983 research outputs found
Radio detection of cosmic rays in the Pierre Auger Observatory
In small-scale experiments such as CODALEMA and LOPES, radio detection of
cosmic rays has demonstrated its potential as a technique for cosmic ray
measurements up to the highest energies. Radio detection promises measurements
with high duty-cycle, allows a direction reconstruction with very good angular
resolution, and provides complementary information on energy and nature of the
cosmic ray primaries with respect to particle detectors at ground and
fluorescence telescopes. Within the Pierre Auger Observatory, we tackle the
technological and scientific challenges for an application of the radio
detection technique on large scales. Here, we report on the results obtained so
far using the Southern Auger site and the plans for an engineering array of
radio detectors covering an area of ~20 km^2.Comment: 4 pages, Proceedings of the 11th Pisa Meeting on Advanced Detector
Theory and simulations of air shower radio emission
A precise understanding of the radio emission from extensive air showers is
of fundamental importance for the design of cosmic ray radio detectors as well
as the analysis and interpretation of their data. In recent years, tremendous
progress has been made in the understanding of the emission physics both in
macroscopic and microscopic frameworks. A consistent picture has emerged: the
emission stems mainly from time-varying transverse currents and a time-varying
charge excess; in addition, Cherenkov-like compression of the emission due to
the refractive index gradient in the atmosphere can lead to time-compression of
the emitted pulses and thus high-frequency contributions in the signal. In this
article, I discuss the evolution of the modelling in recent years, present the
emission physics as it is understood today, and conclude with a description and
comparison of the models currently being actively developed.Comment: Proceedings of the ARENA2012 conference (Erlangen, Germany), to be
published in AIP Conference Proceeding
REAS3: Monte Carlo simulations of radio emission from cosmic ray air showers using an "end-point" formalism
In recent years, the freely available Monte Carlo code REAS for modelling
radio emission from cosmic ray air showers has evolved to include the full
complexity of air shower physics. However, it turned out that in REAS2 and all
other time-domain models which calculate the radio emission by superposing the
radiation of the single air shower electrons and positrons, the calculation of
the emission contributions was not fully consistent. In this article, we
present a revised implementation in REAS3, which incorporates the missing radio
emission due to the variation of the number of charged particles during the air
shower evolution using an "end-point formalism". With the inclusion of these
emission contributions, the structure of the simulated radio pulses changes
from unipolar to bipolar, and the azimuthal emission pattern becomes nearly
symmetric. Remaining asymmetries can be explained by radio emission due to the
variation of the net charge excess in air showers, which is automatically taken
into account in the new implementation. REAS3 constitutes the first
self-consistent time-domain implementation based on single particle emission
taking the full complexity of air shower physics into account, and is freely
available for all interested users.Comment: 18 pages, 13 figures accepted by Astroparticle Physics (2010
Radio detection of cosmic rays: present and future
Digital radio detection of cosmic rays has made tremendous progress over the
past decade. It has become increasingly clear where the potential --- but also
the limitations --- of the technique lie. In this article, we discuss roads
that could be followed in future radio detection efforts and try to evaluate
the associated prospects and challenges.Comment: Contribution to the Proceedings of the UHECR2014 conference,
Springdale, UT; to be published in JPS Conf. Pro
Radio emission from cosmic ray air showers: simulation results and parametrization
We have developed a sophisticated model of the radio emission from extensive
air showers in the scheme of coherent geosynchrotron radiation, providing a
theoretical foundation for the interpretation of experimental data from current
and future experiments. Having verified the model through comparison of
analytic calculations, Monte Carlo simulations and historical experimental
data, we now present the results of extensive simulations performed with our
Monte Carlo code. Important results are the absence of significant asymmetries
in the total field strength emission pattern, the spectral dependence of the
radiation, the polarization characteristics of the emission (allowing an
unambiguous test of the geomagnetic emission mechanism), and the dependence of
the radio emission on important air shower and observer parameters such as the
shower zenith angle, the primary particle energy, the depth of the shower
maximum and the observer position. An analytic parametrization incorporating
the aforementioned dependences summarizes our results in a particularly useful
way.Comment: 33 pages, 24 figures, final version as accepted for publication by
Astropart. Physics, only minor updates since V
Monte Carlo simulations of radio emission from cosmic ray air showers
As a basis for the interpretation of data gathered by LOPES and other
experiments, we have carried out Monte Carlo simulations of geosynchrotron
radio emission from cosmic ray air showers. The simulations, having been
verified carefully with analytical calculations, reveal a wealth of information
on the characteristics of the radio signal and their dependence on specific air
shower parameters. In this article, we review the spatial characteristics of
the radio emission, its predicted frequency spectrum and its dependence on
important air shower parameters such as the shower zenith angle, the primary
particle energy and the depth of the shower maximum, which can in turn be
related to the nature of the primary particle.Comment: 5 pages, Proceedings of International Workshop on Acoustic and Radio
EeV Neutrino detection Activities: ARENA, May 17-19, 2005, DES
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