Determination of Local Ionic Wind Velocity in Corona by Laser Interferometer Taking Into Consideration the Charging–Discharging of Probe Particles

Experimental data on the probe-particle local velocity measured by laser interferometer in air gap of a negative pin-to-plane corona are presented. Small water droplets like mist were used as the probe particles, which can be charged by the corona. Experimental data are complemented with numerical calculations, allowing us to evaluate the drift velocity of the charged droplets and determine therefore a real local velocity of the ionic wind induced by the collisions of negative ions with the neutrals. It is shown the charging of probe particles impacts strongly on their total local velocity. To agree a calculated local velocity of the charged particle with the measured one, the discharging processes were introduced. It is assumed that the discharging processes occur due to emission of electrons from surface of the charged droplets. Proposed mechanism of the secondary emission is associated with the recombination of H atoms and OH radicals on the surface of the charged droplet.