechanisms further increases the penetration of variable generation. The limited time coincidence of <span class="hlt">wind</span> and <span class="hlt">solar</span> generation presents increasing challenges as these sources provide greater than 50% of total demand. System flexibility must be increased to the point of virtually eliminating must-run baseload generators during periods of high <span class="hlt">wind</span> and <span class="hlt">solar</span> generation. Energy storage also becomes increasingly important as lower cost flexibility options are exhausted. The study examines three classes of energy storage - electricity storage, including batteries and pumped hydro, hybrid storage (compressed-air energy storage), and thermal energy storage. Ignoring long-distance transmission options, a combination of load shifting and storage equal to about 12 hours of average demand may keep renewable energy curtailment below 10% in the simulated system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012cosp...39.1229M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012cosp...39.1229M"><span id="translatedtitle">Electric <span class="hlt">Solar</span> <span class="hlt">Wind</span> Sail (E-sail) mission to asteroids</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Merikallio, Sini; Janhunen, Pekka; Toivanen, Petri; Jouni Envall, M.(Tech.).</p> <p>2012-07-01</p> <p>There are an estimated one to two million asteroids of diameter over 1 km in-between the orbits of Mars and Jupiter. Impact threat, mining prospects and the understanding of <span class="hlt">solar</span> system history make asteroids interesting objects for further in-situ studies. Electric <span class="hlt">Solar</span> <span class="hlt">Wind</span> Sail (E-sail) [1] technology enables touring several different asteroids with the same spacecraft. It is a propulsion technology first proposed in 2006 and currently developed with the EUs FP7 funding (http://www.electric-sailing.fi/fp7). The E-sail utilizes long, conducting, highly charged tethers to gather momentum from the <span class="hlt">solar</span> <span class="hlt">wind</span> ions. It does not consume any propellant and is well maneuverable. The Electric <span class="hlt">Solar</span> <span class="hlt">Wind</span> Sail producing 1 N of thrust at 1 AU distance from the Sun could be manufactured to weigh 100-150 kg in total. The constant acceleration gives a large advantage over traditional methods when calculated over the mission lifetime. In a ten year mission a baseline 1 N E-sail could produce 300 MNs of total impulse, Itot. As an example, such a total impulse would be able to move a 3 million ton Earth-threatening asteroid to a safer track [2]. With chemical propellant it would take 100 000 tons of fuel to achieve the same feat. Scientists and miners could have a closer look at several targets and they could decide the next target and the duration of investigations once at the vicinity of the asteroid, so the operations would be very flexible. Such a mission could characterize and map several asteroids, some with rapid fly-bys and a few chosen ones during lengthier rendezvous. [1] Janhunen, P., et. al, Electric <span class="hlt">solar</span> <span class="hlt">wind</span> sail: Towards test missions (Invited article), Rev. Sci. Instrum., 81, 111301, 2010. [2] Merikallio, S. and P. Janhunen, Moving an asteroid with electric <span class="hlt">solar</span> <span class="hlt">wind</span> sail, Astrophys. Space Sci. Trans., 6, 41-48, 2010</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1211591','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1211591"><span id="translatedtitle"><span class="hlt">Solar</span> and <span class="hlt">solar-wind</span> composition results from the genesis mission</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wiens, Roger C.; Burnett, D. S.; Hohenberg, C. M.; Meshik, A.; Heber, V.; Grimberg, A.; Wieler, R.; Reisenfeld, D. B.</p> <p>2007-02-20</p> <p>The Genesis mission returned samples of <span class="hlt">solar</span> <span class="hlt">wind</span> to Earth in September, 2004 for ground-based analyses of <span class="hlt">solar-wind</span> composition, particularly for isotope ratios. Substrates, consisting mostly of high-purity semiconductor materials, were exposed to the <span class="hlt">solar</span> <span class="hlt">wind</span> at L1 from December 2001 to April 2004. In addition to a bulk sample of the <span class="hlt">solar</span> <span class="hlt">wind</span>, separate samples of coronal hole, interstream, and coronal mass ejection material were obtained. While many of the substrates were broken upon landing due to the failure to deploy the parachute, a number of results have been obtained, and most of the primary science objectives will likely be met. These include noble gas (He, Ne, Ar, Kr, and Xe) isotope ratios in the bulk <span class="hlt">solar</span> <span class="hlt">wind</span> and in different solarwind regimes, and the nitrogen and oxygen isotope ( <sup>18</sup>O/<sup>17</sup>O/<sup>16</sup>O) ratios to high precision. The greatest successes to date have been with the noble gases. Light noble gases from bulk <span class="hlt">solar</span> <span class="hlt">wind</span> and separate <span class="hlt">solar-wind</span> regime samples have been analyzed to date. The regime compositions are so far ambiguous on the occurrence of the type of isotopic fractionation expected from Coulomb drag acceleration. Neon results from closed system stepped etching of bulk metallic glass have revealed the nature of isotopic fractionation as a function of depth, which in lunar samples have for years deceptively suggested the presence of a separate <span class="hlt">solar</span> component. Isotope ratios of the heavy noble gases, nitrogen, and oxygen are still in the process of being measured.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2002EGSGA..27.2918R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2002EGSGA..27.2918R"><span id="translatedtitle">Large and Fast <span class="hlt">Solar</span> <span class="hlt">Wind</span> Ion Flux (density) Pulses and Their Possible <span class="hlt">Solar</span> Sources</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Riazantseva, M. O.; Dalin, P. A.; Zastenker, G. N.; Eselevich, M. V.; Eselevich, V. G.</p> <p></p> <p>The special consideration was performed of the large disturbances of <span class="hlt">solar</span> <span class="hlt">wind</span> ion flux (or density, or dynamic pressure) pulses with very sharp fronts. Study of such changes is important as for determination of the nature and properties of plasma insta- bilities on the way of <span class="hlt">solar</span> plasma from Sun to the Earth, as for the understanding of the features of <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere interaction (Space Weather problems). The large set (about 30,000) of the significant (more than 0.5 · E + 08 cm-2 s-1) and fast (shorter than 10 min.) jumps of <span class="hlt">solar</span> <span class="hlt">wind</span> ion flux were selected by obser- vations with high time resolution onboard INTERBALL-1 satellite during 1996-1999 and were compared with other spacecraft (<span class="hlt">WIND</span>, IMP-8, Geotail) data. The absolute and relative values of flux (or pressure) changes, the frequency of their observations as the dependence on their amplitudes, and the behavior of other <span class="hlt">solar</span> <span class="hlt">wind</span> (velocity, temperature) and magnetic field (magnitude and direction) parame- ters were statistically studied. For the subset of about hundred the strongest density changes the conservation of pressure balance (thermal+ magnetic ones) was investi- gated and it was shown that in the many cases such balance is not supported for fast plasma jumps. Also we tried to associate these sharp pulses with possible <span class="hlt">solar</span> sources. Our statistics show that the strong plasma jumps are observed not homogeneously but concentrated in some groups of days that are definitely connected to the slow <span class="hlt">solar</span> <span class="hlt">wind</span> from streamer belts on the Sun or to the <span class="hlt">solar</span> <span class="hlt">wind</span> disturbed by interplanetary shocks.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014ApJ...781L...7L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014ApJ...781L...7L"><span id="translatedtitle">Implications of the Recent Low <span class="hlt">Solar</span> Minimum for the <span class="hlt">Solar</span> <span class="hlt">Wind</span> during the Maunder Minimum</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Lockwood, M.; Owens, M. J.</p> <p>2014-01-01</p> <p>The behavior of the Sun and near-Earth space during grand <span class="hlt">solar</span> minima is not understood; however, the recent long and low minimum of the decadal-scale <span class="hlt">solar</span> cycle gives some important clues, with implications for understanding the <span class="hlt">solar</span> dynamo and predicting space weather conditions. The speed of the near-Earth <span class="hlt">solar</span> <span class="hlt">wind</span> and the strength of the interplanetary magnetic field (IMF) embedded within it can be reliably reconstructed for before the advent of spacecraft monitoring using observations of geomagnetic activity that extend back to the mid-19th century. We show that during the <span class="hlt">solar</span> cycle minima around 1879 and 1901 the average <span class="hlt">solar</span> <span class="hlt">wind</span> speed was exceptionally low, implying the Earth remained within the streamer belt of slow <span class="hlt">solar</span> <span class="hlt">wind</span> flow for extended periods. This is consistent with a broader streamer belt, which was also a feature of the recent low minimum (2009), and yields a prediction that the low near-Earth IMF during the Maunder minimum (1640-1700), as derived from models and deduced from cosmogenic isotopes, was accompanied by a persistent and relatively constant <span class="hlt">solar</span> <span class="hlt">wind</span> of speed roughly half the average for the modern era.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22364040','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22364040"><span id="translatedtitle">IMPLICATIONS OF THE RECENT LOW <span class="hlt">SOLAR</span> MINIMUM FOR THE <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> DURING THE MAUNDER MINIMUM</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Lockwood, M.; Owens, M. J.</p> <p>2014-01-20</p> <p>The behavior of the Sun and near-Earth space during grand <span class="hlt">solar</span> minima is not understood; however, the recent long and low minimum of the decadal-scale <span class="hlt">solar</span> cycle gives some important clues, with implications for understanding the <span class="hlt">solar</span> dynamo and predicting space weather conditions. The speed of the near-Earth <span class="hlt">solar</span> <span class="hlt">wind</span> and the strength of the interplanetary magnetic field (IMF) embedded within it can be reliably reconstructed for before the advent of spacecraft monitoring using observations of geomagnetic activity that extend back to the mid-19th century. We show that during the <span class="hlt">solar</span> cycle minima around 1879 and 1901 the average <span class="hlt">solar</span> <span class="hlt">wind</span> speed was exceptionally low, implying the Earth remained within the streamer belt of slow <span class="hlt">solar</span> <span class="hlt">wind</span> flow for extended periods. This is consistent with a broader streamer belt, which was also a feature of the recent low minimum (2009), and yields a prediction that the low near-Earth IMF during the Maunder minimum (1640-1700), as derived from models and deduced from cosmogenic isotopes, was accompanied by a persistent and relatively constant <span class="hlt">solar</span> <span class="hlt">wind</span> of speed roughly half the average for the modern era.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_17");'>17</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li class="active"><span>19</span></li> <li><a href="#" onclick='return showDiv("page_20");'>20</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_19 --> <div id="page_20" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_18");'>18</a></li> <li><a href="#" onclick='return showDiv("page_19");'>19</a></li> <li class="active"><span>20</span></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="381"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770059881&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770059881&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D90%26Ntt%3Dlazarus"><span id="translatedtitle">A comparison of <span class="hlt">solar</span> <span class="hlt">wind</span> streams and coronal structure near <span class="hlt">solar</span> minimum</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Nolte, J. T.; Davis, J. M.; Gerassimenko, M.; Lazarus, A. J.; Sullivan, J. D.</p> <p>1977-01-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> data from the MIT detectors on the IMP 7 and 8 satellites and the SOLRAD 11B satellite for the <span class="hlt">solar</span>-minimum period September-December, 1976, were compared with X-ray images of the <span class="hlt">solar</span> corona taken by rocket-borne telescopes on September 16 and November 17, 1976. There was no compelling evidence that a coronal hole was the source of any high speed stream. Thus it is possible that either coronal holes were not the sources of all recurrent high-speed <span class="hlt">solar</span> <span class="hlt">wind</span> streams during the declining phase of the <span class="hlt">solar</span> cycle, as might be inferred from the Skylab period, or there was a change in the appearance of some magnetic field regions near the time of <span class="hlt">solar</span> minimum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/282791','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/282791"><span id="translatedtitle">Physical nature of the low-speed <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gosling, J.T.</p> <p>1996-09-01</p> <p>In situ observations indicate that the low-speed <span class="hlt">wind</span> is highly variable. It commonly originates on open field lines that thread coronal streamers in the vicinity of the magnetic equator, but transient ejections are also a source of low-speed flows on occasion. Close to the Sun a large flow shear probably is common at the interface between low- and high-speed flows. Near <span class="hlt">solar</span> activity minimum low-speed flows are confined to a narrow band 40-45{degree} wide centered roughly on the <span class="hlt">solar</span> equator, but near <span class="hlt">solar</span> maximum low-speed flows may dominate at all heliographic latitudes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21163473','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21163473"><span id="translatedtitle">A review of <span class="hlt">solar</span> <span class="hlt">wind</span> ion and electron plasma distributions: Present understanding and Ulysses results</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Goldstein, B. E.</p> <p>1996-07-20</p> <p>Unlike the oral version of this paper at <span class="hlt">Solar</span> <span class="hlt">Wind</span> 8, this written version is not intended as an overview of the observational aspects of <span class="hlt">solar</span> <span class="hlt">wind</span> ion and electron distributions, but discusses only recent results in this area with emphasis on Ulysses measurements. Although primarily a review, some new results on <span class="hlt">solar</span> <span class="hlt">wind</span> proton temperatures at high latitudes are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSM31C4217L','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSM31C4217L"><span id="translatedtitle">Response of polar cap to <span class="hlt">solar</span> <span class="hlt">wind</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>Liou, K.; Sotirelis, T.</p> <p>2014-12-01</p> <p>The ionospheric polar cap is an optically dark area encircled by the luminous auroral oval. It is created by <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetospheric coupling, and its size is proportional to the open magnetic flux available for nightside reconnection. One of the difficulties in the study of <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere coupling is the large spatial domain it involves. Systematic studies of the polar cap dynamics are still rare. This study addresses this issue by utilizing global auroral images, from which the polar cap area can be extracted, acquired with the Ultraviolet Imager on board the Polar satellite. In particular, we quantify the area of polar cap and correlate it with <span class="hlt">solar</span> <span class="hlt">wind</span> parameters. Our preliminary results clearly demonstrate, as expected, a clear relationship between the dayside polar cap area and the north-south component of the interplanetary magnetic field. Other <span class="hlt">solar</span> <span class="hlt">wind</span> parameters also affect the polar cap size but with a lesser degree. We will present a detailed analysis and discuss the resulting implications.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1218485','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1218485"><span id="translatedtitle">Western <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Integration Study: Executive Summary</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>none,</p> <p>2010-05-01</p> <p>This Study investigates the operational impact of up to 35% energy penetration of <span class="hlt">wind</span>, photovoltaics (PVs), and concentrating <span class="hlt">solar</span> power (CSP) on the power system operated by the WestConnect group of utilities in Arizona, Colorado, Nevada, New Mexico, and Wyoming.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010mcia.conf..531B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010mcia.conf..531B"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Monitoring with SWIM-SARA Onboard Chandrayaan-1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhardwaj, A.; Barabash, S.; Sridharan, R.; Wieser, M.; Dhanya, M. B.; Futaana, Y.; Asamura, K.; Kazama, Y.; McCann, D.; Varier, S.; Vijayakumar, E.; Mohankumar, S. V.; Raghavendra, K. V.; Kurian, T.; Thampi, R. S.; Andersson, H.; Svensson, J.; Karlsson, S.; Fischer, J.; Holmstrom, M.; Wurz, P.; Lundin, R.</p> <p></p> <p>The SARA experiment aboard the Indian lunar mission Chandrayaan-1 consists of two instruments: Chandrayaan-1 Energetic Neutral Analyzer (CENA) and the <span class="hlt">SolarWind</span> Monitor (SWIM). CENA will provide measurements of low energy neutral atoms sputtered from lunar surface in the 0.01-3.3 keV energy range by the impact of <span class="hlt">solar</span> <span class="hlt">wind</span> ions. SWIM will monitor the <span class="hlt">solar</span> <span class="hlt">wind</span> flux precipitating onto the lunar surface and in the vicinity of moon. SWIM is basically an ion-mass analyzer providing energy-per-charge and number density of <span class="hlt">solar</span> <span class="hlt">wind</span> ions in the energy range 0.01-15 keV. It has sufficient mass resolution to resolve H+ , He++, He+, O++, O+, and >20 amu, with energy resolution 7% and angular resolution 4:5 22:5. The viewing angle of the instrument is 9 180.Mechanically, SWIM consists of a sensor and an electronic board that includes high voltage supply and sensor electronics. The sensor part consists of an electrostatic deflector to analyze the arrival angle of the ions, cylindrical electrostatic analyzer for energy analysis, and the time-of-flight system for particle velocity determination. The total size of SWIM is slightly larger than a credit card and has a mass of 500 g.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930032138&hterms=leer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dleer','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930032138&hterms=leer&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dleer"><span id="translatedtitle">A parameter study of the two-fluid <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sandbaek, Ornulf; Leer, Egil; Holzer, Thomas E.</p> <p>1992-01-01</p> <p>A two-fluid model of the <span class="hlt">solar</span> <span class="hlt">wind</span> was introduced by Sturrock and Hartle (1966) and Hartle and Sturrock (1968). In these studies the proton energy equation was integrated neglecting the heat conductive term. Later several authors solved the equations for the two-fluid <span class="hlt">solar</span> <span class="hlt">wind</span> model keeping the proton heat conductive term. Methods where the equations are integrated simultaneously outward and inward from the critical point were used. The equations were also integrated inward from a large heliocentric distance. These methods have been applied to cases with low coronal base electron densities and high base temperatures. In this paper we present a method of integrating the two-fluid <span class="hlt">solar</span> <span class="hlt">wind</span> equations using an iteration procedure where the equations are integrated separately and the proton flux is kept constant during the integrations. The technique is applicable for a wide range of coronal base densities and temperatures. The method is used to carry out a parameter study of the two-fluid <span class="hlt">solar</span> <span class="hlt">wind</span>.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950058917&hterms=Heating+frequency&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DHeating%2Bfrequency','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950058917&hterms=Heating+frequency&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3DHeating%2Bfrequency"><span id="translatedtitle">Alpha particle heating at comet-<span class="hlt">solar</span> <span class="hlt">wind</span> interaction regions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sharma, A. S.; Papadopoulos, K.</p> <p>1995-01-01</p> <p>The satellite observations at comet Halley have shown strong heating of <span class="hlt">solar</span> <span class="hlt">wind</span> alpha particles over an extended region dominated by high-intensity, low-frequency turbulence. These waves are excited by the water group pickup ions and can energize the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma by different heating processes. The alpha particle heating by the Landau damping of kinetic Alfven waves and the transit time damping of low-frequency hydromagnetic waves in this region of high plasma beta are studied in this paper. The Alfven wave heating was shown to be the dominant mechanism for the observed proton heating, but it is found to be insufficient to account for the observed alpha particle heating. The transit time damping due to the interaction of the ions with the electric fields associated with the magnetic field compressions of magnetohydrodynamic waves is found to heat the alpha particles preferentially over the protons. Comparison of the calculated heating times for the transit time damping with the observations from comet Halley shows good agreement. These processes contribute to the thermalization of the <span class="hlt">solar</span> <span class="hlt">wind</span> by the conversion of its directed energy into the thermal energy in the transition region at comet-<span class="hlt">solar</span> <span class="hlt">wind</span> interaction.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&list_uids=19238948&dopt=AbstractPlus','TOXNETTOXLINE'); return false;" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&list_uids=19238948&dopt=AbstractPlus"><span id="translatedtitle">Air emissions due to <span class="hlt">wind</span> and <span class="hlt">solar</span> power.</span></a></p> <p><a target="_blank" href="http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?TOXLINE">TOXLINE Toxicology Bibliographic Information</a></p> <p>Katzenstein W; Apt J</p> <p>2009-01-15</p> <p>Renewables portfolio standards (RPS) encourage large-scale deployment of <span class="hlt">wind</span> and <span class="hlt">solar</span> electric power. Their power output varies rapidly, even when several sites are added together. In many locations, natural gas generators are the lowest cost resource available to compensate for this variability, and must ramp up and down quickly to keep the grid stable, affecting their emissions of NOx and CO2. We model a <span class="hlt">wind</span> or <span class="hlt">solar</span> photovoltaic plus gas system using measured 1-min time-resolved emissions and heat rate data from two types of natural gas generators, and power data from four <span class="hlt">wind</span> plants and one <span class="hlt">solar</span> plant. Over a wide range of renewable penetration, we find CO2 emissions achieve approximately 80% of the emissions reductions expected if the power fluctuations caused no additional emissions. Using steam injection, gas generators achieve only 30-50% of expected NOx emissions reductions, and with dry control NOx emissions increase substantially. We quantify the interaction between state RPSs and NOx constraints, finding that states with substantial RPSs could see significant upward pressure on NOx permit prices, if the gas turbines we modeled are representative of the plants used to mitigate <span class="hlt">wind</span> and <span class="hlt">solar</span> power variability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950048909&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dlazarus','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950048909&hterms=lazarus&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dlazarus"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> oscillations with a 1.3 year period</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richardson, John D.; Paularena, Karolen I.; Belcher, John W.; Lazarus, Alan J.</p> <p>1994-01-01</p> <p>The Interplanetary Monitoring Platform 8 (IMP-8) and Voyager 2 spacecraft have recently detected a very strong modulation in the <span class="hlt">solar</span> <span class="hlt">wind</span> speed with an approximately 1.3 year period. Combined with evidence from long-term auroral and magnetometer studies, this suggests that fundamental changes in the Sun occur on a roughly 1.3 year time scale.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015EGUGA..1713062B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015EGUGA..1713062B"><span id="translatedtitle">The <span class="hlt">Solar-Wind</span> Interaction with Comet Churyumov-Gerasimenko</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Burch, James</p> <p>2015-04-01</p> <p>The instruments of the Rosetta Plasma Consortium are providing close-up views of the <span class="hlt">solar-wind</span> interaction with a comet from its dormancy into a period of significant coma development. Although a bow shock has not yet developed, the interactions so far involve significant deflection of the <span class="hlt">solar</span> <span class="hlt">wind</span>; pickup of cometary ions, charge exchange of <span class="hlt">solar-wind</span> ions by the coma resulting in He+ and H- ions being entrained in the <span class="hlt">solar</span> <span class="hlt">wind</span>; the generation of low-frequency 10 - 100 mHz magnetic waves near the comet; electric-fields and waves in the range from DC up to 3.5 MHz, and significant plasma density enhancements, particularly over the neck of the comet. Also observed are negatively-charged nanograins with energies exceeding 20 keV and monoenergetic electron beams (up to 400 eV) indicative of negative charging of shaded regions of the nucleus. As the comet moves closer to the Sun these effects should increase along with the appearance of other expected effects such as a diamagnetic cavity, ionopause, and bow shock along with possibly other new and unexpected plasma and field phenomena.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001GeoRL..28.1355B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001GeoRL..28.1355B"><span id="translatedtitle">Generation mechanism for magnetic holes in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Buti, B.; Tsurutani, B. T.; Neugebauer, M.; Goldstein, B. E.</p> <p>2001-04-01</p> <p>A new mechanism for generation of magnetic holes in the <span class="hlt">solar</span> <span class="hlt">wind</span> is presented. In the high speed <span class="hlt">solar</span> <span class="hlt">wind</span>, large-amplitude right-hand polarized Alfvnic wave packets propagating at large angles to the ambient magnetic field are shown to generate magnetic holes (MHs). Characteristics of these holes crucially depend on plasma ? (? being the ratio of kinetic pressure to magnetic pressure) and the ratio of electron temperature Te to proton temperature Ti. Proton temperature anisotropy is found to be favorable but not essential for the development of MHs. From our simulations we observe MHs with microstructures bounded by sharp gradients (magnetic decreases) in some cases. The holes generated by this process have thicknesses of hundreds of ion Larmor radii, typical of many of the <span class="hlt">solar</span> <span class="hlt">wind</span> hole observations, the depths of the holes are also comparable. The theory can explain the presence of MHs seen in the <span class="hlt">solar</span> <span class="hlt">wind</span> for those cases when anisotropies are not favorable for the development of the mirror mode instability.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008JGRA..113.3103S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008JGRA..113.3103S"><span id="translatedtitle">Electron temperature anisotropy constraints in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>tverK, t?pn; Trvn?ek, Pavel; Maksimovic, Milan; Marsch, Eckart; Fazakerley, Andrew N.; Scime, Earl E.