Self-sustained volume discharge in mixtures of SF6 with hydrocarbons, hydrogen and deuterium for non-chain HF(DF) lasers

This paper reports on the comprehensive studies on a self-sustained volume discharge in SF6-based working media for electrochemical non-chain hydrogen fluoride (deuterium fluoride) lasers. The majority of the experimental results have first been obtained at various values of gas pressure for the discharge gaps with a large interelectrode distance, including plane electrode systems with a strong enhancement of the edge electric field. Some special features of the observed physical phenomena are explained using the developed adequate mathematical models. In particular, a radically new mechanism of the ionization instability in SF6-based mixtures at an intermediate pressure has been first considered and a relevant mathematical theory was developed. On this basis, the experimentally observable break-up of the discharge current into separate filaments in a laser-heated SF6-mixture was qualitatively explained. Some practical applications and recommendations have also been drawn from the performed studies.