On the temperature dependence of the critical reduced electric field in SF6 and mixtures of SF6 with C2H6

Abstract

This paper reports on the determination of the temperature dependence of the critical reduced electric fields (E/N)cr in SF6 and mixtures of SF6 with C2H6 at gas temperatures ranging from 293 to 1500 K. The (E/N)cr values are derived from the quasi-stationary burning voltages of a self-sustained volume discharge in these gases after their being irradiated by a pulse CO2 laser. The mechanism of a laser-induced heating of the mixtures treated, and evaluation of the gas temperatures established due to absorption of the laser energy, are described in detail. The temperature dependence of (E/N)cr established for SF6 is compared with those previously obtained in other studies. A topological approach based on Thom's catastrophe theory is involved to predict and qualitatively describe all possible structurally stable features, which can only be expected in the behaviour of (E/N)cr on changing the time of the thermal action on SF6 from vanishingly small values to infinitely large ones. On this basis, some inferences about the peculiarities of atomic fluorine generation on heating SF6 are drawn.