Shabalin A.N., Charikov Yu.E. «Electron acceleration in models with a vertical current sheet» Научно-технические ведомости Санкт-Петербургского государственного политехнического университета. Физико-математические науки, 16, № S1.2, с. 485-491 (2023)

Model of solar flares with a vertical current sheet and a cusp above the magnetic arcade is considered. In some flares, such magnetic field geometry can be observed directly in the extreme ultraviolet range. According to the model, the relaxation of helmet-like magnetic loops formed due to magnetic field reconnection is supposed. During the relaxation, the magnetic field and the loop length vary with time. Consequently, a betatron acceleration and first-order Fermi electron acceleration appeared. In a kinetic approach the time-dependent kinetic equation for the distribution function of initially accelerated electrons is numerically solved. It is shown that because of such acceleration, the electron energy spectra changes significantly. The proportion of high-energy electrons with energies of more than 200 keV increases by 1–3 orders of magnitude depending on the pitch-angular distribution of accelerated electrons formed in the primary accelerator – the current sheet.

Trofimov D.A., Petrov S.D., Kalishin A.S., Lukin V.V., Serov Yu.A., Chekunov I.V. «Structure and variations of the south-polar ionosphere by GNSS- tomography» Научно-технические ведомости Санкт-Петербургского государственного политехнического университета. Физико-математические науки, 16, № S1.2, с. 505-510 (2023)

The paper is devoted to determination of the total electron content in the vicinity of the South geomagnetic pole using observations by global navigation satellite systems. Observations were carried out at the Russian Antarctic station Vostok in the periods February 2016 – January 2017, February 2018 – February 2019 and February 2020 – January 2021. Observations were made with satellites of GPS and GLONASS systems. Processing of observations was carried out by use of the TEC-suite software. Total electron content series were obtained for the specified time periods. Our results were compared with those of Center for Orbit Determination in Europe, there is a good agreement, based on which we conclude that our data are reliable. For all periods of observation, average daily profiles of changes in the total electron content in winter and summer were plotted. An excess of the winter total electron content measured from global navigation satellite systems observations over the model data provided by Center for Orbit Determination in Europe by about 5 total electron content unit was noted.

Ivanova A.L., Astapov I.I., Bezyazeekov P.A., Bonvech E.A., Borodin A.N., Budnev N.M., Bulan A.V., Chernov D.V., Chiavassa A., Dyachok A.N., Gafarov A.R., Garmash A.Yu., Grenebyuk V.M., Gres E.O., Gres O.A., Gres T.I., Grinyuk A.A., Grishin O.G., Ivanova A.D., Ilushin M.A., Kalmykov N.N., Kindin V.V., Kiryukhin S.N., Kokoulin R.P., Kompaniets K.G., Korosteleva E.E., Kozhin V.A., Kravchenko E.A., Kryukov A.P., Kuzmichev L.A., Lagutin A.A., Lavrova M.V., Lemeshev YU.E., Lubsandorzhiev B.K., Lubsandorzhiev N.B., Malakhov S.D., Mirgazov R.R., Monkhoev R.D., Okuneva E.A., Osipova E.A., PakhorukoV A.L., Pankov L.V., Pan A., Panov A.D., Petrukhin A.A., Podgrudkov D.A., Popova E.G., Postnikov E.G., Prosin V.V., Ptuskin V.S., Pushnin A.A., Raikin R.I., Razumov A.YU., Rubtsov G.I., RYABOV E.V., Samoliga V.S., Satyshev I., Sidorenkov A.YU., Silaev A.A., Silaev A.A., Tarashchansky B.A., Tkachev L.G., Tanaev A.B., Ternovoy M.YU., Ushakov N.A., Volchugov P.A., Volkov N.V., Voronin D.M., Zagorodnikov A.V., Zhurov D.P., Yashin I.I., Vaidyanathan A. «Technique for reconstructing the parameters of eas and primary cosmic rays based on experimental data of the Tunka-Grande scintillation array» Научно-технические ведомости Санкт-Петербургского государственного политехнического университета. Физико-математические науки, 16, № S1.2, с. 389-394 (2023)

The Tunka-Grande scintillation array is a part of a single TAIGA experimental complex located in the Tunka Valley, 50 km from the Lake Baikal. It consists of 19 observation stations deployed on an area of about 0.5 km². The main aim of the Tunka-Grande facility is a detailed study of the energy spectrum and mass composition of cosmic rays in the energy range from 10 PeV to 1 EeV by detecting the charged and muon component of EAS. The article presents a method for reconstructing the parameters of the EAS and primary cosmic rays, the cosmic rays energy spectrum based on 4 measurement seasons, and compares the results obtained with the data of the Tunka-133 and TAIGA-HiSCORE Cherenkov arrays.

