Measurement of Temporally and Spatially Resolved Electron Density in the Filament of a Pulsed Spark Discharge in Water

The temporally and spatially resolved optical emission spectrum of Hα of a pulsed spark discharge in water was experimentally measured. The temporally and spatially resolved electron densities, along the radial direction of the spark filament, for a pulsed spark discharge in water with a conductivity of 100 µS/cm were investigated. The electron density in the spark filament was found to be in the 10¹⁸/cm³ order of magnitude. The highest electron density was measured at the primary stage of the spark filament, and it decreased with time. The radial distribution of electron density increased from the center to the edge of the spark filament.