Simulation of radiation energy release in air showers

Abstract

Abstract. A simulation study of the energy released by extensive air showers in the form of MHz radiation is performed using the CoREAS simulation code. We develop an efficient method to extract this radiation energy from air-shower simulations. We determine the longitudinal profile of the radiation energy release and compare it to the longitudinal profile of the energy deposit by the electromagnetic component of the air shower. We find that the radiation energy corrected for the geometric dependence of the geomagnetic emission scales quadratically with the energy in the electromagnetic component of the air shower with a second order dependency on the atmospheric density at the position of the maximum of the shower development X max . In a measurement where X max is not accessible, this second order dependence can be approximated using the zenith angle of the incoming direction of the air shower with only a minor deterioration in accuracy. This method results in an intrinsic uncertainty of 4% with respect to the electromagnetic shower energy which is well below current experimental uncertainties.

Simulation of the Radiation Energy Release in Air Showers

“…In this work, we study the emission of the radiation energy from the theoretical side using Monte Carlo simulations of air showers and the calculation of the radiation from first-principles based on classical electrodynamics. More details of this analysis can be found in [6].…”

A new method to determine the energy scale for high-energy cosmic rays using radio measurements at the Pierre Auger Observatory

“…5. A quadratic relation with a scatter of less than 3 % is observed [14]. To obtain the cosmic-ray energy from the electromagnetic shower energy, the invisible energy needs to be taken into account, e.g., neutrinos and high-energy muons do not contribute to the radiation energy.…”

“…The charge excess is due to the knock-out of electrons from air molecules and annihilation of positrons in the shower front forming a radially polarized signal [11]. The radio emission from air showers can be calculated from first principles using classical electrodynamics [12,13,14]. The emission originates purely from the well-understood electromagnetic part of the air shower.…”

“…Thus, measurement and theoretical prediction of the radiation energy are directly comparable. For a detailed discussion about the theoretical part refer to [14]. In the following, the CoREAS simulation code [13] is used to simulate air showers and their radio emission.…”

“…[9] (right) The corrected radiation energy estimator vs. the energy in the electromagnetic cascade from CoREAS simulations. Adapted from [14].…”