Study of streamers in gradient density air: Table top modeling of red sprites

Red sprites are large scale weakly ionized non-equilibrium electrical discharges that occur high above thunderstorm clouds, spanning the altitude range 50 kilometers to 90 kilometers above the Earth's surface. Their streamer-like nature has been pointed out by a number of groups. Streamer models used for the description of sprites are usually verified experimentally. However, sprites develop in a highly non-uniform air, where density changes by a factor of ∼2.7 every 7.2 km, whereas streamer studies have been performed at different but uniform densities. In this paper we present the results of the first attempt to simulate sprites in laboratory by using streamer discharges in a gradient density air (the results of this paper were presented in 2009 Fall AGU meeting). The purpose of the experiments is to obtain data that could be used for validation of numerical and analytical models (the first results of a numerical study of red sprites (streamers) in a gradient density atmosphere were recently published by Luque and Ebert (2010)).