Numerical study on plasma dynamics in the Earth magnetosphere in association with characteristic distributions of aurora and field-aligned currents

地球磁层等离子体动力学与极光和场对准电流特征分布的数值研究

• 批准号: 07804029
• 负责人: YAMAMOTO Takashi
• 金额: $ 1.34万
• 依托单位: The University of Tokyo
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07804029/
• 关键词: Field-aligned Current; Auroral Omega Band; Auroral Oval; Interplanetary Magnetic Field; Charge Separation; Plasma Torus; Numerical Simulation; Interchange Instability; 磁気圏・電離圏結合; 2次元数値シミュレーション; プラズマ粒子加速; 異常拡散; 磁力線開-閉境界; 領域"0"対電流; トーラス配位; オメ

So far, the theoretical models for the earth magnetosphere have normally assumed that the distribution of auroral particles with kinetic energies of 1-10 keV is uniform, in terms of the flux tube content, over the auroralzone. This implies that no charge separation occurs in that region, despite of the remarkable activity of aurora, and that boundary processes such as viscous interaction and magnetic reconnection play important roles in the auroral activity and production of region 1 field-aligned currents (FACs). We propose a new paradogm that during a period of southward interplanetary magnetic field (IMF), the so-called plasma 'torus' with plasma concentration on the auroral oval can be formed due to particle escape along the open field lines, and that distortion of the torus configuration by the two-cell convection results in the generaation of the region 1 and region 2 FACs. The plasma torus had been assumed to be absolutely interchange-unstable, and thus it had not been considered as a realistic distribution of the magnetospheric plasma. However, if reversal of the magnetic drift direction across the open-close boundary is taken into account, one can expect that the whole configuration of the torus can be maintained while the interchange instability occurs locally inside it. Our theory predicts that various phenomena such as production of region 0,1 and 2 FACs and formations of discrete aurora and omega band structure are interpreted as results of active behavior of the plasma torus which is "metabolized" through the processes of plasma flow into the tours from the solar wind the plasma escape. The purpose of our numerical simulation is to reproduce the metabolized torus as well as those auroral phenomena. Recently we have obtained the simulation results of the region 0,1 and 2 FACs and the formation of auroral omega band, which are consistent with the satellite servations.

到目前为止，地球磁层的理论模型通常假定具有1-10 keV的动能的极光颗粒的分布是均匀的，就通量管含量而言，在极光区域上。这意味着尽管极光的活性显着，并且诸如粘性相互作用和磁重新连接之类的边界过程在该区域中没有任何电荷分离，但在1.区域1田间对准电流（FACS）中起着重要作用。我们提出了一个新的范围，即在向南的星际磁场（IMF）时期，所谓的等离子体“圆环”，血浆集中在极光椭圆形上，可以由于粒子沿开放式田间线逃脱而形成，而粒子沿开放式田间线逃脱，以及通过两局将对圆环的变形导致两局构造的构构导致该属构成该属的构成属的构成一代face of Regoraecation fore 1和1区。假定血浆圆环是绝对的互换 - 不稳定，因此尚未被视为磁层等离子体的现实分布。但是，如果考虑到跨闭合边界的磁性漂移方向的逆转，则可以期望在互换不稳定在其内部的互换不稳定时，可以保持圆环的整个配置。我们的理论预测，各种现象，例如区域0,1和2 FAC的产生以及离散的Aurora和Omega带结构的形成，被解释为血浆圆度的主动行为的结果，血浆圆环的积极行为通过血浆流入的流量从Solar Wind到质量的群体逃生而“代谢”。我们数值模拟的目的是重现代谢的圆环以及那些具有极光现象。最近，我们获得了区域0,1和2 FACS的模拟结果以及与卫星使用者一致的极光欧米茄带的形成。

项目成果

T.Yamamoto: "A theory for generation of the paired region 1 and region 2 field-aligned currents" J.Geophys. Res.102, A2. 27199-27222 (1996)

T.Yamamoto：“生成配对区域 1 和区域 2 场对准电流的理论”J.Geophys。

T.Yamamoto: "Quasi-steady production of region 1 and region 2 field-aligned currents" Prod.NIPR Symp.Upper Atmos.Phys.11. 108-123 (1998)

T.Yamamoto：“区域 1 和区域 2 场对准电流的准稳定产生”Prod.NIPR Symp.Upper Atmos.Phys.11。

T.Yamamoto: "Formation of auroral omega bands in the paired region 1 and region 2 field-aligned current system" J.Geophys. Res.101, A12. 2571-2544 (1997)

T.Yamamoto：“在配对的区域 1 和区域 2 场对准电流系统中极光欧米茄带的形成”J.Geophys。

T.Yamamoto: "A theory for generation of the paired region 1 and region 2 field-aligned currents" J.Geophys.Res.101 A12. 27199-27222 (1996)

T.Yamamoto：“生成配对区域 1 和区域 2 场对准电流的理论”J.Geophys.Res.101 A12。

T.Yamamoto: "Numerical study on dynamics and polarization of the hot plasma torus in the magneto-sphere:cause of generation of the paired region 1 and region 2 field-aligned currents" J.Geomag.Geoelectr.49,7. 879-922 (1997)

T.Yamamoto：“磁层中热等离子体环面动力学和极化的数值研究：成对区域 1 和区域 2 场对准电流的生成原因”J.Geomag.Geolectr.49,7。