Numerical Study on Discharge Current Path and Performance of a Magnetoplasmadynamic Thruster

Abstract

The discharge current path and performance of a steady-state, self-field magnetoplasmadynamic (MPD) thruster using argon propellant have been examined under the assumption of temperature distributions on the cathode by axisymmetry two-dimensional magnetohydrodynamic (MHD) flow simulation with electrode sheath model as the boundary condition. The discharge current path in the thruster is affected not only by the Hall effect but also by the distribution of thermionic emission from the cathode. When the cathode temperature is decreased from the tip to the root, the discharge current shifts to the cathode tip, which mitigates the current concentration toward the cathode root due to the Hall effect. Then, the thrust is increased as well as the input power, and the thrust efficiency is almost the same as that under the constant temperature distribution on the cathode.