VORTEX COOLING OF THE AFTERSPARK CHANNEL IN A GAS .2. INCLUSION OF THE CASCADE MECHANISM OF DISSIPATION OF TURBULENCE

A simple theoretical model is proposed for cooling of the afterspark c hannel in a gas. This model takes into account the origination of turb ulence and its effect on cooling and expansion of the channel. Basic m echanisms of degeneration of turbulent pulsations are analyzed and tak en into account. It is shown that the cascade mechanism of dissipation (CMD) plays an essential role along with the noncascade mechanism, if vortex motion arising in the cooling channel is so vigorous that the fully developed spectrum of turbulent pulsations of different scales, resulting in rapid viscous dissipation of kinetic energy of turbulence in the short-wave range of the spectrum, has an opportunity to be for med during a time interval smaller than the characteristic time of coo ling [the restoration time of the dielectric strength (RDS)]. Taking i nto account the CMD allows one, in particular, to explain a decrease i n the RDS rate occurring well in advance of its completion. Such an ef fect was observed in experiments with intense spark discharges.