PROJECT TITLE :

Colored Diffuse Mini Jets in Runaway Electrons Preionized Diffuse Discharges

ABSTRACT:

Optical emission of the nanosecond diffuse discharge initiated by runaway electrons in an inhomogeneous electrical field was investigated during a single-pulse and pulse-periodic modes in numerous gases (air, nitrogen, and argon). The amplitude of voltage pulses, pulse rise time, and interelectrode distance were, respectively, 200 kV, zero.five ns, and 13 mm for single-pulse mode, and thirteen kV, 4 ns, and a pair of mm for pulse-periodic mode. In the only-pulse mode, the diffuse mini jets (DMJs) of different colors with lengths up to seven mm appear near electrodes. Blue DMJs were observed close to electrodes with a little radius of curvature made of a chrome steel. Red DMJs were observed close to the grounded flat electrode created of aluminum and in the middle of discharge gap close to a spark channel. It had been shown that radiation intensity of DMJs increased with the increase in nitrogen pressure up to zero.four MPa, however subsequent increase in pressure up to 0.7 MPa led to the decrease in radiation intensity. In the pulse-periodic mode, colored DMJs are observed additionally, the dimensions of which was ~1 mm. During this mode, the spectral and amplitude-temporal parameters of the radiation of DMJs are studied. It had been shown that the colour of DMJs is decided by the radiation of electrode metal vapors. It had been shown that the DMJs originate from the brilliant spots (explosive centers) on electrodes.