908 research outputs found
Steady magnetic-field generation via surface-plasma-wave excitation
International audienceThe possibility of inducing a magnetic field via surface plasma-wave excitation is investigated with a simple nonrelativistic hydrodynamic model. A static magnetic field is predicted at the plasma surface, scaling with the square of the surface-wave field amplitude, and the influence of the electron plasma density is studied. In the case of resonant surface-wave excitation by laser this result can be applied to low intensities such that the electron quiver velocity in the field of the surface wave is less than its thermal velocity
Efficient laser-overdense plasma coupling via surface plasma waves and steady magnetic field generation
International audienceThe efficiency of laser overdense plasma coupling via surface plasma wave excitation is investigated. Two-dimensional particle-in-cell simulations are performed over a wide range of laser pulse intensity from 10 15 to 10 20 W cm À2 lm 2 with electron density ranging from 25 to 100n c to describe the laser interaction with a grating target where a surface plasma wave excitation condition is fulfilled. The numerical studies confirm an efficient coupling with an enhancement of the laser absorption up to 75%. The simulations also show the presence of a localized, quasi-static magnetic field at the plasma surface. Two interaction regimes are identified for low (Ik 2 10 17 W cm À2 lm 2) laser pulse intensities. At " relativistic " laser intensity, steady magnetic fields as high as $580 MG lm/k 0 at 7 Â 10 19 W cm À2 lm 2 are obtained in the simulations
ASTRI SST-2M prototype and mini-array simulation chain, data reduction software, and archive in the framework of the Cherenkov Telescope Array
The Cherenkov Telescope Array (CTA) is a worldwide project aimed at building
the next-generation ground-based gamma-ray observatory. Within the CTA project,
the Italian National Institute for Astrophysics (INAF) is developing an
end-to-end prototype of the CTA Small-Size Telescopes with a dual-mirror
(SST-2M) Schwarzschild-Couder configuration. The prototype, named ASTRI SST-2M,
is located at the INAF "M.C. Fracastoro" observing station in Serra La Nave
(Mt. Etna, Sicily) and is currently in the scientific and performance
validation phase. A mini-array of (at least) nine ASTRI telescopes has been
then proposed to be deployed at the Southern CTA site, by means of a
collaborative effort carried out by institutes from Italy, Brazil, and
South-Africa. The CTA/ASTRI team is developing an end-to-end software package
for the reduction of the raw data acquired with both ASTRI SST-2M prototype and
mini-array, with the aim of actively contributing to the global ongoing
activities for the official data handling system of the CTA observatory. The
group is also undertaking a massive Monte Carlo simulation data production
using the detector Monte Carlo software adopted by the CTA consortium.
Simulated data are being used to validate the simulation chain and evaluate the
ASTRI SST-2M prototype and mini-array performance. Both activities are also
carried out in the framework of the European H2020-ASTERICS (Astronomy ESFRI
and Research Infrastructure Cluster) project. A data archiving system, for both
ASTRI SST-2M prototype and mini-array, has been also developed by the CTA/ASTRI
team, as a testbed for the scientific archive of CTA. In this contribution, we
present the main components of the ASTRI data handling systems and report the
status of their development.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC
2017), Bexco, Busan, Korea. All CTA contributions at arXiv:1709.0348
Grid services for the MAGIC experiment
Exploring signals from the outer space has become an observational science
under fast expansion. On the basis of its advanced technology the MAGIC
telescope is the natural building block for the first large scale ground based
high energy gamma-ray observatory. The low energy threshold for gamma-rays
together with different background sources leads to a considerable amount of
data. The analysis will be done in different institutes spread over Europe.
Therefore MAGIC offers the opportunity to use the Grid technology to setup a
distributed computational and data intensive analysis system with the nowadays
available technology. Benefits of Grid computing for the MAGIC telescope are
presented.Comment: 5 pages, 1 figures, to be published in the Proceedings of the 6th
International Symposium ''Frontiers of Fundamental and Computational
Physics'' (FFP6), Udine (Italy), Sep. 26-29, 200
The MAGIC Experiment and Its First Results
With its diameter of 17m, the MAGIC telescope is the largest Cherenkov
detector for gamma ray astrophysics. It is sensitive to photons above an energy
of 30 GeV. MAGIC started operations in October 2003 and is currently taking
data. This report summarizes its main characteristics, its rst results and its
potential for physics.Comment: 6 pages, 3 figures, to be published in the Proceedings of the 6th
International Symposium ''Frontiers of Fundamental and Computational
Physics'' (FFP6), Udine (Italy), Sep. 26-29, 200
The electromagnetic calorimeter of the AMS-02 experiment
The electromagnetic calorimeter (ECAL) of the AMS-02 experiment is a
3-dimensional sampling calorimeter, made of lead and scintillating fibers. The
detector allows for a high granularity, with 18 samplings in the longitudinal
direction, and 72 sampling in the lateral direction. The ECAL primary goal is
to measure the energy of cosmic rays up to few TeV, however, thanks to the fine
grained structure, it can also provide the separation of positrons from
protons, in the GeV to TeV region. A direct measurement of high energy photons
with accurate energy and direction determination can also be provided.Comment: Proceedings of SF2A conference 201
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