VOLT-AMPERE CHARACTERISTICS OF LOW CURRENT DC DISCHARGES IN AR, H-2, CH4 AND SF6

In this paper we show new results for a wide range of characteristics of low current diffuse (Townsend-dark discharge regime) discharges in Ar, H-2, CH4, SF6. The measured observables include: volt-ampere chara cteristics, ranges of free running oscillations, frequency and damping of induced oscillations and we also determine the negative differenti al resistance (the negative differential voltage to current ratio). Th e measurements were performed for pressures between 0.027 and 1 Torr a nd for distances between electrodes in the range from 1 to 3 cm.