Discontinuous plasma flows in magnetohydrodynamics and in the physics of magnetic reconnection
B.V. Somov Lomonosov Moscow State University, Shternberg State Astronomical Institute, Universitetskii prosp. 13, Moscow, 119889, Russian Federation
This paper reviews the current status of the theory of discontinuous magnetohydrodynamic (MHD) flows and its application to the physics of magnetic reconnection in astrophysical plasmas and in laboratory and numerical simulation studies. The emphasis is on the study of continuous transitions occurring between different types of discontinuities as the plasma flow parameters are gradually and continuously varied. The properties of the Syrovatskii reconnecting current layer are described and the possibility of the splitting of the current layer into a system of MHD discontinuities is demonstrated. A simplified analytical model of magnetic reconnection is used to examine the system of shock waves associated with the current layer. With this system as an example, some implications of the conditions of continuous transitions and the possibility of additional plasma heating by a shock wave are considered.