Pin-Plane Electrical Discharge Driven by a MOSFET DC Current Source

The generation of atmospheric pressure nonequilibrium plasma using electrical discharges is an active area of research due to its significance in a wide spectrum of applications including medicine, combustion, and manufacturing. In our attempt to create a helium plasma jet in a pin-plane discharge with a constant current source, we observed self-pulsating behavior. We present the results of the electrical, optical, and spectroscopic measurements carried out to characterize the discharge. The duration of the discharge is a few tens of nanoseconds, and the repetition rate is in the few tens of kHz. The effect of the gap distance and gas flow is discussed. The effective capacitance formed by the space charge in the discharge region plays an important role in determining the pulsing frequency. The results of voltage swing, current pulse, and light emission are also discussed. Such self-pulsating discharges can be used to produce helium plasmas under ambient conditions in applications such as plasma medicine.