Investigation of multipactor-induced surface plasma discharge and temporal mode transition

Abstract

Multipactor over a dielectric in vacuum inclines to engender interfacial gas desorption or evaporation, precipitating surface flashover and insulator failure. However, no consensus has been achieved regarding the exact mechanism during final breakdown stage, an expatiation of which therefore serves as our major motivation for this letter. By implementing the particle-in-cell simulation code, we investigate the microscopic evolution of the discharge development process and confirm the major component escalating the explosive space charge accumulation. The obtained current waveform validates the balance of charged particles between electrodes, corroborated by experimental results. A theoretical discharge model is then constructed to elucidate the physical reasoning of the previous phenomenon. Two distinct discharge modes are defined correspondingly, and the transition therein is found to be induced by rapid plasma density build-up.

Modelling vacuum flashover mitigation with complex surface microstructure: mechanism and application

“…In our simulation, it is found that the optimal size is 100 μm long and 20 μm wide. This result fits (33).…”

“…Previous researchers have studied the flashover mechanism by the simulation as well as the theoretical work, here brief summaries of flashover stages and theoretical progresses are provided [8, 17, 33, 34]. A flashover process can be divided into three stages.…”

“…The simulation shows that the strong ionisation takes place first near the anode, leads to the dynamic charging behaviour and forms the initial source of the plasma [7]. Ions are then accelerated by the external field and collide on the cathode with intense energy, which causes SE emission (SEE) and the metal sputtering [33].…”

“…In the end, during the final discharge stage, the gas is further ionised and the ionisation becomes the dominant electron source. Also, a phenomenon is observed from the simulation that during the final breakdown, a cloud of metal ions and atoms from the cathode appears near the cathode [33]. These ions, in turn, collide on the cathode, regenerative feedback is formed and contributes to the discharge process.…”

On the role of secondary electron emission in capacitively coupled radio‐frequency plasma sheath: A theoretical ground

“…Secondary electron emission (SEE) on solid surface induced by either electron or ion is ubiquitous in many plasma apparatuses like Hall thruster, Langmuir probe and dielectric barrier discharge, etc. [17][18][19][20] In terms of CCP discharge between two metallic electrodes, ion-induced SEE is more predominant and extensive amount of experimental and simulation works have been conducted to illustrate its influences. Early work of Misium et al involved SEE in their rf discharge model using fluid theory with constant secondary electron (SE) velocity.…”