arXiv subjects

V. Ryabov

Publications and source records attributed to V. Ryabov.

9 recordsLinked to original sources

arXiv2023

Disturbances in the Doppler frequency shift of ionospheric signal and in telluric current caused by the atmospheric waves from an explosive eruption of Hunga Tonga volcano on January 15, 2022

After an explosive eruption of the Hunga Tonga volcano on January 15, 2022, disturbances were observed at a distance of about 12000km in Northern Tien Shan among the variations of the atmosphere pressure, of telluric current, and of the Doppler frequency shift of ionospheric signal. At 16:00:55UTC a pulse of atmospheric pressure was detected there with a peak amplitude of 1.3hPa and propagation speed of 0.3056km/s, equal to the velocity of Lamb wave. In the variations of the Doppler frequency shift, the disturbances of two types were registered on the 3212km and 2969km long inclined radio-paths, one of which arose as a response to the passage of a Lamb wave (0.3059km/s) through the reflection point of radio wave, and another as reaction to the acoustic-gravity wave (0.2602km/s). Two successive perturbations were also detected in the records of telluric current at the arrival times of the Lamb and acoustic-gravity waves into the registration point. According to the parameters of the Lamb wave, an energy transfer into the atmosphere at the explosion of the Hunga Tonga volcano was roughly estimated as 2000Mt of TNT equivalent.

physics.geo-ph↗

arXiv2022

Probing Fundamental Physics With Multi-Modal Cosmic Ray Events

The Horizon-T experiment in Tien Shan is based on the idea of measuring the time at which EAS disc passes the observation level with nanosecond accuracy. The detector system consists of ten charged particles registration points located at distances of up to several hundred meters from each other. The points are equipped with detectors based on registration of Cherenkov radiation in glass and registration of scintillation light in polystyrene. The detectors register the arrival times of charged particles at the observation level with a resolution of ~2 ns, as required to study the spatial and temporal characteristics of the EAS and the structure of the multi-modal events specifically. Over the period of the Horizon-T data taking since 2017 to present, a large number of multi-modal events were detected. The data has presented numerous challenges that show the direction towards the further development of the detector system and of the analysis methods and techniques that could be applied to these multi-modal events.

hep-ex↗

arXiv2021

Scaling violation in interaction of cosmic ray hadrons and the nature of the 3 PeV knee in the spectrum of primary cosmic rays

Energy spectra of the most energetic hadrons in the core region of extensive air showers (EAS) were studied in dependence on the EAS energy $E_0$ in the hybrid experiment HADRON at the Tien Shan mountain cosmic ray station. For the first time by direct measurement it was found in this experiment that the slope of the power energy spectrum of EAS hadrons diminishes itself locally, and the average hadron energy, correspondingly, increases between the $E_0$ borders 3PeV and 20PeV. Such behavior agrees with threshold appearance in EAS, in the same energy range, of a long-flying penetrative component which was earlier revealed at the Tien Shan station. Now we reconsider this Tien Shan result in comparison with the new data of modern collider experiments. The analysis permits to state unambiguously an astrophysical nature of the penetrative EAS component, and to discuss its probable connection with the origin of the famous knee in the energy spectrum of cosmic rays at $E_0\simeq 3$ PeV.

astro-ph.HE↗

arXiv2021

The rise of muon content in extensive air showers after the 3 PeV knee of the primary cosmic ray spectrum according to data of the Tien Shan mountain installation

We put together the experimental results on muon component of extensive air showers (EAS) which were gained with various techniques at the detector complex of the Tien Shan mountain station. According to this comparison, the problem of the EAS muon content in the range of primary cosmic ray energies (1-100)PeV seems to be more complicated than it was usually supposed. Generally, from the models of nuclear interaction it follows that the EAS which have produced gamma-hadron families in the Tien Shan X-ray emulsion chamber did preferably originate from interaction of the light cosmic ray nuclei, such that their muon abundance must be ~1.5 times below an average calculated over all showers. In contrary, the experimental muon counts in the EAS with families demonstrate a (1.5-2)-fold excess above the average, and this difference starts to be observable in the showers with the energy above the 3PeV knee of the primary cosmic ray spectrum. Later on, the rise of muon production in EAS after the knee was confirmed at Tien Shan by another experiment on detection of the neutrons stemmed from interaction of cosmic ray muons. Thus, the results obtained by the two completely different methods do mutually agree with each other but contradict to the common models of hadron interaction.

astro-ph.HE↗

arXiv2020

The prolonged gamma ray enhancement and the short radiation burst events observed in thunderstorms at Tien Shan

