Measurement of plasma parameters for copper using excimer laser-induced breakdown spectroscopy

Abstract

Laser-assisted spark switches are promising devices for generating fast and controllable electrical discharges in high-voltage systems. In this study, the characteristics of plasma generated by an excimer laser in a spark gap were investigated using optical emission spectroscopy and electrical diagnostics. Copper emission lines were analyzed using the Boltzmann plot method to determine the plasma temperature. The electron temperature was estimated to be approximately 25 167 K (≈2.17 eV). The spectroscopic analysis also included oxygen emission lines, with the O,I line near 480 nm exhibiting a typical full width at half-maximum of approximately 0.1 nm under the plasma conditions generated by the excimer laser. The breakdown behavior of the spark gap was analyzed using Paschen’s law. For an electrode gap of 3 mm at atmospheric pressure, the calculated breakdown voltage was approximately 8.7 kV, which is in good agreement with the experimental observations. Electrical measurements showed that laser irradiation significantly influenced the discharge dynamics by reducing the delay time and stabilizing the breakdown process. Plasma conductivity was evaluated using both macroscopic and microscopic approaches. The calculated macroscopic conductivity was 2059.37 S/m, whereas the microscopic conductivity derived from the plasma parameters was 2065.21 S/m. The close agreement between these values confirms the consistency of the theoretical models and the reliability of the experimentally determined plasma parameters. Overall, the results demonstrate that excimer laser irradiation effectively initiates and controls spark discharges while producing plasma conditions suitable for spectroscopic diagnostics.