The electric field induced by extensive air showers generated by high energy cosmic rays is considered and, more specifically, its dependence on the shower incident angle.

Figure: charge profiles along the shower axis y for both vertical (0°) and tilted (75°) proton-induced showers. The electric field shape of a single-charge is also represented as a function of y. Calculations have been performed for impact parameter b = 2 km and gamma = 60. Figure: charge profiles along the shower axis y for both vertical (0°) and tilted (75°) proton-induced showers. The electric field shape of a single-charge is also represented as a function of y. Calculations have been performed for impact parameter b = 2 km and gamma = 60.
It is shown that for distances between the shower axis and the observation point larger than a few hundred meters, non-vertical showers produce larger fields than vertical ones. This may open up new prospects since, to some extent, the consideration of non-vertical showers modifies the scope of the radio-detection domain.

Published by Thierry Gousset, Olivier Ravel, Christelle Roy in Astroparticle Physics 22, June 2004, P. 103–107 https://doi.org/10.1016/j.astropartphys.2004.05.004