Temporal evolution of multipactor discharge

Multipactor is an important resonant discharge phenomenon on which there have been surprisingly few publications in the open literature. Here, we extend the theoretical analysis of an idealized model. Emphases have been placed on the mutual interactions between the multipactor discharge and the RF. We show that the multipactor current may reach a very high level, transiently, before it settles to a steady state. The multipactor current saturates primarily by its loading of the cavity; the image space charge force associated with the multipactor electrons plays a relatively minor role. When saturation occurs, the secondary emission coefficient is unity, corresponding to the “first cross-over point” in the secondary electron yield curve. The parameters attained in the steady state agree with the predicted values from an analytic theory. The analysis is extended to include the effects of an external magnetic field