Measuring radio emission from ultra-high energy (UHE) cosmic ray of neutrino induced particle showers in air or in more dense materials is a very efficient way for detecting them. This radio signal contains rich information on the structure of the emitting shower and in turn on the initiating UHE particle. The angle of arrival and the energy of this particle can be extracted rather straightforwardly from the radio signals (when measured with a sufficient number of antennas). The radio signal footprint also contains information on more refined quantities, such as X_max (the penetration depth where the particle number reaches a maximum) as well as other shape parameters of the shower. These parameters are important for extracting the composition of cosmic rays or for learning about atmospheric electric fields. One generally relies on forward modelling approaches to extract these shower parameters.
In the presentation a very quick summary of the arguments for measuring radio emission will be presented, to continue with a summary of the basic physics governing radio emission. This will lead to a particular macroscopic forward modelling approach, MGMR. Some of the virtues and vices of this model will be discussed in comparison to microscopic approaches.
Prof.Olaf Scholten(Kapteyn Institute, University of Groningen)