We report the observation results of the hard radiation flashes which accompanied the lightning discharges above the mountains of Northern Tien Shan. Time series of the counting rate intensity, numerical estimations of absolute flux, and energy distribution of accelerated electrons and of (20-2000)keV gamma rays were obtained at the height of 3700m a.s.l., immediately within thunderclouds, and in closest vicinity ($<$100m) to discharge region. Two different kinds of radiation emission events are presented here: a relatively prolonged rise of gamma ray intensity with minute-scale duration (the thunderstorm ground enhancement, TGE) which has preceded a negative field variation, and a short sub-millisecond radiation burst, which accompanied a close lightning discharge in thundercloud. It was revealed also an indication to positron generation in thunderclouds at the time of gamma ray emission, as well as modulation of the neutron counting rate in Tien~Shan neutron monitor which was operating at a (1.5-2)km order distance from the region of lightning development.

physics.ao-ph↗

arXiv2019

Underground neutron events at Tien Shan and the properties of the $10^{14}-10^{17}$ eV EAS muonic component

The events of multiple neutron production under 2000g/cm$^2$ thick rock absorber were studied at the Tien~Shan mountain cosmic ray station, at the altitude of 3340m above the sea level. From comparison of the experimental and Geant4 simulated neutron multiplicity spectra it follows that the great bulk of these events can be explained by interaction of cosmic ray muons with internal material of the neutron detector. In synchronous operation of the underground neutron monitor with the Tien~Shan shower detector system it was found that the characteristics of the muonic component of extensive air showers which is seemingly responsible for generation of the neutron events underground do change noticeably within the energy range of the knee of primary cosmic ray spectrum. Some peculiar shower events were detected when the neutron signal reveals itself only $\sim$(100--1000)\,$μ$s after the passage of the shower particles front which probably means an existence of corresponding delay of the muon flux in such events.

astro-ph.HE↗

arXiv2019

Measurements of the low energy neutron and gamma ray accompaniment of extensive air showers in the knee region of primary cosmic ray spectrum

Purposeful investigation of radiation fluxes strongly delayed in relation to the main particles front of extensive air shower (EAS) was undertaken at the Tien Shan Mountain Cosmic Ray Station. It was found that the passage of the EAS can be accompanied by the delayed thermal neutrons and by the soft $(30-50)$ keV gamma rays, mostly concentrated within a region of about $(5-10)$ m around shower axis, where the integral radiation fluence can vary in the limits of $(10^{-4}-1)$ cm$^{-2}$ for neutrons, and of $(0.1-1000)$ cm$^{-2}$ for gamma rays. The dependence of signal multiplicity on the shower size $N_e$ has a power shape both for the neutron and gamma ray components, with a sharp increase of its power index around the value of $N_e\approx 10^6$, which corresponds to the position of the $3\cdot10^{15}$ eV knee in the primary cosmic ray spectrum. Total duration of detectable radiation signal after the EAS passage can be of some tens of milliseconds in the case of neutron component, and up to a few whole seconds for gamma rays. The delayed accompaniment of low-energy radiation particles can be an effective probe to study the interaction of the hadronic component of EAS.

astro-ph.HE↗

arXiv2017

Digital receivers for low-frequency radio telescopes UTR-2, URAN, GURT

This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. Since 1998, digital receivers performing on-the-fly dynamic spectrum calculations or waveform data recording without data loss have been used at the UTR-2 radio telescope, the URAN VLBI system, and the GURT new generation radio telescope. Here we detail these receivers developed for operation in the strong interference environment that prevails in the decameter wavelength range. Data collected with these receivers allowed us to discover numerous radio astronomical objects and phenomena at low frequencies, a summary of which is also presented.

astro-ph.IM↗

arXiv2005

First measurement of the omega-meson production at RHIC by PHENIX

The PHENIX experiment at RHIC measured the omega-meson production in the range of pT from 2.5 GeV/c to 9.5 GeV/c in p+p and d+Au collision systems at sqrt{s_{NN}}=200 GeV. We present the consistent results of two independent measurements in decay channels omega-->pi^{0}pi^{+}pi^{-}$ and omega-->pi^{0}gamma. The omega/pi^{0} ratio was found to be 0.90+/-0.06. The Nuclear Modification Factor R_{dA} is 1.3+/-0.2 both in the Minimum Biased and (0%-20%) central event samples. The mass of the omega-meson was measured to be consistent with the PDG value within the errors of the measurement. We also measured the K_{S}^{0}-meson production in K_{S}^{0}-->pi^{0}pi^{0} in the same collision systems.

hep-ex↗