Comprehensive comparison of radio emission predicted by CoREAS and ZHAireS

C. SALVATTORE CRUZ SANCHEZ; P. HANSEN; M. TUEROS; J. ALVAREZ-MUÑIZ; D. MELO

Auger Gap Note

Pierre Auger Collaboration

Lugar: Malargue; Año: 2023 vol. 2023 p. 1 - 25

0395-2037

In the last two decades there has been an enormous progress on the radio detection of cosmic-ray-induced extensive air showers (EAS). At the Pierre Auger Observatory the AERA antenna array was constructed to detect radio emission from EAS. As an integral part of the future AugerPrime upgrade, radio antennas will be placed on each of the Surface Detector stations. These experimental developments require a detailed knowledge of the properties of the emitted radiation to be able to interpret and analyze the collected data. The two main and most used Monte Carlo simulation packages that predict radio pulses in EAS are CoREAS and ZHAireS. We present here a comprehensive comparison of the predicted radio pulses emitted by EAS simulated with ZHAireS and CoREAS. We have performed a set of simulations of the radio emission in EAS induced by different primary particles, shower directions, and magnetic field configurations. We have compared the frequency spectrum of the electric field amplitude at the ground at several observer positions with respect to the shower axis. To make this comparison, we have used in both simulations as similar as possible input parameters and settings, as well as the same realistic atmospheric refractive index n > 1 depending on altitude. Furthermore, we selected simulated showers with very similar values of X max . We found a good agreement, with differences typically less than 10%, between the predictions of CoREAS and ZHAireS for the dominant components of the electric field in the frequency range between a few MHz and hundreds of MHz where most of the experiments exploiting the radio technique operate. For reproducibility of our results, we give the detailed input directives used in both codes as well as other details of the simulations.