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Bame SJ Anderson RC Asbridge JR Baker DN Feldman WC Fuselier SA Gosling JT McComas DJ Thomsen MF Young DT Zwickl RD 《Science (New York, N.Y.)》1986,232(4748):356-361
A strong interaction between the solar wind and comet Giacobini-Zinner was observed oh 11 September 1985 with the Los Alamos plasma electron experiment on the International Cometary Explorer (ICE) spacecraft. As ICE approached an intercept point 7800 kilometers behind the nucleus from the south and receded to the north, upstream phenomena due to the comet were observed. Periods of enhanced electron heat flux from the comet as well as almost continuous electron density fluctuations were measured. These effects are related to the strong electron heating observed in the cometary interaction region and to cometary ion pickup by the solar wind, respectively. No evidence for a conventional bow shock was found as ICE entered and exited the regions of strongest interaction of the solar wind with the cometary environment. The outer extent of this strong interaction zone was a transition region in which the solar wind plasma was heated, compressed, and slowed. Inside the inner boundary of the transition region was a sheath that enclosed a cold intermediate coma. In the transition region and sheath, small-scale enhancements in density were observed. These density spikes may be due to an instability associated with cometary ion pickup or to the passage of ICE through cometary ray structures. In the center of the cold intermediate coma a narrow, high-density core of plasma, presumably the developing plasma tail was found. In some ways this tail can be compared to the plasma sheet in Earth's magnetotail and to the current sheet in the tail at Venus. This type of configuration is expected in the double-lobe magnetic topology detected at the comet, possibly caused by the theoretically expected draping of the interplanetary magnetic field around its ionosphere. 相似文献
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McComas DJ Alexashov D Bzowski M Fahr H Heerikhuisen J Izmodenov V Lee MA Möbius E Pogorelov N Schwadron NA Zank GP 《Science (New York, N.Y.)》2012,336(6086):1291-1293
As the Sun moves through the local interstellar medium, its supersonic, ionized solar wind carves out a cavity called the heliosphere. Recent observations from the Interstellar Boundary Explorer (IBEX) spacecraft show that the relative motion of the Sun with respect to the interstellar medium is slower and in a somewhat different direction than previously thought. Here, we provide combined consensus values for this velocity vector and show that they have important implications for the global interstellar interaction. In particular, the velocity is almost certainly slower than the fast magnetosonic speed, with no bow shock forming ahead of the heliosphere, as was widely expected in the past. 相似文献
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Bame SJ Barraclough BL Feldman WC Gisler GR Gosling JT McComas DJ Phillips JL Thomsen MF Goldstein BE Neugebauer M 《Science (New York, N.Y.)》1992,257(5076):1539-1543
Plasma observations at Jupiter show that the outer regions of the Jovian magnetosphere are remarkably similar to those of Earth. Bow-shock precursor electrons and ions were detected in the upstream solar wind, as at Earth. Plasma changes across the bow shock and properties of the magnetosheath electrons were much like those at Earth, indicating that similar processes are operating. A boundary layer populated by a varying mixture of solar wind and magnetospheric plasmas was found inside the magnetopause, again as at Earth. In the middle magnetosphere, large electron density excursions were detected with a 10-hour periodicity as planetary rotation carried the tilted plasma sheet past Ulysses. Deep in the magnetosphere, Ulysses crossed a region, tentatively described as magnetically connected to the Jovian polar cap on one end and to the interplanetary magnetic field on the other. In the inner magnetosphere and lo torus, where corotation plays a dominant role, measurements could not be made because of extreme background rates from penetrating radiation belt particles. 相似文献
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McComas DJ Allegrini F Bagenal F Crary F Ebert RW Elliott H Stern A Valek P 《Science (New York, N.Y.)》2007,318(5848):217-220
Jupiter's magnetotail is the largest cohesive structure in the solar system and marks the loss of vast numbers of heavy ions from the Jupiter system. The New Horizons spacecraft traversed the magnetotail to distances exceeding 2500 jovian radii (R(J)) and revealed a remarkable diversity of plasma populations and structures throughout its length. Ions evolve from a hot plasma disk distribution at approximately 100 R(J) to slower, persistent flows down the tail that become increasingly variable in flux and mean energy. The plasma is highly structured-exhibiting sharp breaks, smooth variations, and apparent plasmoids-and contains ions from both Io and Jupiter's ionosphere with intense bursts of H(+) and H(+)(3). Quasi-periodic changes were seen in flux at approximately 450 and approximately 1500 R(J) with a 10-hour period. Other variations in flow speed at approximately 600 to 1000 R(J) with a 3- to 4-day period may be attributable to plasmoids moving down the tail. 相似文献
