A Discharge Slipping over the Surface of Water as a Source of UV Radiation and Hydroxyl Radicals in a Liquid

A high-voltage repetitively pulsed surface spark discharge propagating along the water–gas interface, when Ar is used as the gaseous medium, is studied. In the experiments, a generator with a storage capacitor energy of up to 1.6 J, a voltage of up to 20 kV, and a pulse duration of 2–3 μs is used. The energy characteristics of the discharge are measured as a function of its length from 40 to 140 mm. The UV radiation intensity is measured by actinometry in the wavelength range from 200 to 380 nm. It is established that the UV radiation yield along the discharge length is constant, almost independent of its length, and is directly proportional to the energy input into the discharge. The energy cost of a radiation photon is 150 eV. Quantitative estimates of the production of hydroxyl radicals depending on the length of the plasma channel and the energy input into the discharge are carried out.