The discharge mode transition of vacuum ARC induced by a trigger resistance

Summary form only given. Vacuum arc ion sources are widely applied in many areas, such as accelerator injection, ion implantation, and heavy ion fusion. Generally vacuum arcs are ignited by external pulsed triggering sources or lasers, but those means inevitably increase the complexity of whole system. In this paper, a simpler power supply method of triggering a vacuum arc is introduced. By this method, external triggering devices are replaced by a resistance connecting between trigger electrode and anode. The triggering effect of this method is compared with that uses an independent pulsed generator, and the influences of resistance value on rise-time and jitter are investigated. A smooth transition of discharge mode from surface flashover to non-surface vacuum breakdown can be carried out by adjusting the resistance value. The ion current and the spatial distribution of ion current are diagnosed by a collecting plane and an electrostatic probe during the transition of discharge mode. Experiments show that this trigger method is reliable for a vacuum arc discharge on microsecond scale. With the mode transition from surface flashover to non-surface vacuum breakdown, the ion current increases gradually, reaching two times at least. A possible growth mechanism of ion current is discussed in detail.Through the embedment of trigger resistance, a compact vacuum arc ion source can be designed. For some areas that require miniaturizing the whole vacuum arc system, the resistance triggering is a good choice.