Monte Carlo method for finding the ionization and secondary emission coefficients and I-V characteristic of a Townsend discharge in hydrogen

Secondary cathode emission coefficients for hydrogen are determined from experimental data on breakdown by calculating the number of ionization events in gaps using the Monte Carlo method. Other parameters being calculated are the ionization rate, Townsend ionization coefficients (with demonstration of their nonlocality), velocity of electron drift toward the anode, and probabilities of electron return to the cathode. The calculated and measured values are in reasonable agreement. Gaps with pd = 0.37-17.0 Torr cm are considered. It is shown that the observed negative differential resistance of the Townsend discharge can be related to a decrease in the probability of electron return to the cathode with increasing E/N only if the value of pd is near the minimum in the Paschen curve.