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Negative Corona Current Pulses in SF 6 – Air Mixtures
Author(s) -
Kúdelčík J.,
Zahoranová A.,
Choma K.,
Černák M.
Publication year - 2002
Publication title -
contributions to plasma physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.531
H-Index - 47
eISSN - 1521-3986
pISSN - 0863-1042
DOI - 10.1002/1521-3986(200208)42:5<546::aid-ctpp546>3.0.co;2-3
Subject(s) - cathode , materials science , corona discharge , corona (planetary geology) , ionization , atomic physics , current (fluid) , atmospheric pressure , waveform , graphite , electron , analytical chemistry (journal) , ion , electrode , voltage , chemistry , physics , meteorology , composite material , thermodynamics , nuclear physics , organic chemistry , quantum mechanics , chromatography , astrobiology , venus
Abstract Current waveforms of first negative corona pulses have been measured in dry air + SF 6 mixtures at a pressure of 50 kPa and various overvoltages. Effects of changing cathode secondary electron emission were studied using a copper cathode coated by CuI and graphite. It is concluded that in the mixtures containing less than 10 % of SF 6 the negative corona pulse is associated with the formation of a cathode‐directed streamer in the immediate vicinity of the cathode. In the mixtures containing more than 20 % of SF 6 the streamer is quenched and, consequently, the discharge is governed by the Townsend ionisation mechanism fed by cathode photoemission processes.