Cosmic ray spectrum obtained from the energy scattered by the particles of extensive air showers in the atmosphere and the galactic model

The differential energy spectrum of cosmic rays that is obtained on the basis of the measurements of Cherenkov radiation from extensive air showers in an energy range of 10¹⁵–10²⁰ eV is compared with the model of the propagation of primary particles in the interstellar medium with fractal properties. It is found that the shape of the experimental spectrum is in good agreement with the shape of the calculated spectrum of “all particles” at 10¹⁵–10¹⁸ eV. The average mass composition of cosmic rays that is calculated on the basis of five components does not contradict the average mass composition obtained from the experimental data for several parameters in this energy range.     

Cosmic ray energy spectrum from measurements of air showers

This review focuses on high-energy cosmic rays in the PeV energy range and above. Of particular interest is the knee of the spectrum around 3 PeV and the transition from cosmic rays of Galactic origin to particles from extra-galactic sources. Our goal is to establish a baseline spectrum from 1014 to 10^20 eV by combining the results of many measurements at different energies. In combination with measurements of the nuclear composition of the primaries, the shape of the energy spectrum places constraints on the number and spectra of sources that may contribute to the observed spectrum.     

Cosmic ray air showers in the knee energy region

The cosmic ray extensive air showers in the knee energy region have been studied by the North Bengal University array. The differential size spectra at different atmospheric depths show a systematic shift of the knee towards smaller shower size with the increase in atmospheric depth. The measured values of spectral indices at below and above the knee are −2.45 ±0.03 and −2.91 ±0.05 respectively. Measurements at different atmospheric depths correspond to the same values within the error limits both for below and above the knee. The present experimental results have been compared with similar such experiments     

Cosmic ray spectrum produced by galactic supernova remnants

Cosmic ray acceleration by supernova shocks is considered. A new numerical code is used to describe the cosmic ray acceleration and shock wave evolution. The magnetohydrodynamic turbulence generation in the shock precursor by streaming instability of accelerated particles is taken into account. The cosmic ray spectrum produced by supernova explosion in uniform interstellar medium is simulated.     

High energy physics in the atmosphere: phenomenology of cosmic ray air showers

The properties of cosmic rays with energies above 10⁶ GeV have to be deduced from the spacetime structure and particle content of the air showers which they initiate. In this review we summarize the phenomenology of these giant air showers. We describe the hadronic interaction models used to extrapolate results from collider data to ultra high energies, and discuss the prospects for insights into forward physics at the LHC. We also describe the main electromagnetic processes that govern the longitudinal shower evolution, as well as the lateral spread of particles. Armed with these two principal shower ingredients and motivation from the underlying physics, we provide an overview of some of the different methods proposed to distinguish primary species. The properties of neutrino interactions and the potential of forthcoming experiments to isolate deeply penetrating showers from baryonic cascades are also discussed. We finally venture into a terra incognita endowed with TeV-scale gravity and explore anomalous neutrino-induced showers.     

Macroscopic model of radio emission from extensive air showers

A macroscopic model of radio emission from extensive air showers is developed. This model is appropriate for calculating this radio emission at frequencies below 100 MHz. It is constructed on the basis of an analysis of the radiation integral and is verified by comparing field observables predicted by the model with the respective results obtained within the microscopic approach to calculating radio emission from extensive air showers.     

Search for heavy mass particles in extensive air showers

A large multiplate cloud chamber with fast timing scintillators inside is being operated with the extensive air shower array at Ootacamund to further elucidate the time structure of high energy hardons in air showers. The major interest in the present investigation is to understand the nature of the large delay (>20 ns) high energy (>40 GeV) events that appeared as strong cndidates for heavy mass particles in an earlier experiment carried out with a total absorption spectrometer. Two events observed during one year’s operation of the experiment are discussed. Now deceased.     

Methods for estimating the energy of extensive air showers

A multilevel scheme for calculating estimates of the energy of extensive air showers on the basis of signals in different detectors is considered. The numerical energy estimates at specified values of signals in scintillation detectors are smaller than the experimental ones by a factor of about 1.6. The results of the calculation confirmed that the total flux of Cherenkov light is proportional to the shower energy. The flux of fluorescent light generated within 100 m from the shower core is due to only 60% of the total energy.     

