Conditions of Runaway Electrons Effective Generation at a Discharge in Dense Gas

Summary form only given. In the report the experimental research results for the high-voltage discharge in air are presented on which basis the physical model of a discharge effectively generating runaway electrons in dense gas is constructed. The specified model assumes that a "spatial area" of electron transition to the runaway mode is originally formed near to a high-voltage electrode for the account and under condition of its electric potential increase rate excess in relation to the ionization wave velocity transferred the potential from this electrode into a gas expanding this "spatial area" and lowering electric field intensity down to under critical value for running away. It leads to ending runaway electrons primary beam formation. This primary beam created during the shares of a nanosecond the area of not compensated volumetric positive charge in gas. This charge area, in turn, represents itself as a high-voltage electrode in relation to an earthed electrode or an electrode with the floating potential, causing the generation near to it (them) of a secondary (counter) beam of runaway electrons what compensated an available volumetric positive charge. The secondary beam of fast electrons, instead of short circuit of inter-electrode interval by slow electrons as believe other models, leads to often observed subnanosecond duration of current pulses behind the anode and can give almost zero amplitude of the fast electron current behind the anode at presence of the lot of fast electrons in an inter-electrode interval. It is shown, that such model explains in the consistent image the available experimental results of different authors. Conditions for effective generation of fast electrons in dense gas are expressed as the formula suitable both for multi-electrode, and for one-electrode discharges