Penning discharge breakdown curves

Particularities of Penning discharge breakdown curves are discovered and explained. The Penning discharge loss mechanism of fast electrons emitted by electrodes-reflector and oscillating in the cell is established. This mechanism consists of the nonmonotonic dependence of electron trapping in the Penning cell on magnetic field and anode voltage. It determines the particularities of discharge breakdown curves under low pressures p=10^-3-10^-1 Pa when the electron free-motion-path significantly exceeds the cell sizes. The nonmonotonicity of electron losses is demonstrated, in particular, by the existence of anode voltages V_A1, V_A2, V_A3 , ordered as V_A1<V_A2<V_A3, when the discharge ignites under V_A1 and V_A3 but the breakdown does not occur under V_A2