</p> <p>2008-03-01</p> <p>We have performed a statistical study of a substantial amount of electron data acquired in the <span class="hlt">solar</span> <span class="hlt">wind</span> to understand the constraints on electron temperature anisotropy by plasma instabilities and Coulomb collisions. We use a large data set of electron measurements from three different spacecraft (Helios I, Cluster II, and Ulysses) collected in the low ecliptic latitudes covering the radial distance from the Sun from 0.3 up to 4 AU. We estimate the electron temperature anisotropy using fits of the measured electron velocity distribution functions acquired in situ. We use a two population (core and halo) analytical model and properties of both populations are studied separately. We examine all the acquired data in terms of temperature anisotropy versus parallel electron plasma beta, and we relate the measurements to the growth rates of unstable modes. The effect of Coulomb collisions is expressed by the electron collisional age Ae defined as the number of collisions suffered by an electron during the expansion of the <span class="hlt">solar</span> <span class="hlt">wind</span>. We show that both instabilities and collisions are strongly related to the isotropisation process of the electron core population. In addition we examine the radial evolution of these effects during the expansion of the <span class="hlt">solar</span> <span class="hlt">wind</span>. We show that the bulk of the <span class="hlt">solar</span> <span class="hlt">wind</span> electrons are constrained by Coulomb collisions, while the large departures from isotropy are constrained by instabilities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19730003086','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19730003086"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> interaction with Comet Bennett (1969i</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.; Rahe, J.; Donn, B. D.; Neugebauer, M.</p> <p>1972-01-01</p> <p>The relations are examined between the <span class="hlt">solar-wind</span> and Comet Bennett during the period 23 March to 5 April 1970. A large kink was observed in the ion tail of the comet on April 4, but no <span class="hlt">solar</span> <span class="hlt">wind</span> stream was observed in the ecliptic plane which could have caused the kink. Thus, either there was no correlation between the <span class="hlt">solar</span> <span class="hlt">wind</span> at the earth and that at Comet Bennett (which was 40 deg above the ecliptic) or the kink was caused by something other than a high-speed stream. The fine structure visible in photographs of the kink favors the second of these alternatives. It is shown that a shock probably passed through Comet Bennett on March 31, but no effect was seen in photographs of the comet. A stream preceded by another shock and a large abrupt change in momentum flux might have intercepted the comet between 24 March and 28 March, but again no effect was seen in photographs of the Comet. In view of these results, the possibility must be considered that a large, abrupt change in momentum flux of the <span class="hlt">solar-wind</span> is neither necessary nor sufficient to cause a large kink in a comet tail.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790052174&hterms=lemons&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dlemons','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790052174&hterms=lemons&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dlemons"><span id="translatedtitle">The source of electrostatic fluctuations in the <span class="hlt">solar-wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Lemons, D. S.; Asbridge, J. R.; Bame, S. J.; Feldman, W. C.; Gary, S. P.; Gosling, J. T.</p> <p>1979-01-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> electron and ion distribution functions measured simultaneously with or close to times of intense electrostatic fluctuations are subjected to a linear Vlasov stability analysis. Although all distributions tested were found to be stable, the analysis suggests that the ion beam instability is the most likely source of the fluctuations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20120010150&hterms=solar+energy+effects&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dsolar%2Benergy%2Beffects','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20120010150&hterms=solar+energy+effects&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dsolar%2Benergy%2Beffects"><span id="translatedtitle">The <span class="hlt">Solar</span> <span class="hlt">Wind</span> in the Outer Heliosphere and Heliosheath</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Richardson, J. D.; Burlaga, L. F.</p> <p>2011-01-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> environment has a large influence on the transport of cosmic rays. This chapter discusses the observations of the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma and magnetic field in the outer heliosphere and the heliosheath. In the supersonic <span class="hlt">solar</span> <span class="hlt">wind</span>, interaction regions with large magnetic fields form barriers to cosmic ray transport. This effect, the "CR-B" relationship, has been quantified and is shown to be valid everywhere inside the termination shock (TS). In the heliosheath, this relationship breaks down, perhaps because of a change in the nature of the turbulence. Turbulence is compressive in the heliosheath, whereas it was non-compressive in the <span class="hlt">solar</span> <span class="hlt">wind</span>. The plasma pressure in the outer heliosphere is dominated by the pickup ions which gain most of the flow energy at the TS. The heliosheath plasma and magnetic field are highly variable on scales as small as ten minutes. The plasma flow turns away from the nose roughly as predicted, but the radial speeds at Voyager 1 are much less than those at Voyager 2, which is not understood. Despite predictions to the contrary, magnetic reconnection is not an important process in the inner heliosheath with only one observed occurrence to date.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900047745&hterms=model+driven&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmodel%2Bdriven','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900047745&hterms=model+driven&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dmodel%2Bdriven"><span id="translatedtitle">Investigations of a turbulence-driven <span class="hlt">solar</span> <span class="hlt">wind</span> model</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Isenberg, Philip A.</p> <p>1990-01-01</p> <p>This work presents an investigation of the properties of the one-dimensional, two-fluid turbulence-driven <span class="hlt">solar</span> <span class="hlt">wind</span> model introduced by Hollweg and Johnson (1988). It is found that the model has serious difficulties in reproducing the observed high-speed <span class="hlt">wind</span> at 1 AU. In particular, the model proton temperatures are lower than those observed by a factor of 2 or more, and the highest temperature models yield excessive wave intensities at 1 AU. It appears that the problem stems from the specific spatial distribution of heat deposition in the model. Thus this study does not rule out a turbulence-driven fast <span class="hlt">solar</span> <span class="hlt">wind</span>, since other forms of the turbulent evolution could probably achieve better results. A three-fluid version of the model is also presented to show that the addition of alpha particles does not significantly reduce the extreme proton temperatures displayed near the sun by the Hollweg and Johnson work. Finally, it is suggested that the additional heating needs to be located well beyond the critical point, implying that the heating mechanism for the fast <span class="hlt">solar</span> <span class="hlt">wind</span> is likely not the same as that heating the <span class="hlt">solar</span> corona.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=227150','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=227150"><span id="translatedtitle">Livestock water pumping with <span class="hlt">wind</span> and <span class="hlt">solar</span> power</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>Recent developments in pumping technologies have allowed for efficient use of renewable energies like <span class="hlt">wind</span> and <span class="hlt">solar</span> to power new pumps for remote water pumping. A helical type, positive displacement pump was developed a few years ago and recently modified to accept input from a variable power sourc...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19840005044&hterms=Planck+Max&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2528Planck%2BMax%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19840005044&hterms=Planck+Max&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3D%2528Planck%2BMax%2529"><span id="translatedtitle">Iron charge states observed in the <span class="hlt">solar</span> <span class="hlt">wind</span></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.; Galvin, A. B.; Gloeckler, G.; Hovestadt, D.; Klecker, B.; Scholer, M.</p> <p>1983-01-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> measurements from the ULECA sensor of the Max-Planck-Institut/University of Maryland experiment on ISEE-3 are reported. The low energy section of approx the ULECA sensor selects particles by their energy per charge (over the range 3.6 keV/Q to 30 keV/Q) and simultaneously measures their total energy with two low-noise solid state detectors. <span class="hlt">Solar</span> <span class="hlt">wind</span> Fe charge state measurements from three time periods of high speed <span class="hlt">solar</span> <span class="hlt">wind</span> occurring during a post-shock flow and a coronal hole-associated high speed stream are presented. Analysis of the post-shock flow <span class="hlt">solar</span> <span class="hlt">wind</span> indicates the charge state distributions for Fe were peaked at approx +16, indicative of an unusually high coronal temperature (3,000,000 K). In contrast, the Fe charge state distribution observed in a coronal hole-associated high speed stream peaks at approx -9, indicating a much lower coronal temperature (1,400,000 K). This constitutes the first reported measurements of iron charge states in a coronal hole-associated high speed stream.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH11B4040M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH11B4040M"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Simulations Based on Ooty IPS Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Muehe, S. C.; Kim, T. K.; Pogorelov, N. V.</p> <p>2014-12-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> is a constantly-flowing stream of charged particles that expands from the sun's outer atmosphere into interplanetary space. This plasma carries the sun's magnetic field along with it, where it interacts with and causes disruptions in the earth's magnetic field. Our understanding of the <span class="hlt">solar</span> <span class="hlt">wind</span> is vital to efforts toward minimizing the impact of these disturbances on both ground and space-based systems. Using interplanetary scintillation data gathered by the ground-based Ooty Radio Telescope (ORT) in India, we have constructed boundary maps of <span class="hlt">solar</span> <span class="hlt">wind</span> velocities at 1 day intervals. For a simple, first approximation, we use what is called the "P-point" method to crudely estimate the <span class="hlt">solar</span> <span class="hlt">wind</span> velocity at the point of closest approach to the Sun along each line of sight. Then we trace the P-point values back to a spherical surface at 0.2 AU where we interpolate them to a structured gird. The resulting boundary maps can serve as the initial input to a time-dependent MHD tomography program being developed at the University of Alabama in Huntsville.</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://adsabs.harvard.edu/abs/2015TESS....120001J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015TESS....120001J"><span id="translatedtitle">How Reliable Is the Prediction of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Background?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jian, Lan K.; MacNeice, Peter; Taktakishvili, Aleksandre; Odstrcil, Dusan; Jackson, Bernard; Yu, Hsiu-Shan; Riley, Pete; Sokolov, Igor</p> <p>2015-04-01</p> <p>The prediction of <span class="hlt">solar</span> <span class="hlt">wind</span> background is a necessary part of space weather forecasting. Multiple coronal and heliospheric models have been installed at the Community Coordinated Modeling Center (CCMC) to produce the <span class="hlt">solar</span> <span class="hlt">wind</span>, including the Wang-Sheely-Arge (WSA)-Enlil model, MHD-Around-a-Sphere (MAS)-Enlil model, Space Weather Modeling Framework (SWMF), and heliospheric tomography using interplanetary scintillation (IPS) data. By comparing the modeling results with the OMNI data over 7 Carrington rotations in 2007, we have conducted a third-party validation of these models for the near-Earth <span class="hlt">solar</span> <span class="hlt">wind</span>. This work will help the models get ready for the transition from research to operation. Besides visual comparison, we have quantitatively assessed the models’ capabilities in reproducing the time series and statistics of <span class="hlt">solar</span> <span class="hlt">wind</span> parameters. Using improved algorithms, we have identified magnetic field sector boundaries (SBs) and slow-to-fast stream interaction regions (SIRs) as focused structures. The success rate of capturing them and the time offset vary largely with models. For this period, the 2014 version of MAS-Enlil model works best for SBs, and the heliospheric tomography works best for SIRs. General strengths and weaknesses for each model are identified to provide an unbiased reference to model developers and users.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010ASSP...19..531B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010ASSP...19..531B"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Monitoring with SWIM-SARA Onboard Chandrayaan-1</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Bhardwaj, A.; Barabash, S.; Sridharan, R.; Wieser, M.; Dhanya, M. B.; Futaana, Y.; Asamura, K.; Kazama, Y.; McCann, D.; Varier, S.; Vijayakumar, E.; Mohankumar, S. V.; Raghavendra, K. V.; Kurian, T.; Thampi, R. S.; Andersson, H.; Svensson, J.; Karlsson, S.; Fischer, J.; Holmstrom, M.; Wurz, P.; Lundin, R.</p> <p></p> <p>The SARA experiment aboard the Indian lunar mission Chandrayaan-1 consists of two instruments: Chandrayaan-1 Energetic Neutral Analyzer (CENA) and the <span class="hlt">SolarWind</span> Monitor (SWIM). CENA will provide measurements of low energy neutral atoms sputtered from lunar surface in the 0.01-3.3 keV energy range by the impact of <span class="hlt">solar</span> <span class="hlt">wind</span> ions. SWIM will monitor the <span class="hlt">solar</span> <span class="hlt">wind</span> flux precipitating onto the lunar surface and in the vicinity of moon. SWIM is basically an ion-mass analyzer providing energy-per-charge and number density of <span class="hlt">solar</span> <span class="hlt">wind</span> ions in the energy range 0.01-15 keV. It has sufficient mass resolution to resolve H+ , He++, He+, O++, O+, and >20 amu, with energy resolution 7% and angular resolution 4:5° × 22:5. The viewing angle of the instrument is 9° × 180°.Mechanically, SWIM consists of a sensor and an electronic board that includes high voltage supply and sensor electronics. The sensor part consists of an electrostatic deflector to analyze the arrival angle of the ions, cylindrical electrostatic analyzer for energy analysis, and the time-of-flight system for particle velocity determination. The total size of SWIM is slightly larger than a credit card and has a mass of 500 g.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021404&hterms=magnetic+anisotropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmagnetic%2Banisotropy','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021404&hterms=magnetic+anisotropy&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dmagnetic%2Banisotropy"><span id="translatedtitle">The latitudinal distribution of magnetic holes in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Winterhalter, D.; Neugebauer, M.; Smith, E. J.; Balogh, A.</p> <p>1995-01-01</p> <p>A large number of magnetic holes have been found in the Ulysses data during its cruise in the ecliptic. They are interpreted as convecting structures, probably caused by the mirror instability which exists in high beta plasmas with anisotropic temperatures. The characteristics of the holes reflect the <span class="hlt">solar</span> <span class="hlt">wind</span> condition of the region in which the holes are formed, and the point of observation may be far removed from where the instability occurs. A preliminary survey appears to indicate that the number of holes has no significant radial dependence. However, the number of holes does appear to increase with increasing heliographic latitude. Yet the large scale <span class="hlt">solar</span> <span class="hlt">wind</span> structures with their compression regions disappeared at approximately 57 deg south latitude. Thus any causal relationship between the holes and large scale <span class="hlt">solar</span> <span class="hlt">wind</span> structures is questionable. The temperature anisotropy and high beta required by the mirror instability must be generated by other mechanisms. In order to tie the magnetic holes and the mirror instability to their cause, the evolution of their characteristics with heliocentric distance and latitude needs to be investigated. With the progression of Ulysses around the sun a survey will be conducted to ascertain the characteristics of the magnetic holes as a function of heliographic latitude and heliocentric distance. A comparison of the results with the <span class="hlt">solar</span> <span class="hlt">wind</span> conditions may lead to the identification of the magnetic hole generating mechanism(s).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/19238948','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/19238948"><span id="translatedtitle">Air emissions due to <span class="hlt">wind</span> and <span class="hlt">solar</span> power.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Katzenstein, Warren; Apt, Jay</p> <p>2009-01-15</p> <p>Renewables portfolio standards (RPS) encourage large-scale deployment of <span class="hlt">wind</span> and <span class="hlt">solar</span> electric power. Their power output varies rapidly, even when several sites are added together. In many locations, natural gas generators are the lowest cost resource available to compensate for this variability, and must ramp up and down quickly to keep the grid stable, affecting their emissions of NOx and CO2. We model a <span class="hlt">wind</span> or <span class="hlt">solar</span> photovoltaic plus gas system using measured 1-min time-resolved emissions and heat rate data from two types of natural gas generators, and power data from four <span class="hlt">wind</span> plants and one <span class="hlt">solar</span> plant. Over a wide range of renewable penetration, we find CO2 emissions achieve approximately 80% of the emissions reductions expected if the power fluctuations caused no additional emissions. Using steam injection, gas generators achieve only 30-50% of expected NOx emissions reductions, and with dry control NOx emissions increase substantially. We quantify the interaction between state RPSs and NOx constraints, finding that states with substantial RPSs could see significant upward pressure on NOx permit prices, if the gas turbines we modeled are representative of the plants used to mitigate <span class="hlt">wind</span> and <span class="hlt">solar</span> power variability. PMID:19238948</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19760046362&hterms=solution+plasma+process&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsolution%2Bplasma%2Bprocess','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19760046362&hterms=solution+plasma+process&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsolution%2Bplasma%2Bprocess"><span id="translatedtitle">Depletion of <span class="hlt">solar</span> <span class="hlt">wind</span> plasma near a planetary boundary</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Zwan, B. J.; Wolf, R. A.</p> <p>1976-01-01</p> <p>A mathematical model is presented that describes the squeezing of <span class="hlt">solar</span> <span class="hlt">wind</span> plasma out along interplanetary magnetic field lines in the region between the bow shock and the effective planetary boundary (in the case of the earth, the magnetopause). In the absence of local magnetic merging the squeezing process should create a 'depletion layer', a region of very low plasma density just outside the magnetopause. Numerical solutions are obtained for the dimensionless magnetohydrodynamic equations describing this depletion process for the case where the <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic field is perpendicular to the <span class="hlt">solar</span> <span class="hlt">wind</span> flow direction. For the case of the earth, the theory predicts that the density should be reduced by a factor exceeding 2 in a layer about 700-1300 km thick if the Alfven Mach number in the <span class="hlt">solar</span> <span class="hlt">wind</span>, is equal to 8. Scaling of the model calculations to Venus and Mars suggests layer thicknesses about 1/10 and 1/15 those of the earth, respectively, neglecting diffusion and ionospheric effects.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('https://www.gpo.gov/fdsys/pkg/FR-2011-11-29/pdf/2011-29991.pdf','FEDREG'); return false;" href="https://www.gpo.gov/fdsys/pkg/FR-2011-11-29/pdf/2011-29991.pdf"><span id="translatedtitle">76 FR 73783 - Residential, Business, and <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Resource Leases on Indian Land</span></a></p> <p><a target="_blank" href="http://www.gpo.gov/fdsys/browse/collection.action?collectionCode=FR">Federal Register 2010, 2011, 2012, 2013, 2014</a></p> <p></p> <p>2011-11-29</p> <p>... energy evaluation and <span class="hlt">wind</span> and <span class="hlt">solar</span> resource development); (3) leases for religious, educational... <span class="hlt">wind</span> energy evaluation leases (WEELs) and <span class="hlt">wind</span> and <span class="hlt">solar</span> resource (WSR) development leases. For <span class="hlt">wind</span>... Native American Tribal Governments,'' Executive Order 13175 (59 FR 22951, November 6, 2000), and 512 DM...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19990028046&hterms=magnetic+signature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bsignature','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19990028046&hterms=magnetic+signature&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dmagnetic%2Bsignature"><span id="translatedtitle">Signature of open magnetic field lines in the extended <span class="hlt">solar</span> corona and of <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Antonucci, E.; Giordano, S.; Benna, C.; Kohl, J. L.; Noci, G.; Michels, J.; Fineschi, S.</p> <p>1997-01-01</p> <p>The observations carried out with the ultraviolet coronagraph spectrometer onboard the <span class="hlt">Solar</span> and Heliospheric Observatory (SOHO) are discussed. The purpose of the observations was to determine the line of sight and radial velocity fields in coronal regions with different magnetic topology. The results showed that the regions where the high speed <span class="hlt">solar</span> <span class="hlt">wind</span> flows along open field lines are characterized by O VI 1032 and HI Lyman alpha 1216 lines. The global coronal maps of the line of sight velocity were reconstructed. The corona height, where the <span class="hlt">solar</span> <span class="hlt">wind</span> reaches 100 km/s, was determined.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22036908','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22036908"><span id="translatedtitle">THREE-DIMENSIONAL EVOLUTION OF <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> DURING <span class="hlt">SOLAR</span> CYCLES 22-24</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Manoharan, P. K.</p> <p>2012-06-01</p> <p>This paper presents an analysis of three-dimensional evolution of <span class="hlt">solar</span> <span class="hlt">wind</span> density turbulence and speed at various levels of <span class="hlt">solar</span> activity between <span class="hlt">solar</span> cycles 22 and 24. The <span class="hlt">solar</span> <span class="hlt">wind</span> data used in this study have been obtained from the interplanetary scintillation (IPS) measurements made at the Ooty Radio Telescope, operating at 327 MHz. Results show that (1) on average, there was a downward trend in density turbulence from the maximum of cycle 22 to the deep minimum phase of cycle 23; (2) the scattering diameter of the corona around the Sun shrunk steadily toward the Sun, starting from 2003 to the smallest size at the deepest minimum, and it corresponded to a reduction of {approx}50% in the density turbulence between the maximum and minimum phases of cycle 23; (3) the latitudinal distribution of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed was significantly different between the minima of cycles 22 and 23. At the minimum phase of <span class="hlt">solar</span> cycle 22, when the underlying <span class="hlt">solar</span> magnetic field was simple and nearly dipole in nature, the high-speed streams were observed from the poles to {approx}30 Degree-Sign latitudes in both hemispheres. In contrast, in the long-decay phase of cycle 23, the sources of the high-speed <span class="hlt">wind</span> at both poles, in accordance with the weak polar fields, occupied narrow latitude belts from poles to {approx}60 Degree-Sign latitudes. Moreover, in agreement with the large amplitude of the heliospheric current sheet, the low-speed <span class="hlt">wind</span> prevailed in the low- and mid-latitude regions of the heliosphere. (4) At the transition phase between cycles 23 and 24, the high levels of density and density turbulence were observed close to the heliospheric equator and the low-speed <span class="hlt">solar</span> <span class="hlt">wind</span> extended from the equatorial-to-mid-latitude regions. The above results in comparison with Ulysses and other in situ measurements suggest that the source of the <span class="hlt">solar</span> <span class="hlt">wind</span> has changed globally, with the important implication that the supply of mass and energy from the Sun to the interplanetary space has been significantly reduced in the prolonged period of low <span class="hlt">solar</span> activity. The IPS results are consistent with the onset and growth of the current <span class="hlt">solar</span> cycle 24, starting from the middle of 2009. However, the width of the high-speed <span class="hlt">wind</span> at the northern high latitudes has almost disappeared and indicates that the ascending phase of the current cycle has almost reached the maximum phase in the northern hemisphere of the Sun. However, in the southern part of the hemisphere, the <span class="hlt">solar</span> activity has yet to develop and/or increase.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910041672&hterms=krypton&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dkrypton','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910041672&hterms=krypton&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dkrypton"><span id="translatedtitle"><span class="hlt">Solar-wind</span> krypton and solid/gas fractionation in the early <span class="hlt">solar</span> nebula</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wiens, Roger C.; Burnett, D. S.; Neugebauer, M.; Pepin, R. O.</p> <p>1991-01-01</p> <p>The <span class="hlt">solar</span>-system Kr abundance is calculated from <span class="hlt">solar-wind</span> noble-gas ratios, determined previously by low-temperature oxidations of lunar ilmenite grains, normalized to Si by spacecraft <span class="hlt">solar-wind</span> measurements. The estimated Kr-83 abundance of 4.1 + or - 1.5 per million Si atoms is within uncertainty of estimates assuming no fractionation, determined from CI-chondrite abundances of surrounding elements. This is significant because it is the first such constraint on solid/gas fractionation, though the large uncertainty only confines it to somewhat less than a factor of two.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.P32B..03S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.P32B..03S"><span id="translatedtitle">MESSENGER observations of Mercury's magnetosphere under extreme <span class="hlt">solar</span> <span class="hlt">wind</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>Slavin, J. A.; DiBraccio, G. A.; Gershman, D. J.; Imber, S. M.; Sundberg, T.; Boardsen, S. A.; Sarantos, M.; Anderson, B. J.; Korth, H.; Zurbuchen, T.; Raines, J. M.; Ho, G. C.; Krimigis, S. M.; Baker, D. N.; Johnson, C. L.; Winslow, R. M.; Killen, R. M.; McNutt, R. L.; Solomon, S. C.