The results of an experimental study of the capture, transport, and subsequent destruction of the air cavity into bubbles by the magnetic fluid in the area of the ‘magnetic vacuum’ of the annular magnet are discussed. The study was performed using video recording and recording of electromagnetic and acoustic signals.

The Yakutsk array has been used to study cosmic rays since 1974. Charged particles such as electrons, positrons and muons are detected, as well as radio signals emitted by air showers. However, the characteristic shower component detected by the array is Cherenkov light. This article briefly reviews recent results from the Yakutsk array group.

A proposed new method for measuring the Cherenkov light from extensive air showers (EAS) of cosmic rays (CR), which allows to determine not only the primary particle energy and angle of arrival, but also the parameters of the shower in the atmosphere - the maximum depth and “age”. For measurements, it is proposed to use Cherenkov light produced by EAS in a ground network of wide-angle telescopes, which are separated from each other by a distance 100-300 m depending on the total number of telescopes operating in coincidence, acting autonomously, or includes a detector of the charged components, radio waves, etc. as part of the EAS. The energy measurement and CR angle of arrival, data on the depth of the maximum and the associated mass of the primary particle generating the EAS is particularly important in the study of galactic cosmic rays for E> 10 14 eV, where currently there are no direct measurements of the maximum depth of the EAS.

Arrival directions of ultra-high energy cosmic rays (UHECRs) in the equatorial system, detected with the Yakutsk array in the energy range (10(17) - 10(1) eV), are re-analyzed using a new approximation for the zenith angle distribution of the event rate of extensive air showers (EAS). While the null hypothesis cannot be rejected based on the data used here, an upper limit on the fraction of cosmic rays from a separable source in the uniform background is derived as a function of declination and energy.

Arrival directions of ultra-high energy cosmic rays (UHECRs) in the equatorial system, detected with the Yakutsk array in the energy range (1017 -10 19 eV), are re-analyzed using a new approximation for the zenith angle distribution of the event rate of extensive air showers (EAS). While the null hypothesis cannot be rejected based on the data used here, an upper limit on the fraction of cosmic rays from a separable source in the uniform background is derived as a function of declination and energy.

This report presents a prototype Cherenkov telescope, the observation method of Cherenkov light from extensive air showers (EAS) generated by cosmic rays (CRs) above 1016 eV and preliminary observations. The interest in Cherenkov light differential detectors of EAS is caused by the possibility to measure the depth of the cascade maximum, Xmax, and/or the shower age via angular and temporal distributions of the Cherenkov signal. In particular, it was shown, using EAS model simulations, that the pulse width measured at the periphery of the shower, r > 300 m, at sea level is pronouncedly connected with Xmax. The Cherenkov detector is a wide-angle telescope working in coincidence with scintillation detectors, integral and differential Cherenkov detectors at the Yakutsk complex EAS.

The Yakutsk array dataset in the energy interval (3✕1016;1019) eV is re-visited in order to interpret the zenith angle distribution of extensive air shower event rate. The close relation of the distribution to the attenuation of the main measurable parameter of showers, S600, is examined. Knowledge of the threshold effect on fluctuations of the parameter is essential in order to calculate surface array exposure.

A proposed new method for measuring the cherenkov light from extensive air showers (EAS) of cosmic rays (CR), which allows to determine not only the primary particle energy and angle of arrival, but also the parameters of the shower in the atmosphere - the maximum depth and "age". For measurements it is proposed to use cherenkov light produced by EAS in a ground network of wide-angle telescopes which are separated from each other by a distance 100-300 m depending on the total number of telescopes operating in coincidence, acting autonomously, or includes a detector of the charged components, radio waves, etc. as part of the EAS. Results of such an array should be developed. The energy measurement and CR angle of the arrival data on the depth of the maximum and the associated mass of the primary particle generating by EAS. This is particularly important in the study of galactic cosmic ray for $E> 10^{14} $eV, where currently there are no direct measurements of the maximum depth of the EAS.

We present the results of the analysis of cosmic rays spectrum in energy domain above $10^{17}$ eV. The analysis covers extensive air showers registered over the course of continuous observations from 1974 to 2017. A new refined relation was applied to reconstruct primary energy in individual events. It was derived from the lateral distribution of responses of surface and underground detectors of the Yakutsk EAS array obtained in air shower simulations with four hadron interaction models -- QGSJet01, QGSJet-II-04, SIBYLL-2.1 EPOS-LHC. The resulting new energy estimation is 1.4 times lower than the values obtained earlier with calorimetric method.

