Study of High-Frequency AC Discharge Phenomena Based on a Tesla Coil System^*

This study is based on a Tesla coil discharge experimental platform, combined with high-speed imaging technology, to investigate the development process of AC discharge arcs. Through experiments with multiple groups of different gap lengths, the branching behavior, brightness characteristics, and current waveform changes of the AC arc discharge were analyzed. The results show that when arc branching occurs, the branches are denser near the high-voltage side, and the branches generally extend simultaneously until the main discharge path is formed, after which all branches disappear together. The brightness of the discharge arc exhibits a “double peak” characteristic, with the first peak corresponding to the formation of the main discharge path. Subsequently, the brightness undergoes a dimming and then brightening process, finally fading gradually after the second peak. The waveform of the grounding current can be divided into three phases: the sinusoidal spike phase, the peak phase, and the sinusoidal attenuation phase. The number of steps in the leader development of AC discharge corresponds to the number of peak drops in the current waveform. This study provides new methods and theoretical support for a deeper understanding of the microscopic process of AC high-voltage discharges.