Comparison of Simulated Plasma Flow Field in a Two-Dimensional Magnetoplasmadynamic Thruster With Experimental Data

Comprehensive comparisons of the numerically simulated results of plasma flow fields in a 100-kW-class 2-D magnetoplasmadynamic thruster with the available experimental data are conducted. The propellant is argon of 1.25 g/s, and the discharge current is varied from 8 to 12 kA. The physical model includes a nonequilibrium single level of ionization and a collisional radiative model for argon ion to assess the reaction processes in detail. The data we mainly compared are the current path, electron number density, and electron temperature. There is qualitative agreement between the calculated and experimental results except for the electron temperature. In order to explain the disagreement of the electron temperature, we estimate the excitation temperature from the distributions of the excited ions in 4s and 4p states, the radiation of which was employed to determine the electron temperature in the experiment. As a result, it is found that the calculated excitation temperature becomes close to the measured result and that the plasma deviates from the partial local thermodynamic equilibrium near the anode surface. Regarding the thrust and thrust efficiency, their features against variation of the discharge current are well captured by the simulation, although they are slightly overestimated compared with the measured values.