Spatiotemporal optical emission spectroscopy to estimate electron density and temperature of plasmas in solution

In this article, we discuss the electron density and the temperature of plasmas in solution, which produce an attractive reaction field for processing. The measurement of the electron density and the estimation of the electron temperature of the plasma in NaCl solution were performed using spatiotemporally resolved optical emission spectroscopy. The electron densities were estimated to be of the order of 10⁶cm^-3 from the Stark broadening of the H _β line. The electron temperatures of the plasma were estimated to be in the range of 0.2-1.4 eV based on the electron-neutral bremsstrahlung. The estimated values were confirmed to be consistent with the experimental values of voltage and current density in the assumption of the Boltzmann equation.