Enhancement of the radar signal of air showers due to time compression

TL;DR

This paper explores the potential of radar detection of extensive air showers by simulating radio wave reflections off plasma produced by high-energy particles, focusing on viewing angles less than 25 degrees.

Contribution

It introduces a simulation framework for radar detection of air showers considering specific geometries and analyzes the radar echo's spectral properties.

Findings

Radar signals are enhanced due to time compression effects.

Reflected radio wave power depends on shower geometry and plasma properties.

Feasibility of radar detection at small viewing angles is supported by simulation results.

Abstract

We investigate the feasibility of detecting extensive air showers by the radar technique at viewing angles smaller than $\sim 25^\circ$ to the shower axis. Considering a bistatic radar setup and shower geometries in which the receiver points into the arriving shower, we simulate reflection of radio waves off the short-lived plasma produced by the high-energy shower particles in the air. Using the Thomson cross-section for scattering of radio waves and summing coherently contributions of the reflected radio wave over the volume of the plasma disk, we obtain the time evolution of the signal. We analyze the spectral power density of the radar echo and the received power. Based on the obtained results, we discuss possible modes of the radar detection of extensive air showers.