Structure of Barrier Discharge in Long Dielectric Tube Filled with Low-Pressure Gas

We presented the results of simulating the growth of a plasma column in a barrier discharge ignited in a long dielectric tube at a low-pressure of a molecular gas (nitrogen/air at a pressure of 1 Torr). The spatial images of the plasma structure and the electric field that occur in the pulse-periodic mode of a barrier discharge in gas with external ring electrodes (pulse duration of 1 μs, voltage amplitude of 5 kV, pulse repetition frequency of up to 200 kHz) are presented. The plasma diffuse channel as a negative streamer is formed between the positively charged plasma of the column and the end wall of the discharge tube. It is shown that near the head of the growing diffuse channel, the electric fields are sufficient to form a flow of runaway electrons.