Feasibility of radar detection of extensive air showers
  Reflection of radio waves off the short-lived plasma produced by the high-energy shower particles in the air is simulated, considering various radar setups and shower geometries. We show that the plasma produced by air showers has to be treated always as underdense. Therefore, we use the Thomson cross-section for scattering of radio waves corrected for molecular quenching and we sum coherently contributions of the reflected radio wave over the volume of the plasma disk to obtain the time evolution of the signal arriving at the receiver antenna. The received power and the spectral power density of the radar echo are analyzed. Based on the obtained results, we discuss possible modes of radar detection of extensive air showers. We conclude that the scattered signal is too weak for the radar method to provide an efficient and inexpensive method of air shower detection. 
J. Stasielak, R. Engel, S. Baur, P. Neunteufel, R. \v{S}m\'ida, F.   Werner, H. Wilczy\'nski
astro-ph.IM astro-ph.HE