Transient-mode multipactor discharge

Summary form only given. Multipactor discharge is a resonant condition in which electrons impact material surfaces in phase with an alternating rf or microwave electric field. A growing and/or sustained discharge requires the electrode secondary electron coefficient, delta(E_e), to be greater than unity at the impacting electron energy (E_e). E₁, the minimum energy for delta > 1, is highly dependent on electrode surface preparation and conditioning, and contaminated surfaces will generally experience a lower E₁ than the same clean or "conditioned" surface. A transient or pulsed mode of multipactor discharge can exist when the rf voltage and the corresponding electron energy distribution occur near E₁. Initially, a discharge may form if sufficient number of electrons have impact energies greater than E₁. Yet, as surface contaminants are removed with subsequent electron impacts, E₁ can quickly increase, causing the electron impact energy to become insufficient for discharge-sustaining secondary emission. As a result, the discharge extinguishes until surface contaminants return. This new TMM discharge has been shown to occur indefinitely for a constant contamination source at a range of rf voltages. Both TMM frequency and intensity have been shown to depend on the contamination rate and the rf voltage relative to E₁, and experimental TMM results are shown for copper and aluminum. Experimental results are presented along with supporting Monte Carlo electron-tracking simulation results.