Laser monitor visualization of gas-dynamic processes under pulse-periodic discharges initiated by runaway electrons in atmospheric pressure air

Abstract

Gas-dynamic processes that run in pulse-periodic discharges initiated by runaway electrons in atmospheric pressure air are studied with CuBr-laser based laser monitor and schlieren method. Voltage pulses (U = 13 kV, FWHM is 10 ns, front length is 4 ns, negative polarity, f = 60–3200 Hz) applied to a coneshaped copper cathode with cone base diameter, apex angle, and corner radius of cone vertex of 6 mm, 30°, and 0.2 mm, respectively. A flat copper anode was located at a distance of 2 mm from the cathode. It is established that discharge plasma products with copper vapors are carried in a radial direction along the anode surface to a distance of 24 mm for 2.5 ms. The temperature of the gas heated is ~1 × 10³ K. It is shown that the use of the laser monitor in transmitted light provides for contrast images of optical inhomogeneities that appear in gas discharges.