Exploring the argon breakdown with symmetric and asymmetric electrode configurations in DC discharge: Validation of Paschen's Law

Paschen’s law relates the breakdown voltage (V_B) of a gas to the product of background gas pressure (p) and inter-electrode distance (d), predicting a characteristic minimum voltage at a specific pd value. This law was derived for the uniform electric field between the high and low voltage electrodes. As per Paschen’s law, the breakdown voltage should remain the same for a given value of pd. With this objective, sets of experiments are performed to explore the role of symmetric and asymmetric electrode configurations and inter-electrode distance on Paschen’s breakdown law. The experimental results revealed that the breakdown voltage and minimum value of pd strongly depend on electrode geometries (symmetric or asymmetric electrodes) and inter-electrode distances. The experimentally observed pd curves are fitted with standard Paschen’s law to verify the validity of this standard law in a non-uniform E-field. A modified empirical relation for V_B is proposed, incorporating variable power-law dependencies and fitting parameters to better capture the observed behaviour. This work thus provides a more accurate framework for predicting argon gas breakdown in discharge devices and highlights the need for further refinement of breakdown models in real-world applications.