</p> <p>2012-12-01</p> <p>MESSENGER observations of Mercury's dayside magnetosphere near local noon have been examined to identify instances of extremely high <span class="hlt">solar</span> <span class="hlt">wind</span> ram pressure and/or strong southward magnetosheath magnetic field. Intervals of high <span class="hlt">solar</span> <span class="hlt">wind</span> ram pressure were defined on the basis of magnetic field intensity, B, just inside the magnetopause of ~300 nT or greater. If the internal plasma pressure is negligible, the corresponding upstream <span class="hlt">solar</span> <span class="hlt">wind</span> pressure is at least ~ 36 nPa. Intense southward magnetic field in the magnetosheath was defined to be at least ~200 nT in magnitude. Four instances of high <span class="hlt">solar</span> <span class="hlt">wind</span> pressure during subsolar magnetospheric passes were identified, two with northward magnetosheath magnetic field, one with intense southward magnetic field, and one with intense, but variable north-south magnetic field. One interval of intense southward magnetosheath magnetic field was found with only a moderately high (B ~ 200 nT) <span class="hlt">solar</span> <span class="hlt">wind</span> ram pressure. Despite Mercury's magnetic dipole field having a moment of only 190-200 nT-RM3, where RM is Mercury's radius, the subsolar magnetopause was found to stand off from the planetary surface by at least 0.25 RM for each magnetopause crossing even when high ram pressure was accompanied by an intense southward magnetosheath magnetic field. Analysis of the magnetopause location and magnetic field intensity shows that the magnetic fields of greater than ~ 250 nT at ~ 0.25 RM altitude cannot be the result of just Mercury's internal magnetic field and the magnetic field produced by the Chapman-Ferraro current system; additional magnetic fields, most likely due to induction currents in the outer layers of Mercury's interior, are also required. The three intervals with strong southward magnetosheath magnetic field all yielded intense reconnection signatures at the magnetopause, including strong magnetic field normal to the magnetopause; jetting of magnetosheath plasma away from the equatorial regions; showers of flux transfer events; and deep, broad diamagnetic decreases in the cusp. These results suggest that although Mercury's surface is shielded from direct <span class="hlt">solar</span> <span class="hlt">wind</span> impact at low to moderate latitudes even during intervals of intense reconnection and very high ram pressure by magnetic field induction inside the planet, the <span class="hlt">solar</span> <span class="hlt">wind</span> precipitation in the cusp region appears to maximize under such conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2005AIPC..746.1171S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2005AIPC..746.1171S"><span id="translatedtitle">The Plasma Magnet for Sailing the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Slough, John</p> <p>2005-02-01</p> <p>Plasma sail propulsion based on the plasma magnet is a unique system that taps the ambient energy of the <span class="hlt">solar</span> <span class="hlt">wind</span> with minimal energy and mass requirements. The coupling to the <span class="hlt">solar</span> <span class="hlt">wind</span> is made through the generation of a large-scale (> 30 km) dipolar magnetic field. Unlike the original magnetic sail concept, the coil currents are conducted in a plasma rather than a superconducting coil. In this way the mass of the sail is reduced by orders of magnitude for the same thrust power. The plasma magnet consists of a pair of polyphase coils that produce a rotating magnetic field (RMF) that drives the necessary currents in the plasma to inflate and maintain the large-scale magnetic structure. The plasma magnet is deployed by the Lorentz self-force on the plasma currents, expanding outward in a disk-like shape until the expansion is halted by the <span class="hlt">solar</span> <span class="hlt">wind</span> pressure. It is virtually propellantless as the intercepted <span class="hlt">solar</span> <span class="hlt">wind</span> replenishes the small amount of plasma required to carry the magnet currents. Unlike a solid magnet or sail, the plasma magnet expands with falling <span class="hlt">solar</span> <span class="hlt">wind</span> pressure to provide constant thrust. A small prototype plasma magnet has been built and tested. The RMF coils generated over 10 kA of plasma currents with a radial expansion pressure sufficient to expand the dipole field to well over the 30 km scale that would supply as much as 5 MW of thrust power. The antenna and driver need weigh no more than 10 kg, and can operate from a 300 V supply. With the predicted scaling with size, it is possible to test the concept in the laboratory with a greatly enhanced laboratory <span class="hlt">solar</span> <span class="hlt">wind</span> source. Plans for a laboratory scaled experiment will be outlined that incorporate an intensified <span class="hlt">solar</span> <span class="hlt">wind</span> source and thrust measurement to assess the power gain predicted. With the successful demonstration of thrust power at the several hundred kW level, a large tank test would be the next step, and provide the final confirmation of the scaling needed for a space-based demonstration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/977319','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/977319"><span id="translatedtitle">Large Scale <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Integration in Germany</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ernst, Bernhard; Schreirer, Uwe; Berster, Frank; Pease, John; Scholz, Cristian; Erbring, Hans-Peter; Schlunke, Stephan; Makarov, Yuri V.</p> <p>2010-02-28</p> <p>This report provides key information concerning the German experience with integrating of 25 gigawatts of <span class="hlt">wind</span> and 7 gigawatts of <span class="hlt">solar</span> power capacity and mitigating its impacts on the electric power system. The report has been prepared based on information provided by the Amprion GmbH and 50Hertz Transmission GmbH managers and engineers to the Bonneville Power Administration (BPA) and Pacific Northwest National Laboratory representatives during their visit to Germany in October 2009. The trip and this report have been sponsored by the BPA Technology Innovation office. Learning from the German experience could help the Bonneville Power Administration engineers to compare and evaluate potential new solutions for managing higher penetrations of <span class="hlt">wind</span> energy resources in their control area. A broader dissemination of this experience will benefit <span class="hlt">wind</span> and <span class="hlt">solar</span> resource integration efforts in the United States.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSM11D..04B','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSM11D..04B"><span id="translatedtitle">Exploring <span class="hlt">Solar-Wind</span>/Magnetosphere/Ionosphere Connections (Invited)</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Borovsky, J. E.; Denton, M. H.; Lavraud, B.</p> <p>2009-12-01</p> <p>Superposed-epoch analysis of several data sets is employed to study the coupled <span class="hlt">solar-wind</span>/magnetosphere/ionosphere system. Three stormtime couplings are highlighted. (1) During CIR-driven storms the enhanced <span class="hlt">solar-wind</span> density owing to the compression of the slow <span class="hlt">wind</span> produces a superdense plasma sheet in the magnetosphere which is temporally connected to the stormtime dropout and recovery of relativisitic electrons in the outer radiation belt. (2) During CIR-driven storms, the reversed IMF sector structure upstream of the stream interface drives a calm before the storm and the calm results in a filling of the outer plasmasphere which in turn results in a pre-storm decay of the outer electron radiation belt. (3) During CME- or CIR-driven storms a calm before the storm leads to a cool dense plasma sheet which results in better ring-current fuel and a larger Dst perturbation during the storm.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19790049170&hterms=nonequilibrium+conditions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dnonequilibrium%2Bconditions','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19790049170&hterms=nonequilibrium+conditions&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dnonequilibrium%2Bconditions"><span id="translatedtitle">Nonequilibrium ionization in <span class="hlt">solar</span> and stellar <span class="hlt">winds</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dupree, A. K.; Moore, R. T.; Shapiro, P. R.</p> <p>1979-01-01</p> <p>Substantial and systematic departures from ionization equilibrium can occur in the <span class="hlt">solar</span> transition region and corona when mass outflows are present. Modeling calculations illustrate the general characteristics of the ionization balance in such regions. The presence of nonequilibrium conditions suggests a natural explanation for the extended region of EUV line emission that is observed above the <span class="hlt">solar</span> limb. Comparison with observations of a coronal hole on the disk indicates that outflow may not start until temperatures of about 250,000 K are reached. Additional consequences include a diminution of the density discrepancy between ultraviolet and radio observations of coronal holes, and potential effects on the energy balance in <span class="hlt">solar</span> and stellar atmospheres undergoing mass loss.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22126712','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22126712"><span id="translatedtitle">HEMISPHERIC ASYMMETRIES IN THE POLAR <span class="hlt">SOLAR</span> <span class="hlt">WIND</span> OBSERVED BY ULYSSES NEAR THE MINIMA OF <span class="hlt">SOLAR</span> CYCLES 22 AND 23</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ebert, R. W.; Dayeh, M. A.; Desai, M. I.; McComas, D. J.; Pogorelov, N. V.</p> <p>2013-05-10</p> <p>We examined <span class="hlt">solar</span> <span class="hlt">wind</span> plasma and interplanetary magnetic field (IMF) observations from Ulysses' first and third orbits to study hemispheric differences in the properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> and IMF originating from the Sun's large polar coronal holes (PCHs) during the declining and minimum phase of <span class="hlt">solar</span> cycles 22 and 23. We identified hemispheric asymmetries in several parameters, most notably {approx}15%-30% south-to-north differences in averages for the <span class="hlt">solar</span> <span class="hlt">wind</span> density, mass flux, dynamic pressure, and energy flux and the radial and total IMF magnitudes. These differences were driven by relatively larger, more variable <span class="hlt">solar</span> <span class="hlt">wind</span> density and radial IMF between {approx}36 Degree-Sign S-60 Degree-Sign S during the declining phase of <span class="hlt">solar</span> cycles 22 and 23. These observations indicate either a hemispheric asymmetry in the PCH output during the declining and minimum phase of <span class="hlt">solar</span> cycles 22 and 23 with the southern hemisphere being more active than its northern counterpart, or a <span class="hlt">solar</span> cycle effect where the PCH output in both hemispheres is enhanced during periods of higher <span class="hlt">solar</span> activity. We also report a strong linear correlation between these <span class="hlt">solar</span> <span class="hlt">wind</span> and IMF parameters, including the periods of enhanced PCH output, that highlight the connection between the <span class="hlt">solar</span> <span class="hlt">wind</span> mass and energy output and the Sun's magnetic field. That these enhancements were not matched by similar sized variations in <span class="hlt">solar</span> <span class="hlt">wind</span> speed points to the mass and energy responsible for these increases being added to the <span class="hlt">solar</span> <span class="hlt">wind</span> while its flow was subsonic.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/9933156','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/9933156"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> outflow and the chromospheric magnetic network</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hassler; Dammasch; Lemaire; Brekke; Curdt; Mason; Vial; Wilhelm</p> <p>1999-02-01</p> <p>Observations of outflow velocities in coronal holes (regions of open coronal magnetic field) have recently been obtained with the <span class="hlt">Solar</span> and Heliospheric Observatory (SOHO) spacecraft. Velocity maps of Ne7+ from its bright resonance line at 770 angstroms, formed at the base of the corona, show a relationship between outflow velocity and chromospheric magnetic network structure, suggesting that the <span class="hlt">solar</span> <span class="hlt">wind</span> is rooted at its base to this structure, emanating from localized regions along boundaries and boundary intersections of magnetic network cells. This apparent relation to the chromospheric magnetic network and the relatively large outflow velocity signatures will improve understanding of the complex structure and dynamics at the base of the corona and the source region of the <span class="hlt">solar</span> <span class="hlt">wind</span>. PMID:9933156</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19900061749&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dluhmann','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19900061749&hterms=luhmann&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D60%26Ntt%3Dluhmann"><span id="translatedtitle">Plasma observations of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with Mars</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Vaisberg, O. L.; Luhmann, J. G.; Russell, C. T.</p> <p>1990-01-01</p> <p>Measurements with the plasma analyzers on the Mars-2, 3 and 5 spacecraft show that Mars deflects a large fraction of the incoming <span class="hlt">solar</span> <span class="hlt">wind</span> flow to form a strong bow shock. The bow shock is about 1.41 Rm from the center of the planet at the subsolar point and about 2.40 Rm at the terminator. These distances are similar to those for Venus at times of moderate <span class="hlt">solar</span> activity. The inferred effective obstacle altitude is about 400-700 km. An ion cushion has been found which is similar in its properties to the Venus magnetic barrier. The formation of this cushion appears to cause the deflection of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Inside the cushion but well above the ionosphere is found a region where the ions are at the background, the electrons are cool and the magnetic pressure dominates. This region may resemble a planetary magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040161509&hterms=chlorine+effects&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dchlorine%2Beffects','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040161509&hterms=chlorine+effects&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dchlorine%2Beffects"><span id="translatedtitle">The <span class="hlt">Latitude</span> <span class="hlt">Dependence</span> of the Effect of Pinatubo on Stratospheric Ozone</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Stolarski, Richard S.; Douglass, Anne R.</p> <p>2004-01-01</p> <p>Statistical analysis of TOMS and SBLT total ozone data indicate that the eruption of Pinatubo in 1991 led to a significant decrease in ozone at northern midlatitudes with little or no effect at southern midlatitudes. We argue that this puzzling absence of a southern hemisphere effect may be an artifact of the statistical analysis. We have run a 3D CTM simulation of the past 30 years of stratospheric photochemistry with variable forcing due to chlorine/bromine compounds, <span class="hlt">solar</span> ultraviolet radiation, and volcanic aerosols. This integration used <span class="hlt">winds</span> from the FVGCM, which has similar interannual variability to the atmosphere. When this CTM output was examined with a standard time-series analysis, we found an effect of Pinatubo in the southern hemisphere, but not in the northern hemisphere. We then reran the CTM without volcanic aerosols. The subtraction of the two simulations indicated that, as expected, that Pinatubo affected both hemispheres in the model. This means that the northern hemisphere effect was in the model but did not show up in the statistical analysis. We also had an on-line parameterized chemical ozone tracer with seasonally repeating production and loss over the simulation. We used this as a dynamical surrogate to remove interannual variability from the original model output. The residual time series was then analyzed for the Pinatubo effect and we were able to find it in both hemispheres. We suggest that the combination of the two volcanoes, El Chichon and Pinatubo, with the <span class="hlt">solar</span> cycle and interannual variability led to this problem of analysis in the northern hemisphere of our model. We furthermore suggest that a similar think may be occurring in the southern hemisphere of the data. An analysis of the atmosphere's southern hemisphere with a good dynamical surrogate may solve the mystery of the missing southern hemisphere effect of Pinatubo on ozone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=PIA11150&hterms=panel+solar&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dpanel%2Bsolar','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=PIA11150&hterms=panel+solar&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dpanel%2Bsolar"><span id="translatedtitle"><span class="hlt">Solar</span> Panel Buffeted by <span class="hlt">Wind</span> at Phoenix Site</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p></p> <p>2008-01-01</p> <p><p/> <span class="hlt">Winds</span> were strong enough to cause about a half a centimeter (.19 inch) of motion of a <span class="hlt">solar</span> panel on NASA's Phoenix Mars lander when the lander's Surface Stereo Imager took this picture on Aug. 31, 2008, during the 96th Martian day since landing. <p/> The lander's telltale <span class="hlt">wind</span> gauge has been indicating <span class="hlt">wind</span> speeds of about 4 meters per second (9 miles per hour) during late mornings at the site. <p/> These conditions were anticipated and the <span class="hlt">wind</span> is not expected to do any harm to the lander. <p/> The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015JGRA..120.2494M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015JGRA..120.2494M"><span id="translatedtitle">An optimum <span class="hlt">solar</span> <span class="hlt">wind</span> coupling function for the AL index</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>McPherron, Robert L.; Hsu, Tung-Shin; Chu, Xiangning</p> <p>2015-04-01</p> <p>We define a coupling function as a product of <span class="hlt">solar</span> <span class="hlt">wind</span> factors that partially linearizes the relation between it and a magnetic index. We consider functions that are a product of factors of <span class="hlt">solar</span> <span class="hlt">wind</span> speed V, density N, transverse magnetic field B?, and interplanetary magnetic field (IMF) clock angle ?c each raised to a different power. The index is the auroral lower (AL index) which monitors the strength of the westward electrojet. <span class="hlt">Solar</span> <span class="hlt">wind</span> data 1995-2014 provide hour averages of the factors needed to calculate optimum exponents. Nonlinear inversion determines both the exponents and linear prediction filters of short data segments. The averages of all exponents are taken as optimum exponents and for V, N, B?, and sin(?c/2) are [1.92, 0.10, 0.79, 3.67] with errors in the second decimal. Hourly values from 1966 to 2014 are used next to calculate the optimum function (opn) and the functions VBs (eys), epsilon (eps), and universal coupling function (ucf). A yearlong window is advanced by 27 days calculating linear prediction filters for the four functions. The functions eps, eys, ucf, and opn, respectively, predict 43.7, 61.2, 65.6, and 68.3% of AL variance. The opn function is 2.74% better than ucf with a confidence interval 2.60-2.86%. Coupling strength defined as the sum of filter weights (nT/mV/m) is virtually identical for all functions and varies systematically with the <span class="hlt">solar</span> cycle being strongest (188 nT/mV/m) at <span class="hlt">solar</span> minimum and weakest (104) at <span class="hlt">solar</span> maximum. Saturation of the polar cap potential approaching <span class="hlt">solar</span> maximum may explain the variation.</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/2008PhDT........23Z','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008PhDT........23Z"><span id="translatedtitle">Simulation and optimum design of hybrid <span class="hlt">solar-wind</span> and <span class="hlt">solar-wind</span>-diesel power generation systems</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Zhou, Wei</p> <p></p> <p><span class="hlt">Solar</span> and <span class="hlt">wind</span> energy systems are considered as promising power generating sources due to its availability and topological advantages in local power generations. However, a drawback, common to <span class="hlt">solar</span> and <span class="hlt">wind</span> options, is their unpredictable nature and dependence on weather changes, both of these energy systems would have to be oversized to make them completely reliable. Fortunately, the problems caused by variable nature of these resources can be partially overcome by integrating these two resources in a proper combination to form a hybrid system. However, with the increased complexity in comparison with single energy systems, optimum design of hybrid system becomes more complicated. In order to efficiently and economically utilize the renewable energy resources, one optimal sizing method is necessary. This thesis developed an optimal sizing method to find the global optimum configuration of stand-alone hybrid (both <span class="hlt">solar-wind</span> and <span class="hlt">solar-wind</span>-diesel) power generation systems. By using Genetic Algorithm (GA), the optimal sizing method was developed to calculate the system optimum configuration which offers to guarantee the lowest investment with full use of the PV array, <span class="hlt">wind</span> turbine and battery bank. For the hybrid <span class="hlt">solar-wind</span> system, the optimal sizing method is developed based on the Loss of Power Supply Probability (LPSP) and the Annualized Cost of System (ACS) concepts. The optimization procedure aims to find the configuration that yields the best compromise between the two considered objectives: LPSP and ACS. The decision variables, which need to be optimized in the optimization process, are the PV module capacity, <span class="hlt">wind</span> turbine capacity, battery capacity, PV module slope angle and <span class="hlt">wind</span> turbine installation height. For the hybrid <span class="hlt">solar-wind</span>-diesel system, minimization of the system cost is achieved not only by selecting an appropriate system configuration, but also by finding a suitable control strategy (starting and stopping point) of the diesel generator. The optimal sizing method was developed to find the system optimum configuration and settings that can achieve the custom-required Renewable Energy Fraction (fRE) of the system with minimum Annualized Cost of System (ACS). Du to the need for optimum design of the hybrid systems, an analysis of local weather conditions (<span class="hlt">solar</span> radiation and <span class="hlt">wind</span> speed) was carried out for the potential installation site, and mathematical simulation of the hybrid systems' components was also carried out including PV array, <span class="hlt">wind</span> turbine and battery bank. By statistically analyzing the long-term hourly <span class="hlt">solar</span> and <span class="hlt">wind</span> speed data, Hong Kong area is found to have favorite <span class="hlt">solar</span> and <span class="hlt">wind</span> power resources compared with other areas, which validates the practical applications in Hong Kong and Guangdong area. Simulation of PV array performance includes three main parts: modeling of the maximum power output of the PV array, calculation of the total <span class="hlt">solar</span> radiation on any tilted surface with any orientations, and PV module temperature predictions. Five parameters are introduced to account for the complex dependence of PV array performance upon <span class="hlt">solar</span> radiation intensities and PV module temperatures. The developed simulation model was validated by using the field-measured data from one existing building-integrated photovoltaic system (BIPV) in Hong Kong, and good simulation performance of the model was achieved. Lead-acid batteries used in hybrid systems operate under very specific conditions, which often cause difficulties to predict when energy will be extracted from or supplied to the battery. In this thesis, the lead-acid battery performance is simulated by three different characteristics: battery state of charge (SOC), battery floating charge voltage and the expected battery lifetime. Good agreements were found between the predicted values and the field-measured data of a hybrid <span class="hlt">solar-wind</span> project. At last, one 19.8kW hybrid <span class="hlt">solar-wind</span> power generation project, designed by the optimal sizing method and set up to supply power for a telecommunication relay station on a remote island of Guangdong province, was studied. Simulation and experimental results about the operating performances and characteristics of the hybrid <span class="hlt">solar-wind</span> project have demonstrated the feasibility and accuracy of the recommended optimal sizing method developed in this thesis.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1995xmm..pres...11.','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1995xmm..pres...11."><span id="translatedtitle">Ulysses sees differences in <span class="hlt">solar</span> <span class="hlt">wind</span> at high, low latitudes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p></p> <p>1995-06-01</p> <p>Scientists presenting results today of their data at the spring meeting of the American Geophysical Union in Baltimore, Md., said the speed of the <span class="hlt">solar</span> <span class="hlt">wind</span> over the southern pole is high, compared to its low velocity near the Sun's equator. The <span class="hlt">solar</span> <span class="hlt">wind</span> is the hot ionized gas that escapes from the <span class="hlt">solar</span> corona and expands into interplanetary space. At the present minimum of the <span class="hlt">solar</span> activity cycle, the angle between the Sun's rotational and magnetic equators has decreased -- in these conditions Ulysses found that the region of low-speed <span class="hlt">solar</span> <span class="hlt">winds</span> were confined more closely to the rotational equator than in earlier portions of the <span class="hlt">solar</span> cycle. Now on its way to the northern <span class="hlt">solar</span> pole, Ulysses is nearly 62 degrees north of the Sun's equator today. The second phase of the primary mission -- to explore the northern pole of the Sun -- will begin on June 19, when the spacecraft reaches 70 degrees north latitude, The spacecraft will reach a maximum northern latitude of 80,2 degrees on 31 July 1995. Ulysses' trajectory from 80 degrees south of the equator in September 1994, back down to the Sun's equator in March 1995, also brought the spacecraft within 1.3 astronomical units (121 million miles, 194 million km) of the Sun, the closest Ulysses would ever travel to the Sun since it was launched on October 6, 1990. The spacecraft picked up speed during this phase allowing the entire region to be scanned in just six months time. Scientists refer to this phase of the mapping as the "fast latitude scan", Ulysses had left the equatorial plane in early 1992 after a gravitational swingby of Jupiter, and had gradually climbed in latitude until reaching 80 degrees south in September 1994. Ulysses' observations during the fast latitude scan have shown that the <span class="hlt">solar</span> <span class="hlt">wind</span> being continuously emitted by the Sun is distinctly different at high and low latitudes, said Dr. Edward J. Smith, Ulysses project scientist at NASA's Jet Propulsion Laboratory, for the joint NASA-European Space Agency mission. Data from science experiments onboard the spacecraft also revealed the strong influence of the Sun's magnetic equator which is inclined, or tilted, with respect to the Sun's rotational equator. "As the Sun rotates, the magnetic equator appears to wobble up and down and the <span class="hlt">solar</span> <span class="hlt">wind</span> in the region occupied by the Earth alternates between the two types of <span class="hlt">solar</span> <span class="hlt">wind</span>," Smith said. The high latitude <span class="hlt">solar</span> <span class="hlt">wind</span>, as reported in the May 19 issue of Science, is fast and relatively smooth, whereas the low latitude <span class="hlt">solar</span> <span class="hlt">wind</span> travels more slowly, These velocity differences are organised by magnetic latitude rather than heliographic latitude, As the Sun rotates, the wobble introduced by the magnetic field causes the fast, high latitude <span class="hlt">solar</span> <span class="hlt">wind</span> to alternate with slow, low latitude <span class="hlt">solar</span> <span class="hlt">wind</span>, Before the slow <span class="hlt">solar</span> <span class="hlt">wind</span> has time to reach the orbit of Earth, it is overtaken by the faster <span class="hlt">wind</span>, forming a high pressure "front". "These fronts are the equivalent of weather fronts on Earth and are responsible for much of the interplanetary 'weather' which causes aurora -- spectacular curtains of light seen in the northern and southern hemispheres of Earth's atmosphere," Smith said, "These fronts also cause magnetic storms, which can interrupt radio and satellite communications on Earth." Scientists at the American Geophysical Union meetings, describing the return of Ulysses to the equatorial zone, reported a drop in the <span class="hlt">solar</span> <span class="hlt">wind</span> speed by a factor of two - from approximately 2 million miles per hour (800 kilometres per second) over the southern pole to approximately I million miles per hour (400 kilometres per second) along the equator - and the reappearance after two years of large excursions in speed, particle density and magnetic field strength. "Magnetic fields characteristic of the north <span class="hlt">solar</span> hemisphere, which point outward from the sun, are seen interspersed with inward-directed fields from the southern hemisphere," Smith said, "This change in the magnetic field polarity indicates whether the <span class="hlt">solar</span> <span class="hlt">wind</span> is coming from the South or from the north. Thus, the equatorial zone in which the Earth is located is aiternatingly traversed by particles originating from northern or southern regions of the Sun." "Periodic excursions in the flux of <span class="hlt">solar</span> energetic particles between low and high intensity have also reappeared," added Dr. Richard G. Marsden, the European Space Agency project scientist for Ulysses. "They accompany the <span class="hlt">solar</span> <span class="hlt">wind</span> fronts -- called interaction regions -- in which energy is transferred to these particles by shocks associated with the interaction regions." An unexpected feature of the Ulysses observations was the detection of these energetic particles at higher latitudes than the shucks that are known to create them. "We really don't know for certain the explanation of these results," Marsden said. "Possible explanations are that the shucks extend to higher latitudes farther from the Sun, or that the particles can diffuse rapidly in latitude without being nearly so much scattered in longitude. These results, when properly understood, will aid us in understanding the creation and propagation of <span class="hlt">solar</span> energetic particles." Ulysses crossed the Sun's equator on March 5, 1995, making its closest approach at the same time. This period was also marked by a rare line-up of the Earth, Sun and spacecraft that scientists can a conjunction. At this time, the radio beam path from the spacecraft to the Earth swept through all <span class="hlt">solar</span> latitudes from the south pole to the equator as it probed the Sun's corona. Radio scientists used this opportunity to remotely measure the density of the corona, The scientists warned that this simple global configuration of the Sun to date -- of high speeds over the poles and low speeds near the equator -- is very likely tied to the current phase of the Sun's 11-year sunspot cycle. Currently the Sun is very near to its minimum of activity, with just a few spots observed at low, latitudes. In particular the equatorial zone has been found to be only half as wide during the fast pole-to-equator passage -- taking place from September 1994 through March 1995 -- compared to the earlier equator-to-pole passage. The shrinking of the equatorial zone in the intervening two years shows the closer correspondence between the Sun's rotational and magnetic equators. The Jet Propulsion Laboratory manages the U.S, portion of the Ulysses mission for NASA's Office of Space Science, Washington, D,C. * Ulysses is a joint ESA/NASA mission. WA developed the probe and is contributing an estimated ECU 170 million up to 1995 to its in-light operation. European research laboratories provided half of the scientific instruments. NASA provided the other half of the experiments flown, a radio-isotopic power generator and the launch; it is also maintaining day-to-day communications with the probe via its dedicated antennas.