Simulink-Based Analysis of Time-Varying Spark Resistance Characteristics in Underdamped Discharge Circuits

Spark discharge is a critical phenomenon in electrostatic discharge (ESD) and pulsed power applications. The time-varying characteristics of spark resistance significantly impact voltage rise time and energy transfer efficiency. However, accurately measuring spark resistance in underdamped discharge circuits is challenged by current oscillations. To address this, this article proposes a Simulink-based method for reconstructing experimentally measured spark currents to calculate spark resistance. An improved computational model is established by incorporating a spark resistance recovery function term into the Rompe–Weizel (R–W) resistance formula. The model’s accuracy is validated through spark discharge experiments with a 2-mm electrode gap. Furthermore, the influence of discharge voltage and gap length on the temporal evolution of spark resistance is analyzed. Results demonstrate that spark resistance rapidly decreases from a high-impedance state (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 10^{5}~\Omega $ </tex-math></inline-formula>) to a low-impedance state (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lt 1~\Omega $ </tex-math></inline-formula>) within tens of nanoseconds after discharge initiation, followed by a gradual recovery until the gap regains its insulating properties. Quantitative analysis reveals spark resistance is inversely proportional to the discharge voltage and directly proportional to the electrode gap distance.