Experimental study of argon gas breakdown with symmetric and asymmetric electrode configurations

Paschen’s law relates the breakdown voltage ( $V_B$ ) of a gas to the product of the gas pressure ( $p$ ) and the inter-electrode distance ( $d$ ), predicting a characteristic minimum breakdown voltage at a specific $pd$ value. In this study, the roles of electrode configurations (symmetric and asymmetric) and inter-electrode spacing on gas breakdown processes (or Paschen’s law) are examined. Numerous sets of experiments are performed with both symmetric and asymmetric electrode configurations of different sizes to obtain Paschen curves at different inter-electrode distances. The experimentally obtained Paschen’s curves for different electrode configurations are fitted using a proposed modified empirical relation for $V_B$ , incorporating variable power-law dependencies and fitting parameters to better capture the observed deviations. Upon closer inspection, we observed that the breakdown voltage ( $V_B$ ) and the corresponding $pd$ value ( $pd_{\min}$ ) are influenced by both electrode configurations and inter-electrode discharge gap. The variation in $V_B$ and $pd_{\min}$ for different electrode configurations is explained by analysing the electric field distributions between the electrodes (cathode and anode) for an applied voltage.