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2001AGUFMSM41B0800F','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2001AGUFMSM41B0800F"><span id="translatedtitle">Dayside Erosion During Intervals of Tenuous <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Farrugia, C. J.; Muehlbachler, S.; Torbert, R. B.; Biernat, H. K.</p> <p>2001-12-01</p> <p>We present six data examples where we infer erosion of the dayside magnetosphere during intervals of very tenuous <span class="hlt">solar</span> <span class="hlt">wind</span> (density < 1 cm-3). The interplanetary observations were made by the <span class="hlt">Wind</span> spacecraft when the average <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure P dyn and the interplanetary magnetic field (IMF) Bz were in the ranges (0.07, 0.62) nPa and (-7.6, -0.9) nT, respectively. The inner magnetospheric signature of erosion we focus on is a decrease in the strength of the geostationary magnetic field, as monitored by NOAA's GOES spacecraft. We obtain this decrease as a function of IMF Bz by comparing each event with a reference day, May 11, 1999. During the reference day the lowest P dyn of the set was attained (0.07 nPa), IMF Bz > 0, and the geomagnetic field at geostationary orbit was dipolar. The central point we make is that although compared to the reference day the P dyn in each event is higher, the strength of the geostationary field is weaker. We interpret this as evidence that the field compression due to P dyn has been overcome by the field depression due to erosion. Correcting empirically for the compression of the geostationary field due to <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure, we find that for the tenuous <span class="hlt">solar</span> <span class="hlt">winds</span> we consider the decrease of the geostationary field, Δ BGS, is related to IMF Bz as Δ BGS (nT)= -2.8 + 2.3 Bz (nT). This work is supported by NASA Living with a Star Grant NAG5-10883 and DARA grant 50 OC 8911 0.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21371727','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21371727"><span id="translatedtitle">Detection of fast nanoparticles in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Meyer-Vernet, N.; Maksimovic, M.; Lecacheux, A.; Le Chat, G.; Czechowski, A.; Mann, I.; Goetz, K.; Kaiser, M. L.; Cyr, O. C. St.; Bale, S. D.</p> <p>2010-03-25</p> <p>Dust grains in the nanometer range bridge the gap between atoms and larger grains made of bulk material. Their small size embodies them with special properties. Due to their high relative surface area, they have a high charge-to-mass ratio, so that the Lorentz force in the <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic field exceeds the gravitational force and other forces by a large amount, and they are accelerated to a speed of the order of magnitude of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed. When such fast nanoparticles impact a spacecraft, they produce craters whose matter vaporises and ionises, yielding transient voltages as high as do much larger grains of smaller speed. These properties are at the origin of their recent detection at 1 AU in the <span class="hlt">solar</span> <span class="hlt">wind</span>. We discuss the detection of fast nanoparticles by wave instruments of different configurations, with applications to the recent detections on STEREO/WAVES and CASSINI/RPWS. Finally we discuss the opportunities for nanoparticle detection by wave instruments on future missions and/or projects in the inner heliosphere such as Bepi-Colombo and <span class="hlt">Solar</span> Orbiter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22118614','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22118614"><span id="translatedtitle">Small <span class="hlt">solar</span> <span class="hlt">wind</span> transients: Stereo-A observations in 2009</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Yu, W.; Farrugia, C. J.; Galvin, A. B.; Simunac, K. D. C.; Popecki, M. A.; Lugaz, N.; Kilpua, E. K. J.; Moestl, C.; Luhmann, J. G.; Opitz, A.; Sauvaud, J.-A.</p> <p>2013-06-13</p> <p>Year 2009 was the last year of a long and pronounced <span class="hlt">solar</span> activity minimum. In this year the <span class="hlt">solar</span> <span class="hlt">wind</span> in the inner heliosphere was for 90% of the time slow (< 450 km s{sup -1}) and with a weaker magnetic field strength compared to the previous <span class="hlt">solar</span> minimum 1995-1996. We choose this year to present the results of a systematic search for small <span class="hlt">solar</span> <span class="hlt">wind</span> transients (STs) observed by the STEREO-Ahead (ST-A) probe. The data are from the PLASTIC and IMPACT instrument suites. By 'small' we mean a duration from {approx}1 to 12 hours. The parameters we search for to identify STs are (i) the total field strength, (ii) the rotation of the magnetic field vector, (iii) its smoothness, (iv) proton temperature, (v) proton beta, and (vi) Alfven Mach number. We find 45 examples. The STs have an average duration of {approx}4 hours. Ensemble averages of key quantities are: (i) maximum B = 7.01 nT; (ii) proton {beta}= 0.18; (iii) proton thermal speed = 20.8 km s{sup -1}; and (iv) Alfven Mach number = 6.13. No distinctive feature is found in the pitch angle distributions of suprathermal electrons. Our statistical results are compared with those of STs observed near Earth by <span class="hlt">Wind</span> during 2009.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21163475','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21163475"><span id="translatedtitle">Some remarks on waves in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Kellogg, P. J.; Goetz, K.; Monson, S. J.; Balogh, A.; Forsyth, R. J.</p> <p>1996-07-20</p> <p>Waves are significant to the <span class="hlt">solar</span> <span class="hlt">wind</span> in two ways--as modifiers of the particle distribution functions, and as diagnostics. In addition, the <span class="hlt">solar</span> <span class="hlt">wind</span> serves as an important laboratory for the study of plasma wave processes, as it is possible to make detailed measurements of phenomena which are too small to be easily measured by laboratory sized sensors. The waves, both electromagnetic and electrostatic, which are part of the <span class="hlt">solar</span> type III burst phenomenon, have been extensively studied as examples of nonlinear plasma phenomena, and also used as remote sensors to trace the <span class="hlt">solar</span> magnetic field. The observations made by Ulysses show that the field can be traced in this way out to perhaps a little more than an A.U., but then the electromagnetic part of the type III burst fades out. Nevertheless, sometimes Langmuir waves appear at Ulysses at an appropriate extrapolated time. This seems to support the picture in which the electromagnetic waves at the fundamental plasma frequency are trapped in density fluctuations. Recently it has been found that Langmuir waves are associated with magnetic holes. This may help to elucidate the nature of magnetic holes. Nonlinear processes are important in the transformation of wave energy to particle energy. Some recent examples from <span class="hlt">Wind</span> data are shown.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2010RScI...81k1301J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2010RScI...81k1301J"><span id="translatedtitle">Invited Article: Electric <span class="hlt">solar</span> <span class="hlt">wind</span> sail: Toward test missions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Janhunen, P.; Toivanen, P. K.; Polkko, J.; Merikallio, S.; Salminen, P.; Haeggstrm, E.; Seppnen, H.; Kurppa, R.; Ukkonen, J.; Kiprich, S.; Thornell, G.; Kratz, H.; Richter, L.; Krmer, O.; Rosta, R.; Noorma, M.; Envall, J.; Ltt, S.; Mengali, G.; Quarta, A. A.; Koivisto, H.; Tarvainen, O.; Kalvas, T.; Kauppinen, J.; Nuottajrvi, A.; Obraztsov, A.</p> <p>2010-11-01</p> <p>The electric <span class="hlt">solar</span> <span class="hlt">wind</span> sail (E-sail) is a space propulsion concept that uses the natural <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure for producing spacecraft thrust. In its baseline form, the E-sail consists of a number of long, thin, conducting, and centrifugally stretched tethers, which are kept in a high positive potential by an onboard electron gun. The concept gains its efficiency from the fact that the effective sail area, i.e., the potential structure of the tethers, can be millions of times larger than the physical area of the thin tethers wires, which offsets the fact that the dynamic pressure of the <span class="hlt">solar</span> <span class="hlt">wind</span> is very weak. Indeed, according to the most recent published estimates, an E-sail of 1 N thrust and 100 kg mass could be built in the rather near future, providing a revolutionary level of propulsive performance (specific acceleration) for travel in the <span class="hlt">solar</span> system. Here we give a review of the ongoing technical development work of the E-sail, covering tether construction, overall mechanical design alternatives, guidance and navigation strategies, and dynamical and orbital simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/21133454','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/21133454"><span id="translatedtitle">Invited article: Electric <span class="hlt">solar</span> <span class="hlt">wind</span> sail: toward test missions.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Janhunen, P; Toivanen, P K; Polkko, J; Merikallio, S; Salminen, P; Haeggstrm, E; Seppnen, H; Kurppa, R; Ukkonen, J; Kiprich, S; Thornell, G; Kratz, H; Richter, L; Krmer, O; Rosta, R; Noorma, M; Envall, J; Ltt, S; Mengali, G; Quarta, A A; Koivisto, H; Tarvainen, O; Kalvas, T; Kauppinen, J; Nuottajrvi, A; Obraztsov, A</p> <p>2010-11-01</p> <p>The electric <span class="hlt">solar</span> <span class="hlt">wind</span> sail (E-sail) is a space propulsion concept that uses the natural <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure for producing spacecraft thrust. In its baseline form, the E-sail consists of a number of long, thin, conducting, and centrifugally stretched tethers, which are kept in a high positive potential by an onboard electron gun. The concept gains its efficiency from the fact that the effective sail area, i.e., the potential structure of the tethers, can be millions of times larger than the physical area of the thin tethers wires, which offsets the fact that the dynamic pressure of the <span class="hlt">solar</span> <span class="hlt">wind</span> is very weak. Indeed, according to the most recent published estimates, an E-sail of 1 N thrust and 100 kg mass could be built in the rather near future, providing a revolutionary level of propulsive performance (specific acceleration) for travel in the <span class="hlt">solar</span> system. Here we give a review of the ongoing technical development work of the E-sail, covering tether construction, overall mechanical design alternatives, guidance and navigation strategies, and dynamical and orbital simulations. PMID:21133454</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19960021400&hterms=thermodynamics+under+electric+field&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dthermodynamics%2Bunder%2Belectric%2Bfield','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19960021400&hterms=thermodynamics+under+electric+field&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dthermodynamics%2Bunder%2Belectric%2Bfield"><span id="translatedtitle">Measurements of electric fields in the <span class="hlt">solar</span> <span class="hlt">wind</span>: Interpretation difficulties</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Chertkov, A. D.</p> <p>1995-01-01</p> <p>The traditionally measured electric fields in the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma (about 1-10 mV/m) are not the natural, primordial ones but are the result of plasma-vehicle interaction. The theory of this interaction is not complete now and current interpretation of the measurements can fail. The state of fully ionized plasma depends on the entropy of the creating source and on the process in which plasma is involved. The increasing twofold of a moving volume in the <span class="hlt">solar</span> <span class="hlt">wind</span> (with energy transfer across its surface which is comparable with its whole internal energy) is a more rapid process than the relaxation for the pressure. The presumptive source of the <span class="hlt">solar</span> <span class="hlt">wind</span> creation - the induction electric field of the <span class="hlt">solar</span> origin - has very low entropy. The state of plasma must be very far from the state of thermodynamic equilibrium. The internal energy of plasma can be contained mainly in plasma waves, resonant plasma oscillations, and electric currents. The primordial microscopic oscillating electric fields could be about 1 V/m. It can be checked by special measurements, not ruining the natural plasma state. The tool should be a dielectrical microelectroscope outside the distortion zone of the spacecraft, having been observed from the latter.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AIPC.1539..311Y','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AIPC.1539..311Y"><span id="translatedtitle">Small <span class="hlt">solar</span> <span class="hlt">wind</span> transients: Stereo-A observations in 2009</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Yu, W.; Farrugia, C. J.; Galvin, A. B.; Simunac, K. D. C.; Kilpua, E. K. J.; Popecki, M. A.; Moestl, C.; Lugaz, N.; Luhmann, J. G.; Opitz, A.; Sauvaud, J.-A.</p> <p>2013-06-01</p> <p>Year 2009 was the last year of a long and pronounced <span class="hlt">solar</span> activity minimum. In this year the <span class="hlt">solar</span> <span class="hlt">wind</span> in the inner heliosphere was for 90% of the time slow (< 450 km s-1) and with a weaker magnetic field strength compared to the previous <span class="hlt">solar</span> minimum 1995-1996. We choose this year to present the results of a systematic search for small <span class="hlt">solar</span> <span class="hlt">wind</span> transients (STs) observed by the STEREO-Ahead (ST-A) probe. The data are from the PLASTIC and IMPACT instrument suites. By "small" we mean a duration from ~1 to 12 hours. The parameters we search for to identify STs are (i) the total field strength, (ii) the rotation of the magnetic field vector, (iii) its smoothness, (iv) proton temperature, (v) proton beta, and (vi) Alfvén Mach number. We find 45 examples. The STs have an average duration of ~4 hours. Ensemble averages of key quantities are: (i) maximum B = 7.01 nT; (ii) proton β = 0.18; (iii) proton thermal speed = 20.8 km s-1 and (iv) Alfvén Mach number = 6.13. No distinctive feature is found in the pitch angle distributions of suprathermal electrons. Our statistical results are compared with those of STs observed near Earth by <span class="hlt">Wind</span> during 2009.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20080045448&hterms=Terminator&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DTerminator','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20080045448&hterms=Terminator&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3DTerminator"><span id="translatedtitle">Neutral <span class="hlt">Solar</span> <span class="hlt">Wind</span> Generated by Lunar Exospheric Dust at the Terminator</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Collier, Michael R.; Stubbs, Timothy J.</p> <p>2007-01-01</p> <p>We calculate the flux of neutral <span class="hlt">solar</span> <span class="hlt">wind</span> observed on the lunar surface at the terminator due to <span class="hlt">solar</span> <span class="hlt">wind</span> protons penetrating exospheric dust with: (1) grains larger that 0.1 microns and (2) grains larger than 0.01 microns. For grains larger than 0.1 microns, the ratio of the neutral <span class="hlt">solar</span> <span class="hlt">wind</span> to <span class="hlt">solar</span> <span class="hlt">wind</span> flux is estimated to be approx.10(exp -4)-10(exp -3) at <span class="hlt">solar</span> <span class="hlt">wind</span> speeds in excess of 800 km/s, but much lower (less than 10(exp -5) at average to low <span class="hlt">solar</span> <span class="hlt">wind</span> speeds. However, when the smaller grain sizes are considered, the ratio of the neutral <span class="hlt">solar</span> <span class="hlt">wind</span> flux to <span class="hlt">solar</span> <span class="hlt">wind</span> flux is estimated to be greater than or equal to 10(exp -5) at all speeds and at speeds in excess of 700 km/s reaches 10(exp -3)-10(exp -2). These neutral <span class="hlt">solar</span> <span class="hlt">wind</span> fluxes are easily measurable with current low energy neutral atom instrumentation. Observations of neutral <span class="hlt">solar</span> <span class="hlt">wind</span> from the surface of the Moon could provide a very sensitive determination of the distribution of very small dust grains in the lunar exosphere and would provide data complementary to optical measurements at ultraviolet and visible wavelengths. Furthermore, neutral <span class="hlt">solar</span> <span class="hlt">wind</span>, unlike its ionized counterpart, is .not held-off by magnetic anomalies, and may contribute to greater space weathering than expected in certain lunar locations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19940033515&hterms=open+source&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dopen%2Bsource','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19940033515&hterms=open+source&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dopen%2Bsource"><span id="translatedtitle">Signatures of shock drivers in the <span class="hlt">solar</span> <span class="hlt">wind</span> and their dependence on the <span class="hlt">solar</span> source location</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>1993-01-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> and energetic ion observations following 40 interplanetary shocks with well-established <span class="hlt">solar</span> source locations have been examined in order to determine whether signatures characteristic of the coronal material forming the shock driver are present. The signatures considered include magnetic-field-aligned bidirectional ion flows observed by the ISEE 3 and IMP 8 spacecraft; bidirectional <span class="hlt">solar</span> <span class="hlt">wind</span> electron heat fluxes; <span class="hlt">solar</span> <span class="hlt">wind</span> plasma proton and electron temperature depressions; low-beta plasma; enhanced, low-variance magnetic fields; and energetic ion depressions. Several shock driver signatures are commonly observed following shocks originating from within about 50 deg of central meridian, and are generally absent for other events. We conclude that shock drivers generally extend up to about 100 deg in longitude, centered on the <span class="hlt">solar</span> source longitude. Since shocks from central meridian events are not usually associated with all the shock driver signatures examined, the absence of a driver cannot be confirmed from consideration of one of these signatures alone. We also find evidence that a few bidirectional energetic ion and <span class="hlt">solar</span> <span class="hlt">wind</span> electron heat flux events following shocks (in particular from far eastern sources) may occur on open field lines outside of shock drivers.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/1037937','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/1037937"><span id="translatedtitle">Western <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Integration Study: Hydropower Analysis</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Acker, T.; Pete, C.</p> <p>2012-03-01</p> <p>The U.S. Department of Energy's (DOE) study of 20% <span class="hlt">Wind</span> Energy by 2030 was conducted to consider the benefits, challenges, and costs associated with sourcing 20% of U.S. energy consumption from <span class="hlt">wind</span> power by 2030. This study found that with proactive measures, no insurmountable barriers were identified to meet the 20% goal. Following this study, DOE and the National Renewable Energy Laboratory (NREL) conducted two more studies: the Eastern <span class="hlt">Wind</span> Integration and Transmission Study (EWITS) covering the eastern portion of the U.S., and the Western <span class="hlt">Wind</span> and <span class="hlt">Solar</span> Integration Study (WWSIS) covering the western portion of the United States. The WWSIS was conducted by NREL and research partner General Electric (GE) in order to provide insight into the costs, technical or physical barriers, and operational impacts caused by the variability and uncertainty of <span class="hlt">wind</span>, photovoltaic, and concentrated <span class="hlt">solar</span> power when employed to serve up to 35% of the load energy in the WestConnect region (Arizona, Colorado, Nevada, New Mexico, and Wyoming). WestConnect is composed of several utility companies working collaboratively to assess stakeholder and market needs to and develop cost-effective improvements to the western wholesale electricity market. Participants include the Arizona Public Service, El Paso Electric Company, NV Energy, Public Service of New Mexico, Salt River Project, Tri-State Generation and Transmission Cooperative, Tucson Electric Power, Xcel Energy and the Western Area Power Administration.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/21574692','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/21574692"><span id="translatedtitle">A MODEL FOR THE SOURCES OF THE SLOW <span class="hlt">SOLAR</span> <span class="hlt">WIND</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Antiochos, S. K.; Mikic, Z.; Titov, V. S.; Lionello, R.; Linker, J. A.</p> <p>2011-04-20</p> <p>Models for the origin of the slow <span class="hlt">solar</span> <span class="hlt">wind</span> must account for two seemingly contradictory observations: the slow <span class="hlt">wind</span> has the composition of the closed-field corona, implying that it originates from the continuous opening and closing of flux at the boundary between open and closed field. On the other hand, the slow <span class="hlt">wind</span> also has large angular width, up to {approx}60{sup 0}, suggesting that its source extends far from the open-closed boundary. We propose a model that can explain both observations. The key idea is that the source of the slow <span class="hlt">wind</span> at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices and quasi-separatrix layers in the heliosphere. We compute analytically the topology of an open-field corridor and show that it produces a quasi-separatrix layer in the heliosphere that extends to angles far from the heliospheric current sheet. We then use an MHD code and MDI/SOHO observations of the photospheric magnetic field to calculate numerically, with high spatial resolution, the quasi-steady <span class="hlt">solar</span> <span class="hlt">wind</span>, and magnetic field for a time period preceding the 2008 August 1 total <span class="hlt">solar</span> eclipse. Our numerical results imply that, at least for this time period, a web of separatrices (which we term an S-web) forms with sufficient density and extent in the heliosphere to account for the observed properties of the slow <span class="hlt">wind</span>. We discuss the implications of our S-web model for the structure and dynamics of the corona and heliosphere and propose further tests of the model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20110007840','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20110007840"><span id="translatedtitle">A Model for the Sources of the Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Antiochos, Spiro K.; Mikic, Z.; Titov, V. S.; Lionello, R.; Linker, J. A.</p> <p>2010-01-01</p> <p>Models for the origin of the slow <span class="hlt">solar</span> <span class="hlt">wind</span> must account for two seemingly contradictory observations: The slow <span class="hlt">wind</span> has the composition of the closed-field corona, implying that it originates from the continuous opening and closing of flux at the boundary between open and closed field. On the other hand, the slow <span class="hlt">wind</span> has large angular width, up to approximately 60 degrees, suggesting that its source extends far from the open-closed boundary. We propose a model that can explain both observations. The key idea is that the source of the slow <span class="hlt">wind</span> at the Sun is a network of narrow (possibly singular) open-field corridors that map to a web of separatrices and quasi-separatrix layers in the heliosphere. We compute analytically the topology of an open-field corridor and show that it produces a quasi-separatrix layer in the heliosphere that extends to angles far front the heliospheric current sheet. We then use an MHD code and MIDI/SOHO observations of the photospheric magnetic field to calculate numerically, with high spatial resolution, the quasi-steady <span class="hlt">solar</span> <span class="hlt">wind</span> and magnetic field for a time period preceding the August 1, 2008 total <span class="hlt">solar</span> eclipse. Our numerical results imply that, at least for this time period, a web of separatrices (which we term an S-web) forms with sufficient density and extent in the heliosphere to account for the observed properties of the slow <span class="hlt">wind</span>. We discuss the implications of our S-web model for the structure and dynamics of the corona and heliosphere, and propose further tests of the model.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2007JGRA..112.6208R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2007JGRA..112.6208R"><span id="translatedtitle">Radiation belt electrons respond to multiple <span class="hlt">solar</span> <span class="hlt">wind</span> inputs</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Rigler, E. J.; Wiltberger, M.; Baker, D. N.</p> <p>2007-06-01</p> <p>The multivariate statistical basis that underlies both single- and multi-input linear prediction filter analyses is reviewed, providing context necessary to understand the full capabilities and limitations of such models. A brief reanalysis of single-input filters is conducted primarily as a contrast to subsequent analysis of multi-input linear filters, which (1) guarantee similar or better prediction capabilities than single-input linear filters and (2) reduce bias in estimated filter coefficients that is inherent to underspecified linear models when ordinary least squares algorithms are employed. The former is clearly valuable from a practical standpoint, but the latter helps build confidence in any physical interpretations of both the filter coefficients, which often emulate stable low-order dynamical response functions quite well, as well as prediction error statistics that can be used to provide a lower bound on the fractional or percent variance of radiation belt electron flux that can be attributed to each different <span class="hlt">solar</span> <span class="hlt">wind</span> input. We find that the <span class="hlt">solar</span> <span class="hlt">wind</span> bulk speed tends to be the primary driver of electron flux enhancements at magnetic L shells larger than 4, with little or no relation to flux decreases. Changes in the <span class="hlt">solar</span> <span class="hlt">wind</span>'s magnetic field strength tend to temporarily reduce electron fluxes between L = 4 and L = 8, while enhancing it between L = 3 and L = 4. In contrast to predictions generated by single-input linear filters, multi-input filters show that <span class="hlt">solar</span> <span class="hlt">wind</span> plasma density only contributes weakly to electron flux variability, although it does so consistently across nearly all L shells. Finally, we studied two distinct 4-year intervals within the most recent <span class="hlt">solar</span> cycle and found that smaller, more time-stationary prediction errors are generated by multi-input linear filters. We therefore conclude that multi-input filters more accurately reflect real dynamic relationships than any single-input linear filter alone.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20050192586','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20050192586"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Fluctuations and Their Consequences on the Magnetosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Li, Xin-Lin</p> <p>2005-01-01</p> <p>Efforts have been made to extract the physical meaning of each term in our prediction model of the Dst index using the <span class="hlt">solar</span> <span class="hlt">wind</span> as the only input. The work has been published Journal of Geophysical Research (Temerin and Li, 21002). We found different terms in the model representing different current in the magnetospheric system and each current has different rise and decay times, with the symmetric ring current the slowest, then the partial ring current, then the tail current. We also have been trying to understand the physical meaning of the diffusion coefficient used in our prediction model of relativistic electron fluxes at geostationary orbit. The model reproduced the observations of MeV electron flux variations well, the diffusion coefficient had be assumed only die to local magnetic field fluctuations, leading to its 10th power dependence on the L. We have studied the theoretical derivation of the diffusion coefficient and we believe that the effect electric field fluctuations at smaller L could become more significant. We have expanded our previous radiation belt electron prediction model, which predicted MeV electron geosynchronous orbit based on <span class="hlt">solar</span> <span class="hlt">wind</span> measurements, to predict MeV electrons inside geosynchronous orbit. The model results are compared with measurements from Polar/CEPPAD. Prediction efficiencies of 0.56 and 0.54, respectively, at L=6 and L=4, have been achieved over the entire year of 1998. This work wa reported at 2003 Fall AGU and has been accepted for publication in Space Weather (Barker et al., 2005). We also have used simultaneous measurements of the upstream <span class="hlt">solar</span> <span class="hlt">wind</span> and of energetic electrons at geosynchronous orbit to analyze the response of electrons over a very wide energy range, 50 keV-6MeV, to <span class="hlt">solar</span> <span class="hlt">wind</span> variations. Enhancements of energetic electron fluxes over this whole energy range are modulated by the <span class="hlt">solar</span> <span class="hlt">wind</span> speed and the polarity of the interplanetary magnetic field (IMF). The <span class="hlt">solar</span> <span class="hlt">wind</span> speed seems to be a dominant controlling parameter for electrons of all energy. This work has been published in Space Weather (Li et al., 2005).