Laser mechanism for streamer propagation

Experimentally observed streamer evolution is shown to be governed by stimulated photoionizing radiation emitted from the plasma of an avalanche as a result of impact-radiative recombination. Absorption of the radiation in the gas near the avalanche plasma leads to ionization of the gas and to the appearance of secondary electron avalanches. The process is repeated periodically until the streamer spans the discharge gap. This mechanism is called the laser mechanism due to the directed stimulated emission which contributes to the streamer evolution.