2-D Extended Fluid Model of Applied-Field Magnetoplasmadynamic Thruster With Solid and Hollow Cathodes

In this paper, a 2-D model for simulation of an applied-field magnetoplasmadynamic (AF-MPD) thruster with solid and hollow cathodes was built using COMSOL Multiphysics. Extended fluid model was used for self-consistent simulation of discharge processes in the thruster. Ion energy balance equation was developed and added to extended fluid model. A viscously dominated steady-state fully formed gas flow was considered with argon gas used as a propellant. Electron transport properties as well as rates of electron-impact reactions were calculated using electron energy distribution function. Plasmachemical reactions taken into account included direct and stepwise ionization of argon atoms, excitation of metastable levels, three-body and radiation recombination, and so on. Coupling fluid equations with Poisson equation for electric potential allowed for self-consistent description of plasma and sheaths. Distribution of such discharge parameters as charged and excited particle densities and fluxes, charged particles´ mean energies and temperatures, and gas temperature and electric potential were obtained. Comparison of simulation results allowed for concluding that using hollow cathode in an AF-MPD thruster can contribute to power efficiency and lifetime of the device.