INVESTIGADORES
TUEROS Matias Jorge
artículos
Título:
Coherent radiation from extensive air showers in the ultrahigh frequency band
Autor/es:
J. ALVAREZ-MUÑIZ; W. R. CARVALHO JR.; A. ROMERO-WOLF; M. TUEROS; E. ZAS
Revista:
PHYSICAL REVIEW D
Editorial:
AMER PHYSICAL SOC
Referencias:
Lugar: New York; Año: 2012 vol. 86 p. 123007 - 123016
ISSN:
1550-7998
Resumen:
Using detailed
Monte Carlo simulations we have characterized the features of the radio
emission of inclined air showers in the ultrahigh frequency band
(300 MHz3 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.