MATHEMATICAL MODELING OF MHD-FLOWS IN CHANNELS WITH A LONGITUDINAL MAGNETIC FIELD
A numerical model of MHD acceleration in coaxial channels (nozzles) with the longitudinal magnetic field is presented. The properties of the flow depend mainly on the ratio of the plasma velocity and the Alfven one, corresponding to the longitudinal magnetic field. The longitudinal field helps to overcome current crises in super-Alfven flows near the electrodes. Increase of the longitudinal field causes another type of flows, sub-Alfven, with widely different properties and acceleration parameters. Special attention is given to combined flows which consolidate super- and sub-Alfven flows.