Ac Electrical Breakdown of Neon with External Electrodes

Abstract

Results are presented of an experimental and theoretical investigation of ac electrical breakdown of neon in glass cells with external electrodes. The calculations are based upon a Townsend avalanche model that takes into account the effect of both the space charge and the surface charge on the glass walls that separate the electrodes from the gas. The experimental and theoretical results give a discharge current pulse in each half-cycle of the applied sine wave that are in agreement. Profiles are calculated of the electric field-to-pressure ratio as a function of position in the discharge gap with time as a parameter. These profiles exhibit a linear dependence on distance from the cathode wall as the discharge current reaches its peak, a behavior similar to that which occurs in the cathode-fall region of dc glow discharges. The calculated propagating luminous fronts associated with the electric field buildup in the cathode region also compare well with experiment. Under the present set of operating conditions, the Townsend avalanche model including space-charge effects adequately accounts for the discharge mechanism. These results are also shown to account for the behavior of the ac plasma display panel.