Radio-Emission from Cosmic Ray Air-Showers - A Theoretical Perspective   for LOPES
  High-energy cosmic ray air-showers have been known for over 30 years to emit strong radio pulses in the regime between a few and several 100 MHz (Allan 1971). To date, however, a thorough analysis of the emission mechanisms has not yet been conducted. Adopting a simplified shower geometry and electron-positron energy distribution, we calculate theoretical pulse spectra in the scheme of synchrotron emission from highly relativistic electron-positron pairs gyrating in the Earth's magnetic field. These calculations will play an important role for the calibration of observational data of radio-emission from cosmic ray air-showers acquired with LOPES and later LOFAR and SKA. 
Tim Huege and Heino Falcke (Max-Planck-Institut fuer Radioastronomie,   Bonn, Germany)