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/159784','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/159784"><span id="translatedtitle">Radar <span class="hlt">wind</span> profiler observations of <span class="hlt">solar</span> semidiurnal atmospheric tides</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Whiteman, C.D.; Bian, X.</p> <p>1995-04-15</p> <p>Semidiurnal <span class="hlt">solar</span> tides in the mid-latitude troposhphere are investigated using harmonic analysis of 404 MHz radar profiler <span class="hlt">wind</span> data obtained from a wide longitude zone in the U.S. The tides are apparent above a 1000-m-deep surface layer and increase in amplitude with height, attaining speeds of 0.5-0.7 m/s at 5-7 km. Observed <span class="hlt">wind</span> characteristics agree well with tidal characteristics obtained with a dynamical model driven by observed global semidiurnal horizontal pressure gradients. 10 refs., 6 figs., 1 tab.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013SoPh..285..111H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013SoPh..285..111H"><span id="translatedtitle">Observations of Rapid Velocity Variations in the Slow <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Hardwick, S. A.; Bisi, M. M.; Davies, J. A.; Breen, A. R.; Fallows, R. A.; Harrison, R. A.; Davis, C. J.</p> <p>2013-07-01</p> <p>The technique of interplanetary scintillation (IPS) is the observation of rapid fluctuations of the radio signal from an astronomical compact source as the signal passes through the ever-changing density of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Cross-correlation of simultaneous observations of IPS from a single radio source, received at multiple sites of the European Incoherent SCATter (EISCAT) radio antenna network, is used to determine the velocity of the <span class="hlt">solar</span> <span class="hlt">wind</span> material passing over the lines of sight of the antennas. Calculated velocities reveal the slow <span class="hlt">solar</span> <span class="hlt">wind</span> to contain rapid velocity variations when viewed on a time-scale of several minutes. <span class="hlt">Solar</span> TErrestrial RElations Observatory (STEREO) Heliospheric Imager (HI) observations of white-light intensity have been compared with EISCAT observations of IPS to identify common density structures that may relate to the rapid velocity variations in the slow <span class="hlt">solar</span> <span class="hlt">wind</span>. We have surveyed a one-year period, starting in April 2007, of the EISCAT IPS observing campaigns beginning shortly after the commencement of full science operations of the STEREO mission in a bid to identify common density structures in both EISCAT and STEREO HI datasets. We provide a detailed investigation and presentation of joint IPS/HI observations from two specific intervals on 23 April 2007 and 19 May 2007 for which the IPS P-Point (point of closest approach of the line of sight to the Sun) was between 72 and 87 <span class="hlt">solar</span> radii out from the Sun's centre. During the 23 April interval, a meso-scale (of the order of 105 km or larger) transient structure was observed by HI-1A to pass over the IPS ray path near the P-Point; the observations of IPS showed a micro-scale structure (of the order of 102 km) within the meso-scale transient. Observations of IPS from the second interval, on 19 May, revealed similar micro-scale velocity changes, however, no transient structures were detected by the HIs during that period. We also pose some fundamental thoughts on the slow <span class="hlt">solar</span> <span class="hlt">wind</span> structure itself.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/servlets/purl/971292','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/servlets/purl/971292"><span id="translatedtitle">The genesis <span class="hlt">solar-wind</span> sample return mission</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Wiens, Roger C</p> <p>2009-01-01</p> <p>The compositions of the Earth's crust and mantle, and those of the Moon and Mars, are relatively well known both isotopically and elementally. The same is true of our knowledge of the asteroid belt composition, based on meteorite analyses. Remote measurements of Venus, the Jovian atmosphere, and the outer planet moons, have provided some estimates of their compositions. The Sun constitutes a large majority, > 99%, of all the matter in the <span class="hlt">solar</span> system. The elemental composition of the photosphere, the visible 'surface' of the Sun, is constrained by absorption lines produced by particles above the surface. Abundances for many elements are reported to the {+-}10 or 20% accuracy level. However, the abundances of other important elements, such as neon, cannot be determined in this way due to a relative lack of atomic states at low excitation energies. Additionally and most importantly, the isotopic composition of the Sun cannot be determined astronomically except for a few species which form molecules above sunspots, and estimates derived from these sources lack the accuracy desired for comparison with meteoritic and planetary surface samples measured on the Earth. The <span class="hlt">solar</span> <span class="hlt">wind</span> spreads a sample of <span class="hlt">solar</span> particles throughout the heliosphere, though the sample is very rarified: collecting a nanogram of oxygen, the third most abundant element, in a square centimeter cross section at the Earth's distance from the Sun takes five years. Nevertheless, foil collectors exposed to the <span class="hlt">solar</span> <span class="hlt">wind</span> for periods of hours on the surface of the Moon during the Apollo missions were used to determine the helium and neon <span class="hlt">solar-wind</span> compositions sufficiently to show that the Earth's atmospheric neon was significantly evolved relative to the Sun. Spacecraft instruments developed subsequently have provided many insights into the composition of the <span class="hlt">solar</span> <span class="hlt">wind</span>, mostly in terms of elemental composition. These instruments have the advantage of observing a number of parameters simultaneously, including charge state distributions, velocities, and densities, all of which have been instrumental in characterizing the nature of the <span class="hlt">solar</span> <span class="hlt">wind</span>. However, these instruments have lacked the ability to make large dynamic range measurements of adjacent isotopes (i.e., {sup 17}O/{sup 16}O {approx} 2500) or provide the permil (tenths of percent) accuracy desirable for comparison with geochemical isotopic measurements. An accurate knowledge of the <span class="hlt">solar</span> and <span class="hlt">solar-wind</span> compositions helps to answer important questions across a number of disciplines. It aids in understanding the acceleration mechanisms of the <span class="hlt">solar</span> <span class="hlt">wind</span>, gives an improved picture of the charged particle environment near the photosphere, it constrains processes within the Sun over its history, and it provides a database by which to compare differences among planetary systems with the <span class="hlt">solar</span> system's starting composition, providing key information on planetary evolution. For example, precise knowledge of <span class="hlt">solar</span> isotopic and elemental compositions of volatile species in the Sun provides a baseline for models of atmospheric evolution over time for Earth, Venus, and Mars. Additionally, volatile and chemically active elements such as C, H, O, N, and S can tell us about processes active during the evolution of the <span class="hlt">solar</span> nebula. A classic example of this is the oxygen isotope system. In the 1970s it was determined that the oxygen isotopic ratio in refractory inclusions in primitive meteorites was enriched {approx}4% in {sup 16}O relative to the average terrestrial, lunar, and thermally processed meteorite materials. In addition, all processed <span class="hlt">solar</span>-system materials appeared to each have a unique oxygen isotopic composition (except the Moon and Earth, which are thought to be formed from the same materials), though differences are in the fraction of a percent range, much smaller than the refractory material {sup 16}O enrichment. Several theories were developed over the years to account for the oxygen isotope heterogeneity, each theory predicting a different <span class="hlt">solar</span> isotopic composition and each invoking a different early <span class="hlt">solar</span>-system process to produce the heterogeneity. Other volatiles such as C, N, and H may also have experienced similar effects, but with only two isotopes it is often impossible to distinguish with these elements between mass-dependent fractionation and other effects such as mixing or mass-independent fractionation. Table 1 provides a summary of the major measurement objectives of the Genesis mission. Determining the <span class="hlt">solar</span> oxygen isotopic composition is at the top of the list. Volatile element and isotope ratios constitute six of the top seven priorities. A number of disciplines stand to gain from information from the Genesis mission, as will be discussed later. Based on the Apollo <span class="hlt">solar-wind</span> foil experiment, the Genesis mission was designed to capture <span class="hlt">solar</span> <span class="hlt">wind</span> over orders of magnitude longer duration and in a potentially much cleaner environment than the lunar surface.</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/1999xmm..pres...30.','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999xmm..pres...30."><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">winds</span> surfs waves in the Sun's atmosphere!</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p></p> <p>1999-06-01</p> <p>The fact that this electrified plasma speeds up to almost 3 million kilometres per hour as it leaves the Sun - twice as fast as originally predicted - has been known for years. The interpretation of how it happens is the real and surprising novelty: "The waves in the Sun's atmosphere are produced by vibrating <span class="hlt">solar</span> magnetic field lines, which give <span class="hlt">solar</span> <span class="hlt">wind</span> particles a push just like an ocean wave gives a surfer a ride" said Dr John Kohl, principal investigator for the Ultraviolet Coronal Spectrometer (UVCS) - the instrument among the 12 aboard SOHO which gathered the data - and for the Spartan 201 mission. The outermost <span class="hlt">solar</span> atmosphere, or corona, is only seen from Earth during a total eclipse of the Sun, when it appears as a shimmering, white veil surrounding the black lunar disc. The corona is an extremely tenuous, electrically charged gas, known as plasma, that flows throughout the <span class="hlt">solar</span> system as the <span class="hlt">solar</span> <span class="hlt">wind</span>. The waves are formed by rapidly vibrating magnetic fields in the coronal plasma. They are called magneto - hydro - dynamic (MHD) waves and are believed to accelerate the <span class="hlt">solar</span> <span class="hlt">wind</span>. The <span class="hlt">solar</span> <span class="hlt">wind</span> is made up of electrons and ions, electrically charged atoms that have lost electrons. The electric charge of the <span class="hlt">solar</span> <span class="hlt">wind</span> particles forces them to travel along invisible lines of magnetic force in the corona. The particles spiral around the magnetic field lines as they rush into space. "The magnetic field acts like a violin string: when it's touched, it vibrates. When the Sun's magnetic field vibrates with a frequency equal to that of the particle spiraling around the magnetic field, it heats it up, producing a force that accelerates the particle upward and away from the Sun," says Dr. Ester Antonucci, an astronomer at the observatory of Turin, Italy, and co-investigator for SOHO's UVCS an instrument developed with considerable financial support by the Italian Space Agency, ASI. In a way this is similar to what happens if two people hold a string at opposite ends after threading it through an object, like a ring. If one person wiggles the string rapidly up and down, waves form in the string that move toward the person at the other end. The ring will "surf" these waves and move toward the other person as well. Try it! "Even with this major discovery, there are questions left to answer. The observations have made it abundantly clear that heavy particles like oxygen 'surf' on the waves, and there is also mounting evidence that waves are responsible for accelerating the hydrogen atoms, the most common constituent of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Future observations are needed to establish this fact. Many other kinds of particles, such as helium (second most common) have never been observed in the accelerating part of the corona, and new observations are also needed to refine our understanding of how the waves interact with the <span class="hlt">solar</span> <span class="hlt">wind</span> as a whole," said Dr. Steven Cranmer of the Harvard-Smithsonian Center for Astrophysics, lead author of the research to be published in the Astrophysical Journal*. Nevertheless, SOHO has again been able to reveal another of the Sun's mysteries: "This is another triumph for SOHO, stealing a long-held secret from our Sun", said Dr Martin Huber, Head of ESA Space Science Department and co-investigator for UVCS. *Ref. Article by S.Cranmer, G.B. Field and J.L. Kohl on Astrophysical Journal ( June 20, Vol 518, p. 937-947) available on the web at: http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v518n2/39802/sc0.html</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999xmm..pres...29.','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999xmm..pres...29."><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">winds</span> surfs waves in the Sun's atmosphere!</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p></p> <p>1999-07-01</p> <p>The fact that this electrified plasma speeds up to almost 3 million kilometres per hour as it leaves the Sun - twice as fast as originally predicted - has been known for years. The interpretation of how it happens is the real and surprising novelty: "The waves in the Sun's atmosphere are produced by vibrating <span class="hlt">solar</span> magnetic field lines, which give <span class="hlt">solar</span> <span class="hlt">wind</span> particles a push just like an ocean wave gives a surfer a ride" said Dr John Kohl, principal investigator for the Ultraviolet Coronal Spectrometer (UVCS) - the instrument among the 12 aboard SOHO which gathered the data - and for the Spartan 201 mission. The outermost <span class="hlt">solar</span> atmosphere, or corona, is only seen from Earth during a total eclipse of the Sun, when it appears as a shimmering, white veil surrounding the black lunar disc. The corona is an extremely tenuous, electrically charged gas, known as plasma, that flows throughout the <span class="hlt">solar</span> system as the <span class="hlt">solar</span> <span class="hlt">wind</span>. The waves are formed by rapidly vibrating magnetic fields in the coronal plasma. They are called magneto - hydro - dynamic (MHD) waves and are believed to accelerate the <span class="hlt">solar</span> <span class="hlt">wind</span>. The <span class="hlt">solar</span> <span class="hlt">wind</span> is made up of electrons and ions, electrically charged atoms that have lost electrons. The electric charge of the <span class="hlt">solar</span> <span class="hlt">wind</span> particles forces them to travel along invisible lines of magnetic force in the corona. The particles spiral around the magnetic field lines as they rush into space. "The magnetic field acts like a violin string: when it's touched, it vibrates. When the Sun's magnetic field vibrates with a frequency equal to that of the particle spiraling around the magnetic field, it heats it up, producing a force that accelerates the particle upward and away from the Sun," says Dr. Ester Antonucci, an astronomer at the observatory of Turin, Italy, and co-investigator for SOHO's UVCS an instrument developed with considerable financial support by the Italian Space Agency, ASI. In a way this is similar to what happens if two people hold a string at opposite ends after threading it through an object, like a ring. If one person wiggles the string rapidly up and down, waves form in the string that move toward the person at the other end. The ring will "surf" these waves and move toward the other person as well. Try it! "Even with this major discovery, there are questions left to answer. The observations have made it abundantly clear that heavy particles like oxygen 'surf' on the waves, and there is also mounting evidence that waves are responsible for accelerating the hydrogen atoms, the most common constituent of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Future observations are needed to establish this fact. Many other kinds of particles, such as helium (second most common) have never been observed in the accelerating part of the corona, and new observations are also needed to refine our understanding of how the waves interact with the <span class="hlt">solar</span> <span class="hlt">wind</span> as a whole," said Dr. Steven Cranmer of the Harvard-Smithsonian Center for Astrophysics, lead author of the research to be published in the Astrophysical Journal*. Nevertheless, SOHO has again been able to reveal another of the Sun's mysteries: "This is another triumph for SOHO, stealing a long-held secret from our Sun", said Dr Martin Huber, Head of ESA Space Science Department and co-investigator for UVCS. *Ref. Article by S.Cranmer, G.B. Field and J.L. Kohl on Astrophysical Journal ( June 20, Vol 518, p. 937-947) available on the web at: http://www.journals.uchicago.edu/ApJ/journal/issues/ApJ/v518n2/39802/sc0.html</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015SoPh..290.2589S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015SoPh..290.2589S"><span id="translatedtitle">Reconstruction of Helio-Latitudinal Structure of the <span class="hlt">Solar</span> <span class="hlt">Wind</span> Proton Speed and Density</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Sokół, Justyna M.; Swaczyna, Paweł; Bzowski, Maciej; Tokumaru, Munetoshi</p> <p>2015-09-01</p> <p>The modeling of the heliosphere requires continuous three-dimensional <span class="hlt">solar</span> <span class="hlt">wind</span> data. The in-situ out-of-ecliptic measurements are very rare, so that other methods of <span class="hlt">solar</span> <span class="hlt">wind</span> detection are needed. We use the remote-sensing data of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed from observations of interplanetary scintillation (IPS) to reconstruct spatial and temporal structures of the <span class="hlt">solar</span> <span class="hlt">wind</span> proton speed from 1985 to 2013. We developed a method of filling the data gaps in the IPS observations to obtain continuous and homogeneous <span class="hlt">solar</span> <span class="hlt">wind</span> speed records. We also present a method to retrieve the <span class="hlt">solar</span> <span class="hlt">wind</span> density from the <span class="hlt">solar</span> <span class="hlt">wind</span> speed, utilizing the invariance of the <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure and energy flux with latitude. To construct the synoptic maps of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed we use the decomposition into spherical harmonics of each of the Carrington rotation map. To fill the gaps in time we apply the singular spectrum analysis to the time series of the coefficients of spherical harmonics. We obtained helio-latitudinal profiles of the <span class="hlt">solar</span> <span class="hlt">wind</span> proton speed and density over almost three recent <span class="hlt">solar</span> cycles. The accuracy in the reconstruction is, due to computational limitations, about 20 %. The proposed methods allow us to improve the spatial and temporal resolution of the model of the <span class="hlt">solar</span> <span class="hlt">wind</span> parameters presented in our previous paper (Sokół et al., <span class="hlt">Solar</span> Phys. 285, 167, 2013) and give a better insight into the time variations of the <span class="hlt">solar</span> <span class="hlt">wind</span> structure. Additionally, the <span class="hlt">solar</span> <span class="hlt">wind</span> density is reconstructed more accurately and it fits better to the in-situ measurements from Ulysses.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20110023419&hterms=aurora&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Daurora','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20110023419&hterms=aurora&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Daurora"><span id="translatedtitle"><span class="hlt">Solar</span> Rotational Periodicities and the Semiannual Variation in the <span class="hlt">Solar</span> <span class="hlt">Wind</span>, Radiation Belt, and Aurora</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Emery, Barbara A.; Richardson, Ian G.; Evans, David S.; Rich, Frederick J.; Wilson, Gordon R.</p> <p>2011-01-01</p> <p>The behavior of a number of <span class="hlt">solar</span> <span class="hlt">wind</span>, radiation belt, auroral and geomagnetic parameters is examined during the recent extended <span class="hlt">solar</span> minimum and previous <span class="hlt">solar</span> cycles, covering the period from January 1972 to July 2010. This period includes most of the <span class="hlt">solar</span> minimum between Cycles 23 and 24, which was more extended than recent <span class="hlt">solar</span> minima, with historically low values of most of these parameters in 2009. <span class="hlt">Solar</span> rotational periodicities from S to 27 days were found from daily averages over 81 days for the parameters. There were very strong 9-day periodicities in many variables in 2005 -2008, triggered by recurring corotating high-speed streams (HSS). All rotational amplitudes were relatively large in the descending and early minimum phases of the <span class="hlt">solar</span> cycle, when HSS are the predominant <span class="hlt">solar</span> <span class="hlt">wind</span> structures. There were minima in the amplitudes of all <span class="hlt">solar</span> rotational periodicities near the end of each <span class="hlt">solar</span> minimum, as well as at the start of the reversal of the <span class="hlt">solar</span> magnetic field polarity at <span class="hlt">solar</span> maximum (approx.1980, approx.1990, and approx. 2001) when the occurrence frequency of HSS is relatively low. Semiannual equinoctial periodicities, which were relatively strong in the 1995-1997 <span class="hlt">solar</span> minimum, were found to be primarily the result of the changing amplitudes of the 13.5- and 27-day periodicities, where 13.5-day amplitudes were better correlated with heliospheric daily observations and 27-day amplitudes correlated better with Earth-based daily observations. The equinoctial rotational amplitudes of the Earth-based parameters were probably enhanced by a combination of the Russell-McPherron effect and a reduction in the <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere coupling efficiency during solstices. The rotational amplitudes were cross-correlated with each other, where the 27 -day amplitudes showed some of the weakest cross-correlations. The rotational amplitudes of the > 2 MeV radiation belt electron number fluxes were progressively weaker from 27- to 5-day periods, showing that processes in the magnetosphere act as a low-pass filter between the <span class="hlt">solar</span> <span class="hlt">wind</span> and the radiation belt. The A(sub p)/K(sub p) magnetic currents observed at subauroral latitudes are sensitive to proton auroral precipitation, especially for 9-day and shorter periods, while the A(sub p)/K(sub p) currents are governed by electron auroral precipitation for 13.5- and 27-day periodicities.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19950040056&hterms=leer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dleer','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19950040056&hterms=leer&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dleer"><span id="translatedtitle">Neutral hydrogen in the <span class="hlt">solar</span> <span class="hlt">wind</span> acceleration region</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Olsen, Espen Lyngdal; Leer, Egil; Holzer, Thomas E.</p> <p>1994-01-01</p> <p>Observation of <span class="hlt">solar</span> Ly alpha radiation scattered by coronal neutral hydrogen atoms can be used to investigate the acceleration region of the <span class="hlt">solar</span> <span class="hlt">wind</span>. In this paper we focus on the use of these observations to study Alfven waves, which can accelerate the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma to flow speeds observed in high-speed streams if their amplitude at the coronal base is 20 km/s or larger. The wave amplitude is then larger than the proton thermal speed in the outer corona, so that the mean proton speed (averaged over a wave period) is significantly larger than the proton thermal speed. For low-frequency wave the hydrogen atoms follow the proton motion in the waves, while for higher frequencies the protons move relative to the neutrals. Nevertheless, in the higher frequency case, the rates for charge exchange and recombination are high enough to broaden the velocity distribution function of neutral hydrogen. Both the wave motion of the hydrogen atoms in low-frequency Alfven waves and the 'heating' by higher frequency waves lead to a broadening of the scattered <span class="hlt">solar</span> Ly alpha line. For coronal base amplitues of 20 km/s, the line broadening increases with heliocentric distance beyond 4-5 <span class="hlt">solar</span> radii.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/7760930','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/7760930"><span id="translatedtitle">Nitrogen isotope abundances in the recent <span class="hlt">solar</span> <span class="hlt">wind</span>.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Kim, J S; Kim, Y; Marti, K; Kerridge, J F</p> <p>1995-06-01</p> <p>Although lunar crystalline rocks are essentially devoid of nitrogen, the same is not true of the lunar regolith. The nitrogen contents of individual regolith samples (which can be as high as 0.012% by mass) correlate strongly with abundances of noble gases known to be implanted in the lunar surface by <span class="hlt">solar</span> radiation, indicating that lunar regolith nitrogen is also predominantly of <span class="hlt">solar</span> origin. The large variability in 15N/14N ratios measured in different regolith samples may thus reflect long-term changes in the isotopic composition of the <span class="hlt">solar</span> radiation. But attempts to explain these variations have been hampered by the lack of any firm constraint on 15N/14N in the present <span class="hlt">solar</span> <span class="hlt">wind</span>. Here we report measurements of nitrogen isotopes from two lunar samples that have had simple (and relatively recent) exposure histories. We find that nitrogen implanted in the lunar surface during the past 10(5) to 5 x 10(7) years has a 15N/14N ratio approximately 40% higher than that in the terrestrial atmosphere, which is substantially lower than most previous estimates. This isotopic signature probably represents the best measure of 15N/14N in the present-day <span class="hlt">solar</span> <span class="hlt">wind</span>. PMID:7760930</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830025552','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830025552"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> iron abundance variations at <span class="hlt">solar</span> <span class="hlt">wind</span> speeds up to 600 km s sup -1, 1972 to 1976</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mitchell, D. G.; Roelof, E. C.; Bame, S. J.</p> <p>1982-01-01</p> <p>The Fe/H ratios in the peaks of high speed streams (HSS) were analyzed during the decline of <span class="hlt">Solar</span> Cycle 20 and the following minimum (October 1972 to December 1976). The response of the 50 to 200 keV ion channel of the APL/JHU energetic particle experiment (EPE) on IMP-7 and 8 was utilized to <span class="hlt">solar</span> <span class="hlt">wind</span> iron ions at high <span class="hlt">solar</span> <span class="hlt">wind</span> speeds (V or = 600 km/sec). Fe measurements with <span class="hlt">solar</span> <span class="hlt">wind</span> H and He parameters were compared from the Los Alamos National Laboratory (LANL) instruments on the same spacecraft. In general, the Fe distribution parameters (bulk velocity, flow direction, temperature) are found to be similar to the LANL He parameters. Although the average Fe/H ration in many steady HSS peaks agrees within observational uncertainties with the nominal coronal ratio of 4.7 x 0.00001, abundance variations of a factor of up to 6 are obtained across a given coronal-hole associated HSS.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH33A4128H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH33A4128H"><span id="translatedtitle">Minor Ion Species in the <span class="hlt">Solar</span> <span class="hlt">Wind</span> As Seen with SOHO/Celias/Mtof</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Heidrich-Meisner, V.; Berger, L.; Wimmer-Schweingruber, R. F.; Wurz, P.; Bochsler, P. A.; Ipavich, F. M.; Gloeckler, G.; Klecker, B.; Paquette, J. A.