Since 2003, significant efforts have been devoted to the understanding of the radio emission of extensive air showers above 20 MHz. Despite some studies led until the early nineties, the band available below 20 MHz has remained unused for 20 years.
The radio technique for the detection of high-energy cosmic rays consists in measuring the electric field created by the particle showers created inside a medium by the primary cosmic ray. The electric field is then used to infer the properties of the primary particle.
The composition of ultra-high energy cosmic rays is still poorly known and constitutes a very important topic in the field of high-energy astrophysics.
CODALEMA is one of the pioneer experiments dedicated to the radio detection of ultra high energy cosmic rays (UHECR), located at the radio observatory of Nançay (France).
We describe the experimental setup and the results of RAuger, a small radio-antenna array, consisting of three fully autonomous and self-triggered radio-detection stations, installed close to the center of the Surface Detector (SD) of the Pierre Auger Observatory in Argentina.
We present a microscopic computation of the radio emission from air showers initiated by ultra-high energy cosmic rays in the atmosphere.
We discuss electric fields generated by cosmic ray air showers at large impact parameters b.
The new setup of the CODALEMA experiment installed at the Radio Observatory in Nançay, France, is described. It includes broadband active dipole antennas and an extended and upgraded particle detector array.
Based on a new approach to the detection of radio transients associated with extensive air showers induced by ultra-high-energy cosmic rays, the experimental apparatus CODALEMA is in operation, measuring about 1 event per day corresponding to an energy threshold ≈5 · 1016 eV.
Taking advantage of recent technical progress which has overcome some of the difficulties encountered in the 1960’s in the radio detection of extensive air showers induced by ultra high energy cosmic rays (UHECR), a new experimental apparatus (CODALEMA) has been built and operated.
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.
