| 各向异性等离子体中撕裂模不稳定性和磁场重联的数值研究 |
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| 引用本文： | 马颖娟,王水.各向异性等离子体中撕裂模不稳定性和磁场重联的数值研究[J].地球物理学报,2001,44(4):437-445. |
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| 作者姓名： | 马颖娟 王水 |
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| 作者单位： | 中国科学技术大学地球和空间科学系,合肥230026 |
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| 基金项目： | 国家自然科学基金资助项目 ( 49774 2 4 3，4 9834 0 30 ) |
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| 摘 要： | 应用二维三分量时变可压缩磁流体动力学模拟方法,数值研究了各向异性等离子体(P⊥≠P∥,T⊥≠T∥)中的撕裂模不稳定性和磁场重联过程.计算结果表明,在短暂的线性增长之后,不稳定性将趋于非线性饱和.线性增长率随着各向异性程度|P⊥/P∥|增强而增大,随着等离子体β值减小及磁场y分量By增大而降低.在强垂直各向异性(P⊥>P∥)的情况下,电流片中磁场重联形成的磁岛达到非线性饱和后,在X型点附近形成空腔结构;随着空腔的增大,磁岛逐渐变小,并最终消失.在P⊥>P∥情况下,仅在电流片中心区域可以激发火蛇管不稳定性,电流片中不能形成大型磁岛.
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| 关 键 词： | 各向异性 撕裂模 磁镜模 磁场重联 |
| 文章编号： | 0001-5733(2001)04-0437-09 |
| 收稿时间： | 2000-08-28 |
NUMERICAL STUDIES OF TEARING MODE INSTABILITY AND MAGNETIC RECONNECTION IN ANISOTROPIC PLASMA |
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| MA YING,JUAN\ \ WANG SHUI.NUMERICAL STUDIES OF TEARING MODE INSTABILITY AND MAGNETIC RECONNECTION IN ANISOTROPIC PLASMA[J].Chinese Journal of Geophysics,2001,44(4):437-445. |
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| Authors: | MA YING JUAN\ \ WANG SHUI |
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| Institution: | Department of Earth and Space Sciences, University of Science and Technology of China, Hefei 230026, China |
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| Abstract: | The tearing mode instability and magnetic reconnection process in an anisotropic plasma (P ⊥≠P ∥ , T ⊥≠T ∥ ） are numerically studied by a two dimensional three component time dependant compressible MHD simulation. It is found that the instability tends to become nonlinear saturation after, a short period of linear growth. The growth rate will increase when the intensity of pressure anisotropy P ⊥/P ∥ increases, while it will decrease with the decrease of the plasma β and the augment in the y component B y of magnetic field. In case of a large perpendicular anisotropy (P ⊥>P ∥ ）, when the magnetic island formed in the current sheet by magnetic reconnection becomes nonlinear saturation, there will be cavity structures formed near the X points. The cavities become larger gradually while the magnetic islands become smaller and vanish at last. In the plasma with a parallel anisotropy (P ⊥ ∥ ）, the fire hose instability can only be excited in the central region of current sheet, and large magnetic island can't be formed in the current sheet. |
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| Keywords: | Anisotropy Tearing mode Mirror mode Magnetic reconnection |
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