Relaxation oscillations as a tool for determining breakdown voltage in DC discharges at low pressures

Abstract This paper aims to address the challenge of determining the breakdown voltage in DC discharges across a broad range of pressures and operating parameters, including cases where discharge properties exhibit oscillatory behavior. At higher pressures or lower values of the reduced electric field ( E/N , where E is the electric field and N is the gas density), discharges tend to become unstable. This instability renders standard procedures for establishing the breakdown voltage ineffective. Preventing or damping the oscillations by adjusting circuit elements to obtain reliable measurements under stable voltage–current conditions can be challenging. This is especially true when suitable choices of components are not available across all pressure ranges. To overcome this limitation, a novel technique based on the analysis of the relaxation oscillations has been developed. Focusing on the part of the period at the lowest discharge currents, which corresponds to the conditions just above the breakdown, this method enables accurate identification of the breakdown voltage and significantly expands the operational measurement range, even when voltage and current are in oscillations. Thus, it becomes possible to determine transport and breakdown data in a broader range of conditions.