Monkhoev R.D., Astapov I.I., Bezyazeekov P.A., Bonvech E.A., Borodin A.N., Budnev N.M., Bulan A.V., Vaidyanathan A., Volkov N.V., Volchugov P.A., Voronin D.M., Gafarov A.R., Gres E.O., Gress O.A., Gress T.I., Grishin O.G., Garmash A.Y., Grebenyuk V.M., Grinyuk A.A., Dyachok A.N., Zhurov D.P., Zagorodnikov A.V., Ivanova A.D., Ivanova A.L., Iliushin M.A., Kalmykov N.N., Kindin V.V., Kiryukhin S.N., Kokoulin R.P., Kolosov N.I., Konstantin G.C., Korosteleva E.E., Kozhin V.A., Kravchenko E.A., Kryukov A.P., Kuzmichev L.A., Chiavassa A., Lagutin A.A., Lavrova M.V., Lemeshev Y.E., Lubsandorzhiev B.K., Lubsandorzhiev N.B., Malakhov S.D., Mirgazov R.R., Okuneva E.A., Osipova E.A., Pakhorukov A.L., Pan A., Panov A.D., Pankov L.V., Petrukhin A.A., PodgrudkoV D.A., Popova E.G., Postnikov E.B., Prosin V.V., Ptuskin V.S., Pushnin A.A., Razumov A.Y., Raikin R.I., Rubtsov G.I., Ryabov E.V., Samoliga V.S., Satyshev I., Silaev A.A., Silaev A.A., Sidorenkov A.Y., Skurikhin A.V., Sokolov A.V., Sveshnikova L.G., Tabolenko V.A., Tanaev A.B., Tarashchansky B.A., Ternovoy M.Y., Tkachev L.G., Ushakov N.A., Chernov D.V., Yashin I.I «Method for gamma-hadron separation according to the experimental data of the Tunka-Grande array» Научно-технические ведомости Санкт-Петербургского государственного политехнического университета. Физико-математические науки, 16, № S1.2, с. 480-484 (2023)

The Tunka-Grande array is a part of unified experimental complex, which also includes Tunka-133 and TAIGA-HiSCORE (High Sensitivity COsmic Rays and gamma Explorer) wide-angle Cherenkov arrays, TAIGA-IACT array (Imaging Atmospheric Cherenkov Telescope) and TAIGA-Muon scintillation array. This complex is located in the Tunka Valley (Buryatia Republic, Russia), 50 km from Lake Baikal. It is designed to study the energy spectrum and the mass composition of charged cosmic rays in the energy range 100 TeV-1000 PeV, to search for diffuse gamma rays above 100 TeV and to study local sources of gamma rays with energies above 30 TeV. This report outlines 3 key points. The first is the description of the Tunka-Grande scintillation array. The second one presents the strategy of the search for diffuse gamma rays based on a computer simulation of the Tunka-Grande array. The third one is devoted to the prospects for future research in the field of gamma-ray astronomy using simulation results.

Ivanova A.L., Astapov I.I., Bezyazeekov P.A., Bonvech E.A., Borodin A.N., Budnev N.M., Bulan A.V., Chernov D.V., Chiavassa A., Dyachok A.N., Gafarov A.R., Garmash A.Yu., Grenebyuk V.M., Gres E.O., Gres O.A., Gres T.I., Grinyuk A.A., Grishin O.G., Ivanova A.D., Ilushin M.A., Kalmykov N.N., Kindin V.V., Kiryukhin S.N., Kokoulin R.P., Kompaniets K.G., Korosteleva E.E., Kozhin V.A., Kravchenko E.A., Kryukov A.P., Kuzmichev L.A., Lagutin A.A., Lavrova M.V., Lemeshev YU.E., Lubsandorzhiev B.K., Lubsandorzhiev N.B., Malakhov S.D., Mirgazov R.R., Monkhoev R.D., Okuneva E.A., Osipova E.A., PakhorukoV A.L., Pankov L.V., Pan A., Panov A.D., Petrukhin A.A., Podgrudkov D.A., Popova E.G., Postnikov E.G., Prosin V.V., Ptuskin V.S., Pushnin A.A., Raikin R.I., Razumov A.YU., Rubtsov G.I., RYABOV E.V., Samoliga V.S., Satyshev I., Sidorenkov A.YU., Silaev A.A., Silaev A.A., Tarashchansky B.A., Tkachev L.G., Tanaev A.B., Ternovoy M.YU., Ushakov N.A., Volchugov P.A., Volkov N.V., Voronin D.M., Zagorodnikov A.V., Zhurov D.P., Yashin I.I., Vaidyanathan A. «Technique for reconstructing the parameters of eas and primary cosmic rays based on experimental data of the Tunka-Grande scintillation array» Научно-технические ведомости Санкт-Петербургского государственного политехнического университета. Физико-математические науки, 16, № S1.2, с. 389-394 (2023)

