Effect of continuous current during pauses between successive strokes on the decay of the lightning channel

A one-dimensional model is used to study the dynamics of the hydrodynamic parameters of the lightning channel in the return stroke and after the pulse current is damped. The effect of the continuous residual electric current during pauses between the successive strokes on the plasma cooling in the channel is analyzed. It is shown that a continuous electric current, which is several orders of magnitude lower than the peak current in the return stroke, is capable of maintaining the channel conductivity. This effect cannot be explained merely by Joule heating but is largely governed by the fact that the turbulent heat transport is substantially suppressed. In this case, even a continuous current as low as 50-100 A is capable of maintaining the conductivity of the lightning channel at a level at which only M-components can develop in the channel rather than the dart leader of the subsequent stroke.