Investigation of the Geomagnetic Tail by the GEOTAIL Satellite

GEOTAIL 卫星对地磁尾的研究

• 批准号: 04044168
• 负责人: NISHIDA Atsuhiro
• 金额: $ 16万
• 依托单位: Institute of Space and Astronautical Science
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1992
• 资助国家: 日本
• 起止时间: 1992 至 1994
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-04044168/
• 关键词: Magnetosphere; GEOTAIL satellite; Magnetotail; Neutral sheet; Interplanetary magnetic field; Magnetic reconnection; Slow-mode shock; Plasma waves; GEOTAIL衛星; 磁気圏境界面; 太陽風; 惑星間空間; プラズモイド; ラングミュア波; 磁力線再結合; プラズマ加速; 磁気中性線; 広周波数帯静電ノイズ

1. Global structure of the distant tail GEOTAIL observations have confirmed that the magnetotail extends to 200 Re and beyond. It flaps violently north-south as well as east-west with amplitudes comparable to its average radius of about 20 Re, but there is no indication that it is filamentary. Plasma sheet is clearly distinguishable from the lobe or the magnetosheath by high temperature (around 1 keV) and low density (around 0.1/cc). Its magnetic structure and internal convection profile are governed by the north-south polarity of the interplanetary magnetic field.2. Distant tail under the southward IMF Under the southward IMF,magnetic field lines convect toward the neutral sheet where they are reconnected. The probability that open field lines are reconnected earthward of 150 Re is about 75%. The reconnection rate is the highest at the tail axis and decreases toward the flanks by a factor of 2 to 3.3. Plasma heating and relaxation at the plasma-sheet lobe boundary At the plasma sheet boundary, the slow-mode shock is formed in the convective flow where the cold ions of the lobe become heated. Very energetic ions flow upstream from the shock. The mixed population of cold and hot particles in this boundary region is a rich source of plasma waves whose non-linear development is seen.4. Distant tail under northward IMF Under the northward IMF,the open field lines which are presumably produced in the cusp region of the dayside magnetopause sweep across the tail. The convection is parallel to the neutral sheet which is highly twisted in the direction of IMF and has opposite directions (dawn to dusk vs dusk to dawn) on opposite sides of the neutral sheet. The source of the hot plasma in the plasma sheet which is located in the open field lines poses a new problem.

1. GEOTAIL观测证实，磁尾延伸到200 Re及以上。它猛烈地向南北和东西方向摆动，振幅相当于它的平均半径约20 Re，但没有迹象表明它是一个行星。等离子体片可以通过高温（约1 keV）和低密度（约0.1/cc）与波瓣或磁鞘清楚地区分开来。它的磁结构和内部对流分布受行星际磁场的南北极性控制。在向南的IMF下，磁力线向中性片对流，在那里它们重新连接。150 Re的开路磁力线重新接地的概率约为75%。重联率在尾轴处最高，向侧翼方向下降2 ~ 3.3倍。在等离子体片边界处的等离子体加热和弛豫在等离子体片边界处，慢模激波形成于对流中，在对流中瓣的冷离子被加热。高能离子从激波逆流而上。边界区的冷热粒子混合群是等离子体波的丰富来源，其发展呈非线性.在北向IMF下的远尾在北向IMF下，可能产生于向阳侧磁层顶尖区的开磁力线扫过尾。对流平行于在IMF方向上高度扭曲的中性片，并且在中性片的相对侧上具有相反的方向（黎明到黄昏vs黄昏到黎明）。位于开放场线中的等离子体片中的热等离子体的源提出了新的问题。

项目成果

T.Yamamoto,et al.: "Dense plasmas in the distant magnetotail as observed by Geotail" Geophysical Research Letters. 21. 2879-2882 (1994)

T.Yamamoto 等人：“Geotail 观察到的遥远磁尾中的密集等离子体”地球物理研究快报。

H.Kawano,et al.: "A flux rope followed by recurring encounters with traveling compression regions:Geotail observations" Geophysical Research Letters. 21. 2891-2894 (1994)

H.Kawano 等人：“磁通绳随后反复遭遇移动压缩区域：Geotail 观测”地球物理研究快报。

M.Hirahara,et al.: "Acceleration and heating of cold ion beams in the plasma sheet boundary layer observed with Geotail" Geophysical Research Letters. 21. 3003-3006 (1994)

M.Hirahara 等人：“用 Geotail 观察到的等离子片边界层中冷离子束的加速和加热”地球物理研究快报。

A.T.Y.Lui,D.J.Williams,T.Yamamoto,S.Kokubun,L.A.Frank,K.Tsuruda: "A filament of energetic particles near the high-latitude dawn magnetopause" Geophysical Research Letters. 21. 3011-3014 (1994)

A.T.Y.Lui、D.J.Williams、T.Yamamoto、S.Kokubun、L.A.Frank、K.Tsuruda：“高纬度黎明磁层顶附近的高能粒子细丝”地球物理研究快报。

F.S.Mozer, et al.: "Direct entry of dense flowing plasmas into the distant tail lobes" Geophysical Research Letters. 21. 2959-2962 (1994)

F.S.Mozer 等人：“密集流动等离子体直接进入遥远的尾叶”地球物理研究快报。