Ion-ion recombination in SF6 and in SF6-C2H6 mixtures for high values of E/N

Ion-ion recombination coefficients in a decaying SF6 plasma and in SF6-C2H6 mixtures are measured in the pressure range 15-90 Torr for reduced field s trengths 100-250 Td. The charge composition is analysed and dominating ion- ion recombination channels in such plasmas are determined. Relations for es timating the potential drop at the electrodes are obtained for decaying pla sma in strongly electronegative gases. The results of measurements are extr apolated for estimating the ion-ion recombination coefficient in SF6 for ne arly critical field strengths. It is concluded that the ion-ion recombinati on should be taken into account in calculations of the discharge characteri stics in non-chain reaction HF lasers.