Study on Global Structure of Space Plasma Wave Energy by Using Large Scale Ray-Tracing

利用大规模射线追踪研究空间等离子体波能的整体结构

• 批准号: 63420016
• 负责人: KIMURA Iwane
• 金额: $ 17.47万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (A)
• 财政年份: 1988
• 资助国家: 日本
• 起止时间: 1988 至 1990
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63420016/
• 关键词: Ray tracing; Satellite Akebono; Magnetospheric Plasma; Wave normal vector; Whistler mode; Ion cyclotron mode; Graphic routine; 磁気圏プラズマ; EXOSーD(Akebono)衛星; オメガ信号; 伝搬ベクトル計測; 波動ー粒子相互作用; トリガ-ド放射; 磁気圏; 宇宙空間プラズマ; 科学衛星EXOS-D(あけぼの); 波動粒子相互作用

The main objectives of this project were (1) to extend our ray tracing technique for calculating ray paths of VLF and ELF waves in the earth magnetosphere and (2) to apply this technique to the VLF and ELF waves observed by Akebono satellite for interpretation of these wave phenomena. Important results are summarized :1. The computer programs for ray tracing of VLF whistler mode and ELF ion cyclotron mode, both originally developed for supercomputers, were transplanted to workstations and completed various graphic routines to represent the results of calculation on a display and to get hardcopies on request.2. Application of the above ray tracing system to the wave data observed by the Akebono Satellite are as follows :a) By the VLF wave instruments on-board the satellite, Omega signals (10.2KHz) for ground navigation have been observed and spatial distributions of their signal intensity and wave normal direction in the magnetosphere were determined. These results can be compared with those theoretically calculated by ray tracing technique, if an appropriate Plasma model in the magnetosphere is given. We have developed a method to make a plasma density model which best fits the electron density actually observed along the satellite trajectory. It was found the results of ray tracing using the plasma model thusmade satisfactorily agree with those observed by Akebono.b) By the ELF wave instrument on-board the satellite, new ELF emission phenomena were discovered, which exist only in the magnetic equatorial region in the frequency range below 100Hz. These emissions are closely related with ion cyclotron frequency of Helium and Oxygen ions, so that they are interpreted as ion cyclotron mode emissions generated by an anisotropic temperature of super-thermal protons. In order to confirm this hypothesis, our ray tracing technique has been used and our interpretation was found to be satisfactory.

该项目的主要目标是：（1）扩展我们的射线追踪技术，用于计算地球磁层中VLF和ELF波的射线路径;（2）将这一技术应用于Akebono卫星观测到的VLF和ELF波，以解释这些波现象。主要结果如下：1.将最初为超级计算机开发的VLF哨声模式和ELF离子回旋模式的射线追迹程序移植到工作站上，完成各种图形程序，将计算结果显示在显示器上，并根据需要提供硬拷贝.利用Akebono卫星上的甚低频测波仪器观测到了用于地面导航的Omega信号（10.2KHz），并确定了其信号强度和波法线方向在磁层中的空间分布。如果给出一个合适的磁层等离子体模型，这些结果可以与射线追踪技术的理论计算结果进行比较。我们已经发展了一种方法，使等离子体密度模型，最适合的电子密度实际观察到的沿着卫星轨道。B）星载ELF波仪发现了新的ELF辐射现象，这种现象只存在于磁赤道区，频率范围在100 Hz以下。这些发射与氦离子和氧离子的离子回旋频率密切相关，因此它们被解释为由超热质子的各向异性温度产生的离子回旋模式发射。为了证实这一假设，我们的射线追踪技术已被使用，我们的解释是令人满意的。

项目成果

大村善治: J.Geomag.Geoelectr.40. 946-961 (1988)

大村义治：J.Geomag.Geolectr.40。946-961 (1988)

A. Sawada, Y. Kishi, M. Yamamoto, A. Sakurai, Y. Kasahara, and I. Kimrra: "Propagation characteristics of Omega signals and their triggered emissions observed by EXOS-D satellite" Geophysical Research Letters. 18. 321-324 (1991)

A. Sawada、Y. Kishi、M. Yamamoto、A. Sakurai、Y. Kasahara 和 I. Kimrra：“EXOS-D 卫星观测到的 Omega 信号及其触发发射的传播特性”地球物理研究快报。

大村磐根: "AGU Monograph:Plasma waves and instabilities at comets and magnetospheres "Ray paths of electromagnetic and electrostatic waves in the earth and planetary magnetospheres"" American Geophysical Uinon, (1989)

Iwane Omura：“AGU 专着：彗星和磁层的等离子波和不稳定性“地球和行星磁层中电磁波和静电波的射线路径””美国地球物理 Uinon，（1989 年）

山本 正幸、大村 磬根、長野 勇、橋本 弘蔵、岡田 敏美、林 幹治、澤田 晃、伊藤 嘉彦、軒内 栄一: "あけぼの(EXOSーD)搭載VLE装置による初期観測結果" 宇宙科学研究報告. 25. 63-73 (1990)

Masayuki Yamamoto、Mone Omura、Isamu Nagano、Hiroshi Hashimoto、Toshimi Okada、Mikiharu Hayashi、Akira Sawada、Yoshihiko Ito、Eiichi Kenuchi：“利用 Akebono (EXOS-D) 上的 VLE 仪器进行的初步观测结果” 空间科学研究报告 25。 63-73 (1990)

I. Kimura: "Ray paths of electromagnetic and electrostatic waves in the earth and planetary magnetospheres" AGU Monograph. 53. 161-171 (1989)

I. Kimura：“地球和行星磁层中电磁波和静电波的射线路径”AGU 专着。