2020, 40(1): 65-71.
doi: 10.11728/cjss2020.01.065
Abstract:
The Large High Altitude Air Shower Observatory (LHAASO) is located in Daocheng, Sichuan. Featured with frequent thunderstorms in summer, it is beneficial to study the influence of atmospheric electric field on cosmic rays during thunderstorms. In this paper, Monte Carlo simulations are performed to study the effects of thunderstorms electric field on positrons and electrons at LHAASO. The energy distribution of electrons changes in the field. In low energy region, the total number of electrons and positrons increases significantly, while at high energies, it does not change obviously. In an electric field of 1700V·cm-1, above the threshold field of the Relativistic Runaway Electron Avalanche (RREA) process, the electrons with energy less than 120MeV can be accelerated. While the energy is below 60MeV, the number of electrons increases exponentially, with the increase amplitude up to about 2252%. It is consistent with the theory of RREA. In an field of 1000V·cm-1 (below the threshold of the RREA process), electrons with energy less than 70MeV can be accelerated, and its quantity significantly increases, but the amplification (about 86%) is far lower than that of the critical field of the RREA process. The results may provide important information to study the variations of cosmic ray intensity at LHAASO detection surface during thunderstorms.