Magnetohydrodynamic simulation of a solar flare: 1. Current sheet in the corona

摘要

The results of modeling the preflare situation in the solar corona, obtained using a numerical solution for a complete set of three-dimensional MHD equations, are reviewed. Any assumptions concerning the flare development character or the active region's behavior before a flare are not introduced. The initial and boundary conditions on the photosphere are specified from magnetic field measurements before a flare. The photospheric field sources are approximated by magnetic dipoles. The usage of the PERESVET program indicated that a current sheet is formed in the vicinity of a singular magnetic field line in the corona. The sheet is formed due to disturbances coming from the photosphere. The energy necessary for a flare is stored in the current sheet magnetic field during 2-3 days. The main construction principles of the PERESVET program, which makes it possible to use the maps of a measured photospheric field as boundary conditions, are presented.