Spontaneous oscillations in a Hall thruster

Low frequency oscillations in a stationary plasma thruster (SPT) have been studied using optical diagnostics and numerical models. The regime of low frequency, large amplitude current oscillations has been especially investigated. The current oscillations are associated with strong oscillations of the light emitted by the plasma in that region. A quasi-neutral hybrid model of the plasma can reproduce these plasma oscillations and suggests that they are due to an ionization instability in the exhaust region associated with the depletion of neutral atoms by electron impact ionization.