Saturation of a One-Sided Multipactor in Crossed Fields

We analyze the saturation mechanism of a vacuum resonance microwave discharge (multipactor) for systems in which a magnetostatic field returns electrons to the metal surface with secondary-emission multiplying. The steady-state model suggested earlier is improved essentially. In particular, we take into account the near-surface interaction of saturated electron bunches during the limited time of discharge-electron-surface impact. It is found that the Coulomb defocusing of electron bunches prevails over their microwave focusing (toward the resonance phase of the field), making it possible to extract superfluous secondary electrons when the electron bunches are reproduced on the discharge surface. Basic characteristics of the discharge, such as its existence conditions and proper fields and phase disposition of the resonance electron bunches, are determined as functions of the magnetostatic field and the secondary-emission coefficient. The results are discussed in comparison with the data of known experiments. An explanation of some differences related to both the observation conditions and the used analytical model is given.