Validation of straight-line signal propagation for radio signal of very inclined cosmic ray air showers

Abstract

An ongoing challenge for radio-based detectors of high-energy cosmic particles is the accurate description of radio signal propagation in natural nonuniform media. For radio signals originating from extensive air showers, the current state of the art simulations often implicitly assume straight-line signal propagation. The refraction due to a nonuniform atmosphere is however expected to have an effect on the received signal and associated reconstruction. This effect is currently not completely understood for the most inclined geometries. Here, we present a study regarding the validity of straight-line signal propagation when simulating radio emission associated with very inclined air shower geometries. To this end, the calculation of the electric field based on the end point formalism used in CoREAS was improved by use of tabulated ray tracing data. We find a difference of 2% in radiation energy and a difference of O(0.01°) on direction reconstruction when working at frequencies below 600 MHz. We thus find that, for frequencies up to 600 MHz and zenith angles up to 88°, the current straight-line based simulation approaches are accurate.

References in corpus (12)

• The IceCube high-energy starting event sample: Description and flux characterization with 7.5 years of data
• The energy spectrum of cosmic rays beyond the turn-down around $10^{17}$ eV as measured with the surface detector of the Pierre Auger Observatory
• REAS3: Monte Carlo simulations of radio emission from cosmic ray air showers using an "end-point" formalism
• Macroscopic Treatment of Radio Emission from Cosmic Ray Air Showers based on Shower Simulations
• In situ radioglaciological measurements near Taylor Dome, Antarctica and implications for UHE neutrino astronomy
• Design and Initial Performance of the Prototype for the BEACON Instrument for Detection of Ultrahigh Energy Particles
• Modeling in-ice radio propagation with parabolic equation methods
• Simulations of reflected radio signals from cosmic ray induced air showers
• TAROGE-M: Radio Antenna Array on Antarctic High Mountain for Detecting Near-Horizontal Ultra-High Energy Air Showers
• Refractive displacement of the radio-emission footprint of inclined air showers simulated with CoREAS
• Simulation of radio signals from cosmic-ray cascades in air and ice as observed by in-ice Askaryan radio detectors
• The Radio Detector of the Pierre Auger Observatory -- status and expected performance