The Tunka-Grande scintillation array is a part of a single TAIGA experimental complex located in the Tunka Valley, 50 km from the Lake Baikal. It consists of 19 observation stations deployed on an area of about 0.5 km². The main aim of the Tunka-Grande facility is a detailed study of the energy spectrum and mass composition of cosmic rays in the energy range from 10 PeV to 1 EeV by detecting the charged and muon component of EAS. The article presents a method for reconstructing the parameters of the EAS and primary cosmic rays, the cosmic rays energy spectrum based on 4 measurement seasons, and compares the results obtained with the data of the Tunka-133 and TAIGA-HiSCORE Cherenkov arrays.

Monkhoev R.D., Astapov I.I., Bezyazeekov P.A., Bonvech E.A., Borodin A.N., Budnev N.M., Bulan A.V., Vaidyanathan A., Volkov N.V., Volchugov P.A., Voronin D.M., Gafarov A.R., Gres E.O., Gress O.A., Gress T.I., Grishin O.G., Garmash A.Y., Grebenyuk V.M., Grinyuk A.A., Dyachok A.N., Zhurov D.P., Zagorodnikov A.V., Ivanova A.D., Ivanova A.L., Iliushin M.A., Kalmykov N.N., Kindin V.V., Kiryukhin S.N., Kokoulin R.P., Kolosov N.I., Konstantin G.C., Korosteleva E.E., Kozhin V.A., Kravchenko E.A., Kryukov A.P., Kuzmichev L.A., Chiavassa A., Lagutin A.A., Lavrova M.V., Lemeshev Y.E., Lubsandorzhiev B.K., Lubsandorzhiev N.B., Malakhov S.D., Mirgazov R.R., Okuneva E.A., Osipova E.A., Pakhorukov A.L., Pan A., Panov A.D., Pankov L.V., Petrukhin A.A., PodgrudkoV D.A., Popova E.G., Postnikov E.B., Prosin V.V., Ptuskin V.S., Pushnin A.A., Razumov A.Y., Raikin R.I., Rubtsov G.I., Ryabov E.V., Samoliga V.S., Satyshev I., Silaev A.A., Silaev A.A., Sidorenkov A.Y., Skurikhin A.V., Sokolov A.V., Sveshnikova L.G., Tabolenko V.A., Tanaev A.B., Tarashchansky B.A., Ternovoy M.Y., Tkachev L.G., Ushakov N.A., Chernov D.V., Yashin I.I «Method for gamma-hadron separation according to the experimental data of the Tunka-Grande array» Научно-технические ведомости Санкт-Петербургского государственного политехнического университета. Физико-математические науки, 16, № S1.2, с. 480-484 (2023)

The Tunka-Grande array is a part of unified experimental complex, which also includes Tunka-133 and TAIGA-HiSCORE (High Sensitivity COsmic Rays and gamma Explorer) wide-angle Cherenkov arrays, TAIGA-IACT array (Imaging Atmospheric Cherenkov Telescope) and TAIGA-Muon scintillation array. This complex is located in the Tunka Valley (Buryatia Republic, Russia), 50 km from Lake Baikal. It is designed to study the energy spectrum and the mass composition of charged cosmic rays in the energy range 100 TeV-1000 PeV, to search for diffuse gamma rays above 100 TeV and to study local sources of gamma rays with energies above 30 TeV. This report outlines 3 key points. The first is the description of the Tunka-Grande scintillation array. The second one presents the strategy of the search for diffuse gamma rays based on a computer simulation of the Tunka-Grande array. The third one is devoted to the prospects for future research in the field of gamma-ray astronomy using simulation results.

Bodganov A.A., Repman G.A., Tuboltsev Yu.V., Chichagov Yu.V., Kholupenko E.E., Krasilchtchikov A.M. «Development of detector cluster based on silicon photomultipliers for the Cherenkov gamma-ray telescope TAIGA-IACT» Научно-технические ведомости Санкт-Петербургского государственного политехнического университета. Физико-математические науки, 16, № S1.2, с. 410-416 (2023)

A new experimental detector cluster for the TAIGA-IACT telescope has been developed. The cluster contains 28 pixels based on MicroFJ-60035 silicon photomultipliers, whose signal is digitized with an analog memory chip (switched capacitor array) DRS4 at a frequency of up to 5 GHz. The paper describes the device and the operation principles of the detector cluster, reveals the peculiarities encountered in the development process. Dark chamber tests of the cluster with a point source of short pulses of ultraviolet light have allowed us to obtain dependencies of the cluster conversion coefficient and the maximum value of the recorded signal on the overvoltage of the silicon detectors.

