THEORY OF LOW-VOLTAGE ARC IN NOBLE GAS

The most preferable ionization mechanism for low-voltage arc (LVA) is the step ionization by Maxwellian tail of electron distribution function. This mechanism provides low emitter voltage drop [MATH] (E1 is the excitation energy of the lowest metastable level). The mechanism of noble gas ionization mas analyzed in /1/. The theoretical analysis included step and associative ionization and the reverse processes of three particle and dissociative recombination. The conversion of atomic ions into molecular ones and molecular ion dissociation were also taken into account. It was shown that LVA plasma must consist mainly of atomic ions. The small concentration of molecular ions may be calculated from the condition of ionization equlibrium. that established because of large value of dissociative recombination coefficient. The conversion of atomic ions into molecular ions, that is essential at large pL value ( p is a pressure, L is a gap), may strongly diminish the concentration of atomic ions and consequently the whole plasma concentration

THEORY OF HOLLOW CATHODE IN ATMOSPHERIC ARC IN NOBLE GAS

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