Simulations and theory of radio emission from cosmic ray air showers

In the last few years, interest in radio detection of cosmic ray air showers has risen continuously. By now, large-scale application of the radio technique is under investigation in the framework of LOFAR and the Pierre Auger Observatory. The experimental efforts are accompanied by new approaches to describe and model the underlying radiation mechanisms, to lay the foundation for an interpretation of the experimental data. In this article, I review the current radio emission theory and simulations, with slight focus on the geosynchrotron model and its predictions for the information content of the radio signals.