行星际瞬态激波传播特性研究

This project develops a piecewise parabolic method that is suitable for treating magnetohydrodynamic (MHD) shocks. Using this method, we investigate the interaction between transient shocks and interplanetary medium in the inner heliosphere, explore the quantitative law and physical origin of the anisotropic propagation of shocks, build up two-dimensional MHD models of the solar wind accelerated and heated by Alfvén waves, and analyse the governing effect of the flow-tube geometry on the acceleration and heating of the solar wind. The developed numerical scheme is of general application value for MHD numerical simulations in various strata of the solar-terrestrial space. The revealed anisotropy of shock propagation is consistent with the observational conclusions on the east-west asymmetry and the "same and opposite side" effect. It is found that the heliospheric current sheet does not affect the shock propagation at all, the influence of the heliospheric plasma sheet on shocks tunrs out to be negligible, and the interplanetary high- and low-speed stream structure and the spiral magnetic field serves as a main factor and fundametal cause in creating the anisotropy of shock propagation. The multi-dimensional features of the propagation and evolution of interplanetary flow velocity enhancement disturbances and slow shocks are explored and the results obtained have verified and extended the basical conclusions reached by previous one-dimensional analyses.

太阳爆发事件产生的行星际瞬态激波，会显著改变内日球结构和近地空间环境。本项目发展适合处理磁流体激波的逐段抛物线方法，对行星际瞬态激波的传播特性进行系统的数值模拟，对比观测事实和前人结论，探讨激波各向异性传播的定量规律和物理机制，为近地空间激波扰动预报提供理论依据。所发展的算法对各类日地扰动的传播研究具有普遍的应用价值。.