Energy and composition sensitivity of geosynchrotron radio emission from cosmic ray air showers

Based on CORSIKA and REAS2 simulations, we investigate the sensitivity of geosynchrotron radio emission from extensive air showers to the primary cosmic ray energy and mass. It is found that at a characteristic lateral distance, the amplitude of the bandpass-filtered radio signal is directly proportional to the energy deposited in the atmosphere by the electromagnetic cascade, with an RMS uncertainty due to shower-to-shower fluctuations of less than 3%. In addition, the ratio of this radio amplitude and that at a larger lateral distance is directly related to the atmospheric depth of the air shower maximum, with an RMS uncertainty of ∼ 15–20 g cm . Through the measurement of these quantities, geosynchrotron radio emission from cosmic ray air showers could thus be used to infer the primary particle energy and mass on a shower-to-shower basis.