An improvement on the numerical simulation of CME event between two coronal streamers

Via an adequate superposition of a dipolar and a hexapolar field, the conjectured magnetic field is improved so that it has opposite signs in the southern and northern poles. Then, by adopting the system of ideal MHD equations, a steady self-consistent solution for the interaction of the conjectured magnetic field and solar wind is obtained, giving a background structure with two coronal streamers qualitatively close to the observation. A model of the triggering of CME events with concentric magnetic configuration is adopted to study features of propagation of CMEs in the solar corona. The results show that the propagation of CME is confined between two coronal streamers. The closed magnetic configuration of CME is similar to that on the transverse section of magnetic cloud. This may be used to interpret some features of the observed magnetic clouds at 1 AU. In the vicinity of the CME, there are areas where pressure and Lorentz force play the chief role. This may be helpful for the analysis of observational data of CME events at 1 AU.