Pinch Effect Oscillations in a High Current Toroidal Ring Discharge

Abstract

A toroidal ring discharge with currents greater than 104 amperes has been studied with a rotating mirror camera. The photographs show a lateral oscillation of the discharge, which consists of an alternate contraction and expansion of the current filament. The frequency of the oscillations increases with decrease in pressure or increase in voltage and is inversely proportional to the square root of the atomic weight of the gas. The oscillations are thought to be due to plasma ion waves, which are excited by the large `pinch' effect forces.