The influence of metastable molecules on the streamer progression

Abstract

The measurement of the de-activation rate of the N2 vibrational metastables produced by a gas discharge in short gaps at atmospheric pressure indicates that their concentration remains significantly high for some hundreds of microseconds. The creation and destruction of the metastables in air at atmospheric pressure have been analyzed. The theoretical interpretation is consistent with the experimental results. The effect of a pre-existing metastable trail on the streamer propagation has been analyzed. It is suggested that the metastable molecules act as an energy reserve which is transferred to the electrons in superelastic collisions. The balance of the energy exchanges is analyzed in detail.