Time-dependent physics of a single-surface multipactor discharge

The time-dependent physics of the single-surface multipactor is investigated by using both particle-in-cell (PIC) and Monte Carlo (MC) simulations. An oscillation of the normal surface field and number of electrons at twice the rf was observed in the PIC code. The temporal relationship between the fields normal and parallel to the surface traces a closed curve in the ac saturation state. The shape of the curve depends on the amplitude of the rf electric field normalized to the rf (normalized electric field). In comparison with the PIC simulation result, the oscillation in the MC simulation appears only when the normalized electric field is so large that the time step of the MC simulation is smaller than the rf period.