1997 Fiscal Year Final Research Report Summary
Non-Thermal Ion Populations in the Interplanetary Space
| Project/Area Number |
08044093
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | Ehime University |
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Principal Investigator |
HASEBE Nobuyuki Ehime University, Professor, 工学部, 教授 (10127904)
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| Co-Investigator(Kenkyū-buntansha) |
WILKEN B. Max-Planck Institute for Aeronomy, Senior Researcher, 上級研究員
KNOW H. University Kiel, Institute of Nuclear Phys., Senior Researcher, 上級研究員
REAMES D. NASA/GSFC,Lab.for High Energy Astrophysics, Senior Researcher, 上級研究員
UGAI Masayuki Ehime University, Faculty of Engineering, Professor, 工学部, 教授 (10036444)
DOKE Tadayoshi Waseda University, Adovanced Research Center for Science and Engineering, Profes, 理工学総合研究センター, 教授 (60063369)
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| Project Period (FY) |
1996 – 1997
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| Keywords | Solar Energetic Particle / Galactic Cosmic Ray / Solar Flar / Corotating Interaction Region / Coronal Mass Ejection / Particle Acceleration / Particle Propagation / Solar Modulation |
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| Research Abstract |
The objectives of this study is to understand the dynamics occurring in the heliosphere and to draw a global picture of the heliosphere ranging from the solar atmosphere to the boundary of the heliosphere. The simultaneous and continuous observations at multi-points in the interplanetary space have allowed us to study the compostition of non-theral ion populations, their energy spectra and the time variation in a broad range of energies between spra-thermal energy and relativistic one. The main results in this study are the following :
1) The anomalous component of Ar and S in cosmic rays were observed by the collaboration of GEOTAIL and WIND satellites for the first time in the world.
2) It was found that small variation of galactic cosmic ray (GCR) intensity was observed at higher latitude, suggesting that GCRs are modulated even at higher latitude.
3) Energetic ions associated with Corotating Interaction Region (CIR) ion events obsserved at 1AU receive continuum energy gain even after
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passing of magnetic sector region. The intensity decreases in associated with CIR events have a good correlation with the enhancement of the ion intensity and the solar wind velocity.
4) The mean free path of cosmic ray in the turbulent region at interplanetary shock is one fifths or smaller than that in the normal interplanetary space.
5) The temporal variation of ion intensity accelerated in the interplanetary space depends on the heliographic latitude where events occur.
6) Many low energy solar neutrons are generated by internuclear cascade processes in the solar atmosphere.
8) Energetic ions accelerated at the solar flare site have characteristic abundances produced by the resonant wave-particle interactions in the flare plasma.
9) The mechanism of heavy ion accelerataion by cascading Alfven waves in impulsive solar flares is suggested.
10) It was shown that effective proton accelerations in the reconnection regions in the geo-magnetosphere are performed in the three characteristic regions, using test particle simulations on the spontaneous fast magnetic reconnection model.
11) In the reconnection regions, the dominant acceleration occurs when a particle has a curvature drift at the shock front.
The particle environment in the heliosphere as well as geomagnetosphere is remarkably influenced associated with the coronal mass ejection and particle acceleration at the solar surface. The understanding of the complex coupled system between the Sun, Interplanetary space and Planetary magnetosphere, has been deepened through this study. Less
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