Novel application of GECAM to monitor high-energy cosmic rays in low Earth orbit

Résumé fourni par la source

Abstract High-energy cosmic-ray monitoring in low Earth orbit (LEO) is important for space science and exploration, yet it is usually limited to the dedicated cosmic-ray detectors. Here we show that GECAM, although designed as a gamma-ray all-sky monitor, can monitor high-energy cosmic rays through its novel design of simultaneous-event (STE). We first combine multi-component incident-particle models with \textsc{Geant4} simulations to calibrate the particle component--energy--multiplicity response of STE, and then apply to the GECAM observation data during geomagnetic storms. The simulations show that STE signals are dominated by GeV--TeV protons, whereas the highest-fold channels, especially STE(21--25), contain a significant contribution from $\sim 10$--$20$ GeV electrons. Thus, STE(5--20) mainly trace rigidity-dependent variations of primary protons, while STE(21--25) provides an electron-sensitive diagnostic. By analyzing the GECAM observation data during geomagnetic storms, we find a STE multiplicity-dependent response which is consistent with rigidity-dependent Forbush modulation and time-dependent geomagnetic transmissivity near cutoff and penumbral regions. These results demonstrate that GECAM can monitor high-energy cosmic-ray variations in LEO as a Micro Cosmic-Ray Observatory (MICRO), complementing those dedicated cosmic-ray instruments.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.