Chudaev S.O., Afanasiev N.T., Lukyantsev D.S. «Diagnostics of CME cavity using data of multiwave measurements of behind-the-limb solar radio bursts» Научно-технические ведомости Санкт-Петербургского государственного политехнического университета. Физико-математические науки, 16, № S1.2, с. 383-388 (2023)

Mathematical modeling of the behind-the-limb radio bursts propagation characteristics at the second harmonic of the local plasma frequency of the solar corona was performed for analytical models of the electron density of the circumsolar plasma and CMEs. The features of the bursts trajectories are studied depending on the parameters of the CMEs and the initial coordinates of solar radio sources. The conditions for the strong effect of CME on radio bursts are determined. The possibility of determining the CME cavity’s parameters from the data of multiwave measurements of the group delays of behind-the-limb radio bursts is shown.

Chukov V.N. «Structure of acoustic lauegram on the ewald circle of reflection for the rayleigh wave scattering» Научно-технические ведомости Санкт-Петербургского государственного политехнического университета. Физико-математические науки, 16, № S1.2, с. 557-564 (2023)

The acoustic Lauegram of the Rayleigh wave the Laue–Bragg–Wulff high-frequency scattering on a rectangle rough band of an isotropic solid, having periodic lattice of an arbitrary number of the roughness discontinuities, is theoretically investigated in details in dependence on the angle of scattering φs at a fixed ratio of the lattice unit cell size to the wavelength and parameters of the lattice. The Ewald conception of the circle of reflection is used. The problem of an arbitrary number, defined beforehand, of the resonances of scattering, i.e. nodes of the reciprocal lattice, for any φs, defined beforehand, lying on the Ewald circle of reflection, is first solved analytically in the present work in the classical case, i.e. without influence of the amplitude form-factor of the lattice. It is found, that increasing of the number of resonances for any φs is necessarily accompanied by the increasing of the Ewald circle of reflection radius, i.e. of the Rayleigh wave frequency, at fixed sizes of a discontinuities lattice. It is obtained first, that amplitude form-factor of the discontinuities lattice strongly influences the structure of the acoustic Lauegram: arbitrary number of the resonances of scattering for any φs can be placed on the Ewald circle of reflection without variation of its radius by using of the appropriate amplitude form-factor of a discontinuities lattice of a solid roughness.

Churkin K.O., Andreev A.O., Nefedyev Yu.A., Kolosov Yu.A., Korchagina E.P., Demina N.Yu., Borovskih V.S. «Analysis of comet C/1969 Y1 parameters using isophote structural modeling» Научно-технические ведомости Санкт-Петербургского государственного политехнического университета. Физико-математические науки, 16, № S1.2, с. 530-535 (2023)

This work is devoted to the construction of a brightness structural model of the long-period comet Bennett C/1969 Y1. This comet belongs to the comets of the Jupiter family (JF) and has a Tisserand’s parameter T>2. Determining the brightness characteristics of the comet has been one of the most important goals of cometary observations over the past century. The complexity of such studies lies in the fact that we are dealing with extended sources moving relative to background stars. The problem of obtaining reliable estimates of the distribution of brightness parameters (BPs) for long-period comets also remains especially important, because for many of them observations were made back in the days when high-precision methods, such as CCD-matrices and other technical tools, were not available. At the same time, most of the determined stellar magnitudes of long-period comets were related to the gaseous coma surrounding the comet’s nucleus, and not to the comet’s nucleus itself. At the same time, cosmic ultraviolet observations of comets in the Lyman-alpha hydrogen lines made it possible to obtain very important data for estimating the emission of H₂O by the cometary nucleus, as well as other types of molecules (e.g. C₂, C₃, CN, OH). In the presence of dependencies between the productivity of the H₂O cometary nucleus and its brightness characteristics, the determination of BPs of cometary nuclei has acquired a new meaning. However, the dependence of the size of the nucleus on its BPs is not linear, since there is a correlation with the albedo of the surface of the nucleus. In this work, BPs and albedo for comet Bennett C/1969 Y1 are studied. Taking into account the data obtained and the solution of the described problems, we applied the author’s isophote method to analyze the structure of the brightness characteristics of Bennett C/1969 Y1.