Idealized model for plasma acceleration in an MHD channel

A quasi-one-dimensional plasma acceleration by a self-induced magnetic field was analyzed in the magnetohydrodynamic framework. The magnetic Reynolds number was a similar parameter to describe the fields of flow and discharge current. The discharge current was found to be concentrated not only at the exit but also the entrance of the channel. By suitable electrode geometry, the current concentration was relaxed and the thrust efficiency was enhanced compared with the straight geometry.