The breakdown process of a liquid trigatron

A description of the mechanism of a breakdown of the liquid trigatron is proposed on the basis of the experimental data obtained in the past and additional measurements presented in the paper. Liquid trigatrons are considered both with the trigger at the cathode and at the anode. The mechanism proposed is as follows: in a liquid trigatron, some of the liquid in the gap will be vaporized and a local region of low density will develop there due to heat produced in the plasma of the triggering spark. There will also be increased probability for electron ionization in the plasma region. If the time lag is long enough, this vaporization of part of the liquid in the gap will transform the nature of a process of breakdown and gas phase will be involved. The breakdown condition is formed basically by electric-field distortion and intensification due to the positive space charge in the gap. In consequence, for the cathode triggered trigatron, if the field in the gap is high enough, negative streamers will develop. When the main gap voltage V is higher, the distance for which plasma region together with growing space charge must move in the gap before the main discharge will start, will be shorter, as is shown by the measurements. For the anode triggered trigatron, the growing space charge reinforces the electric field ahead of the plasma to allow development of a positive streamer. In the range of high values of V the avalanche produced by the photoelectrons is large and the positive streamer can be initiated immediately. In effect the corresponding time lag will be very short, as the measurements show.<
>