Applied-Field Magnetoplasmadynamic Thrusters, Part 1: Numerical Simulations Using the MACH2 Code

Abstract

Numericalmodeling of the NASALewis Research Center 100-kW, steady-state, applied-Ž eld magnetoplasmadynamic thruster is performed using the magnetohydrodynamicscodeMACH2 for a range of applied magnetic Ž eld strengths and discharge currents. Overall performance trends, obtained experimentally with argon propellant, are captured by the simulations. Magnitudes of plasma voltage vs applied Ž eld strength also agree well. Interrogation of the calculated  owŽ eld offers a new visualization of applied-Ž eld magnetoplasmadynamic thruster operation, comprising the following elements: 1) the back electromotive force is the dominant contributor to the plasma voltage for the geometry examined; 2) viscous forces oppose applied azimuthal electromagnetic forces and limit the maximum rotational speed to a constant independent of applied Ž eld or current value; 3) viscous heating and conversion of thermal energy to axial directed kinetic energy is the main acceleration mechanism; and 4) the low-density, low-conductivity argon plasma for the regime examined does not interact with the applied Ž eld in the manner of a magnetic nozzle.