Role of streamers in the formation of a corona discharge in a highly nonuniform electric field

The ignition of a corona discharge on a tip electrode with a small radius of curvature in air at atmospheric pressure is studied. It is established that the initiation of the corona discharge in a highly nonuniform electric field at any voltage polarity is due to the formation of ball streamers at high (${\geq}\,10\,$kV/$\mu$s) and low (${\leq}\,0.2\,$kV/ms) rates of the tension increase in the tip—plane gap. It is shown that the current amplitude through the gap of the first streamers at a positive tip electrode polarity is approximately half of that at a negative polarity, and the frequency of their appearance differs by two or more orders of magnitude. It is established that the high pulse repetition frequencies at the same voltage across the gap lead to higher average currents through the gap and a larger observed glowing area in the case of the negative polarity tip electrode in the formation region of ball streamers.