Step propagation of a streamer in an electronegative gas

It is shown on the basis of numerical simulation and an experimental investigation that a streamer can propagate in a step manner in an electronegative gas. The experiments and most calculations were performed for air under close to normal conditions. The step motion is associated with the appearance of a secondary ionization wave near the electrode and propagation of this wave along the channel of the streamer; this wave maintains the channel in a conducting state and allows for the propagation of the streamer in a nonuniform external field over distances which are inaccessible under ordinary conditions of a streamer discharge. Simulation in heated air, oxygen, and SF6 demonstrated that the phenomenon studied is common for various gases and that the special features of its manifestation remain in a wide range of decay rates of the streamer channel. (C) 2000 MAIK "Nauka/Interperiodica".