Electrical discharges in Martian analogue materials have previously been generated by
agitation of the material in a low-pressure carbon dioxide environment. These results have
led to the supposition that lightning is likely on Mars, on the basis that the surface material
becomes triboelectrically charged, and the charges are then gravitationally separated in
dust storms. We have reproduced one of these experiments and find that triboelectric
charging of the Martian regolith simulant by the walls of the vessel used can adequately …