Simulation of a Single Streamer Traveling Along Two Counterpropagating Helium Jets in Ambient Air

Variation of the structure of one guided streamer moving along two counterpropagating helium jets is studied by means of numerical simulation. It is shown, in agreement with experimental results, that, due to variation of the gas composition along the streamer path, the radial intensity profile changes during streamer propagation. Its form, being initially, just after emerging from the first tube, an annular one, changes to a spherical one far from the tube, in the middle of the gap, and returns again to an annular one when approaching the second tube.