Publication de 4 numéros par an
ISSN Imprimer: 1093-3611
ISSN En ligne: 1940-4360
Indexed in
LARGE AMPLITUDE OSCILLATIONS IN ELECTRIC ARCS SUSTAINED ON HETEROGENEOUS ELECTRODES IN GASEOUS ATMOSPHERE
RÉSUMÉ
In an electric arc, which is free burning in a gaseous atmosphere between electrical contact pieces, or during etching by arcing of oxidised metal surfaces, one can observe large amplitude voltage oscillations. These oscillations should be distinguished from the ordinary voltage noise observed in most of electric arcs. They are related on the nature of the cathode material, notably on the presence on the surface of particles or layers of insulating or low conduction material, such as oxides or nitrides. The light intensity emitted by the arc is time related with the arc voltage oscillations. Interpretation of the origin of these oscillations involves temperature variations on the cathode surface and in the plasma column, and fluctuations of the concentration of the metal vapour content in the plasma.