Effect of limiting the cathode surface on direct current microhollow cathode discharge in helium
Résumé
This paper describes how to light several microdischarges in parallel without having to individually ballast each one. The V-I curve of a microhollow cathode discharge is characterized by a constant voltage in the normal glow regime because the plasma is able to spread over the cathode surface area to provide the additional secondary electrons needed. If one limits the cathode surface area, the V-I characteristic can be forced into an abnormal glow regime in which the operating voltage must increase with the current. It is then possible to light several microdischarges mounted in parallel without ballasting them individually. Microdischarges are nonequilibrium discharges spatially confined to dimensions smaller than 1 mm. They are a promising approach to the generation and maintenance of stable dc glow discharges at atmospheric pressure and they present interesting challenges for plasma science ͑impact of quantum electrodynamics on spontaneous emission rate and quasineu-trality breaking͒. 1 Parallel microplasmas can be created using several kinds of microdevices. 2 Some teams use ballasts to individually initiate the plasma in each microcavity independently. 3,4
Domaines
Physique [physics]Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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