A proposed new method for measuring the cherenkov light from extensive air showers (EAS) of cosmic rays (CR), which allows to determine not only the primary particle energy and angle of arrival, but also the parameters of the shower in the atmosphere – the maximum depth and “age”. For measurements it is proposed to use Cherenkov light produced by EAS in a ground network of wide-angle telescopes which are separated from each other by a distance 100–300 m depending on the total number of telescopes operating in coincidence, acting autonomously, or includes a detector of the charged components, radio waves, etc. as part of the EAS. Results of such an array should be developed. The energy measurement and CR angle of the arrival data on the depth of the maximum and the associated mass of the primary particle generating by EAS. This is particularly important in the study of galactic cosmic ray for E > 1014 eV, where currently there are no direct measurements of the maximum depth of the EAS.

Cherenkov telescope for study cosmic rays L.V.TIMOFEEV Figure 1: The photo multiplier Hamamatsu R2486 with coordinate-sensitive anode consisting of 16X16 crossed wires has been chosen for the Cherenkov telescope prototype.

The results of the Yakutsk array experiment aimed at investigations of ultra-high energy cosmic rays (UHECRs) are presented. We outline the current status of the instrument and an outlook for future directions and areas of study.

One of the main goals of investigations using present and future giant extensive air shower (EAS) arrays is the mass composition of ultra-high energy cosmic rays (UHECRs). A new approach to the problem is presented, combining analysis of arrival directions with the statistical test of the pairs of EAS samples. An idea of the method is to search for possible correlations of UHECR masses with their presumably separate sources. The method is based on a non-parametric statistical test, specifically Wilcoxon rank sum routine, which does not depend on the populations fitting any parameterized distributions.

In this work we present cosmic ray spectrum (CR) and mass composition data obtained from Cherenkov radiation measurements at the Yakutsk EAS array. Mass composition was determined from the maximum of shower developmentXmax. The energy dependence ofXmax was compared to simulation results (EPOS and QGSjetII-03) for p and Fe primaries. Within the framework of these models and superimposition method, an estimation for mass composition of cosmic rays was made in energy region of 10 − 5 × 10 eV. At E0 = 10 eV, 〈log A〉 value is 2.6 ± 0.4. Discrepancy in estimated values results as from precision ofXmax measuring in various experiments, so from systematics arising from the chosen hadronic model. Two scenarios were considered for interpretation of the obtained result: 1)CR spectrum is generated by supernovae remnants (SNRs) and dominates at10 eV, at higher energies spectrum is formed by particles of metagalactic origin (dip-scenario); 2)Spectrum is composed of three components: CR from SNRs, galactic cosmic rays modulated by galactic star wind near 10 eV and metagalactic CR with hard spectrum above10 eV (ankle-scenario). It is shown that energy dependence of CR mass composition better fits to the anklescenario, while spectrum is well-described by the dipscenario. The unambiguous answer to this question requires more precise experimental data on mass composition and further theoretical research.

Model calculations are performed of extensive air shower (EAS) component energies using a variety of hadronic interaction parameters. A conversion factor from electromagnetic component energy to the energy of ultra-high energy cosmic rays (UHECRs) and its model and primary mass dependence is studied. It is shown that model dependence of the factor minimizes under the necessary condition of the same maximum position and muon content of simulated showers.

Transport equations for cascading particles in extensive air shower of cosmic rays can be transformed to Volterra equations of the second kind. The numerical resolvent for equation is constructed on the two-dimensional lattice in the case of longitudinal development of shower. The method can be used as an efficient alternative to Monte Carlo technique becoming cumbersome at the highest energies.

In the work the data of the Yakutsk complex EAS array and their comparison with calculation in the case of primary nuclei of different chemical elements are presented. The calculation by QGSJET model have been used interpreting experimental data.

The design, development approach, and development results for the main oxidizer turbopump assembly (main oxidizer TPA) for the 60,000 lb (270 kN) RL60 oxygen-hydrogen engine are described. The main oxidizer TPA was developed by the Chemical Automatics Design Bureau (CADB) under a program funded by Pratt & Whitney to develop a new generation of expander cycle engines. The purpose of developing the main oxidizer TPA was to give the engine good performance while holding down manufacturing and maintenance costs. The main oxidizer TPA pumps liquid oxygen, and the turbine’s drive fluid is gaseous hydrogen. Main oxidizer TPA development methodology based on CADB’s extensive experience consisting of element-byelement development of its component parts on model (substitute) media and conditions is presented. The authors note that element-by-element development ensures good performance of the assembly, as well as determining the operating limits of its structural components, and reveals ways of improving the TPA design. Types and results of main oxidizer TPA testing are presented.