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

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 $\mu$s. 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.