Theory of high harmonic generation in relativistic laser interaction with overdense plasma

High harmonic generation due to the interaction of a short ultra relativistic laser pulse with overdense plasma is studied analytically and numerically. On the basis of the ultra relativistic similarity theory we show that the high harmonic spectrum is universal, i.e. it does not depend on the interaction details. The spectrum includes the power law part $I_n\propto n^{-8/3}$ for $n<\sqrt{8\alpha}\gamma_{\max}^3$, followed by exponential decay. Here $\gamma_{\max}$ is the largest relativistic $\gamma$-factor of the plasma surface and $\alpha$ is the second derivative of the surface velocity at this moment. The high harmonic cutoff at $\propto \gamma_{\max}^3$ is parametrically larger than the $4 \gamma_{\max}^2$ predicted by the ``oscillating mirror'' model based on the Doppler effect. The cornerstone of our theory is the new physical phenomenon: spikes in the relativistic $\gamma$-factor of the plasma surface. These spikes define the high harmonic spectrum and lead to attosecond pulses in the reflected radiation.Comment: 12 pages, 9 figure

Features of soils of the natural park “Scherbakovsky” Volgograd region

The paper presents the results of a study of the soil cover of the Shcherbakovsky Nature Park in the Kamyshinsky district of the Volgograd region. To achieve the results 12 soil sections were laid along the studied soil catena (1.5 km), so that morphological and chemical features of the soils of the study area were investigated. Variety and diversity are due to vertical zonality and geological and hydrological peculiarities. So, in the gullies and in massive forest plantations various dark humus and gley soils have become widespread. On steppe, slope and watershed areas lithosolic light humus luvisols and light humus lithozems were formed. On areas with open sand surface, humus psammozems with protohumus horizons W, as well as light humus (AJ-C) and humus soils (A-C), and a variety of soil-forming rocks of the natural park were found. In relief depressions they are represented mainly by gleyed sandy, as well as proluvial-deluvial deposits with inclusions of large fragments of opokas. On steppe and steep-slope areas, the soil-forming rocks are thick layers of opoka deposits. Their upper boundary varies from 20 to 60 cm depth depending on the meso- and microrelief. On the watersheds, the soilforming rocks are represented by sandy, ferruginous deposits with new formations of clay and pseudofibres. The parent rock is registered starting from 100 cm depth and consists of large blocks of hardened sandstone. The chemical properties of the studied soils are characterized by a neutral or slightly acidic pH. Easily soluble salts are leached from all soil horizons. The maximum values of Сorg are typical of humus and transitional horizons. The studies conducted in the Shcherbakovsky Nature Park are of greatest importance for monitoring the state of soils, and also allowed us to identify the features of the genesis of underdeveloped soils and luvisols of the dry-steppe natural zone

Lanthanoid-doped quaternary garnets as phosphors for high brightness cathodoluminescence-based light sources

Gadolinium-yttrium- aluminum-gallium garnets (GYAGG) doped and codoped with Eu, Tb, and Ce were manufactured as ceramics to develop long-wavelength phosphors for high-brightness white light sources based on cathodoluminescence (CL). The CL light yield (LY) of Tb-doped ceramics at high-intensity electron beam excitation is shown to be more than twice as high as that of the conventional phosphor YAG:Ce, whereas codoping with Eu to redshift the chromaticity results in reducing the LY approximately to the level of YAG:Ce. The LY might be substantially improved by using a mix of Tb- and Eu-doped GYGAG powders instead of a single codoped GYGAG to produce ceramic phosphor. The high LY is explained by favorable contribution of Gd sublattice in excitation transfer to activator ions. Chromaticity of phosphors GYGAG:Tb, Eu can be tuned in a wide range by varying the ratio of Tb to Eu concentration. They are radiation resistant and stabile in the temperature range from 300 to 450 K. © 2022 The Author(s)Ministry of Education and Science of the Russian Federation, Minobrnauka: 075-11-2021-070, 075-15-2021-1353, FEUZ-2020-0060This work was supported by the Ministry of Science and Higher Education of the Russian Federation (FEUZ-2020-0060, No. 075-15-2021-1353 & 075-11-2021-070)

Towards effective indirect radioisotope energy converters with bright and radiation hard scintillators of (Gd,Y)3Al2Ga3O12 family

Ceramics of quaternary garnets (Gd,Y)3Al2Ga3O12 doped with Ce, Tb have been fabricated and evaluated as prospective materials for indirect energy converters of α-and β-voltaic. Samples were characterized at excitation with an X-ray source and an intense 150 keV electron beam and showed good temperature stability of their emission and tolerance to irradiation. The role of X-rays accompanied the α-particle emitting in the increase of the conversion efficiency is clarified. The garnet-type structure of the matrix in the developed materials allows the production of quality crystalline mass with a light yield exceeding that of the commonly used YAG: Ce scintillator by a factor of two times. © 2022 Korean Nuclear SocietyMinistry of Education and Science of the Russian Federation, Minobrnauka: 075-15-2021-1353, FEUZ-2020-0060; Ministerstwo Edukacji i Nauki, MNiSW: 075-11-2021-070; Ministry of Science and Higher Education of the Russian FederationAuthors with affiliations b, d, e and f acknowledge support from Russian Ministry of Science and Education grant No. 075-15-2021-1353 . The scientific equipment provided by shared research facilities “Scientific Research Analytical Center of National Research Center “Kurchatov Institute” – IREA” was used, with financial support of Russian Federation, represented by the Ministry of Science and Higher Education, agreement No. 075-11-2021-070 dated August 19, 2021. The work was partially supported by the Ministry of Science and Higher Education of the Russian Federation (through the basic part of the government mandate, project No. FEUZ-2020-0060 ) (authors with affiliation “c”).Authors with affiliations b, d, e and f acknowledge support from Russian Ministry of Science and Education grant No. 075-15-2021-1353. The scientific equipment provided by shared research facilities “Scientific Research Analytical Center of National Research Center “Kurchatov Institute” – IREA” was used, with financial support of Russian Federation, represented by the Ministry of Science and Higher Education, agreement No. 075-11-2021-070 dated August 19, 2021. The work was partially supported by the Ministry of Science and Higher Education of the Russian Federation (through the basic part of the government mandate, project No. FEUZ-2020-0060) (authors with affiliation “c”)

