The problem of cosmic ray mass composition is considered in the context of its current state and prospects for achieving progress in the nearest future due to improving data quality of ground-based ...Extensive Air Shower arrays of different scales. The theoretically motivated approach based on scaling description of electron and muon lateral distributions measured with surface detectors with nearly 100
duty cycle is discussed as a tool for robust mass composition estimation within a single method in a broad primary energy range applicable for different experiments taking into account their upcoming upgrades.
The results of a complex approach to the study of sensitivity of spatial distributions of electron and muon components of extensive air showers (EAS), measured by scintillation detectors, to ...variations in the temperature profile of the atmosphere are presented. To describe the lateral dependence of the spatial distribution function (SDF) of electrons in electron–photon cascades (EPC) and the SDF of muons of EAS, the method of the adjoint equations and also the variational theory of sensitivity, developed by the authors, were used. Spatial distributions of electron and muon components of EAS, as well as the corresponding differential temperature coefficients, were simulated by Monte Carlo methods. To assess the effect of variations in the temperature profile of the atmosphere on the spatial distribution of particles satellite monitoring of main parameters of the system ‘‘atmosphere–underlying surface’’ was carried out at locations of Yakutsk complex EAS array and TAIGA observatory. As a result, coefficients of differential sensitivity of spatial distributions of electrons and muons to variations in the temperature profile of the atmosphere were obtained for the first time. Corrective function that relates the energy release in scintillation detectors of various thicknesses with the electrons’ density above the detector at various distances from the shower axis were established. Based on the obtained data, a method for correcting the EAS detectors’ readings in view of the temperature effect has been developed. It is shown that changes in SDFs of the EAS electromagnetic component due to variations in the atmospheric temperature profile in one annual cycle of operation can exceed 10
.
A new scenario of the formation of observed ultrahigh-energy cosmic-ray electron/positron and nuclei spectra is discussed within a nonclassical (superdiffusion) model of particle propagation in ...highly inhomogeneous interstellar and intergalactic media. It is shown that the proposed scenario provides a consistent description of data from highly precise satellite measurements, ground-based hybrid EAS arrays, and Cherenkov telescopes using the spectra of leptons and nuclei, and the mass composition of cosmic rays in the super- and ultrahigh ranges of energy.
Recent balloon-borne and satellite experiments have established new features in the behavior of the spectra of cosmic rays. An analysis of all the data showed that hardening of most abundant primary ...cosmic ray nuclei spectra with increasing rigidity is observed in > 200 GV region. At the same time, rigidity dependences of secondary cosmic rays are distinctly different. The AMS-02 data show that above 200 GV the secondary cosmic rays Li, Be, B harden more than the primary He, C, O. In this paper we discuss a new scenario that self-consistently describes these new features of the cosmic ray spectra. We demonstrate that the measured by the AMS-02 changes in the slope of the cosmic ray spectra caused by the transition from the contribution of multiple distant Galactic sources, including the nuclear interactions of the particles accelerated by these sources with an interstellar medium during their wandering in the Galaxy, to the contribution of mainly local ones. We also found that the spectral universality is observed at rigidity R > 105 GV.
The possibility for a self-consistent description of all the basic features of the observed cosmic ray spectra and primary composition variations in the energy range of 1015 ÷ 1020 eV within the ...Galactic origin scenario is examined. We assume the existence of Galactic sources that accelerate particles up to ∼ 3 · 1018Z eV and take into account a highly inhomogeneous (fractal-like) distribution of matter and magnetic fields in the Galaxy that leads to extremely large free paths of particles (“Lévy flights”), along with an overwhelming contribution to the cosmic ray fluxes observed above ∼1018 eV from particles reaching the Solar System without scattering. Our scenario was refined on the basis of recent experimental results on primary mass composition. Model predictions, which could be verified with the improved high-precision measurements in the nearest future are discussed.
We consider the problem of night-time atmosphere monitoring at the locations of the Yakutsk EAS array and the TAIGA observatory for the annual October-April period of observations at these ...facilities. It is shown that the use of data from instruments aboard Terra, Aqua, Suomi-NPP and NOAA-20 satellites, received by the ground stations of the Altai State University, Russia, and processed to Level 2 (retrieval of geophysical parameters of the atmosphere), gives the possibility of the near-real-time monitoring observations of the cloud cover structure and the temperature profiles at night with a spatial resolution and a frequency sufficient for meteorological correction of the detector readings.
The sensitivity of the lateral distribution of the EAS electron component to variations in the atmospheric temperature profile is investigated. An approach developed by the authors on the basis of ...the variational theory of sensitivity is used to solve the problem. The differential sensitivity coefficients of the lateral distribution of EAS electrons to variations in the temperature profile are obtained for the first time. A method of adjusting a ground-based EAS array’s data for the temperature effect is proposed.
The TAIGA experiment in the Tunka valley near Lake Baikal is planning an extension with new TAIGA-Muon scintillation detector stations. The main purpose of TAIGA is gamma-ray astronomy in the TeV to ...PeV energy range and cosmic ray physics. The purpose of the Taiga-Muon detectors is to measure the muon component of air showers for improving cosmic ray composition measurements as well as gamma–hadron separation above 100 TeV. Monte Carlo simulations of the experiment are done with the software packages CORSIKA and GEANT4. Extensive air showers of primary particles in the energy range 100–3000 TeV are created with CORSIKA. The trigger efficiency is calculated and used for optimization. The suppression factor of hadronic showers versus electromagnetic showers is studied, leading to an optimum depth of soil absorber (2 m), at the lowest energy range. Data on the identification efficiency for primary gamma-quanta and proton events are presented as well as the suppression factor.
A new approach to deducing the mass composition of primary cosmic rays is proposed using the air showers universality and the scaling property of the electron lateral distribution function. ...Experimental data from the KASCADE, MSU, and KASCADE-Grande arrays have been analyzed, allowing conclusions as to the variations of mass composition above the knee to be drawn independently of the hadron-nucleus interaction model.
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The paper is devoted to the modeling and analysis of data detected by the TAIGA-IACT installation in the stereo mode. Five Imaging Atmospheric Cherenkov Telescopes (IACT) with a viewing angle of ...9.6° are expected to be included in the installation. Today there are three telescopes spaced far apart (from 320 to 500 m) in the installation. The effective area of the installation is as large as 0.6 km
2
; therefore, it is possible to conduct statistically significant measurements of weak γ-ray sources in the energy range above 10 TeV over a reasonable observation time (300–400 h). The Monte Carlo procedure for simulating the hadrons and γ-rays detected by the telescopes is described as is the procedure for reconstructing the parameters of extensive air showers, such as the arrival direction of an event, the axis position, the depth of the maximum of shower development (
X
max
), and the primary-particle energy. In order to solve the problem of γ-hadron separation, the criteria for selecting γ-rays detected in the stereo mode have been optimized and the effective area of the installation has been calculated.
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