NONEQUILIBRIUM MHD CHANNEL THEORY AND NUMERICAL-SIMULATION

The internal plasma processes and performance parameters of a non-equi librium MHD channel are presented and analyzed. The one-dimensional mo del assumes uniform properties over the channel cross-sectional area a nd allows for variations of gas velocity, pressure, temperature, densi ty, electric field, current density, electrical conductivity and elect ron temperature in the direction of the flow. The plasma composition i s determined by particle balance equations which include collisional, radiative, diffusion and flow processes. The model provides a comprehe nsive description of the plasma processes, since it accounts for two-s tep ionization with the formation of excited state atoms, includes the particle convection and turbulent diffusion processes in both particl e and electron energy balance equations and allows for radiative and t hermal non-equilibrium. The electron energy balance equation is used f or calculation of the electron temperature and its variation inside th e channel and includes the energy input due to the applied electromagn etic field, balanced by the energy losses due to convection and elasti c and inelastic collisions of the electrons with neutrals and excited state atoms in the plasma. The set of equations pertinent to the const ant Mach number and cross-sectional area are also presented, and a sam ple calculation is performed for the segmented electrode generator ope rating in the Faraday mode with a gaseous mixture of helium seeded wit h a few percent cesium.