Experimental Simulation of Non-uniformity in Column Sprite Glow

Plasma diffuse jets (PDJs) generating in low-pressure air are experimentally studied. We consider them as a laboratory model of column red sprites. It has been established that red-colored radiation of a positive column of a glow discharge is superimposed on streamer radiation in a PDJ with an increase in the discharge current duration. The positive column in some cases can consist of periodic bright regions. Based on the experimental results, an explanation is suggested for the following phenomena observed in red columnar sprites: (1) the emergence of a region with a brighter luminescence (“glow”) in the upper part of the column sprites; (2) the appearance of bright dots (“beads”) after the passage of the front of the first streamers forming the column sprites.