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.

Ion acceleration up to energy keV in a low-inductive vacuum discharge was investigated experimentally in detail. It was shown that the acceleration started at a distance about - 3 mm from the cathode and continued all the way to the anode. Negative potential `bursts' moving together with the plasma jet front were discovered. They apparently trapped ions and accelerated them to the observed high energies. A mechanism for the generation of the `bursts' and the plasma acceleration due to the jet constriction is proposed.

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Results of the time-of-flight measurements of the cathode plasma jet velocity in a low voltage vacuum spark are presented. It is found that the mean velocity of ions in the plasma jet varies over a wide range of values. When the discharge current increases from 0.6 to 11 kA the ion velocity at a distance of 35 cm from the copper cathode goes up to 7 × 10 4 m s −1 , i.e. exceeds nearly six times the corresponding value of 1.3 × 10 4 m s −1 for the dc arc. The intensity of the ion beam in this case increases by more than two orders of magnitude.

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