Onset in magnetoplasmadynamic thrusters with finite-rate ionization

Quasi-one-dimensional self-field flow in a magnetoplasmadynamic thruster is analyzed, including the effect of nonequilibrium ionization. This theory, like the frozen flow theory, predicts the occurrence of the destructive "onset" phenomenon due to an excessive back Electromotive Force (EMF). Comparison between this theory and experiments on a straight coaxial thruster is given and is shown to be good within the limits of quasi-one-dim ensionality. The back-EMF onset mechanism is also shown here to be influenced by wall friction and heat transfer, and a choking condition incorporating these effects is derived. a a* A B B* Bt CD DH F h h* hc J J* k kb kf