A Study on the Contributing Factors of RF Breakdown in Atmospheric Air

DC and RF breakdown at 3.3 MHz was studied in centimeter size gaps − 1 − 10 mm – with comparison to small gaps in literature and Monte Carlo simulations in atmospheric conditions. As a point of reference, DC breakdown using stainless-steel Bruce-profile electrodes were measured to compare with RF measurements. RF breakdown with a slow rising envelope (
$\sim 5\ \text{mV}/\mu\mathrm{s}$
) yielded approximately 80% of DC measurements (∼25 kV/cm in 5 mm gap), which agrees with Monte Carlo simulations and results found in literature. Increasing the envelope rise time to greater than
$1000\ \mathrm{V}/\mu \mathrm{s}$
yielded ∼120% of DC measurements (∼37 kV/cm in 5 mm gap). Comparisons with Monte Carlo simulations which included photon processes – theorized to be critical to obtaining accurate results – furthered understanding of the processes involved in pre-ionization before breakdown occurs.