Effect of the discharge parameters on the generation of deuterium ions in the plasma of a high-current pulsed vacuum arc with a composite zirconium deuteride cathode

Abstract

We have studied the mass and charge composition of an ion beam extracted from the plasma of a vacuum arc with a zirconium deuteride cathode for various durations of the arc current pulse (half width at half amplitude) of 2, 4, 7, and 17 μs. It has been established that the fraction of deuterium ions in the vacuum arc plasma increases with the current and the dependence achieve saturation for current of about 1 kA. For the fraction of deuterium atoms in the cathode at a level of 40%, the fraction of deuterium ions in the vacuum arc plasma can exceed 80%. The experimental results have been interpreted theoretically. It has been shown that the main sources of deuterium ions in a microsecond arc discharge are cathode spots. We have developed a model of deuterium desorption during the operation of cathode spots for quantitatively estimating the concentration of deuterium ions in the arc plasma.