Features of treatment of patients with diabetes mellitus and comorbid pathology

As of 2019, there are 463 million people with diabetes worldwide. And according to the forecast of the International diabetes Federation, the number of patients with diabetes will only increase and by 2030 will reach 578 million people. At the same time, each patient should have an individual treatment plan that includes treatment of not only the main disease, but also its complications, as well as concomitant diseases. Often, when treating these patients, polypharmacotherapy occurs. The article deals with the features of diabetes therapy taking into account comorbid pathology in the city of Yekaterinburg.На 2019 год в мире насчитывают 463 миллионов человек, страдающих сахарным диабетом. И по прогнозу Международной диабетической федерации число больных сахарным диабетом будет только увеличиваться и к 2030 году составит 578 миллионов человек. При этом у каждого пациента должен быть разработан индивидуальный план лечения, включающий в себя терапию не только основного заболевания, но и его осложнения, а также сопутствующие заболевания. Нередко при лечении данных пациентов возникает полифармакотерапия. В статье рассмотрены особенности терапии сахарного диабета с учетом коморбидной патологии в городе Екатеринбурге

Enhanced superchannel transmission using phase conjugation

We demonstrate polarisation insensitive dual-band optical phase conjugation for multiple 400Gbit/s optical superchannels using a Raman amplified transmission link with a realistic span length of 75km. The resultant increase in transmission distance is confirmed analytically

Luminescence Spectroscopy of Quaternary Garnets Doped with Trivalent Rare-Earth Ions

Spectroscopy and energy transport in multi–ion ceramics with garnet structure (GYAGG) doped with rare–earth ions (Ce3+, Tb3+, Eu3+) were studied by photoluminescence (PL), cathodoluminescence (CL) and X–ray luminescence (XRL) methods.The work was partially supported by the Ministry of Science and Higher Education of the Russian Federation (through the basic part of the government mandate, project No. FEUZ-2020-0060)

Хэнтей-Даурская складчатая система Монголо-Охотского пояса (магматизм, седиментогенез, геодинамика)

The geostructural, petrological, geochemical, geochronological and biostratigraphic studies were conducted in the Hentei-Dauria fold system of the Mongolia-Okhotsk orogenic belt. This Paleozoic system is composed mainly of three heterochronous rock associations related to the onset and development of oceanic basins and active margins in the conjugation zone of the Siberian continent and the Mongolia-Okhotsk ocean. This region developed in three stages: (1) Late Caledonian (Ordovician – Early Silurian), (2) Early Hercynian (Late Silurian – Devonian), and (3) Late Hercynian (Carboniferous–Permian). In the Late Caledonian, oceanic seafloor spreading was initiated, deep-sea siliceous deposits were formed, basaltic and andesitic pillow lavas were erupted, and layered and cumulative gabbros, gabbro-dolerite dykes and subduction zones with island-arc magmatism were formed. After a short quiescence period, new zones of spreading and subduction occurred at the active margins of the Mongolia-Okhotsk ocean in the Early Hercynian. In the Late Hercynian, large back-arc sedimentary basins, accretionary prisms and connecting intraplate magmatic complexes were formed in all structures of the Hentei-Dauria fold system. As a result of our studies, we propose a comprehensive model showing the geodynamic development of the Hentei-Dauria fold system that occurred in the area of the Mongolia-Okhotsk Ocean and its margins.В результате проведенных структурно-геологических, петролого-геохимических, геохронологических и биостратиграфических исследований установлено, что палеозойская Хэнтей-Даурская складчатая система Монголо-Охотского орогенного пояса сложена главным образом тремя разновозрастными ассоциациями пород, связанными с заложением и развитием океанических бассейнов и активных окраин в зоне сопряженного взаимодействия Сибирского континента и Монголо-Охотского океана в течение трех этапов: 1) позднекаледонского (ордовикско-раннесилурийского), во время которого произошло заложение океанического спредингового бассейна и формирование глубоководных кремнистых отложений, излияние пиллоу-лав базальтов и андезибазальтов, образование расслоенных и кумулятивных габбро, даек габбро-долеритов, а также зон субдукции с островодужным магматизмом, 2) раннегерцинского (позднесилурийско-девонского), когда после небольшого перерыва вновь произошло заложение новых зон спрединга и субдукции на активных окраинах Монголо-Охотского океана, и 3) позднегерцинского (каменноугольно-пермского), завершившегося образованием крупных задуговых осадочных бассейнов, формированием аккреционных призм и сшивающих внутриплитных магматических комплексов во всех структурах Хэнтей-Даурской складчатой системы. На основе полученных данных разработана комплексная модель геодинамического развития Хэнтей-Даурской складчатой системы, сформированной на месте Монголо-Охотского океана и его окраин.