Monte Carlo simulations of radio pulses in atmospheric showers using ZHAireS

TL;DR

This paper uses ZHAireS, a Monte Carlo simulation tool, to predict radio pulses from atmospheric air showers, highlighting the influence of geometry and refractive index on emission characteristics.

Contribution

It introduces detailed Monte Carlo simulations of radio emissions from air showers considering complex atmospheric effects without assuming specific emission mechanisms.

Findings

Radio emission is influenced significantly by shower geometry and refractive index.

Polarization and electric field characteristics depend on atmospheric and geometric factors.

Results support a superposition of geomagnetic and charge excess emission mechanisms.

Abstract

We present predictions for the radio pulses emitted by extensive air showers using ZHAireS, an AIRES-based Monte Carlo code that takes into account the full complexity of ultra-high energy cosmic-ray induced shower development in the atmosphere, and allows the calculation of the electric field in both the time and frequency domains. We do not presuppose any emission mechanism, but our results are compatible with a superposition of geomagnetic and charge excess radio emission effects. We investigate the polarization of the electric field as well as the effects of the refractive index n and shower geometry on the radio pulses. We show that geometry, coupled to the relativistic effects that appear when using a realistic n>1, play a prominent role on the radio emission of air showers.