The emission of energetic electrons from the complex streamer corona adjacent to leader stepping

摘要: We here propose a model to capture the complexity of streamer corona adjacent leader stepping and relate it production energetic electrons serving as source X-rays $\gamma$-rays, manifesting in terrestrial gamma-ray flashes (TGFs). During its stepping, tip is accompanied by consisting multitudinous streamers perturbing air vicinity leaving residual charge behind. explore relative importance perturbations preionization on run-away 2.5D cylindrical Monte Carlo particle simulations ambient fields 16 kV cm$^{-1}$ 50 at ground pressure. levels between $10^{10}$ m$^{-3}$ $10^{13}$ m$^{-3}$, channel widths 0.5 1.5 times original perturbation 0\% 50\% air. observe that preionized perturbed accelerate more efficiently than non-ionized uniform with dominating acceleration. find unperturbed $10^{11}$ are sufficient explain electron rates measured conjunction flashes. In air, rate runaway varies from s$^{-1}$ $10^{17}$ maximum energies some hundreds eV up keV above below breakdown strength. presented number matches alignment observations Conclusively, zone ahead tips allows explaining emission photons discharges.