Pulsations of the geomagnetic field associated with variations in cosmic ray intensity during thunderstorms

It was discovered that strong variations in the intensity of secondary cosmic rays observed during thunderstorms and earlier interpreted as a consequence of the cyclic generation of electrons and positrons in a strong electric field are accompanied in some cases by well-pronounced pulsations of the geomagnetic field. An experiment was performed with the CARPET array for studying extensive air showers of cosmic rays. This array, located in the Baksan Valley (North Caucasus), was used as a particle detector. Magnetic measurements were made using a high-precision magnetic variation station located deep underground in a tunnel of the Baksan Neutrino Observatory at a distance of about 4 km from the CARPET array.     

Direction of the anisotropy vector of TeV cosmic rays

The preliminary results of measuring the direction of the stellar anisotropy vector of cosmic rays with the Carpet array at the Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) are presented. The direction of the anisotropy vector is determined by analyzing the distribution of time delays of the signal from distant detectors of the array with respect to its central part. It is shown that the anisotropy vector has the direction α₀ (R.A.) ≈ 1.5 h, δ₀ ≈ 62° in the equatorial coordinate system. At such a direction, the CR anisotropy measured with the Baksan Underground Scintillation Telescope and the Andyrchi array is ≈0.2%.     

Studying the muon and hadron components of extensive air showers with the Carpet-2 array

The method of separating muons and hadrons recorded by the Muon Detector of the Carpet-2 air shower array of Baksan Neutrino Observatory (Institute for Nuclear Research, Russian Academy of Sciences) is described. The results of studying characteristics of the muon and hadron components of extensive air showers (EAS) with N _e ≥ 10⁵ are presented. For the range of distances 40–55 m from shower axes the numbers of hadrons with energies higher than 30 GeV and muons with energies above 1 GeV are obtained as functions of the shower size N _e .     

Two Bursts of Ultra-High Energy Gamma Rays Detected by the Baksan Air Shower Array

Physics of Atomic Nuclei - During a Cygnus X-3 campaign many years ago the Carpet air shower array of the Baksan Neutrino Observatory had recorded two bursts from two different sources: from the...     

Effect of the near-Earth electric field on the intensity of the soft component of cosmic rays

The transformation of the energy spectrum of the electron-positron component of cosmic rays in the energy range 10–100 MeV in the near-Earth electric field of thunderstorm atmosphere has been estimated analytically by solving the kinetic equation for secondary cosmic rays in the one-dimensional case. The solution obtained adequately describes the observed variations in the soft component in moderate electric fields (±7 kV m^?1).     

Variations of Cosmic Ray Muons during Thunderstorms

Journal of Experimental and Theoretical Physics - This article briefly reviews the results of an experiment initiated by A.E. Chudakov. The first results were obtained in pioneering works under his...     

Lateral distribution function of charged particles in EAS near the axis

High-precision measurements of the lateral distribution function (LDF) of charged particles near the axis of extensive air showers (EASes) were performed with the CARPET air shower array of the Baksan Neutrino Observatory for several ranges of N _e , including the knee region. For the sake of comparison with the experiment, calculations for primary protons and iron nuclei were made using the CORSIKA code (the QGSJET01C model of interaction). The measured experimental LDF is compared with our calculations.     

Statistical properties of variations in cosmic ray muons during thunderstorms

An analysis is made of experimental data on variations in muons with a threshold of 100 MeV, detected by the CARPET air shower array in the Baksan Valley during thunderstorms of 2008. It is shown that with using a special criterion for selecting statistically significant variations (0.2%), muon intensity variations are observed in the majority of cases. Their characteristic duration is ∼8 min. Their amplitudes can have different polarities and do not exceed 1%.     

Cygnus X-3 observation in gamma-ray energy range >1014 eV

Summary We present experimental data on observations of Cygnus X-3 using an air shower array. The angular resolution of the array is of the order of 1 degree and the median energy of showers isE ₀≿10¹⁴ eV. During one year of observation there was no absolute excess of the number of showers from the source region and a small peak at the phase plot has only limited statistical significance. The value of UHE gammaray flux (if there exists any) seems to be in contradiction with values previously reported by Kiel and Haverah Park groups. We have analysed separately a sample of experimental data covering the short period in October 1985, when a radioburst from Cygnus X-3 was observed. Considerable excess of showers from the source was found in this sample: it lasted for three days with the maximal effect (40% excess) in the first one, 14th of October 1985.

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Riassunto Presentiamo i risultati sperimentali di osservazioni di Cygnus X-3 condotte mediante un apparato sciami. La risoluzione angolare dell'apparato è dell'ordine di 1 grado e l'energia mediana degli eventiE ₀≿10¹⁴ eV. Durante un anno di osservazioni non si è rivelato alcun eccesso assoluto di conteggi dalla regione della sorgente; un debole picco nel diagramma di fase ha una limitata significatività statistica. Il limite superiore al flusso di raggi gamma di altissima energia sembra essere in contraddizione con i valori riportati dai gruppi di Kiel ed Haverah Park. Abbiamo analizzato separatamente i dati dell'Ottobre 1985 in coincidenza con il burst osservato da Cygnus X-3 a frequenze radio. Si è trovato, in questo campione, un notevole eccesso di conteggi dalla sorgente della durata di tre giorni, il massimo effetto (40%) è osservato il 14 ottobre 1985.

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Резюме Мы приводим эксперементальные данные наблюдений излучения Лебедь X-3, использыя антенную решетку для детектирования атмосферных ливней. Угловое разрешение антенной решетки имеет порядок одного градуса, а медианная энергия ливней составляетE≿10¹⁵ эВ. В течение одного года наблюдений не было обнаружено абсолютного увеличения числа ливней из области источника, а небольшой пик на фазовой диаграмме имеет только ограниченную статистическую значимость. Верхний предел потока гамма-лучей сверхвысоких энергий, по-видимому, находится в противоречии с ранее опубликованными величннами. Мы анализируем отдельно выборку экспериментальных данных, полученных в течение короткого периода октября 1985, когда наблюдалаць радиовспышка из Лебедя X-3. В этой выборке обнаружен значительный избытол ливней из источнка в течение трех дней, причем максимальный эффект (40%) наблюдался 14 октября.

     

The Carpet-3 EAS Array for Investigation of Gamma-Radiation with Energy $$\boldsymbol{E>100}$$ TeV

Physics of Atomic Nuclei - The Carpet-3 experiment for investigation of gamma radiation with energy above 100 TeV is currently being prepared at the Baksan Neutrino Observatory of the Institute for...