Two step current increases in glow discharge development in neon filled diode at 4 mbar

The results are presented of investigating temporal and spatial development of electrical glow discharge in a neon filled tube under 4mbar pressure. Linear increasing voltage (at 5 V/s increasing voltage rate) is applied to the gas diode. Time dependence of 585.2 nm line light emitted from negative glow is observed from various positions in the diode during formation of electrical discharge. The results show that the development of glow discharge starts in the gap, and propagates to the cathode and in the space around and behind the cathode. An unexpected two-step current rise is found. In the stationary regime, most of the emitted light occupied the cathode carrier rod. This indicates the position where the secondary electron emission is intensive. It corresponds to the second step in the current increase app. 3 ms after the breakdown has already taken place. It is assumed that this step originates from different surface characteristics of the rode material. The analysis of time dependencies of the current and light from the negative glow, from different positions in the gas diode, suggests that the observation of deexcitation processes in gas can be used for determination of early discharge formative processes, as well as processes that lead to the stationary regime in the gas diode tube.