Influence of magnetic Reynolds number on power generated by an ideal MHD device

The present note is concerned with the derivation of a simple expression for the power of an ideal, one-dimensional MHD generator which is not restricted by the usual assumption of a very small magnetic Reynolds number. The expression applies to pulsed MHD generators and possibly other devices. It is found that, as the magnetic Reynolds number increases, the power to the load approaches an asymptotic limit. The derivation of the considered equation by means of different approaches is considered, taking into account the magnetic pressure acting on the plasma in a region of the magnetic field B0 and the energy contained in a magnetic field per unit volume. (G.R.)