Cosmic ray constraints on the annihilations of relic particles in the galactic halo

We re-evaluate the fluxes of cosmic ray antiprotons, positrons and gamma rays to be expected from the annihilations of relic particles in the galactic halo. We stress the importance of observational constraints on the possible halo density of relic particles, and specify their annihilation cross sections by the requirement that their cosmological density close the Universe. We use a Monte Carlo programme adapted to fit e⁺e⁻ data to calculate the p̄, e⁺ and γ spectra for some supersymmetric relic candidates. We find significantly smaller p̄ fluxes than previously estimated, and conclude that present upper limits on cosmic ray p̄ and e⁺ do not exclude any range of sparticle masses. We discuss the prospects for possible future constraints on sparticles from cosmic γ rays.     

Delayed muons in extensive air showers and double-front showers

The results of a long-term experiment performed in the period between 1995 and 2006 with the aid of the MUON-T underground (20 mwe) scintillation facility arranged at the Tien Shan mountain research station at an altitude of 3340 m above sea level are presented. The time distribution of delayed muons with an energy in excess of 5 GeV in extensive air showers of energy not lower than 106 GeV with respect to the shower front was obtained with a high statistical significance in the delay interval between 30 and 150 ns. An effect of the geomagnetic field in detecting delayed muons in extensive air showers was discovered. This effect leads to the asymmetry of their appearance with respect to the north-south direction. The connection between delayed muons and extensive air showers featuring two fronts separated by a time interval of several tens of to two hundred nanoseconds is discussed. This connection gives sufficient grounds to assume that delayed muons originate from the decays of pions and kaons produced in the second, delayed, front of extensive air showers.     

Acoustic phenomena caused by extensive air showers in Baikal

The sonic files were written in the scheme of trigger start from a scintillation facility in order to study the acoustic phenomena caused by extensive air showers (EASs). With an aim to study the acoustic effects, the methods of peaks and anticoincidences (with an amplitude-independent algorithm) and the method of small peaks were suggested. Similar sonic effects (obtained in different geometries and at different noise levels) indicate that acoustic phenomena caused by EASs are detected.     

Simulations of radio emission from ultrahigh-energy extensive air showers

The radio emission from extensive air showers with energies up to 10¹⁷ eV has been calculated. The calculated lateral distribution of the radio emission is in good agreement with the LOPES-10 experimental data.     

Detection and analysis of radio pulses from extensive air showers

Radio pulses from extensive air showers (EAS) at 30, 44, and 60 MHz frequencies have been studied, using wide band broad-side arrays of half-wave dipole antenna systems. The experimental results support the theoretical prediction that the field strength of radio emission depends on the shower size. An asymmetry has been noticed in the pulse height distributions of radio pulses detected by North-South and East-West directed arrays. These observations are in agreement with the theory that the charge separation mechanism is predominant in generating radio pulses from EAS and radio emission is polarised in the East-West direction. Experimental data are compared with those of earlier workers.     

On the angular distribution of extensive air showers

Angular distributions of extensive air showers with different number of charged particles in the range 2.5 × 10⁵–4 × 10⁷ are derived using the experimental data obtained with the EAS MSU array. Possible approximations of the obtained distributions with different empiric functions available in literature, are analyzed. It is shown that the exponential function provides the best approximation of the angular distributions in the sense of the χ² criterion.     

Cosmic ray spectrum measured by the PRISMA-32 setup

The results of measurements of the spectrum of extensive air showers (EASs) by the number of neutrons detected by the PRISMA-32 setup are presented. The neutron component is formed during the interaction of high-energy shower hadrons with nuclei of atmospheric and Earth’s surface atoms. The PRISMA-32 setup consists of 32 en-detectors and operates in the continuous mode for about 5 years.     

Spatial distribution of Čerenkov light from extensive air showers

The spatial distribution function of Čerenkov radiation from particles of extensive air showers with energies in the interval 10¹²–10¹⁷ eV calculated by the computer code CORSIKA and the approximation constructed on the basis of this calculation have allowed us to reconstruct the events, that is, to reconstruct the type and energy of the particle that generated extensive air shower from signal amplitudes of Čerenkov light registered with the Tunka-25 facility. The calculated spatial distribution function of Čerenkov light is in good agreement with the fitting function constructed in [1–4] to reconstruct the parameters of extensive air showers registered with the Tunka-25 facility. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 7, pp. 43–48, July, 2006.