Characteristics of micro-discharge process in saline solution with pin-to-pin electrodes driven by a low-voltage high-frequency AC power supply

Low-temperature plasma ablation has been clinically used in minimally invasive surgeries. However, there is still a lack of research on its discharge process and ablation mechanism. This paper investigates the bubble generation process and micro-discharge phenomena of pin-to-pin surgical electrodes in NaCl solution driven by a high-frequency AC power supply at a level of (100-150) V. Microbubbles will occur around electrodes and merge to form a vapor layer that can completely cover the electrodes. Then, micro-discharges in the form of microspark would occur around the grounded electrode. The effects of geometrical and electrical parameters on the generation of vapor layers and micro-discharges are analyzed by the statistical results. It is found that the conductivity of the solution has an important influence on the generation probability and stability of vapor layers together with the occurrence position of micro-discharges. The simulation results of the discharge process and the experimental results match well with each other, and they demonstrate jointly that the discharge process is mainly influenced by the electrolytic effect.