Analytical solutions of the equations of nonisentropic magnetogasdynamic flows in open-quotes smoothly varyingclose quotes channels

Time-independent axisymmetric magnetogasdynamic flows together with their azimuthal self-magnetic field are considered in channels which vary slowly as a function of axial distance. Analytical solutions for nonisentropic flows are obtained. The configurations of the critical (acoustic) surfaces are investigated. Expressions are found in particular cases for the acceleration, thrust enhancement, and power of the streams. Sufficient conditions are found for the absence of current vortices, and the magnitudes of the outflow currents are estimated. The example of flows in a weak magnetic field is used to show the relation between the electric current profile and the channel geometry. 16 refs., 3 figs