地球弓激波及其与行星际激波相互作用

给定地球轨道附近的行星际条件和地球弓激波的几何位形，本文分析向阳侧弓激波强度参数沿激波阵面的分布，以及行星际激波与弓激波的相互作用.对于弓激波阵面相对日地连线轴对称的情形，得到如下结论：（1）弓激波强度参数分布相对由行星际磁场和日地连线构成的基准面对称，各激波强度参数的最大值出现在基准面上.磁压比在垂直激波线一侧较大，而气压比在平行激波点一侧较大，导致总压比相对日地连线大致呈轴对称分布.（2）随着行星际磁场与日地连线夹角的增大，弓激波强度参数的最大值有所减小，且位置朝远离日下点方向偏移；但气压比和总压比的分布基本上不受影响.（3）行星际激波透过弓激波之后，切向磁场比更接近于1，但总磁场跳变幅度增大.（4）透过弓激波之后，行星际准垂直激波的总磁场比更接近于1，准平行激波的总磁场比则反之.

Earth's bow shock and its interaction with interplanetary shocks

Given the interplanetary conditions near the Earth's orbit and the geometrical configuration of the Earth's bow shock, this paper discusses the distributions of various parameters of shock strength over the sunward shock front, and the interaction between the bow shock and interplanetary shocks. For the case of axisymmetrical bow shock front with respect to the Sun-Earth line, we arrive at the following conclusions: (1) The parameters of shock strength are distributed symmetrically with respect to the plane of reference defined by the interplanetary magnetic field (IMF) and the Sun-Earth line, and their maxima appear in the plane of reference. The ratio of magnetic pressure is larger on the side containing the perpendicular-shock line, whereas the ratio of gas pressure is larger on the side containing the parallel-shock point, leading to a distribution of the ratio of total pressure that is largely axisymmetrical with respect to the Sun-Earth line. (2) When the angle between the IMF and the Sun-Earth line increases, the maxima of shock strength parameters of the bow shock decrease and the maximum points shift away from the subsolar point, but the distributions of gas-pressure ratio and total pressure ratio are essentially not affected. (3) After an interplanetary shock is transmitted through the bow shock, the ratio of tangential field strength becomes closer to 1, whereas the jump of total magnetic field strength increases in amplitude. (4) After transmission through the bow shock, the ratio of total magnetic field strength becomes closer to 1 for quasi-perpendicular interplanetary shocks but farther away from 1 for quasi-parallel ones.