行星际电流片与激波特性的东西不对称性  

INTERPLANETARY CURRENT SHEET AND EAST-WEST ASYMMETRY OF SHOCK PROPERTIES

作　　者：贾先哲[1] 杨玉林[1] 刘绍亮[1] 胡友秋[1] 

机构地区：[1]中国科学技术大学地球与空间科学系,合肥230026

出　　处：《地球物理学报》2001年第5期581-588,共8页Chinese Journal of Geophysics

基　　金：国家自然科学基金 (4 99740 3 5 );中国科学技术大学创新工程研究基金资助项目

摘　　要：采用日球赤道面二维二分量MHD模型 ,研究行星际电流片对 1AU附近激波的密度比、气压比、动压差和磁场强度比沿激波阵面分布特性的影响 .结果表明 ,只有当扰动源靠近电流片时 ,这一影响才比较显著 ,且对电流片东侧扰动源形成的激波的影响较强 .当扰动源位于电流片东 (西 )侧时 ,激波动力学参数峰值位置相对扰动源法向东 (西 )偏 ,磁场比峰值位置西偏的程度减弱 (增强 ) .电流片的上述影响与它对激波最快传播方向的偏转效应密切相关 ,而磁场强度比峰值总是西偏 ,则主要取决于行星际磁场的螺旋结构 .Using a two-dimensional and two-component MHD model in the equatorial plane,this paper investigates the influence of the interplanetary current sheet on the distribution of the density ratio,the gas-pressure ratio,the kinetic pressure jump,and the ratio of magnetic field strength along the shock front near 1AU. It is shown that the influence is significant only for the shocks with the disturbance source close to the current sheet. Moreover,this influence is stronger for shocks generated by disturbance sources on the eastern side of the current sheet. When the disturbance source is situated at the eastern (western) side of the current sheet,the peak of the kinetic parameters of the shock deviates eastward (westward) relative to the source center normal, and the western deflection of the peak of the magnetic field strength ratio is weakened (strengthened). The influence of the current sheet is closely related to its effect on the deflection of the fastest propagation direction of the shock. On the other hand, the omnipresent western deflection of the peak of the magnetic field strength ratio stems from the spiral structure of the interplanetary magnetic field.

关 键 词：日球动力学 行星际电流片 MHD激波 不对称性 扰动源 磁场强度 密度比 气压比 动压差 

分 类 号：P353[天文地球—空间物理学]