</p> <p>2014-12-01</p> <p>The continuous <span class="hlt">solar</span> <span class="hlt">wind</span> is typically categorized as either fast or slow <span class="hlt">wind</span>. Unlike the name implies the constitutive difference between these types of <span class="hlt">solar</span> <span class="hlt">wind</span> streams lies not in their respective <span class="hlt">solar</span> <span class="hlt">wind</span> velocity but in their elemental compositions. The long-term averages of the dominant ions in the <span class="hlt">solar</span> <span class="hlt">wind</span> have been measured with various instruments and are remarkably homogeneous. Here, we are interested in investigating the minor species contained in the <span class="hlt">solar</span> <span class="hlt">wind</span>. SOHO/CELIAS/MTOF is a high resolution mass spectrometer which has been continuously operational from 1996 to the present day. The high mass resolution and long life time of MTOF allows to complement the existing observations with the abundances of less abundant species for both typical slow and typical fast <span class="hlt">solar</span> <span class="hlt">wind</span>. This allows to further strengthen the characteristics of both types of <span class="hlt">solar</span> <span class="hlt">wind</span>. In principle MTOF's time resolution of up to five minutes facilitates to investigate the short-term variability of the <span class="hlt">solar</span> <span class="hlt">wind</span>. However, MTOF is a complex instrument that was intended to be in-flight calibrated with its sister instrument SOHO/CELIAS/CTOF. But unfortunately CTOF was only fully operable for about half a year in 1996. Instead we use <span class="hlt">solar</span> <span class="hlt">wind</span> data from ACE/SWICS for the calibration of MTOF whenever both instruments are sufficiently close to each other that we can expect them to observe the same <span class="hlt">solar</span> <span class="hlt">wind</span> stream.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2009AGUFMSH51C..08C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2009AGUFMSH51C..08C"><span id="translatedtitle">Anisotropy of <span class="hlt">Solar</span> <span class="hlt">Wind</span> Turbulence in the Dissipation Range</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, C. H.; Horbury, T. S.; Schekochihin, A. A.; Wicks, R. T.; Alexandrova, O.</p> <p>2009-12-01</p> <p>Although turbulence is readily observed in the <span class="hlt">solar</span> <span class="hlt">wind</span>, some aspects are poorly understood with unexplained observations and conflicting theoretical descriptions. In particular the dissipation range (fluctuations smaller than the ion gyroscale) is only just beginning to be thoroughly investigated. Here we present methods and results from a multi-spacecraft analysis of the <span class="hlt">solar</span> <span class="hlt">wind</span> dissipation range between the ion and electron gyroscales using the four Cluster satellites. We find that the fluctuations are anisotropic, having a higher power in the direction perpendicular to the local mean magnetic field than parallel to it. We also compare the observed anisotropic scaling to predictions for a kinetic Alfven wave cascade. The implications of anisotropic fluctuations for the interpretation of dissipation range measurements in general are also discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1992NCimC..15..575V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1992NCimC..15..575V"><span id="translatedtitle"><span class="hlt">Solar-wind</span> controlled pulsations at low latitudes</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Vellante, M.; Villante, U.</p> <p>1992-10-01</p> <p>Past observations and present models of the <span class="hlt">solar-wind</span> controlled dayside Pc 3-Pc 4 pulsations are reviewed. A year-long comparison between <span class="hlt">solar-wind</span> parameters obtained from IMP-8 and micropulsation measurements made at L'Aquila is presented. This study shows that at low latitudes the relationship between the two phenomena is more clear than at high latitudes. In particular, in agreement with the upstream-wave source mechanism, different frequency regimes of pulsations can be related to different regions of the high-velocity streams. Some examples of spectacular wave trains, with unusual amplitude and period, occurred during the strong geomagnetic storm of March 13, 1989 are also presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19780050652&hterms=1576&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2526%25231576','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19780050652&hterms=1576&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2526%25231576"><span id="translatedtitle">Numerical simulation of MHD shock waves in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Steinolfson, R. S.; Dryer, M.</p> <p>1978-01-01</p> <p>The effects of the interplanetary magnetic field on the propagation speed of shock waves through an ambient <span class="hlt">solar</span> <span class="hlt">wind</span> are examined by numerical solutions of the time-dependent nonlinear equations of motion. The magnetic field always increases the velocity of strong shocks. Although the field may temporarily slow down weak shocks inside 1 AU, it eventually also causes weak shocks to travel faster than they would without the magnetic field at larger distances. Consistent with the increase in the shock velocity, the gas pressure ratio across a shock is reduced considerably in the presence of the magnetic field. The numerical method is used to simulate (starting at 0.3 AU) the large deceleration of a shock observed in the lower corona by ground-based radio instrumentation and the more gradual deceleration of the shock in the <span class="hlt">solar</span> <span class="hlt">wind</span> observed by the Pioneer 9 and Pioneer 10 spacecraft.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19930049682&hterms=open+source&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dopen%2Bsource','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19930049682&hterms=open+source&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D80%26Ntt%3Dopen%2Bsource"><span id="translatedtitle">Counterstreaming <span class="hlt">solar</span> <span class="hlt">wind</span> halo electron events on open field lines?</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Gosling, J. T.; Mccomas, D. J.; Phillips, J. L.</p> <p>1992-01-01</p> <p>Counterstreaming <span class="hlt">solar</span> <span class="hlt">wind</span> halo electron events have been identified as a common 1 AU signature of coronal mass ejection events, and have generally been interpreted as indicative of closed magnetic field topologies, i.e., magnetic loops or flux ropes rooted at both ends in the Sun, or detached plasmoids. In this paper we examine the possibility that these events may instead occur preferentially on open field lines, and that counterstreaming results from reflection or injection behind interplanetary shocks or from mirroring from regions of compressed magnetic field farther out in the heliosphere. We conclude that neither of these suggested sources of counterstreaming electron beams is viable and that the best interpretation of observed counterstreaming electron events in the <span class="hlt">solar</span> <span class="hlt">wind</span> remains that of passage of closed field structures.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19730058135&hterms=planets+shape&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dplanets%2Bshape','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19730058135&hterms=planets+shape&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D40%26Ntt%3Dplanets%2Bshape"><span id="translatedtitle">Interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with the outer planets.</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Dryer, M.; Rizzi, A. W.; Shen, W.-W.</p> <p>1973-01-01</p> <p>The hypersonic analog for the interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with Jupiter, Saturn, Uranus, Neptune, and Pluto is used to provide estimates of shock shapes and locations, as well as average magnetosheath and/or ionosheath properties for these planets. Several representative spacecraft flyby trajectories (designed for outer-planet 'Grand Tour' simulations) are superimposed upon a series of figures in order to provide estimates of potential plasma and field parameters which may be encountered. Consideration is given first to the possibility that several of these planets have intrinsic magnetic fields and, secondly, to the interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> directly on the ionosphere should there actually be no intrinsic field. Saturn and Pluto are chosen as examples of this latter case.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740060901&hterms=Collards&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCollards','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740060901&hterms=Collards&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DCollards"><span id="translatedtitle">Pioneer 10 observations of the <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with Jupiter</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wolfe, J. H.; Mihalov, J. D.; Collard, H. R.; Mckibbin, D. D.; Frank, L. A.; Intriligator, D. S.</p> <p>1974-01-01</p> <p>Detailed analysis of the Pioneer 10 plasma analyzer experiment flight data during the Jupiter flyby in late November and early December 1973 has been performed. The observations show that the interaction of Jupiter's magnetic field with the <span class="hlt">solar</span> <span class="hlt">wind</span> is similar in many ways to that at earth, but the scale size is over 100 times larger. Jupiter is found to have a detached standing bow shock wave of high Alfven Mach number. Like the earth, Jupiter has a prominent magnetopause that deflects the magnetosheath plasma and excludes its direct entry into the Jovian magnetosphere. Unlike that of the earth, the sunward hemisphere of Jupiter's outer magnetosphere is found to be highly inflated with thermal plasma and a high-beta region that is highly responsive to changes in <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19740018157','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19740018157"><span id="translatedtitle">Pioneer 10 observations of the <span class="hlt">solar</span> <span class="hlt">wind</span> interation with Jupiter</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wolfe, J. H.; Mihalov, J. D.; Collard, H. R.; Mckibbin, D. D.; Frank, L. A.; Intriligator, D. S.</p> <p>1974-01-01</p> <p>Pioneer 10 Plasma Analyzer experiment flight data during the Jupiter flyby are presented. The observations show that the interaction of Jupiter's magnetic field with the <span class="hlt">solar</span> <span class="hlt">wind</span> is similar in many ways to that at earth, but the scale size is over 100 times larger. Jupiter is found to have a detached standing bow shock wave of high Alfven Mach number. Jupiter has a prominent magnetopause which deflects the magnetosheath plasma and excludes its direct entry into the Jovian magnetosphere. The sunward hemisphere of Jupiter's outer magnetosphere is found to be highly inflated with thermal plasma and a high beta region which is highly responsive to changes in <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure. Observational arguments are presented which tend to discount a thin disklike magnetosphere but, rather, favor a Jovian magnetosphere, albeit probabily considerably flattened as compared to the earth's magnetosphere, yet still with reasonable thickness. Results concerning the shock jump conditions, the magnetosheath flow field and inferred internal magnetospheric plasma are presented.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/22068812','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/22068812"><span id="translatedtitle">Generation of residual energy in the turbulent <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Gogoberidze, G.</p> <p>2012-10-15</p> <p>In situ observations of the fluctuating <span class="hlt">solar</span> <span class="hlt">wind</span> flow show that the energy of magnetic field fluctuations always exceeds that of the kinetic energy, and therefore the difference between the kinetic and magnetic energies, known as the residual energy, is always negative. The same behaviour is found in numerical simulations of magnetohydrodynamic turbulence. We study the dynamics of the residual energy for strong, anisotropic, critically balanced magnetohydrodynamic turbulence using the eddy damped quasi-normal Markovian approximation. Our analysis shows that for stationary critically balanced magnetohydrodynamic turbulence, negative residual energy will always be generated by nonlinear interacting Alfven waves. This offers a general explanation for the observation of negative residual energy in <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence and in the numerical simulations.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19760024031','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19760024031"><span id="translatedtitle">Mass fractionation of the lunar surface by <span class="hlt">solar</span> <span class="hlt">wind</span> sputtering</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Switkowski, Z. E.; Haff, P. K.; Tombrello, T. A.; Burnett, D. S.</p> <p>1975-01-01</p> <p>The sputtering of the lunar surface by the <span class="hlt">solar</span> <span class="hlt">wind</span> is examined as a possible mechanism of mass fractionation. Simple arguments based on current theories of sputtering and the ballistics of the sputtered atoms suggest that most ejected atoms will have sufficiently high energy to escape lunar gravity. However, the fraction of atoms which falls back to the surface is enriched in the heavier atomic components relative to the lighter ones. This material is incorporated into the heavily radiation-damaged outer surfaces of grains where it is subject to resputtering. Over the course of several hundred years an equilibrium surface layer, enriched in heavier atoms, is found to form. The dependence of the calculated results upon the sputtering rate and on the details of the energy spectrum of sputtered particles is investigated. It is concluded that mass fractionation by <span class="hlt">solar</span> <span class="hlt">wind</span> sputtering is likely to be an important phenomenon on the lunar surface.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH52A..05V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH52A..05V"><span id="translatedtitle">Probability Density Functions for the Variable <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Voros, Z.; Leitner, M.</p> <p>2014-12-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> is a complex plasma system in which structures, fluctuations and turbulence co-exist over multiple scales. Some aspects of this complexity can be described statistically only. In order to study the time evolution of field and plasma fluctuations we consider normal, log-normal, kappa and log-kappa probability distributions. We demonstrate that the shape of distributions shows a large variability controlled for example by the level of plasma compression. For the description of large-scale multi-source fluctuations in the <span class="hlt">solar</span> <span class="hlt">wind</span> nonlinear multiplicative rather than linear additive processes are needed. This indicates that the log-normal or the log-kappa distributions have to be used. The changing statistical features of fluctuations have a large impact on the physics of plasma heating.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19910005747&hterms=solar+vortex&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsolar%2Bvortex','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19910005747&hterms=solar+vortex&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3Dsolar%2Bvortex"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">wind</span> dynamic pressure variations: Quantifying the statistical magnetospheric response</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sibeck, D. G.</p> <p>1990-01-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> dynamic pressure variations are common and have large amplitudes. Existing models for the transient magnetospheric and ionospheric response to the <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure variation are quantified. The variations drive large amplitude (approx 1 R sub E) magnetopause motion with velocities of approx. 60 km/s and transient dayside ionospheric flows of 2 km/s which are organized into double convection vortices. Ground magnetometer signatures are more pronounced under the auroral ionosphere, where they reach 60 to 300 nT, and under the equatorial electrojet. A statistical comparison of transient ground magnetometer events seen at a South Pole station and geosynchronous orbit indicates that all but the weakest ground events are associated with clear compressional signatures at the dayside geosynchronous orbit.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19740034913&hterms=Kinetic+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2528Kinetic%2Btheory%2529','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19740034913&hterms=Kinetic+theory&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D30%26Ntt%3D%2528Kinetic%2Btheory%2529"><span id="translatedtitle">Kinetic theory analysis of <span class="hlt">solar</span> <span class="hlt">wind</span> interaction with planetary objects</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Wu, S. T.; Dryer, M.</p> <p>1973-01-01</p> <p>A purely kinetic treatment is proposed for the interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with any small planetary object. Small refers to those cases where the <span class="hlt">solar</span> <span class="hlt">wind</span> proton's thermal gyroradius is arbitrarily taken to be greater than 0.1 radius of the object under investigation. The 'object' may possibly include an ionosphere or magnetosphere. The collisionless Boltzmann equation, neglecting the magnetic field, is used to calculate steady-state profiles of density and velocity around the obstacle. A low density plasma void in the umbral region and a compression in the penumbral region are clearly found. The present technique, despite its neglect of the interplanetary magnetic field, is proposed as an alternative zeroth order approach to the continuum, local magnetic anomaly, and guiding center approaches used by others for the particular case of moon. Some recent, potentially relevant, observations on and in front of the moon are 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_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/2012cosp...39.1903S','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012cosp...39.1903S"><span id="translatedtitle">Can <span class="hlt">solar</span> <span class="hlt">wind</span> viscous drag account for CME deceleration?</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Subramanian, Prasad; Lara, Alejandro; Borgazzi, Andrea</p> <p>2012-07-01</p> <p>An understanding of the forces that act on Coronal Mass Ejections (CMEs) in the interplanetary medium are of prime importance in predicting their arrival at the Earth. These forces have been evaluated so far only in terms of an empirical drag coefficient C_{D} 1 that quantifies the role of the aerodynamic drag experienced by a typical CME due to its interaction with the ambient <span class="hlt">solar</span> <span class="hlt">wind</span>. We examine microphysical models for viscosity in the turbulent <span class="hlt">solar</span> <span class="hlt">wind</span> and apply them to a simplified model for CME propagation. Using this, we obtain an analytical expression for the dynamical viscosity coefficient and C_{D} as a function of heliocentric distance. This is the first physical characterization of the important issue of the aerodynamic drag experienced by CMEs. Our results elucidate the essential physics involved in explaining observations of CME deceleration and have implications for predictions of CME arrival time at the Earth.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19830026604','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19830026604"><span id="translatedtitle">Coronal sources of the intrastream structure of the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sullivan, J. D.; Bridge, H. S.</p> <p>1983-01-01</p> <p>Short time scale changes in the bulk speed were found not to coincide with X-ray transients near the sub-earth point nor with the number of X-ray bright points within a coronal hole and near the equator. The changes in bulk speed, it is shown, are associated with changes in light areas in a hole which may be associated with the opening or closing of magnetic field lines within the coronal hole. That there is a causal connection between these sudden changes (apperance or disappearance) in light area and sudden changes in the bulk speed of the <span class="hlt">solar</span> <span class="hlt">wind</span> is further evidenced by the spatial proximity on the Sun of these changing light regions to the source position of stream lines from Levine's model that connect into the same <span class="hlt">solar</span> <span class="hlt">wind</span> streams.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015MNRAS.453L..64C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015MNRAS.453L..64C"><span id="translatedtitle">Magnetic field rotations in the <span class="hlt">solar</span> <span class="hlt">wind</span> at kinetic scales</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, C. H. K.; Matteini, L.; Burgess, D.; Horbury, T. S.</p> <p>2015-10-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> magnetic field contains rotations at a broad range of scales, which have been extensively studied in the magnetohydrodynamics range. Here, we present an extension of this analysis to the range between ion and electron kinetic scales. The distribution of rotation angles was found to be approximately lognormal, shifting to smaller angles at smaller scales almost self-similarly, but with small, statistically significant changes of shape. The fraction of energy in fluctuations with angles larger than ? was found to drop approximately exponentially with ?, with e-folding angle 9.8 at ion scales and 0.66 at electron scales, showing that large angles (? > 30) do not contain a significant amount of energy at kinetic scales. Implications for kinetic turbulence theory and the dissipation of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence are discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013MS%26E...52g2003C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013MS%26E...52g2003C"><span id="translatedtitle">A desalination plant with <span class="hlt">solar</span> and <span class="hlt">wind</span> energy</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Chen, H.; Ye, Z.; Gao, W.</p> <p>2013-12-01</p> <p>The shortage of freshwater resources has become a worldwide problem. China has a water shortage, although the total amount of water resources is the sixth in the world, the per capita water capacity is the 121th (a quarter of the world's per capita water capacity), and the United Nations considers China one of the poorest 13 countries in the world in terms of water. In order to increase the supply of fresh water, a realistic way is to make full use of China's long and narrow coastline for seawater desalination. This paper discusses a sea water desalination device, the device adopts distillation, uses the greenhouse effect principle and <span class="hlt">wind</span> power heating principle, and the two-type start is used to solve the problem of vertical axis <span class="hlt">wind</span> turbine self-starting. Thrust bearings are used to ensure the stability of the device, and to ensure absorbtion of <span class="hlt">wind</span> energy and <span class="hlt">solar</span> energy, and to collect evaporation of water to achieve desalination. The device can absorb <span class="hlt">solar</span> and <span class="hlt">wind</span> energy instead of input energy, so it can be used in ship, island and many kinds of environment. Due to the comprehensive utilization of <span class="hlt">wind</span> power and <span class="hlt">solar</span> power, the efficiency of the device is more than other passive sea water desalting plants, the initial investment and maintenance cost is lower than active sea water desalting plant. The main part of the device cannot only be used in offshore work, but can also be used in deep sea floating work, so the device can utilise deep sea energy. In order to prove the practicability of the device, the author has carried out theory of water production calculations. According to the principle of conservation of energy, the device ais bsorbing <span class="hlt">solar</span> and <span class="hlt">wind</span> power, except loose lost part which is used for water temperature rise and phase transition. Assume the inflow water temperature is 20 C, outflow water temperature is 70 C, the energy utilization is 60%, we can know that the water production quantity is 8 kg/ m2 per hour. Comparing with the disk <span class="hlt">solar</span> distillation apparatus, of which water production quantity is only 3-4kg/m2 per hour only in sunny day, but can't be used at night, the water production quantity is highly increased. So the device should have a good application prospect.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20000074663&hterms=High+tide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DHigh%2Btide','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20000074663&hterms=High+tide&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3DHigh%2Btide"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Influence on the Oxygen Content of Ion Outflow in the High Altitude Polar Cap During <span class="hlt">Solar</span> Minimum Conditions</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Elliott, Heather A.; Comfort, Richard H.; Craven, Paul D.; Chandler, Michael O.; Moore, Thomas E.</p> <p>2000-01-01</p> <p>We correlate <span class="hlt">solar</span> <span class="hlt">wind</span> and IMF properties with the properties of O(+) and H(+) in the polar cap in early 1996 during <span class="hlt">solar</span> minimum conditions at altitudes between 5.5 and 8.9 Re geocentric using the Thermal Ion Dynamics Experiment (TIDE) on the POLAR satellite. Throughout the high altitude polar cap, we observe H(+) to be more abundant than O(+). H(+) is a significant fraction of both the ionosphere and the <span class="hlt">solar</span> <span class="hlt">wind</span>, and O(+) is not a significant species in the <span class="hlt">solar</span> <span class="hlt">wind</span>. O(+) is the major species in the ionosphere so the faction of O(+) present in the magnetosphere is commonly used as a measure of the ionospheric contribution to the magnetosphere. For these reasons, 0+ is of primary interest in this study. We observe O(+) to be most abundant at lower latitudes when the <span class="hlt">solar</span> <span class="hlt">wind</span> speed is low (and low Kp), and at higher <span class="hlt">solar</span> <span class="hlt">wind</span> speeds (and high Kp) O(+) is observed across most of the polar cap. We also find that O(+) density and parallel flux are well organized by <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure; they both increase with <span class="hlt">solar</span> <span class="hlt">wind</span> dynamic pressure. H(+) is not as highly correlated with <span class="hlt">solar</span> <span class="hlt">wind</span> and IMF parameters, but H(+) density and parallel flux have some negative correlation with IMF By, and some positive correlation with VswBIMF. In this <span class="hlt">solar</span> minimum data set, H(+) is dominant so that contributions of this plasma to the plasma sheet would have a very low O(+) to H(+) ratio.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2003PhDT.......144R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2003PhDT.......144R"><span id="translatedtitle">Heliospheric x-rays due to <span class="hlt">solar</span> <span class="hlt">wind</span> charge exchange</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Robertson, Ina Piket</p> <p></p> <p>X-ray emission due to charge transfer between heavy <span class="hlt">solar</span> <span class="hlt">wind</span> ions and interstellar and geocoronal neutrals has been predicted to exist in both the heliosphere and in the geocorona. The high charge state <span class="hlt">solar</span> <span class="hlt">wind</span> ions resulting from these collisions are left in highly excited states and emit extreme ultraviolet or soft x-ray photons. Models have been created to simulate this type of x-ray emission with interstellar and geocoronal neutrals. Time variations in the x-ray emissions were studied by using measured <span class="hlt">solar</span> <span class="hlt">wind</span> proton fluxes. The Fahr hot model was used to determine interstellar neutral densities. It was found that x-rays from interstellar hydrogen showed little variation in their intensities. The greatest variation was in geocoronal x-rays, although x-rays from interstellar helium can show considerable variation when the look direction is through the helium cone. Simulated images of Earth's geocorona as seen from an observation point outside the geocorona were created. The locations of the bow shock and magnetopause are evident in these images. Time independent maps were created that showed steady-state x-ray intensities due to the interaction between the <span class="hlt">solar</span> <span class="hlt">wind</span> and both interstellar neutrals and the geocoronal neutrals as a function of look direction and time of year. In all cases, the x-ray intensity is highest when the view direction is towards the Sun, but the intensity is also relatively high for view directions intersecting the gravitational focusing cone of interstellar helium. Measured <span class="hlt">solar</span> <span class="hlt">wind</span> proton fluxes are also directly compared with the LTE (long term enhancements) part of the soft x-ray background measured by the Rontgen satellite ROSAT. A significant positive correlation exists. We also show a heliospheric/geocoronal x-ray intensity map for the conditions used by Snowden in producing the 1/4 keV channel soft x-ray background map in galactic coordinates. Our preliminary conclusion is that very roughly 50% of the total background soft x-ray intensity in the galactic plane and 25% at high galactic latitudes can be attributed to the charge transfer process operating within the <span class="hlt">solar</span> system, with the remaining emission coming from outside our heliosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20060039435&hterms=solar+impulse&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Bimpulse','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20060039435&hterms=solar+impulse&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dsolar%2Bimpulse"><span id="translatedtitle">(abstract) Ulysses Observations of Magnetic Nulls in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Winterhalter, D.; Murphy, N.; Tsurutani, B. T.; Smith, E. J.; Balogh, A.; Erdos, G.