MULTIPACTOR ELECTRON DISCHARGE PHYSICS USING AN IMPROVED SECONDARY-EMISSION MODEL

This study details particle-in-cell simulations of the multipactor eff ect and discharges created using this effect. A detailed secondary emi ssion model which accounts for the energy and impact angle dependence of yield is developed to simulate accurately the phenomenon. It is sho wn that a steady state multipactor can be built up from a very low den sity initial electron distribution and an oscillatory steady state can be achieved. Steady state is reached when the cavity detuning and spa ce 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 ene rgy spread of secondary electrons differs from the monoenergetic analy tical model, the weighted average energy is the same. Resistive loadin g of the circuit due to multipacting electrons is presented. The behav ior of the system with Q values of between 20 and 200 is discussed. (C ) 1998 American Institute of Physics.