Solar corona expansion and heliospheric current sheet creation

Heliospheric current sheet (CS) creation has been investigated by numerical solution of 3D MHD equations, using the PERESVET code to the problem of solar corona expansion. The dipole magnetic field corresponds to the solar activity minimum, and typical corona parameters are used as initial conditions. Plasma compression, dissipation, thermal conductivity, and gravitation are taken into account. The normal magnetic field component is an important feature of the heliospheric CS. The sheet cannot be a neutral one. Current generation is similar to action of a short closed MHD generator. The solar wind temperature is determined by plasma cooling because of plasma expansion and heat conduction from the Sun. In the process of expansion the solar wind is accelerated and achieves the supersonic velocity at a distance of about 3 solar radii. The CS is surrounded by a thick plasma sheet. Plasma velocity is decreased inside the sheet as demonstrated by previous workers.