Measurement of time dependence of energy and mass-charge composition of ion flux in short vacuum arc with nanosecond resolution

Abstract

The temporal character of ion flux of a vacuum arc generation in nanosecond range was investigated by means of a multi-channel energy-mass analyser. The results obtained are the waveforms of arc current, discharge voltage and ion flux for few ion fractions with defined energy-to-charge ratios and several mass-to-charge ratios. The results show that the ion flux is constituted by 10–30 ns elementary bursts. These elementary bursts have durations that coincide in common to cathode spot life time estimations. The ion bursts combinations form both subsequent bursts groups and 100–150 ns super-bursts. The occurrence of the super-bursts usually precedes non-stabilities in the arc current and the attempts of the discharge to extinct. Amplitude Fourier spectrum dependence is close to Brownian random process dependence. The Fourier spectra of ion flux contain several local maxima corresponding to supposed cathode spot cycle period.