Dynamics of discharge with electron beam injection in low-pressure gas and weakly ionised plasma

The dynamics of discharge are studied experimentally by applying an impulse voltage to a discharge gap with electron beam injection. Discharge mechanisms in a low pressure gas (0.01-0.27 Pa) and weakly ionised plasma (ion density/neutral gas density approximately=10-7) are found to differ essentially. In the former case, positive space charges are produced locally around the anode. They develop towards the beam source, leading to the collapse of a V-shaped potential profile. Discharge occurs at this moment. In the latter case, the discharge is realised by the collapse of the V-shaped potential caused by the rapid rise of the plasma potential over the whole region at the instant of the application of the impulse voltage.