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Smith EJ Marsden RG Balogh A Gloeckler G Geiss J McComas DJ McKibben RB MacDowall RJ Lanzerotti LJ Krupp N Krueger H Landgraf M 《Science (New York, N.Y.)》2003,302(5648):1165-1169
Recent Ulysses observations from the Sun's equator to the poles reveal fundamental properties of the three-dimensional heliosphere at the maximum in solar activity. The heliospheric magnetic field originates from a magnetic dipole oriented nearly perpendicular to, instead of nearly parallel to, the Sun's rotation axis. Magnetic fields, solar wind, and energetic charged particles from low-latitude sources reach all latitudes, including the polar caps. The very fast high-latitude wind and polar coronal holes disappear and reappear together. Solar wind speed continues to be inversely correlated with coronal temperature. The cosmic ray flux is reduced symmetrically at all latitudes. 相似文献
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Young DT Berthelier JJ Blanc M Burch JL Bolton S Coates AJ Crary FJ Goldstein R Grande M Hill TW Johnson RE Baragiola RA Kelha V McComas DJ Mursula K Sittler EC Svenes KR Szegö K Tanskanen P Thomsen MF Bakshi S Barraclough BL Bebesi Z Delapp D Dunlop MW Gosling JT Furman JD Gilbert LK Glenn D Holmlund C Illiano JM Lewis GR Linder DR Maurice S McAndrews HJ Narheim BT Pallier E Reisenfeld D Rymer AM Smith HT Tokar RL Vilppola J Zinsmeyer C 《Science (New York, N.Y.)》2005,307(5713):1262-1266
During Cassini's initial orbit, we observed a dynamic magnetosphere composed primarily of a complex mixture of water-derived atomic and molecular ions. We have identified four distinct regions characterized by differences in both bulk plasma properties and ion composition. Protons are the dominant species outside about 9 RS (where RS is the radial distance from the center of Saturn), whereas inside, the plasma consists primarily of a corotating comet-like mix of water-derived ions with approximately 3% N+. Over the A and B rings, we found an ionosphere in which O2+ and O+ are dominant, which suggests the possible existence of a layer of O2 gas similar to the atmospheres of Europa and Ganymede. 相似文献
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McNutt RL Haggerty DK Hill ME Krimigis SM Livi S Ho GC Gurnee RS Mauk BH Mitchell DG Roelof EC McComas DJ Bagenal F Elliott HA Brown LE Kusterer M Vandegriff J Stern SA Weaver HA Spencer JR Moore JM 《Science (New York, N.Y.)》2007,318(5848):220-222
When the solar wind hits Jupiter's magnetic field, it creates a long magnetotail trailing behind the planet that channels material out of the Jupiter system. The New Horizons spacecraft traversed the length of the jovian magnetotail to >2500 jovian radii (RJ; 1 RJ identical with 71,400 kilometers), observing a high-temperature, multispecies population of energetic particles. Velocity dispersions, anisotropies, and compositional variation seen in the deep-tail (greater, similar 500 RJ) with a approximately 3-day periodicity are similar to variations seen closer to Jupiter in Galileo data. The signatures suggest plasma streaming away from the planet and injection sites in the near-tail region (approximately 200 to 400 RJ) that could be related to magnetic reconnection events. The tail structure remains coherent at least until it reaches the magnetosheath at 1655 RJ. 相似文献
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Phillips JL Bame SJ Feldman WC Gosling JT Hammond CM McComas DJ Goldstein BE Neugebauer M Scime EE Suess ST 《Science (New York, N.Y.)》1995,268(5213):1030-1033
Solar wind plasma observations made by the Ulysses spacecraft through -80.2 degrees solar latitude and continuing equatorward to -40.1 degrees are summarized. Recurrent high-speed streams and corotating interaction regions dominated at middle latitudes. The speed of the solar wind was typically 700 to 800 kilometers per second poleward of -35 degrees . Corotating reverse shocks persisted farther south than did forward shocks because of the tilt of the heliomagnetic streamer belt. Sporadic coronal mass ejections were seen as far south as -60.5 degrees . Proton temperature was higher and the electron strahl was broader at higher latitudes. The high-latitude wind contained compressional, pressure-balanced, and Alfvénic structures. 相似文献
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Saad Massoud A. H. McComas Steven R. Eisenreich Steven J. 《Water, air, and soil pollution》1985,24(1):27-39
Water, Air, & Soil Pollution - Surficial sediment samples from three shallow Nile Delta lakes (Lake Mariut, Hozha hydrodrome, andke Manzalah) were analyzed for PCBs, DDT-group pesticides, and... 相似文献
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