高纬磁层顶尾部边界层的离子流剪切不稳定性

研究了高纬磁层顶层部边界层在非均匀磁场条件下的离子流剪切不稳定性，由于考虑了尾向电流，我们发现离子流剪切不稳定性的激发与扰动波长有关，并得到了激发该不稳定性的准临界波长的表达式，对于磁层顶存在的波长为地球半径量级的表面波扰动，离子流剪切不稳定性倾向于发生在磁层顶边界层的内边界，沿磁层顶外边界传播的稳定的表面波和其内边界的离子流剪切不稳定性同时存在，这将有助于解释磁鞘太阳与动量持续不断地向地磁层的传输。

SHEARED ION FLOW INSTABLITY IN MAGNETOPAUSE BOUNDARV LAYER AT THE HIGH-LATITUDE MAGNETOTALL

The sheared ion flow instability is studied in an inhomogeneous plasma background of magnetopause boundary layer at the high latitude magnetotail. By considering tail-aligned currents, we find that the instability excitation strongly depend on the disturbed wavelength. The quasi-critical wave number for the instability is obtained. For relative long wavelength perturbation the instability tend to be excited at the inner edge of the boundary layer. The stable surface wave at magnetopause and the K-H instability at the inner edge of the boundary layer can exist at the same time, and that may help to transfer the momentum toward magnetosphere continuously.