Applied-field magnetoplasmadynamic thrusters, part 2: Analytic expressionsfor thrust and voltage

The new visualization of applied-field magnetoplasmadynamic thruster operat ion offered by numerical simulations with the MACH2 code is used to develop an analytic model. This model provides simple expressions for the thrust a nd voltage drop across the plasma that capture all of the trends and in mos t cases the magnitudes of a wide range of experimental data including tests at multiple laboratories on three propellants: argon, hydrogen, and lithiu m. It establishes that the thrust scales as the square root of the product of the applied-field strength, discharge current, and mass-flow rate. Volta ge scales linearly with applied-field strength and is independent of discha rge current and mass-flow rate. This model also provides additional insight s that can be used to improve applied-field magnetoplasmadynamic thruster p erformance.