M. Tueros

Coherent Radiation from Extensive Air Showers in the Ultra-High Frequency Band

Using detailed Monte Carlo simulations we have characterized the features of the radio emission of inclined air showers in the ultrahigh frequency band (300 MHz\char21{}3 GHz). The Fourier spectrum of the radiation is shown to have a sizable intensity well into the GHz frequency range. The emission is mainly due to transverse currents induced by the geomagnetic field and the excess charge produced by the Askaryan effect. At these frequencies only a significantly reduced volume of the shower around the axis contributes coherently to the signal observed on the ground. The size of the coherently emitting volume depends on frequency, shower geometry and observer position, and is interpreted in terms of the relative time delays at observation dominated by the curvature of the shower front. At ground level, the maximum emission at high frequencies is concentrated in an elliptical ringlike region around the intersection of a Cherenkov cone with its vertex at shower maximum and the ground. The frequency spectrum of inclined showers when observed at positions that view shower maximum in the Cherenkov direction, is shown to be in broad agreement with the pulses detected by the Antarctic Impulsive Transient Antenna experiment, making the interpretation that they are due to ultrahigh energy cosmic ray atmospheric showers consistent with our simulations. These results are also of great importance for experiments aiming to detect molecular bremsstrahlung radiation in the GHz range as they present an important background for its detection.

Ultra high frequency geomagnetic radiation from extensive air showers

Using the ZHAireS Monte Carlo code, we show that the Fourier-spectrum of the radio emission of inclined air showers can have a sizable intensity up to the GHz frequency range. At these frequencies only a significantly reduced volume of the shower around the axis contributes coherently to the signal observed on the ground, which is mainly due to the geomagnetic and charge excess mechanisms. At ground level, the maximum emission at high frequencies is concentrated in a ring-like elliptical region defined by the intersection with the ground of a Cherenkov cone with its vertex at shower maximum. The frequency-spectrum of inclined showers, when observed at positions close to the ring-like maximum emission region, is in broad agreement with the pulses detected by the ANITA experiment, making the interpretation that they are due to ultrahigh energy cosmic ray atmospheric showers consistent with our simulations. These results are also relevant for ground-based radio experiments aiming at detecting molecular brems...

The Giant Radio Array for Neutrino Detection (GRAND) : Present and Perspectives

The Giant Radio Array for Neutrino Detection (GRAND) aims at detecting ultra-high energy extraterrestrial neutrinos via the extensive air showers induced by the decay of tau leptons created in the interaction of neutrinos under the Earths surface. Consisting of an array of

Detection of Extensive Air Showers with the self-triggered TREND radio array

\sim10^5

The GRANDproto35 experiment

radio antennas deployed over

Near-field radio emission induced by extensive air showers

\sim 2\times10^5\,\rm {km}^2

Coherent Cherenkov radio pulses from hadronic showers up to EeV energies

, GRAND plans to reach, for the first time, an all-flavor sensitivity of

Radio Morphing - towards a full parametrisation of the radio signal from air showers

\sim1.5\times10^{-10} \,\rm GeV\, cm^{-2} \,s^{-1}\, sr^{-1}

Radio morphing - towards a fast computation of the radio signal from air-showers

above

The Giant Radio Array for Neutrino Detection (GRAND): Science and Design

5\times10^{17}