  The study of hot plasma expansion in a magnetic field is of interest for many
laboratory and astrophysical applications. In this paper, an exactly solvable
analytical model is proposed for an expanding resistive plasma in an external
magnetic field in the regime in which the magnetic field does not perturb the
plasma motion. The model is based on a class of exact solutions for the purely
radial expansion of the plasma in the absence of a magnetic field. This
approximation permits the reduction of the electromagnetic problem to
consideration of a diffusion equation for the magnetic field. Explicit
solutions are derived for a resistive cylindrical plasma expanding into a
uniform ambient magnetic field. Some numerical examples related to the
laser-produced plasma experiments are presented.
