Relaxation of 2D MHD flow transverse to a magnetic field in a bounded domain

MHD plasma flow transverse to a magnetic field in a bounded domain, initially set in a form of a sole vortex, is solved numerically. This problem is of interest for dynamic magnetized plasma systems such as the MAGO/MTF system. For plasma subsequent compression issues in those systems, it is important to know how long the hydrodynamic motion persists in them. This can affect convective plasma cooling and result in impurities entering into the plasma due to wall washing by this flow. A case of large Reynolds numbers (and large magnetic Reynolds) and small Alfven-Mach number MA is considered, i.e. it is assumed that the initial relaxation due to magnetosonic shock waves has already occurred. In this case the MM problem reduces to a problem of 2D hydrodynamic turbulence. Calculations showed that, as it should be for 2D turbulence and in contrast to the case of the 3D turbulence, kinetic energy dissipation proceeds very slowly at small M/sub A/, for times /spl sim/L/sup 2//v (L is the characteristic system size, v is kinematic viscosity). When MA is not small, the kinetic energy dissipation is caused by emission of magnetosonic waves and their subsequent nonlinear (shock-wave) damping.