JOULE HEATING OF A CURRENT LAYER DUE TO PLASMA-DENSITY INHOMOGENEITIES

In the present paper the magnetic field dynamics in the frame of elect ron magnetohydrodynamics (EMHD) theory is considered in the case of a current passing through a plasma of inhomogeneous density. It is shown : (1) due to the Hall effect the Joule heating of a current layer incr eases up to (omega tau)(ei) times the Joule heating of ordinary homoge neous plasma. (2) The EMHD magnetic field dynamics can be considered a s an enhanced magnetic field diffusion in the frame of MHD theory, usi ng ''efficient'' coefficients of plasma conductivity and of magnetic f ield diffusion. The ''efficient'' coefficient of the magnetic field di ffusion cT/10eH in the case of magnetic field-plasma equilibrium is th e same order of magnitude as the Bohm's coefficient cT/16eH. (C) 1996 American Institute of Physics.