Molecular Bremsstrahlung Radiation at GHz Frequencies in Air

Abstract

A detection technique for ultra-high energy cosmic rays, complementary to the fluorescence technique, would be the use of the molecular Bremsstrahlung radiation emitted by low-energy ionization electrons left after the passage of the showers in the atmosphere. In this article, a detailed estimate of the spectral intensity of photons at ground level originating from this radiation is presented. The spectral intensity expected from the passage of the high-energy electrons of the cascade is also estimated. The absorption of the photons in the plasma of electrons/neutral molecules is shown to be negligible. The obtained spectral intensity is shown to be $2\times 10^{-21}$W cm${}^{-2}$ GHz${}^{-1}$ at 10 km from the shower core for a vertical shower induced by a proton of $10^{17.5}$ eV. In addition, a recent measurement of Bremsstrahlung radiation in air at gigahertz frequencies from a beam of electrons produced at 95 keV by an electron gun is also discussed and reasonably reproduced by the model.

20 pages, 9 figures, figures (2,4,7) improved in v2, accepted by Phys. Rev. D

References in corpus (5)

• Observations of Microwave Continuum Emission from Air Shower Plasmas
• First Experimental Characterization of Microwave Emission from Cosmic Ray Air Showers
• Cosmic Rays from the Ankle to the Cut-Off
• An Estimate of the Spectral Intensity Expected from the Molecular Bremsstrahlung Radiation in Extensive Air Showers
• Experimental study of the microwave emission from electrons in air

Cited by in corpus (10)

• Radio detection of Cosmic-Ray Air Showers and High-Energy Neutrinos
• Revealing neutral bremsstrahlung in two-phase argon electroluminescence
• Electroluminescence and electron avalanching in two-phase detectors
• Neutral bremsstrahlung in two-phase argon electroluminescence: further studies and possible applications
• Study of visible-light emission in pure and methane-doped liquid argon
• Observation of primary scintillations in the visible range in liquid argon doped with methane
• Coherent Suppression of Molecular Bremsstrahlung Radiation at GHz Frequencies in the Ionization Trail of Extensive Air Showers
• GIGAS: a set of microwave sensor arrays to detect molecular bremsstrahlung radiation from extensive air shower
• The Small Contribution of Molecular Bremsstrahlung Radiation to the Air-Fluorescence Yield of Cosmic Ray Shower Particles
• Considerations on the radio emission from extended air showers