Electrical discharges in air and CO2 in non-planar geometries.

At the basis of our understanding of dielectric breakdown, i.e., gas discharges, is Townsend's theory. Its formulation as Paschen's law describes non-thermal, self-sustained discharges occurring in high voltage, low current, and low pressure conditions between two parallel plate electrodes (Raizer et al., 1997, ISBN: 978-3540194620). Paschen's law has been developed for various gas mixtures but does not traditionally consider electrodes' geometry and material. Here we propose to develop a new formalism for equations adapted to these constraints and an experimental setup for its validation.

The discharges are produced in Florida Tech's micro Terrestrial Atmosphere Discharge Simulator (μTADS), where the critical (initiation) voltage 'Vcr' is measured at specific pressures 'p' and distances 'd' in air and 'CO_2' mixtures comparable to Earth and Mars atmospheres. We show that the Engel-Steenbeck equation (e.g., Fridman \& Kennedy, 2004, doi: 10.1201/9781482293630): Vcr = B(pd)/(C + \ln(pd)) (where C = \ln[A/\ln(1+1/\gamma)], 'A' and 'B' are empirically determined coefficients for each gas mixture, and γ is the secondary electron emission coefficient) does not adequately characterize the critical voltage under non-planar geometries. This work supports the validation of the new proposed formalism and improvement of safety systems subject to potential discharges.