Dynamic stabilization of the electrothermal instability

The possibility of stabilizing the electrothermal instability by applying an oscillation to the steady current in an MHD generator is examined. A linear, plane wave analysis shows that if the frequency of the oscillation is high enough, then the critical Hall parameter is always increased by the oscillation. However, if the oscillation frequency is much smaller than the growth rate calculated without dynamic stabilization, then the amplitude of a perturbation will move outside the linear range during a period. Therefore, the theory does not predict linear stabilization for low oscillation frequencies.