Radio universality and template-based pulse synthesis

¹ IKP, Karlsruher Institut fur Technologie, 76021 Karlsruhe, Germany
² KVI - Center for Advanced Radiation Technology, Zernikelaan 25 NL-9747 AA Groningen, The Netherlands
³ Astrophysical Institute, Vrije Universiteit Brussel,Pleinlaan 2, 1050 Brussel, Belgium
⁴ Interuniversity Institute for High-Energy, Vrije Universiteit Brussel,Pleinlaan 2, 1050 Brussel, Belgium
⁵ David Butler acknowledges the support by the DFG-funded Doctoral School “Karlsruhe School of Elementary and Astroparticle Physics: Science and Technology”

^★ e-mail: david.butler@kit.edu

Published online: 24 September 2019

Abstract

When discussing radio emission from cosmic ray air showers we commonly make a number of assumptions regardingthe production and propagation physics. Incorporating all of these it should be possible to construct a forward model to predict the radio signal produced by an air shower from simple parameters, an application and generalisation of shower universality to radio emission.

In terms of particle detection shower universality focuses on the one-dimensional longitudinal profile, counting only the number of particles. This appears insufficient in the context of radio emission, the particle cascade develops on the scale of traversed atmospheric depth while electromagnetic radiation scales with the geometric trajectories of the sources. Further a real shower extends several radio wavelengths in the lateral directionwhile analyses often assume a point source on the shower axis.

Our simulation studies show an unanticipated complexity in the radio output responsible for around 10% variation in the signals. We are still in the process of identifying the relevant quantities and improving our analytical modeling accordingly.