Computer Simulation of Earth's Magnetotail Dynamics

地球磁尾动力学的计算机模拟

• 批准号: 01540350
• 负责人: OGINO Tatsuki
• 金额: $ 1.28万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1989
• 资助国家: 日本
• 起止时间: 1989 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-01540350/
• 关键词: Magneto Hydrodynamics; Earth's Magnetosphere; Computer Simulation; Magnetic Reconnection; Helical Plasmoid; Magnetic flux rope; Boundary Layer; Instability phenomena; 太陽風磁気圏相互作用; 地球磁気圏ダイナミックス; 磁気圏境界層

For the first time. we carried out a global MHD simulation on the structure and dynamics of magnetotail depending on the orientation of the interplanetary magnetic field (IMF) in the plane of north-south, east-west. As a results, the magnetic neutral line forms in the plasma sheet for southward IMF and a hot plasma is ejected towards the tail. When there is a large east-west component of IMF during the southward interval of IMF, the magnetic field lines which confine hot plasma become a helical structure. Both edges of the helical plasmoid are gradually winded are concented to the earth's ionosphere as the helical plasmoid somewhat shifts towards the tail. Then a structure like magnetic flux rope, that confines a longitudinal magnetic field instead of plasma, appears between the ionosphere and the edges of the helical plasmoid. The tail reconnection proceeds in the whole plasma sheet region and the hot plasmoid is ejected tailward as a helical plasmoid when all the field lines are disconnected.Moreover we carried out a high resolution MHD simulation in two times grid points by introducing a newly developed MHD code in a modified leap-frog method in order to study a boundary layer phenomena. The thickness of magnetopause is thinner for southward IMF and it is thicker for northward IMF. Thiis is because the magnetic field varies mildly across the magnetopause for northward, on the other hand a high pressure plasma appears in the dayside neutral line to make thinner the magnetopause. When time elapses, the boundary layer (or magnetopause) has a wavy structure for the shake of dayside magnetic merging. The wavy structure enlarges the momentum transfer from magnetosheath to magnetopause.

首次。我们根据行星际磁场（IMF）在南北、东西平面上的方向，对磁尾的结构和动力学进行了全球MHD模拟。结果，在向南 IMF 的等离子体片中形成磁中性线，并向尾部喷射热等离子体。当IMF南向区间存在较大的IMF东西向分量时，限制热等离子体的磁力线变成螺旋结构。当螺旋等离子体团稍微向尾部移动时，螺旋等离子体团的两个边缘逐渐缠绕并集中到地球电离层。然后，在电离层和螺旋等离子体团边缘之间出现像磁通绳一样的结构，它限制了纵向磁场而不是等离子体。尾部重联在整个等离子体片区域进行，当所有场线断开时，热等离子体团以螺旋等离子体团的形式向尾部喷射。此外，我们通过引入新开发的MHD代码在两倍网格点上进行了高分辨率MHD模拟采用改进的蛙跳法来研究边界层现象。南向IMF磁层顶厚度较薄，北向IMF磁层顶厚度较厚。这是因为磁层顶向北的磁场变化较小，另一方面，在日侧中性线出现高压等离子体，使磁层顶变薄。当时间流逝时，边界层（或磁层顶）具有波状结构，以适应日侧磁并合的震动。波状结构扩大了从磁鞘到磁层顶的动量传递。

项目成果

Tsuruda, K., and T. Okada et al: "Electric field Experiment (EFD)" Geotail Interrim Report (ISAS) ,. 33-54 (1990)

Tsuruda, K. 和 T. Okada 等人：“电场实验 (EFD)”Geotail 中期报告 (ISAS)。

Ogino,T.,R.J.Walker,and M.Asahour-Abdalla: "Magnetic flux ropes in 3-dimensional MHD simulations" Geophyscal Monograph Series. (1990)

Ogino,T.、R.J.Walker 和 M.Asahour-Abdalla：“3 维 MHD 模拟中的磁通绳”地球物理学专着系列。

Ogino, T., R. J. Walker, and M. Ashour-Abdalla: "Magnetic flux ropes in 3-dimensional MHD simulation" Geophysical Monograph Ser.Vol. 58. 669-678 (1990)

Ogino, T.、R. J. Walker 和 M. Ashour-Abdalla：“3 维 MHD 模拟中的磁通绳”地球物理专着 Ser.Vol。

Walker,R.J.,and T.Ogino: "“The fororation of isolated masnetic flux tubes on the dayside magnetopause"Electromasnetic Coupling in the Polar Clefts and Caps" Kluwer Academic Publishers, 11-26 (1989)

Walker, R.J. 和 T.Ogino：“日侧磁层顶上隔离磁通管的穿孔”极地裂隙和极帽中的电磁耦合”Kluwer 学术出版社，11-26 (1989)

Matsumoto, H., and T. Okada et al: "Plasma wave Instrument (PWI)" Geotail Interrim Report (ISAS). 118-147 (1990)

Matsumoto, H. 和 T. Okada 等人：“等离子波仪器 (PWI)”Geotail 中期报告 (ISAS)。