Multipactor electron discharge physics using an improved secondary emission model

This study details particle-in-cell simulations of the multipactor effect and discharges created using this effect. A detailed secondary emission model which accounts for the energy and impact angle dependence of yield is developed to simulate accurately the phenomenon. It is shown that a steady state multipactor can be built up from a very low density initial electron distribution and an oscillatory steady state can be achieved. Steady state is reached when the cavity detuning and space charge of the built-up beam balance the phase focusing. The results for a more accurate secondary electron distribution are compared with simpler analytic models and extended. It is shown that, while the energy spread of secondary electrons differs from the monoenergetic analytical model, the weighted average energy is the same. Resistive loading of the circuit due to multipacting electrons is presented. The behavior of the system with $Q$ values of between 20 and 200 is discussed.