Strong-current arc discharges of alternating current

The review of experimental results of strong current (I=10-10/sup 4/ A) quasi-stationary ac discharges in high pressure (P/spl ges/10/sup 5/ Pa) gases is presented. Structure and properties of alternating current arc in vortex, turbulent flows of air, argon, nitrogen, and hydrogen were investigated. The existence of two arc discharge column regimes, contracted and diffusion, has been established. The processes of heat exchange between the arc and surrounding gas for these regimes were studied. Processes in the discharge volume, mechanisms of charge transition in the electrodes neighbor zone, and electrodes' erosion in the spot and without-spot regimes were investigated in dependence of current quantity, gas pressure, and electrode material. Water-cooled copper electrodes were used as well as high-melting ones (tungsten, molybdenum, and other). Prototypes of powerful (N=10-10/sup 3/ kW) ac plasma generators, intended for usage in different plasma-chemical technologies including toxic wastes destruction and treatment, were designed, developed, and manufactured on the basis of these investigations.