33RD INTERNATIONAL COSMIC RAY CONFERENCE, RIO DE JANEIRO 2013 THE ASTROPARTICLE PHYSICS CONFERENCE The EVA code: Macroscopic modeling of radio emission from air showers

Abstract: We discuss the EVA code which is based on a macroscopic approach to calculate radio emission from air showers. Recently it was shown that Cherenkov effects play a crucial role in the emission. The advantage of the macroscopic approach is that it allows for resolving the divergences in the electric field expressions due to these Cherenkov effects, which is done by using the finite extent of the particle distribution in the shower front. Furthermore, the macroscopic approach allows for a more intuitive interpretation of the observed radio-emission pattern in terms of the properties of the air shower such as the longitudinal profile and the thickness of the shower front. The particle distributions and currents in the air shower front are obtained in histograms from a full CONEX Monte-Carlo air shower simulation. A fitting procedure is applied to obtain smooth analytic functions which are used to solve for the radio emission including Cherenkov effects. The EVA code is publicly available