放电间隙导通过程中电流通道头部的加速效应（英文）

On Acceleration of Current Channels Heads at Discharge Gaps Bridging

This paper is devoted to explanation of a phenomenon of current channels heads acceleration which bridges a discharge gap.This phenomenon was discovered experimentally during some works at investigating nanosecond streamer gas discharges of atmospheric pressure in the air and neon.Consideration of the bridging process of the discharge gap is presented in the framework of a model of microstructured current channel.In this case,the channel represents itself as a bunch of microchannels(up to 1 000 and more).Such consideration could be stipulated by the discovered earlier phenomenon of the current channels microstructuring that are realized in the nanosecond discharges of atmospheric pressure.The authors have developed the electro-technical model of the discharge gap bridging by the conducting channel.It is shown that the channel length dependence of the velocity is linear;this is similar to that of the model of the continuous(unstructured)channel.We considered and made estimations that stipulate a possibility of gas heating in the microchannels up to the temperatures of associative ionization beginning in the discharge gap bridging phase.In this case,increase of the charged particles concentration and,consequently,decrease of its resistance cause the head acceleration.It is shown that in case of the continuous channel it is impossible to realize the gas heating up to the temperatures of the associative ionization in these conditions.Obtained results reveal the physical reason of the current channels microstructuring as a consequence of the principle of least action manifestation in the area electric breakdown phenomena of the gases.