Oscillations and analysis of stability for pinch systems

Abstract

Small oscillations of a dense, equilibrium plasma in a strong current channel aro considered in the approximation of two-fluid hydrodynamics of ideal charged liquids. It is shown that chute-type radial oscillations are the ones most likely to affect the system's stability. The instability induced by spontaneous excitation of these oscillations results in a spallation of the diffuse equilibrium state into separate densely compressed current channels. The present investigation of the oscillations near the stability threshold enables one to formulate the stability criterion for the pinch system. It is shown that Bennett-type equilibrium distributions rapidly become unstable with a rise in the current, while the equilibrium distributions for the plasma compressed up to the electron degeneration, are stable, by a considerable margin. The theoretical conclusions on the pinch decay into separate current channels are in agreement with the available experimental data.