Study of substorm simulation

亚暴模拟研究

• 批准号: 15540429
• 负责人: TANAKA Takashi
• 金额: $ 2.18万
• 依托单位: KYUSHU UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2006
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15540429/
• 关键词: substorm; magnetohydrodymanics; convection; field-aligned current; state transition; サブストーム; 磁気圈対流; セパレーターライン; 磁気嵐; テスト粒子追跡; MHDシミュレーション; 宇宙天気; 複合系の物理; 磁気圏対流; テーターオーロラ; 複合系; 磁気嵐急始現象; 有限体積TVDスキーム

Convection is the most fundamental process in understanding the structure of geospace and disturbances observed in the magnetosphere-ionosphere (M-I) system. In this study, a self-consistent configuration of the global convection system is considered under the real topology as a compound system. Investigations are made based on the M-I coupling scheme by analyzing numerical results obtained from magnetohydrodynamic (MHD) simulations which guarantee the self-consistency in the whole system under the BV (magnetic field and velocity) paradigm. It is emphasized in the M-I coupling scheme that convection and field-aligned current (FAC) are different aspects of same physical process characterizing the open magnetosphere. Special attention is given in this study to the energy supplying (dynamo) process that drives the FAC system. In the convection system, the dynamo must be constructed from shear motion together with plasma population regimes to steadily drive the convection. Convection patterns observed in the ionosphere are also the manifestation of achievement in global self-consistency. A primary approach to apply these concepts to the study of geospace is to consider how the M-I system adjusts the relative motion between the compressible magnetosphere and the incompressible ionosphere when responding to given solar-wind conditions. The above principle is also applicable for the study of disturbance phenomena such as the substorm as well as for the study of apparently unique processes such as the flux transfer event (FTE), the sudden commencement (SC), and the theta aurora. Finally, an attempt is made to understand the substorm as the extension of enhanced convection under the southward interplanetary magnetic field (IMF) condition.

对流是理解磁层层（M-I）系统中观察到的地理空间结构和干扰结构的最基本过程。在这项研究中，在实际拓扑结构下将全球对流系统的自洽配置视为复合系统。根据M-1耦合方案进行研究，通过分析从磁性水力动力学（MHD）模拟获得的数值结果，这些模拟保证了BV（磁场和速度）范式下整个系统中的自矛盾。在M-1耦合方案中强调的是，对流和与场对准电流（FAC）是表征开放磁层的相同物理过程的不同方面。在本研究中特别注意驱动FAC系统的能源供应过程（Dynamo）过程。在对流系统中，必须通过剪切运动以及等离子体种群制度构建发电机，以稳步推动对流。在电离层中观察到的对流模式也是全球自稳定性成就的体现。将这些概念应用于地理研究的主要方法是考虑M-1系统如何在响应给定的太阳能条件时调整可压缩磁层和不可压缩电离层之间的相对运动。上述原理还适用于研究扰动现象，例如该物体以及对明显独特的过程（例如通量转移事件（FTE），突然开始（SC）和Theta Aurora）的研究。最后，试图理解该物质是在南向对流磁场（IMF）条件下增强对流的扩展。

项目成果

Substorm onset caused by the two state transition in the magnetosphere

磁层两种状态转变引起的亚暴爆发

• 发表时间: 2005
• 期刊: Multiscale coupling of Sun-Earth processes (in press)
• 作者: Tanaka;T.
• 通讯作者: T.

Formation mechanism of the theta aurora by a transient convection during northward IMF

IMF北移期间短暂对流导致θ极光的形成机制

• 发表时间: 2004
• 期刊: J. Geophys, Res, 109, A09201, doi : 10.1029/2003JA010271, 2004. 109
• 作者: Tanaka;T.;T.Obara;M.Kunitake
• 通讯作者: M.Kunitake

Transient response of the earth's magnetosphere to a localized density pulse in the solar wind : Simulation of traveling convection vortices

地球磁层对太阳风中局部密度脉冲的瞬态响应：行进对流涡旋的模拟

• 发表时间: 2004
• 期刊: J.Geophys.Res. 109,A03204
• 作者: Kataoka;R.;H.Fukunishi;S.Fujita;T.Tanaka;M.Itonaga
• 通讯作者: M.Itonaga

Tanaka, T.: "Formation of magnetospheric plasma population regimes coupled with the dynamo process in the convection system"J.Geophys.Res., doi:10.1029/2002/JA009668. 108(A8). (2003)

Tanaka, T.：“磁层等离子体群形态的形成与对流系统中的发电机过程相结合”J.Geophys.Res.，doi：10.1029/2002/JA009668。

Magnetospheric plasma processes during a sudden commencement revealed from a global MHD simulation

全球 MHD 模拟揭示了突然开始时的磁层等离子体过程

• 发表时间: 2006
• 期刊: Magnetospheric ULF waves : Synthesis and new directions, Geophys. Monogr. Ser.(AGU, Washington D.C.) vol.169
• 作者: Fujita;S.;T.Tanaka
• 通讯作者: T.Tanaka