Streamer discharges in the atmosphere of Primordial Earth

The seminal Miller-Urey experiment suggests that lightning may have contributed to the origin of life on Earth through the formation of amino acids and carbon acids. We here focus on the early stages of lightning in the atmosphere of Primordial Earth, so-called streamer discharges. We discuss rate coefficients for electrons and study electron avalanches and avalanche-to-streamer transitions by modeling the motion of electrons with a 2.5D Particle-in-Cell Monte Carlo code in the strongly reducing atmosphere used by Miller and Urey (MU) and the weakly reducing atmospheric suggested more recently (by Kasting (1993)) for Earth 3.8 Ga ago and compare results with conditions on Modern Earth. Our simulations show that streamers incept at fields of 140-180 Td in Kasting’s mixture and at fields of ≈ 114 Td in the MU mixture, thus their inception is more difficult in Kasting‘s mixture. Conclusively, discharges on Primordial Earth might have been more challenging to incept.