DocumentCode :
1215964
Title :
Macroparticle Dynamics during Multi-Cathode-Spot Vacuum Arcs
Author :
Shalev, S. ; Boxman, Raymond L. ; Goldsmith, S.
Volume :
14
Issue :
1
fYear :
1986
Firstpage :
59
Lastpage :
62
Abstract :
Macroparticle dynamics in multi-cathode-spot (MCS) vacuum arcs were studied by utilizing laser Doppler anemometry (LDA) methods for in situ measurement of the cathodic macroparticle velocities and relative emission rates. Arc current pulses having peak values of 1-2 kA at either 6 or 1 ms after arc initiation were investigated. Systematic dependence of the macroparticle dynamics (i.e., speed and direction of flight) on cathodic thermophysical properties, location of the measurement probe in the interelectrode region, instantaneous value of the arc current, arc current waveform, and macroparticle size was determined. It was found that the macroparticle velocity increased with the melting temperature of the cathode metal, distance from the cathode surface, and the instantaneous value of the arc current, and decreased with macroparticle size and the rise time of the current waveform. All the above dependencies may be understood as direct indications of the plasma-macroparticle interaction during the discharge. The measured instantaneous relative emission rates were found to peak later than the arc current but before the peak average cathode surface temperature, which was estimated using a semi-empirical model. This result may be an indication of the dependence of cathodic erosion in the form of molten metal droplets on the average cathode surface temperature.
Keywords :
Cathodes; Current measurement; Linear discriminant analysis; Plasma measurements; Plasma temperature; Probes; Size measurement; Surface discharges; Vacuum arcs; Velocity measurement;
fLanguage :
English
Journal_Title :
Plasma Science, IEEE Transactions on
Publisher :
ieee
ISSN :
0093-3813
Type :
jour
DOI :
10.1109/TPS.1986.4316498
Filename :
4316498
Link To Document :
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