The convergence of EAS radio emission models and a detailed comparison of REAS3 and MGMR simulations

Understand

Over the previous decade, many approaches for the modelling of radio emission from cosmic ray air showers have been developed.

• However, there remained significant deviations between the models, reaching from important qualitative differences such as unipolar versus bipolar pulses to large variations in the predicted absolute amplitudes of up to factors of 20.
• Only recently, it has been realized that in the many models predicting unipolar pulses, a radio emission contribution due to the time-variation of the number of charged particles or, equivalently, the acceleration of the particles at the beginning and the end of their trajectories, had not been taken into account.
• We discuss here the nature of the underlying problem and demonstrate that by including the missing contribution in REAS3, the discrepancies are reconciled.