Image of a gaseous discharge in microgravity

The electrode gap length of a gaseous discharge in a low-pressure 1 g envir onment is compared with its length in a low-pressure microgravity environme nt for pressures ranging from 30 kPa to atmospheric pressure. The maximum g ap length obtained is measured for both conditions using three separate gas es, Video images of the discharge in microgravity make apparent both the la ck of gravity-induced convection, which gives rise to the arching of the 1 g discharge, and the increase in gap length.