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.