Stimulated ignition and quenching of a cathode spot in a low-power discharge with plasma injection
Experimental results are presented on current commutation in a low-power gas discharge with external plasma injection. A connection between current switching and cathode spot ignition and quenching has been established. Discharge gap filling with dense plasma leads to synchronous spot ignition as well as gap releasing leads to spot quenching. It is shown that the spot ignition takes 1 to 30 ns and evolves as a local explosive heating of the cathode surface (more then 10<sup>12</sup> K/s slew rate has been registered), caused by field-emission current. It is also shown that spot quenching takes less than 100 ps, while the processes leading to quenching evolve simultaneously in all cells of the spot.