</p> <p>1993-01-01</p> <p>High time resolution magnetic field measurements (1 vector/s) at radial distances out to 5.3 AU and heliographic latitudes from 0(deg) to > 35(deg) S reveal the presence of solitary pulses lasting tens of seconds in which the field magnitude approaches or reaches zero. The properties of these nulls, their spatial distribution and relation to <span class="hlt">solar</span> <span class="hlt">wind</span> structures and to similar-apppearing interplanetary and magnetospheric impulses will be discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014JASS...31..149K','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014JASS...31..149K"><span id="translatedtitle">Statistical Properties of Geomagnetic Activity Indices and <span class="hlt">Solar</span> <span class="hlt">Wind</span> Parameters</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Kim, Jung-Hee; Chang, Heon-Young</p> <p>2014-06-01</p> <p>As the prediction of geomagnetic storms is becoming an important and practical problem, conditions in the Earth¡¯s magnetosphere have been studied rigorously in terms of those in the interplanetary space. Another approach to space weather forecast is to deal with it as a probabilistic geomagnetic storm forecasting problem. In this study, we carry out detailed statistical analysis of <span class="hlt">solar</span> <span class="hlt">wind</span> parameters and geomagnetic indices examining the dependence of the distribution on the <span class="hlt">solar</span> cycle and annual variations. Our main findings are as follows: (1) The distribution of parameters obtained via the superimposed epoch method follows the Gaussian distribution. (2) When <span class="hlt">solar</span> activity is at its maximum the mean value of the distribution is shifted to the direction indicating the intense environment. Furthermore, the width of the distribution becomes wider at its maximum than at its minimum so that more extreme case can be expected. (3) The distribution of some certain heliospheric parameters is less sensitive to the phase of the <span class="hlt">solar</span> cycle and annual variations. (4) The distribution of the eastward component of the interplanetary electric field BV and the <span class="hlt">solar</span> <span class="hlt">wind</span> driving function BV2, however, appears to be all dependent on the <span class="hlt">solar</span> maximum/minimum, the descending/ascending phases of the <span class="hlt">solar</span> cycle and the equinoxes/solstices. (5) The distribution of the AE index and the Dst index shares statistical features closely with BV and BV2 compared with other heliospheric parameters. In this sense, BV and BV2 are more robust proxies of the geomagnetic storm. We conclude by pointing out that our results allow us to step forward in providing the occurrence probability of geomagnetic storms for space weather and physical modeling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20040050559&hterms=subcontract&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsubcontract','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20040050559&hterms=subcontract&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3Dsubcontract"><span id="translatedtitle">A Search for <span class="hlt">Solar</span> Sources of High-Speed <span class="hlt">Solar</span> <span class="hlt">Wind</span> Streams</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Mikic, Zoran</p> <p>2002-01-01</p> <p>This report covers technical progress during the third and fourth years of Subcontract No. 5710000474, 'A Search for <span class="hlt">Solar</span> Sources of High-speed <span class="hlt">Solar</span> <span class="hlt">Wind</span> Streams,' between Science Applications International Corporation (SAIC) and the Massachusetts Institute of Technology (MIT), covering the period November 2000 to December 2002. This is a subcontract originating from NASA SR&T Contract NAG5-7967 with MIT. In the following sections we summarize our progress during this reporting period.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20130012782','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20130012782"><span id="translatedtitle">Construction of <span class="hlt">Solar-Wind</span>-Like Magnetic Fields</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Roberts, Dana Aaron</p> <p>2012-01-01</p> <p>Fluctuations in the <span class="hlt">solar</span> <span class="hlt">wind</span> fields tend to not only have velocities and magnetic fields correlated in the sense consistent with Alfven waves traveling from the Sun, but they also have the magnitude of the magnetic field remarkably constant despite their being broadband. This paper provides, for the first time, a method for constructing fields with nearly constant magnetic field, zero divergence, and with any specified power spectrum for the fluctuations of the components of the field. Every wave vector, k, is associated with two polarizations the relative phases of these can be chosen to minimize the variance of the field magnitude while retaining the\\random character of the fields. The method is applied to a case with one spatial coordinate that demonstrates good agreement with observed time series and power spectra of the magnetic field in the <span class="hlt">solar</span> <span class="hlt">wind</span>, as well as with the distribution of the angles of rapid changes (discontinuities), thus showing a deep connection between two seemingly unrelated issues. It is suggested that using this construction will lead to more realistic simulations of <span class="hlt">solar</span> <span class="hlt">wind</span> turbulence and of the propagation of energetic particles.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSH13A2232G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSH13A2232G"><span id="translatedtitle">Low-Frequency Electromagnetic Thermal Fluctuations in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gaelzer, R.; Yoon, P. H.; Ziebell, L. F.; Pavan, J.</p> <p>2012-12-01</p> <p>It is well known that the <span class="hlt">solar</span> <span class="hlt">wind</span> proton temperature anisotropy is constrained in the temperature ratio vs. beta parameter space by the mirror/proton-cyclotron and parallel/oblique firehose instability threshold conditions (Hellinger et al., 2006). However, the actual <span class="hlt">solar</span> <span class="hlt">wind</span> is found in the parameter regime stable to these instabilities (Bale et al., 2009). Since no waves can be generated in the purely collisionless and stable plasma, the source of the low-frequency electromagnetic fluctuations in the <span class="hlt">solar</span> <span class="hlt">wind</span> must be owing to spontaneous thermal effects. The problem of the spontaneously emitted electromagnetic waves from magnetized plasmas is generally poorly understood (Araneda et al., 2011). In the present paper, we formulate the theory of spontaneous thermal emission of electromagnetic radiation in the vicinity of the low-frequency modes of Alfvn, ion-cyclotron, and whistler modes. We carry out a statistical analysis by varying the temperature anisotropy and parallel beta and compare the theoretical fluctuation intensity against the observation such as that reported by Bale et al. (2009). Hellinger et al., GRL, 33, L09101 (2006). Bale et al., PRL, 103, 211101 (2009). Araneda et al., Space Sci. Rev., DOI:10.1007/s11214-011-9773-0 (2011).</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2004cosp...35.1758M','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2004cosp...35.1758M"><span id="translatedtitle">Testing for multifractality of the slow <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Macek, W. M.; Bruno, R.; Consolini, G.</p> <p></p> <p>We analyse time series of one of the Elssäser variables for the low-speed stream of the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma representing Alfvénic fluctuations propagating downstream as measured in situ by the Helios spacecraft in the inner heliosphere. We demonstrate that the influence of noise in the data can be efficiently reduced by moving average and singular-value decomposition filters. We calculate the multifractal spectrum for the flow of the <span class="hlt">solar</span> <span class="hlt">wind</span> directly from the cleaned experimental signal. The resulting spectrum of dimensions shows multifractal structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> in the inner heliosphere. The obtained multifractal spectrum is consistent with that for the multifractal measure on the self-similar weighted Cantor set with the degree of multifractality of ˜ 10-1.This work has been done in the framework of the European Commission Research Training Network Grant No. HPRN-CT-2001-00314 and the State Scientific Research Committee Grant No. 2 P03B 126 24.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20070005042&hterms=Magnetosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DMagnetosphere','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20070005042&hterms=Magnetosphere&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3DMagnetosphere"><span id="translatedtitle">Alfven Waves in the <span class="hlt">Solar</span> <span class="hlt">Wind</span>, Magnetosheath, and Outer Magnetosphere</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Sibeck, D. G.</p> <p>2007-01-01</p> <p>Alfven waves Propagating outward from the Sun are ubiquitous in the <span class="hlt">solar</span> <span class="hlt">wind</span> and play a major role in the <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere interaction. The passage of the waves generally occurs in the form of a series of discrete steepened discontinuities, each of which results in an abrupt change in the interplanetary magnetic field direction. Some orientations of the magnetic field permit particles energized at the Earth's bow shock to gain access to the foreshock region immediately upstream from the Earth's bow shock. The thermal pressure associated with these particles can greatly perturb <span class="hlt">solar</span> <span class="hlt">wind</span> plasma and magnetic field parameters shortly prior to their interaction with the Earth's bow shock and magnetosphere. The corresponding dynamic pressure variations batter the magnetosphere, driving magnetopause motion and transient compressions of the magnetospheric magnetic field. Alfven waves transmit information concerning the dynamic pressure variations applied to the magnetosphere to the ionosphere, where they generate the traveling convection vortices (TCVs) seen in high-latitude ground magnetograms. Finally, the sense of Alfvenic perturbations transmitted into the magnetosheath reverses across local noon because magnetosheath magnetic field lines drape against the magnetopause. The corresponding change in velocity perturbations must apply a weak torque to the Earth's magnetosphere.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19870045504&hterms=wind+power+work&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dwind%2Bpower%2Bwork','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19870045504&hterms=wind+power+work&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D20%26Ntt%3Dwind%2Bpower%2Bwork"><span id="translatedtitle">Evolution of interstellar pickup ions in the <span class="hlt">solar</span> <span class="hlt">wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Isenberg, Philip A.</p> <p>1987-01-01</p> <p>A model is constructed for the evolution of an interstellar pickup ion distribution in the <span class="hlt">solar</span> <span class="hlt">wind</span>. The model assumes that the ions are immediately isotropized at ionization and follows the subsequent development of the distribution function as the particles are convected with the <span class="hlt">solar</span> <span class="hlt">wind</span>. The effects of energy diffusion in an ambient wave field with a power law spectrum, adiabatic deceleration in the expanding <span class="hlt">solar</span> <span class="hlt">wind</span>, and continual addition of newly ionized particles are all included in the model. An analytical expression describing the evolution of the distribution function in phase space velocity and heliocentric radius is obtained. The distribution quickly approaches an asymptotic shape in phase space which depends on the relative efficiency of the energy diffusion process compared to that of adiabatic deceleration. At large distances from the sun the density of pickup ions falls as 1/r in this model. An expression for the distribution function at large distances and for large particle speed is presented. The asymptotic shape should describe the distribution of pickup ions in the outer heliosphere and could be used as an input distribution for a model of the anomalous component of heliosphere and could be used as an input distribution for a model of the anomalous component of cosmic rays. Comparison of this work with the recent observation of He(+) at 1 AU implies that the energy diffusion process is very weak inside 1 AU.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFM.P13C1951P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFM.P13C1951P"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Driven Plasma Fluxes from the Venus Ionosphere</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Perez De Tejada, H. A.; Lundin, R. N.; Zhang, T.; Sauvaud, J. A.; Reyes-Ruiz, M.</p> <p>2012-12-01</p> <p><span class="hlt">SOLAR</span> <span class="hlt">WIND</span> DRIVEN PLASMA FLUXES FROM THE VENUS IONOSPHERE H. Prez-de-Tejada (1), R. Lundin (2), H. Durand-Manterola (1), S. Barabash (2), T. L. Zhang (3), J. A., Sauvaud (4), and M. Reyes-Ruiz (5) 1 - Institute of Geophysics, UNAM, Mxico, D. F. 2 - Swedish Institute of Space Physics, Kiruna, Sweden 3 - Space Research Institute, Graz, Austria 4 - CESR, Toulouse, France 5 - Institute of Astronomy, UNAM, Ensenada, Mxico Measurements conducted with the ASPERA-4 instrument and the magnetometer of the Venus Express spacecraft show that the kinetic pressure of planetary O+ ion fluxes measured in the Venus wake can be significantly larger than the local magnetic pressure and, as a result, those ions are not being driven by magnetic forces but by the kinetic energy of the <span class="hlt">solar</span> <span class="hlt">wind</span>. Beams of planetary O+ ions with those properties have been detected in several orbits of the Venus Express through the wake as the spacecraft traverses by the noon-midnight plane along its near polar trajectory. The momentum flux of the O+ ions leads to superalfvenic flow conditions. It is suggested that such O+ ion beams are produced in the vicinity of the magnetic polar regions of the Venus ionosphere where the <span class="hlt">solar</span> <span class="hlt">wind</span> erodes the local plasma leading to plasma channels that extend downstream from those regions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2008cosp...37.2606R','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2008cosp...37.2606R"><span id="translatedtitle">Modeling the viscous interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with comets</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Reyes-Ruiz, Mauricio</p> <p></p> <p>We study the effects of viscous momentum transport and energy dissipation in the interaction of the <span class="hlt">solar</span> <span class="hlt">wind</span> with the plasma environment of a comet. Analytical calculations are carried out to estimate the rate of viscous dragging of material from the comet's ionosphere to the plasma tail. Numerical simulations are conducted of the plasma tail dynamics and evolution using a 2D code that solves the Navier-Stokes, continuity and energy equations. The results of our calculations are compared to in situ measurements of the flow properties made by the Giotto spacecraft at comet Halley and the ICE spacecraft at comet Giacobinni-Zinner. We find that the profiles of gas velocity and temperature along the spacecraft trajectories are consistent with a low value for the Reynolds number, between 10 and 100, both in the shocked <span class="hlt">solar</span> <span class="hlt">wind</span> and in the comet's tail. Finally, we study the relevance of viscous dragging in the process of plasma tail detachment by a <span class="hlt">solar</span> <span class="hlt">wind</span> ram pressure increase as recently observed for comet 2P/Encke.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2012AGUFMSM23C2327C','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2012AGUFMSM23C2327C"><span id="translatedtitle">The DSCOVR <span class="hlt">Solar</span> <span class="hlt">Wind</span> Mission and Future Space Weather Products</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Cash, M. D.; Biesecker, D. A.; Reinard, A. A.</p> <p>2012-12-01</p> <p>The Deep Space Climate Observatory (DSCOVR) mission, scheduled for launch in mid-2014, will provide real-time <span class="hlt">solar</span> <span class="hlt">wind</span> thermal plasma and magnetic measurements to ensure continuous monitoring for space weather forecasting. DSCOVR will orbit L1 and will serve as a follow-on mission to NASA's Advanced Composition Explorer (ACE), which was launched in 1997. DSCOVR will have a total of six instruments, two of which will provide real-time data necessary for space weather forecasting: a Faraday cup to measure the proton and alpha components of the <span class="hlt">solar</span> <span class="hlt">wind</span>, and a triaxial fluxgate magnetometer to measure the magnetic field in three dimensions. Real-time data provided by DSCOVR will include Vx, Vy, Vz, n, T, Bx, By, and Bz. Such real-time L1 data is used in generating space weather applications and products that have been demonstrated to be highly accurate and provide actionable information for customers. We evaluate current space weather products driven by ACE and discuss future products under development for DSCOVR. New space weather products under consideration include: automated shock detection, more accurate L1 to Earth delay time, and prediction of rotations in <span class="hlt">solar</span> <span class="hlt">wind</span> Bz within magnetic clouds. Suggestions from the community on product ideas are welcome.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19970006691','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19970006691"><span id="translatedtitle">Studies of Interstellar Pickup Ions in the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Isenberg, Philip A.; Lee, Martin A.; Mobius, Eberhard</p> <p>1996-01-01</p> <p>The work under this grant involves studies of the interaction of interstellar pickup ions with the <span class="hlt">solar</span> <span class="hlt">wind</span>, with the goal of a comprehensive model of the particle distributions and wave intensities to be expected throughout the heliosphere, as well as the interactions of those distributions with the <span class="hlt">solar</span> <span class="hlt">wind</span> termination shock. In the past year, we have completed a number of projects, including observations and modeling of the effects of a large scattering mean free path on the pickup He(+) seen at AMPTE, an analytical model of anisotropic pickup tons in a steady radial magnetic field, and a derivation of a reduced <span class="hlt">solar</span> <span class="hlt">wind</span> Mach number due to increased estimates on the inflowing hydrogen density allowing for a weak termination shock. In the next year, we plan to investigate in more detail the correspondence between our models of anisotropic pickup ions and the data on spectra, variations, and proton-He(+) correlation provided by AMPTE, Ulysses, and our instrument on SOHO. We will model the time-dependent pickup ion density resulting from finite periods of radial magnetic field. We will also incorporate the effects of a large mean free path into our analysis of the He(+) focusing cone, leading to more accurate parameter values for the interstellar helium gas. This progress report also includes a discussion of our Space Physics Educational Outreach activities in the past year and plans for the next year.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1990P%26SS...38..627G','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1990P%26SS...38..627G"><span id="translatedtitle">A unified view of <span class="hlt">solar</span> <span class="hlt">wind</span> - Magnetosphere coupling functions</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Gonzalez, W. D.</p> <p>1990-05-01</p> <p>It is shown that all widely used coupling functions about the <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere interaction can be derived as particular cases of general expressions for the electric field and the energy transfer at the magnetopause due to large scale reconnection. Although the <span class="hlt">solar</span> <span class="hlt">wind</span> electric field gets transmitted along the reconnection line (e.g., Gonzalez and Mozer, 1974), it is also shown that the net effect of this transmission in the magnetosphere seems to be associated only to the transverse component (dawn to dusk direction) of this field with respect to the geomagnetic field at the magnetopause. Furthermore, the most general expression for power transfer from the <span class="hlt">solar</span> <span class="hlt">wind</span> to the magnetosphere via a MHD process is shown to lead to similar limits for the coupling as those obtained from the general expression for the reconnection power when the particular values for the power law index introduced by Vasyliunas et al. (1982), about the dependence of the power transfer on the interplanetary Alfven Mach number, are used.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFMSH42B..08J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFMSH42B..08J"><span id="translatedtitle">Testing Turbulence Transport Models using <span class="hlt">Solar</span> <span class="hlt">Wind</span> Data</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Jetha, N.; Zank, G. P.; Kahre, L.</p> <p>2011-12-01</p> <p>There are fundamental questions about the Sun and its influence on our local space environment that require a detailed understanding of turbulence throughout the heliosphere, many of which are addressed by the Zank et al (2011) turbulence model, e.g. the transport of turbulence in the <span class="hlt">solar</span> <span class="hlt">wind</span>, and the coronal heating issue. In order to test and refine this theory, a comparison with data is vital, with the most easily accessible data set being that which describes the transport of turbulent fluctuations in the <span class="hlt">solar</span> <span class="hlt">wind</span>. In this work, we use plasma and magnetic field data from Voyager 2, Pioneer 1 and 2, Helios 1 and 2 and Ulysses in order to fully explore the turbulent fluctuations of the <span class="hlt">solar</span> <span class="hlt">wind</span> from 0.3-95 AU, both in and out of the ecliptic plane. We present a a library of reduced data products, including the total energy in turbulent fluctuations, the energy difference between kinetic and magnetic turbulent fluctuations, the energy contained in cross-helicity, the variance in magnetic field, and the Alfven ratio. These can all be compared against predictions from any turbulence model, e.g. Zank et al (2011), in order to fully understand the transport of turbulence throughout the heliosphere.</p> </li> </ol> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li class="active"><span>24</span></li> <li><a href="#" onclick='return showDiv("page_25");'>25</a></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div><!-- col-sm-12 --> </div><!-- row --> </div><!-- page_24 --> <div id="page_25" class="hiddenDiv"> <div class="row"> <div class="col-sm-12"> <div class="pull-right"> <ul class="pagination"> <li><a href="#" onclick='return showDiv("page_1");'>«</a></li> <li><a href="#" onclick='return showDiv("page_21");'>21</a></li> <li><a href="#" onclick='return showDiv("page_22");'>22</a></li> <li><a href="#" onclick='return showDiv("page_23");'>23</a></li> <li><a href="#" onclick='return showDiv("page_24");'>24</a></li> <li class="active"><span>25</span></li> <li><a href="#" onclick='return showDiv("page_25");'>»</a></li> </ul> </div> </div> </div> <div class="row"> <div class="col-sm-12"> <ol class="result-class" start="481"> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19770057048&hterms=moon+mercury&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmoon%2Bmercury','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19770057048&hterms=moon+mercury&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3Dmoon%2Bmercury"><span id="translatedtitle">The <span class="hlt">solar</span> <span class="hlt">wind</span> and its influence on the atmospheres of moon, Mercury and Venus</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Hartle, R. E.</p> <p>1976-01-01</p> <p>The <span class="hlt">solar</span> <span class="hlt">wind</span> is expected to have an important influence on the atmospheres of the moon, Mercury and Venus and therefore a brief outline of <span class="hlt">solar</span> <span class="hlt">wind</span> theory is presented along with the predicted properties of the <span class="hlt">wind</span> at the orbits of these planets. Since the atmospheres of the moon and possibly Mercury are formed primarily by <span class="hlt">solar</span> <span class="hlt">wind</span> accretion, we present the latest accretion models for these bodies. The expected role the <span class="hlt">solar</span> <span class="hlt">wind</span> plays on both the ionization and termination of the ionosphere of Venus is discussed.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/5452874','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/5452874"><span id="translatedtitle"><span class="hlt">Solar</span> minimum Lyman. alpha. sky background observations from Pioneer Venus orbiter ultraviolet spectrometer: <span class="hlt">Solar</span> <span class="hlt">wind</span> latitude variation</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Ajello, J.M. )</p> <p>1990-09-01</p> <p>Measurements of interplanetary H I Lyman {alpha} over a large portion of the celestial sphere were made at the recent <span class="hlt">solar</span> minimum by the Pioneer Venus orbiter ultraviolet spectrometer. These measurements were performed during a series of spacecraft maneuvers conducted to observe Halley's comet in early 1986. Analysis of these data using a model of the passage of interstellar <span class="hlt">wind</span> hydrogen through the <span class="hlt">solar</span> <span class="hlt">wind</span> system shows that the rate of charge exchange with <span class="hlt">solar</span> <span class="hlt">wind</span> protons is 30% less over the <span class="hlt">solar</span> poles than in the ecliptic. This result is in agreement with a similar experiment performed with Mariner 10 at the previous <span class="hlt">solar</span> minimum.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2011AGUFM.P43F..01H','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2011AGUFM.P43F..01H"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Plasma and UV effects on Surfaces in Space</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Horanyi, M.</p> <p>2011-12-01</p> <p>Dust plasma interactions on airless bodies in space affect both the exposed surfaces and the plasma flow around them. For example, charging, evaporation, and sputtering can shape the spatial and size distributions of small dust particles, and simultaneously alter the composition and energy distribution of the <span class="hlt">solar</span> <span class="hlt">wind</span> flow. Recent Ulysses observations of the temporal variability of the flux and direction of the interstellar dust flow show that the dynamics of submicron sized interplanetary and interstellar dust is determined by their charge and interactions with the large-scale structure of the heliospheric magnetic fields. Future observations by the <span class="hlt">Solar</span> Probe Plus mission near the Sun are expected to identify pick-up ions from the evaporation and sputtering of dust and the effects of mass-loading on the <span class="hlt">solar</span> <span class="hlt">wind</span>. Charging of surfaces, combined with near-surface electric fields can lead to the mobilization and transport of small charged dust particles on all airless bodies in the <span class="hlt">solar</span> system. Halley's comet showed large brightness fluctuations on very short time-scales at distances well beyond 8 AU. Surface charging due to intermittent high-speed <span class="hlt">solar</span> <span class="hlt">wind</span> streams have been suggested to be responsible for lofting small grains, increasing the effective surface area of the dormant nucleus. Images taken of the surface of asteroid Eros indicated the accumulation of fine dust in craters, possibly due to electrostatic dust transport. Remote sensing and in situ observations indicating dust transport on the Moon date back to the Apollo era and remain highly controversial. This presentation, motivated by existing observations, will describe a series of small-scale laboratory experiments and supporting theory to investigate dust charging, the properties of photoelectron sheaths, and the emergence of intense electric fields near boundaries of lit and dark surfaces, and regions shielded and exposed to the <span class="hlt">solar</span> <span class="hlt">wind</span> plasma flow. The Moon is the nearest place where dusty plasma effects could be investigated the easiest. The presentation will conclude with a summary of the science, measurement and instrument requirements for a Lunar Dust Transport Package (LDTP) to be placed on the lunar surface. LDTP will measure the time-dependent characteristics of the plasma sheath, and observe both the high-speed impacts of interplanetary and interstellar dust, and the putative fluxes of low-speed, highly charged lunar dust particles. LDTP will bring closure to decades-long open issues about dusty plasma effects on the lunar surface, and all other airless bodies in our <span class="hlt">solar</span> system.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ncbi.nlm.nih.gov/pubmed/16414894','PUBMED'); return false;" href="http://www.ncbi.nlm.nih.gov/pubmed/16414894"><span id="translatedtitle">Drivers of the <span class="hlt">solar</span> <span class="hlt">wind</span>: then and now.