Cosmic ray electron acceleration and bremsstrahlung generation in the strong electric field of thunderclouds

Abstract

Using an EGS4 user code by which the effect of the external electric field was combined in the EGS4 code, the acceleration of the cosmic ray electrons and the generation of the bremsstrahlung photons are calculated under the electric field simulated a thundercloud. The photon flux increased greatly in the region of 280 kV/m whose field strength is the maximum value in the electric field. Moreover, the energy spectra of photons showed a large increase in the energy region of several MeV, and were almost same distribution that had been observed on the ground during a winter thunderstorm.