Flow of multiple charged accelerated metal ions from low-inductance vacuum spark

Abstract

Results of studies of the short-run beams of multiple charged fast ions that have been found earlier by the authors in a low voltage vacuum spark are presented. The ion emission was due to the formation of micropinches in the cathode plasma jet by the action of the self-magnetic field. A relation between the average velocity of the fast ions and that of the bulk of the ions of the cathode jet was obtained over a wide range of the discharge current amplitudes. The total yield of the multiple charged fast ions per pulse Nf was evaluated from the direct collector measurements with regard to a decrease in ion flow due to several reasons. This value was in satisfactory agreement with evaluation that was obtained from the ballistic pendulum measurements and gave Nf ≈ 5 × 1013–1014 ions per pulse at the average ion charge state of +9 at the maximum of the discharge current Id = 12 kA. Evaluation of current density for these ions gave jf ≈ 3 mA cm−2 at a distance of about 1 m from the anode.