【摘要】 本文用“三层模式”探讨了低纬磁层边界区的可压缩Kelvin-Helmholtz不稳定波的特性。低纬边界层的存在降低了不稳定的阈值,几乎整个低纬边界区都是不稳定的。从内边界向磁层传输的能流和动量流都比双层模式增大,扰动磁场是椭圆偏振的。还讨论了低纬边界区该不稳定性的动力学效应及其与P_c4—5脉动的联系。更多还原

【Abstract】 The features of the Kelvin-Helmholtz unstable waves excited in the low latitude magne-tospheric boundary region (LLMBR) are studied on the basis of an idealized model which consists of three uniform plasma regions: the magnetosheath, the boundary layer, and the magnetosphere. It is found that the lower critical velocity for driving the K-H instability is reduced in the presence of the low latitude boundary layer. The unstable waves can appear almost in the whole LLMBR. The energy flux and the momentum flux into the magnetosphere are stronger in the "3-layer model" than those in the "2-layer model". The perturbed magnetic field is elliptically polarized. Possible relationships between the Pc 4-5 geomagnetic pulsation and the K-H waves excited in the LLMBR are also discussed.更多还原