</span></a></p> <p><a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p>Hollweg, Joseph V</p> <p>2006-02-15</p> <p>Early spacecraft data in the 1960s revealed <span class="hlt">solar</span> <span class="hlt">wind</span> properties, which could not be well explained by models in which the electron pressure gradient was the principal accelerating force. The Alfvn waves discovered around 1970 were thought for a while to provide additional energy and momentum, but they ultimately failed to explain the rapid acceleration of the fast <span class="hlt">wind</span> close to the Sun. By the late 1970s, various data were suggesting the importance of the ion-cyclotron resonance far from the Sun. This notion was soon applied to the acceleration region close to the Sun. The models, which resulted, suggested that the fast <span class="hlt">wind</span> could be driven mainly by the proton pressure gradient. Since the mid-1990s, <span class="hlt">Solar</span> and Heliospheric Observatory has provided remarkable data, which have verified some of the predictions of these theories, and given impetus to studies of the ion-cyclotron resonance as the principal mechanism for heating the coronal holes, and ultimately driving the fast <span class="hlt">wind</span>. After a historical review, we discuss the basic ideas behind current research, emphasizing the particle kinetics. We discuss remaining problems, especially the source of the ion-cyclotron resonant waves. PMID:16414894</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2013AGUFMSM41B2223D','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2013AGUFMSM41B2223D"><span id="translatedtitle">WSA-ENLIL Cone Extension: Improving <span class="hlt">Solar</span> <span class="hlt">Wind</span> Forcing Parameter Estimates 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>Dewey, R. M.; Baker, D. N.; Anderson, B. J.; Benna, M.; Johnson, C. L.; Korth, H.; Gershman, D. J.; Ho, G. C.; McClintock, W. E.; Odstrcil, D.; Raines, J. M.; Schriver, D.; Slavin, J. A.; Solomon, S. C.; Winslow, R. M.; Zurbuchen, T.</p> <p>2013-12-01</p> <p>Understanding magnetospheric and exospheric processes at Mercury requires knowledge of <span class="hlt">solar</span> <span class="hlt">wind</span> 'forcing' conditions. This forcing includes both the background quasi-steady <span class="hlt">solar</span> <span class="hlt">wind</span> and the effects of transient <span class="hlt">solar</span> eruptions, most notably coronal mass ejections (CMEs). The departures from background <span class="hlt">solar</span> <span class="hlt">wind</span> due to CMEs often correspond to more than an order of magnitude greater ram pressure and dynamo electric field applied to the magnetosphere. Observations from the MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft were previously combined with the Wang-Sheeley-Arge (WSA)-ENLIL <span class="hlt">solar-wind</span> modeling tool to calculate such <span class="hlt">solar</span> <span class="hlt">wind</span> forcing parameters as the interplanetary magnetic field (IMF) strength (B); <span class="hlt">solar</span> <span class="hlt">wind</span> velocity (V), density (n), and temperature (T); ram pressure (~nV2); cross-magnetosphere electric field (V×B); and Alfvén Mach number (MA). Previous efforts relied only on the background <span class="hlt">solar</span> <span class="hlt">wind</span>, however, and constituted an incomplete model of <span class="hlt">solar</span> <span class="hlt">wind</span> forcing given that the effects of transient <span class="hlt">solar</span> phenomena were not included. The WSA-ENLIL model with the Cone extension permits inclusion of the effects of CMEs and related transient <span class="hlt">solar</span> phenomena, and thus characterization of the effect of strong <span class="hlt">solar</span> <span class="hlt">wind</span> perturbations on the Mercury system. The Cone extension utilizes the heliocentric location, velocity, and radial size of a CME to propagate it through the inner <span class="hlt">solar</span> system under the assumption of constant angular and radial velocity. This more complete approach provides a firmer basis with which to study magnetospheric and exospheric processes at Mercury and thereby better understand how the <span class="hlt">solar</span> <span class="hlt">wind</span> drives the Mercury system. Comparisons of WSA-ENLIL-Cone model outputs with measured properties from the MESSENGER Magnetometer (MAG), Neutron Spectrometer (NS), and Energetic Particle and Plasma Spectrometer (EPPS) permit quantification of the improvement in <span class="hlt">solar</span> <span class="hlt">wind</span>/IMF specification, particularly during times of the largest <span class="hlt">solar</span> eruptive events over the period 2011-2013.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=19820047464&hterms=Collards&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DCollards','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=19820047464&hterms=Collards&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D10%26Ntt%3DCollards"><span id="translatedtitle">Radial variation of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed between 1 and 15 AU</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Collard, H. R.; Mihalov, J. D.; Wolfe, J. H.</p> <p>1982-01-01</p> <p>Pioneer 10 and 11 <span class="hlt">solar</span> <span class="hlt">wind</span> speeds measured between 1.4 and 15.2 AU are compared with those of IMP 6, 7, and 8 measured at 1 AU for 90-day intervals centered on six <span class="hlt">solar</span> radial alignments between 1973 and 1978. The time profile of the <span class="hlt">solar</span> <span class="hlt">wind</span> speed undergoes change as the distance from the sun increases, which is due to interaction of adjacent <span class="hlt">solar</span> <span class="hlt">wind</span> streams. Speed variations are smaller at greater radial distance and both the highest and lowest speeds disappear as radial distance increases. For periods with extremely high speed <span class="hlt">solar</span> <span class="hlt">wind</span> streams, the mean <span class="hlt">solar</span> <span class="hlt">wind</span> speed decreases as the distance from the sun increases, which must be due to the disappearance of the highest speeds of the streams with increasing distance. It is concluded that at distances from the sun greater than 30-40 AU, the <span class="hlt">solar</span> <span class="hlt">wind</span> behavior may closely resemble that of a radially expanding constant speed plasma.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://ntrs.nasa.gov/search.jsp?R=20150010745&hterms=wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwind','NASA-TRS'); return false;" href="http://ntrs.nasa.gov/search.jsp?R=20150010745&hterms=wind&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D70%26Ntt%3Dwind"><span id="translatedtitle">Anisotropic <span class="hlt">Solar</span> <span class="hlt">Wind</span> Sputtering of the Lunar Surface Induced by Crustal Magnetic Anomalies</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Poppe, A. R.; Sarantos, M.; Halekas, J. S.; Delory, G. T.; Saito, Y.; Nishino, M.</p> <p>2014-01-01</p> <p>The lunar exosphere is generated by several processes each of which generates neutral distributions with different spatial and temporal variability. <span class="hlt">Solar</span> <span class="hlt">wind</span> sputtering of the lunar surface is a major process for many regolith-derived species and typically generates neutral distributions with a cosine dependence on <span class="hlt">solar</span> zenith angle. Complicating this picture are remanent crustal magnetic anomalies on the lunar surface, which decelerate and partially reflect the <span class="hlt">solar</span> <span class="hlt">wind</span> before it strikes the surface. We use Kaguya maps of <span class="hlt">solar</span> <span class="hlt">wind</span> reflection efficiencies, Lunar Prospector maps of crustal field strengths, and published neutral sputtering yields to calculate anisotropic <span class="hlt">solar</span> <span class="hlt">wind</span> sputtering maps. We feed these maps to a Monte Carlo neutral exospheric model to explore three-dimensional exospheric anisotropies and find that significant anisotropies should be present in the neutral exosphere depending on selenographic location and <span class="hlt">solar</span> <span class="hlt">wind</span> conditions. Better understanding of <span class="hlt">solar</span> <span class="hlt">wind</span>/crustal anomaly interactions could potentially improve our results.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=273864','TEKTRAN'); return false;" href="http://www.ars.usda.gov/research/publications/Publications.htm?seq_no_115=273864"><span id="translatedtitle">Analysis of off-grid hybrid <span class="hlt">wind</span> turbine/<span class="hlt">solar</span> PV water pumping systems</span></a></p> <p><a target="_blank" href="http://www.ars.usda.gov/services/TekTran.htm">Technology Transfer Automated Retrieval System (TEKTRAN)</a></p> <p></p> <p></p> <p>While many remote water pumping systems exist (e.g. mechanical windmills, <span class="hlt">solar</span> photovoltaic , <span class="hlt">wind</span>-electric, diesel powered), very few combine both the <span class="hlt">wind</span> and <span class="hlt">solar</span> energy resources to possibly improve the reliability and the performance of the system. In this paper, off-grid <span class="hlt">wind</span> turbine (WT) a...</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/1999nvm..conf...29J','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/1999nvm..conf...29J"><span id="translatedtitle"><span class="hlt">Solar-Wind</span>-Implanted Volatiles in the Lunar Regolith</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Johnson, J. R.; Swindle, T. D.; Lucey, P. G.</p> <p>1999-01-01</p> <p>The epithermal neutron distribution from Lunar Prospector (LP) and the H abundance and maturity of returned lunar soils are being used synergistically to estimate global H distribution. The ability to determine lunar H abundance using a combination of remote sensing and laboratory analyses broadens our understanding of the retentivity of volatiles in the lunar regolith and the nature of the sources from which the volatiles arrived (i.e., <span class="hlt">solar</span> <span class="hlt">wind</span>, cometary impacts). This is relevant to the search for water ice at the lunar poles as well as other potential resources such as H-3. Knowledge of these possible resource-rich regions will be important for future mission planning, instrument selection, and landing-site analyses. The Level I calibrated epithermal neutron distribution maps (initially calibrated to remove major instrumental effects by the LP team) have been used for first-order calibration to H abundance. The equation of Feldman et al. i.e., (epithermal* = epithermal - (0.068 * thermal) was used to minimize the effects of compositional variations between mare and highlands (likely due to major-element concentrations such as Ti, Fe) on the epithermal neutron counting rates. Comparison of the average H abundances for the Apollo landing site soils with the epithermal* neutron counts for the landing sites from results in the rather poor correlation shown. Neglecting the Apollo 11 sample, the sense of the correlation is correct (fewer epithermal* neutrons implies greater H abundance), but the correlation is still mediocre (r=-0.574). This may result from using the average values for the landing sites as opposed to the individual soil sample values. It can be seen in the epithermal* map that the highest counting rates (likely the lowest H abundances) correspond well to regions of fresh, Copernican-age impacts (e.g., Tycho, Hayn, Jackson, possibly Stevinus). This implies a dearth of <span class="hlt">solar-wind</span>-implanted gases, which could be explained by the immaturity of the regolith in these regions. But there are also mare regions near the limbs (Orientale, Crisium) with high values that require other explanations. Further, while the darker regions in the polar areas have been interpreted as water-ice-bearing regions, the low-valued highland terrain west of Sinus Iridium requires further study. Overall, the <span class="hlt">solar-wind</span> fluence model's predictions of highest volatile abundances on the central farside and lowest values on the central nearside are not immediately apparent in the epithermal* map. However, if the lower counting rates (higher H abundances) at longitudes 75-180E are real, it would be consistent with the <span class="hlt">solar</span> <span class="hlt">wind</span> model (at least for that portion of the eastern limb and farside). Hydrogen contents of 54 Apollo bulk lunar soils will be compared to the epithermal neutron counts for the landing sites to determine mare precisely an average correlation. This will be applied to the LP data to estimate H content on the lunar surface. Because exposure age affects retained <span class="hlt">solar-wind</span>-implanted volatile abundances, incorporation of soil maturity using the Is/FeO parameter (reduced:total Fe ratio) and/or spectrally-derived maturity data from lunar soils will also be used in conjunction with H abundances to refine the correlation. Once a H map is constructed, it will be used to test a <span class="hlt">solar-wind</span> fluence model for the Moon developed previously that represents relative <span class="hlt">solar-wind</span>-implanted elemental abundances (assuming minimal variations in impact history and chemical composition of the soils, as well as minimal saturation of soils with volatiles). Deviations of the H distribution from the idealized <span class="hlt">solar</span> fluence model will be investigated by incorporating the effects of local magnetic fields, composition (e.g., Ti, Fe), and soil maturity. further, previous work by the authors has shown that abundances of H-3 (a potential lunar resource relevant as a fuel for future nuclear fusion power) in the lunar regolith can be estimated using the fluence model in combination with surface maturity and Ti maps constructed using Clementine multispectral data. The modeled <span class="hlt">solar-wind</span> fluence distribution map will be updated based on observations of the epithermal neutron-derived H maps, and the Clementine and LP Ti-abundance maps will be incorporated with Clementine surface maturity maps to construct revised estimates of H-3 abundance. The calibration of the LP neutron spectrometer data to provide maps of H abundance will be important in understanding the nature of the <span class="hlt">solar-wind</span>-implanted volatiles in the lunar regolith, particularly the distribution, migration, and retentivity of H relevant to understanding the possible presence of water ice at the lunar poles. Hydrogen maps will be useful in separating the near surface geologic history (e.g., <span class="hlt">solar-wind</span> implantation and micrometeorite bombardment history related to surface maturity) from the underlying crustal evolution, the knowledge of which is a required component of our total understanding of the planetary history of the Moon. The preliminary observations made here regarding correlations of epithermal* neutron counts with geologic features are intriguing and will require further study. Potential improvements to models of <span class="hlt">solar-wind</span> fluence will assist in mapping other volatiles in the regolith, particularly H-3, which along with H and water ice are some of the most promising potential lunar resources available on the Moon. Additional information contained in the original</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20000055757','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20000055757"><span id="translatedtitle">A New View of the Origin of the <span class="hlt">Solar</span> <span class="hlt">Wind</span></span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Woo, Richard; Habbal, Shadia Rifai</p> <p>1999-01-01</p> <p>This paper uses white-light measurements made by the SOHO LASCO coronagraph and HAO Mauna Loa Mk III K-coronameter to illustrate the new view of <span class="hlt">solar</span> <span class="hlt">wind</span> structure deduced originally from radio occultation measurements. It is shown that the density profile closest to the Sun at 1.15 Ro, representing the imprint of the Sun, is carried essentially radially into interplanetary space by small-scale raylike structures that permeate the <span class="hlt">solar</span> corona and which have only been observed by radio occultation measurements. The only exception is the small volume of interplanetary space occupied by the heliospheric plasma sheet that evolves from coronal streamers within a few <span class="hlt">solar</span> radii of the Sun. The radial preservation of the density profile also implies that a significant fraction of field lines which extend into interplanetary space originate from the quiet Sun, and are indistinguishable in character from those emanating from polar coronal holes. The white-light measurements dispel the long-held belief that the boundaries of polar coronal holes diverge significantly, and further support the view originally proposed that the fast <span class="hlt">solar</span> <span class="hlt">wind</span> originates from the quiet Sun as well as polar coronal holes.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2016Ap%26SS.361...44I','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2016Ap%26SS.361...44I"><span id="translatedtitle">The effects of <span class="hlt">solar</span> <span class="hlt">wind</span> on galactic cosmic ray flux at Earth</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Ihongo, G. D.; Wang, C. H.-T.</p> <p>2016-01-01</p> <p>The amount of <span class="hlt">solar</span> <span class="hlt">wind</span> produced continuously by the sun is not constant due to changes in <span class="hlt">solar</span> activity. This unsteady nature of the <span class="hlt">solar</span> <span class="hlt">wind</span> seems to be responsible for galactic cosmic ray flux modulation, hence the flux of incoming galactic cosmic rays observed at the top of the Earth's atmosphere varies with the <span class="hlt">solar</span> <span class="hlt">wind</span> reflecting the <span class="hlt">solar</span> activity. The aforementioned reasons have lead to attempts by several researchers to study correlations between galactic cosmic rays and the <span class="hlt">solar</span> <span class="hlt">wind</span>. However, most of the correlation studies carried out by authors earlier are based on the analyses of observational data from neutron monitors. In this context, we study the effects of <span class="hlt">solar</span> <span class="hlt">wind</span> on galactic cosmic ray flux observed at r ≈ 1 AU, using a theoretical approach and found that the <span class="hlt">solar</span> <span class="hlt">wind</span> causes significant decreases in galactic cosmic ray flux at r ≈1 AU. A short time variation of the calculated flux is also checked and the result is reflected by exposing a negative correlation of the <span class="hlt">solar</span> <span class="hlt">wind</span> with the corresponding galactic cosmic ray flux. This means that the higher the <span class="hlt">solar</span> <span class="hlt">wind</span> the lower the galactic cosmic rays flux and vice-versa. To obtain a better understanding, the calculated flux and its short time variation at 1 AU are compared to data that shows a good fit to the model making it possible to establish a statistically significant negative correlation of -0.988±0.001 between <span class="hlt">solar</span> <span class="hlt">wind</span> variation and galactic cosmic rays flux variation theoretically.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/20140017817','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/20140017817"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> Strahl Broadening by Self-Generated Plasma Waves</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Pavan, J.; Vinas, A. F.; Yoon, P. H.; Ziebell, L. F.; Gaelzer, R.</p> <p>2013-01-01</p> <p>This Letter reports on the results of numerical simulations which may provide a possible explanation for the strahl broadening during quiet <span class="hlt">solar</span> conditions. The relevant processes involved in the broadening are due to kinetic quasi-linear wave-particle interaction. Making use of static analytical electron distribution in an inhomogeneous field, it is found that self-generated electrostatic waves at the plasma frequency, i.e., Langmuir waves, are capable of scattering the strahl component, resulting in energy and pitch-angle diffusion that broadens its velocity distribution significantly. The present theoretical results provide an alternative or complementary explanation to the usual whistler diffusion scenario, suggesting that self-induced electrostatic waves at the plasma frequency might play a key role in broadening the <span class="hlt">solar</span> <span class="hlt">wind</span> strahl during quiet <span class="hlt">solar</span> conditions.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2014AGUFMSH33A4127V','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2014AGUFMSH33A4127V"><span id="translatedtitle"><span class="hlt">Solar</span> <span class="hlt">Wind</span> C, N, and O Abundances and the <span class="hlt">Solar</span> Metallicity</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>von Steiger, R.; Zurbuchen, T.; Shearer, P.; Gilbert, J. A.</p> <p>2014-12-01</p> <p><span class="hlt">Solar</span> <span class="hlt">wind</span> composition provides important constraints to <span class="hlt">solar</span> composition and to the processes that modify such compositional patterns in the atmospheres of the Sun and of active stars. There are a number of ways that composition can be observed, including spectroscopy, helioseismology, and the collection of <span class="hlt">solar</span> samples either in the form of <span class="hlt">solar</span> <span class="hlt">wind</span> or energetic particles. In either case, models are needed to infer compositional constraints from observations. For example, models are needed to interpret <span class="hlt">solar</span> spectroscopy results, and the evolution of these has recently led to significant changes to the previously accepted <span class="hlt">solar</span> composition. The collection of <span class="hlt">solar</span> samples requires a different type of consideration. Most <span class="hlt">solar</span> <span class="hlt">wind</span> and energetic particle samples are fractionated according to first ionization potential (FIP) as first pointed out by Hovestadt et al. in the seventies - elements with FIP below 10 eV are enhanced relative to elements at higher FIP, and He and possibly Ne are further depleted. Besides FIP fractionation there are indications from both isotopic and elemental data that mass fractionation, either through gravitational and/or collisional processes, may also play a role. Based on comparisons of in situ data with coronal spectroscopy it is evident that most of these processes occur at the interface between the photosphere and the corona. However, the high-latitude corona near <span class="hlt">solar</span> minimum appears to undergo much less fractionation, if any at all. Thus it provides a heliospheric sample that is - to within our observational constraints - photospheric in nature. The low-latitude heliosphere further provides direct access to plasmas that have the fractionation pattern qualitatively and quantitatively similar to the one observed in the corona. We present a recent reanalysis of the SWICS observations on both Ulysses and ACE using modern statistical tools. Concentrating on C, N, and O, which together with the recently published Ne (Shearer et al., ApJ, 2014) contribute 96% of the <span class="hlt">solar</span> metallicity, we find that the <span class="hlt">solar</span> <span class="hlt">wind</span> metallicity is significantly higher than the recent compilation of spectroscopic abundances (Asplund et al., ARAA, 2009). It is more in line with earlier spectroscopic results and, more importantly, not incompatible with helioseismology results of the <span class="hlt">solar</span> interior.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://hdl.handle.net/2060/19980169246','NASA-TRS'); return false;" href="http://hdl.handle.net/2060/19980169246"><span id="translatedtitle">A Study of the Structure of the Source Region of the <span class="hlt">Solar</span> <span class="hlt">Wind</span> in Support of a <span class="hlt">Solar</span> Probe Mission</span></a></p> <p><a target="_blank" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p>Habbal , Shadia R.</p> <p>1998-01-01</p> <p>Despite the richness of the information about the physical properties and the structure of the <span class="hlt">solar</span> <span class="hlt">wind</span> provided by the Ulysses and SOHO observations, fundamental questions regarding the nature of the coronal heating mechanisms, their source, and the manifestations of the fast and slow <span class="hlt">solar</span> <span class="hlt">wind</span>, still remain unanswered. The last unexplored frontier to establish the connection between the structure and dynamics of the <span class="hlt">solar</span> atmosphere, its extension into interplanetary space, and the mechanisms responsible for the evolution of the <span class="hlt">solar</span> <span class="hlt">wind</span>, is the corona between 1 and 30 R(sub s). A <span class="hlt">Solar</span> Probe mission offers an unprecedented opportunity to explore this frontier. The uniqueness of this mission stems from its trajectory in a plane perpendicular to the ecliptic which reaches within 9 R(sub s), of the <span class="hlt">solar</span> surface over the poles and 3 - 9 R(sub s), at the equator. With a complement of simultaneous in situ and remote sensing observations, this mission is destined to have a significant impact on our understanding of the fundamental processes that heat the corona and drive the <span class="hlt">solar</span> <span class="hlt">wind</span>. The <span class="hlt">Solar</span> Probe should be able to detect remnants and signatures of the processes which heat the corona and accelerate the <span class="hlt">solar</span> <span class="hlt">wind</span>. The primary objective of this proposal was to explore the structure of the different source regions of the <span class="hlt">solar</span> <span class="hlt">wind</span> through complementary observational and theoretical studies in support of a <span class="hlt">Solar</span> Probe mission.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://adsabs.harvard.edu/abs/2015AnGeo..33..697P','NASAADS'); return false;" href="http://adsabs.harvard.edu/abs/2015AnGeo..33..697P"><span id="translatedtitle">The influence of <span class="hlt">solar</span> <span class="hlt">wind</span> variability on magnetospheric ULF wave power</span></a></p> <p><a target="_blank" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p>Pokhotelov, D.; Rae, I. J.; Murphy, K. R.; Mann, I. R.</p> <p>2015-06-01</p> <p>Magnetospheric ultra-low frequency (ULF) oscillations in the Pc 4-5 frequency range play an important role in the dynamics of Earth's radiation belts, both by enhancing the radial diffusion through incoherent interactions and through the coherent drift-resonant interactions with trapped radiation belt electrons. The statistical distributions of magnetospheric ULF wave power are known to be strongly dependent on <span class="hlt">solar</span> <span class="hlt">wind</span> parameters such as <span class="hlt">solar</span> <span class="hlt">wind</span> speed and interplanetary magnetic field (IMF) orientation. Statistical characterisation of ULF wave power in the magnetosphere traditionally relies on average <span class="hlt">solar</span> <span class="hlt">wind</span>-IMF conditions over a specific time period. In this brief report, we perform an alternative characterisation of the <span class="hlt">solar</span> <span class="hlt">wind</span> influence on magnetospheric ULF wave activity through the characterisation of the <span class="hlt">solar</span> <span class="hlt">wind</span> driver by its variability using the standard deviation of <span class="hlt">solar</span> <span class="hlt">wind</span> parameters rather than a simple time average. We present a statistical study of nearly one <span class="hlt">solar</span> cycle (1996-2004) of geosynchronous observations of magnetic ULF wave power and find that there is significant variation in ULF wave powers as a function of the dynamic properties of the <span class="hlt">solar</span> <span class="hlt">wind</span>. In particular, we find that the variability in IMF vector, rather than variabilities in other parameters (<span class="hlt">solar</span> <span class="hlt">wind</span> density, bulk velocity and ion temperature), plays the strongest role in controlling geosynchronous ULF power. We conclude that, although time-averaged bulk properties of the <span class="hlt">solar</span> <span class="hlt">wind</span> are a key factor in driving ULF powers in the magnetosphere, the <span class="hlt">solar</span> <span class="hlt">wind</span> variability can be an important contributor as well. This highlights the potential importance of including <span class="hlt">solar</span> <span class="hlt">wind</span> variability especially in studies of ULF wave dynamics in order to assess the efficiency of <span class="hlt">solar</span> <span class="hlt">wind</span>-magnetosphere coupling.</p> </li> <li> <p><a target="_blank" onclick="trackOutboundLink('http://www.osti.gov/scitech/biblio/266942','SCIGOV-STC'); return false;" href="http://www.osti.gov/scitech/biblio/266942"><span id="translatedtitle">Helium abundance variations in the <span class="hlt">solar</span> <span class="hlt">wind</span>: Observations from Ulysses</span></a></p> <p><a target="_blank" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p>Barraclough, B.L.; Gosling, J.T.; Mccomas, D.J.; Goldstein, B.E.</p> <p>1995-06-01</p> <p>The abundance of helium in the <span class="hlt">solar</span> <span class="hlt">wind</span> averages approximately 4% but has been observed to vary by more than two orders of magnitude from 0.1 to 30%. Physical processes responsible for this variability are still not clearly understood. Previous work has shown a correlation between low He abundance and coronal streamer plasma and between high He abundance and coronal mass ejections (CMEs). The authors now have out-of-ecliptic data on helium in the <span class="hlt">solar</span> <span class="hlt">wind</span> from the plasma experiment aboard Ulysses. Tentative results show that the average high-latitude helium concentration is comparable to the in-ecliptic value for the present phase of the <span class="hlt">solar</span> cycle, that excursions of the hour-averaged abundance very seldom fall outside the range 2.5 to 6.5%, and that there seems to be very little abundance enhancement associated with CMEs encountered at latitudes greater than 30 deg as opposed to the situation commonly encountered with in-ecliptic CMEs. In addition, preliminary observations of a single CME by both ISEE (in-ecliptic) and Ulysses (out-of-ecliptic) show a considerable He enhancement at ISEE with little or no pe