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Numerical study on physics on physics of auroral pattern formation and plasma elementary processes

Research Project

Project/Area Number 04804028
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Space and upper atmospheric physics
Research InstitutionUniversity of Tokyo

Principal Investigator

YAMAMOTO Takashi  University of Tokyo, Graduate School of Science, Research Associate, 大学院・理学系研究科, 助手 (40143375)

Project Period (FY) 1992 – 1994
Project Status Completed (Fiscal Year 1994)
Budget Amount *help
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1994: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1993: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1992: ¥900,000 (Direct Cost: ¥900,000)
KeywordsMagnetosphere-Ionosphere Coupling / Field-Aligned Current / Interaction between Solar Wind and Magnetosphere / Low-Latitude Boundary Layr / Auroral Omega Band / Plasma Sheet / Two Dimensional Particle Simulation / Charge Separation / 2次元粒子シミュレーション / 中性大気ダイナモ / オーロラリップル / 西方伝播サージ
Research Abstract

(1) Our theoretical study on the characteristic pattern of auroras projected on the ionosphere has elucidated fundamental plasma physics for natural phenomena in the magnetosphere/ionosphere system. First, the processes of charge separation in the magnetosphere have been identified as being responsible for the auroral traveling surge, the omega bands, and the ripples. (The causes of these auroral phenomena had long been beyond understanding of theoretical researchers.) Our approach is unique : by using particle simulations we reproduce the temporal/spatial development of auroras on the ionosphere which is in good agreement with the observations. We further apply the simulation-based analysis to the problem of quasi-steady field-aligned currents. Similarly to the case of auroral dynamics, we successfully reproduced the observatioanlly identified pattern of region 1 and region 2 field-aligned current by the two dimensional simulations. This result leads naturally to a new concept that the paired region 1/region2 field-aligned currents can be produced from the plasma distortion in the closed magnetosphere by the solar wind externally applied in the polar cap region.
(2) Using the d magnetic field model by Tsyganenko, we numerically obtained the distributions of magnetic drift vectors in the magnetically closed region where the effect of the interplanetary magnetic field is relatively small. From this plot we found that the field-aligned currents in the low-latitude boundary layr (LLBL) is likely to be caused by the pressure gradient of a plasma injected from the magnetosheath. (Paper will be presented at SGEPSS,in March 1995.) We will also argue that some features of the LLBL current system, which have been revealed by recent satellite observations, could not be understood in a model of the viscous interaction between the magnetosphere and the solar wind which had long been believed to be a most likely mechanism for the LLBL current generation.

Report

(4 results)
  • 1994 Annual Research Report   Final Research Report Summary
  • 1993 Annual Research Report
  • 1992 Annual Research Report
  • Research Products

    (22 results)

All Other

All Publications (22 results)

  • [Publications] T. Yamamoto: "A Particle Simulation of Giant Undulations on the Evening Diffuse Auroral Boundary" J. Geophys. Res.98. 5758-5800 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T. Yamamoto: "A Thory of Current Generator in the Magnetosphere-Ionosphere Coupling" Proc. NIPR Symp. Upper Atmos Phys.6. 62-69 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T. Yamamoto: "A Particle Simulation of Auroral Omega Bands and Torchlike Structures" J. Geomag. Geoelectr.45. 619-648 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T. Yamamoto: "A Particle Simulation of the Westward-Traveling Surge" J. Geophys. Res.98. 13653-13675 (1993)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T. Yamamoto: "Converctive Generation of "Giant" undulations on the Evening Diffuse Aural Boundary" J. Geophys. Res.99. 19499-19512 (1994)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T.Yamamoto: "A particle Simulation of Giant Undulations on the Evening Diffuse Auroral Boundary" J.Geophys. Res.98. 5785-5800 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T.Yamamoto: "A Theory of Current Generator in the Magnetosphere-Ionosphere Coupling" Proc.NIPR Symp. Upper Atmos. Phys.6. 62-69 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T.Yamamoto: "A Particle Simulation of Auroral Omega Bands and Torch-like Structures" J.Geomag. Geoelectr.45. 619-648 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T.Yamamoto: "A Particle Simulation of the Westward-Traveling Surge" J.Geophys. Res.98. 13653-13675 (1993)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] T.Yamamoto: "Convective Generation of "Giant" Undulations on the Evening Diffuse Auroral Boundary" J.Geophys. Res.99. 19499-19512 (1994)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1994 Final Research Report Summary
  • [Publications] Takashi YAMAMOTO: "A Particle Simulation of Giant Undulations on the Evening Diffuse Auroral Boundary" Journal of Geophysical Research. 98. 5285-5800 (1993)

    • Related Report
      1994 Annual Research Report
  • [Publications] Takashi YAMAMOTO: "A Theory of Current Generator in the Magnetosphere-Ionosphere Coupling" Proc.NIPR Symp.Upper Atmos.Phys.6. 62-69 (1993)

    • Related Report
      1994 Annual Research Report
  • [Publications] Takashi YAMAMOTO: "A Particle Simulation of Auroral Omega Bands and Torch-like Structures" Journal of Geomagnetism and Geoelectricity. 45. 619-648 (1993)

    • Related Report
      1994 Annual Research Report
  • [Publications] Takashi YAMAMOTO: "A Particle Simulation of the Westward-Traveling Surge" Journal of Geophysical Research. 98. 13653-13675 (1993)

    • Related Report
      1994 Annual Research Report
  • [Publications] Takashi YAMAMOTO: "Convective Generation of 〃Giant〃Undulations on the Evening Diffuse Auroral Boundary" Journal of Geophysical Research. 99. 19499-19512 (1994)

    • Related Report
      1994 Annual Research Report
  • [Publications] Takashi YAMAMOTO: "A Particle Simulation of Giant Undulations on the Evening Diffuse Auroral Boundary" Journal of Geophysical Research. 98. 5285-5800 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] Takashi YAMAMOTO: "A Theory of Current Generator in the Magnetosphere-Ionosphere Coupling" Proc.NIPR Symp.Upper Atmos.Phys.6. 62-69 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] Takashi YAMAMOTO: "A Particle Simulation of Auroral Omega Bands and Torch-like Structures" Journal of Geomagnetism and Geoelectricity. 45. 619-648 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] Takashi YAMAMOTO: "A Particle Simulation of the Westward-Traveling Surge" Journal of Geophysical Research. 98. 13653-13675 (1993)

    • Related Report
      1993 Annual Research Report
  • [Publications] Takashi YAMAMOTO: "Convective Generation of “Giant" Undulations on the Evening Diffuse Auroral Boundary" Journal of Geophysical Research. 99. (in press) (1994)

    • Related Report
      1993 Annual Research Report
  • [Publications] Takashi YAMAMOTO: "A Particle Simulation of Giant Undulations on the Evening Diffuse Auroral Boundary" Journal of Geophysical Research. 98. (1993)

    • Related Report
      1992 Annual Research Report
  • [Publications] Takashi YAMAMOTO: "A Theory of Current Generator in the Magnetosphere-Ionosphere Coupling" Proc.NIPR Symp.Upper Atmos.Phys.6. (1993)

    • Related Report
      1992 Annual Research Report

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Published: 1992-04-01   Modified: 2016-04-21  

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