Adiabatic nonlinear waves with trapped particles: II. Wave dispersion

A general nonlinear dispersion relation is derived in a nondifferential form for an adiabatic sinusoidal Langmuir wave in collisionless plasma, allowing for an arbitrary distribution of trapped electrons. The linear dielectric function is generalized, and the nonlinear kinetic frequency shift $\omega_{\rm NL}$ is found analytically as a function of the wave amplitude $a$. Smooth distributions yield $\omega_{\rm NL} \propto \sqrt{a}$, as usual. However, beam-like distributions of trapped electrons result in different power laws, or even a logarithmic nonlinearity, which are derived as asymptotic limits of the same dispersion relation. Such beams are formed whenever the phase velocity changes, because the trapped distribution is in autoresonance and thus evolves differently from the passing distribution. Hence, even adiabatic $\omega_{\rm NL}(a)$ is generally nonlocal.Comment: submitted together with Papers I and II

Scattering properties of singular and aggregate atmospheric hexagonal ice particles

This paper presents the results of calculating and analyzing the light scattering matrix of aggregates of atmospheric hexagonal ice particles located in cirrus clouds. Two types of basic particle shapes for aggregates are considered: a hexagonal column and a hexagonal plate. For both forms, two types of particle arrangement in aggregates were chosen: compact and non-compact. As a result, 4 sets of aggregates were built: compact hexagonal columns, non-compact hexagonal columns, compact hexagonal plates, and non-compact hexagonal plates. Each set consists of 9 aggregates differing in the number of particles in them, and the particles in each individual aggregate have the same shape and size, but different spatial orientation. The light scattering matrices for all aggregates were calculated for the case of arbitrary orientation in the geometric optics approximation. Dependences of the first element of the matrix on the number of particles in aggregate, with different types of particle arrangement, and for two types of shapes are give

Data bank of light backscattering matrices for atmospheric ice crystals of non-convex shape for wavelengths 0.355, 0.532, 1.064 μm

This paper presents the results of calculation and analyzes the light scattering matrix of random oriented ice particles of non-convex shape (hollow column) with cavity angles from 0 to 50 degrees for lidar wavelengths of 0.355, 0.532, and 1.064 microns and refractive indices of 1.3249, 1.3116, and 1.3004. The calculation was carried out within both physical and geometrical optics approximation methods for particle sizes varied from 10 to 100 microns. As a result, it is shown that differential scattering cross-section for non-convex shape (hollow column) demonstrates a power-law dependence on the particle size. However, the linear depolarization ratio has no simple dependence on particle size and is practically independent of wavelength for small particles (L<50 μm). The linear depolarization ratio increases from 0.2 up to 0.5–0.8 with an increase of the cavity angle of the crystal. The elements of the light scattering matrix depending on scattering and cavity angle are give

Enhanced light absorption in Tamm metasurface with a bound state in the continuum

We consider light absorption in a germanium grating placed on top of photonic-crystalline substrate. Such a system supports an optical Tamm state decoupled from the continuous spectrum with its frequency within the photonic band gap. We have demonstrated that application of the Tamm state makes in possible to engineer extremely narrow absorber which provides a 100% absorption in a semiconductor grating in the critical coupling regime. The proposed design may be used at both normal and oblique incidence at the telecom wavelength

Pathology of the shoulder joint and soft tissues: clinical variants, current capabilities of pathogenesis-directed therapy

Pain syndrome in the shoulder occurs in every 5th adult and is the 2nd most frequent reason for seeking primary medical care among all musculoskeletal disorders. Group of local causes of pain syndrome in the shoulder area. The starting point for differential search is patient’s age. For persons younger than 40, the most common causes are joint instability (dislocations / subluxations), as well as mild damage of the rotator cuff muscles due to injury. Patients older than 40 have an increased risk of severe chronic disorders of the above-mentioned muscles, adhesive capsulitis, and osteoarthritis of the shoulder joint. Treatment of shoulder joint and soft tissue pathology is nosological in nature and has to be justified by pathogenesis. Chondroreparants are a new class of pharmaceuticals based on hyaluronic acid modified by low molecular weight compounds using solid-phase stabilization. During physical stabilization (mechanosynthesis) of hyaluronic acid, chemical crosslinkers are not used, which leads to high tolerability and safety. Modified hyaluronic acid in Hyalrepair formulas has a number of structural features leading to its slower biodegradation in the tissues. Chondroreparant Hyalrepair-10 consists of hyaluronic acid, ascorbyl phosphate, zinc, cysteine, and glutathione; Hyalrepair- 2 consists of hyaluronic acid, ascorbyl phosphate, L-proline, L-lysine, and glycine. Use of intra-joint and periarticular injection of hyaluronic acid can be an effective approach in combination pathogenesis-directed therapy of the shoulder and soft tissues

Calculation of the lidar signal by the DDA method applied to the data of satellite remote sensing of cirrus clouds for climate change detection

The purpose of this work is to solve an important issue: the light scattering problem for ice crystals of cirrus clouds less than 10 μm and matching the obtained solution with the existing solution obtained within the physical optics approximation. The article presents a solution to the problem of light scattering by hexagonal ice particles of cirrus clouds with sizes from 0.05 to 5.17 μm for a wavelength 0.532 μm, obtained within the discrete dipole approximation. It is found that the obtained solution is in good agreement with the physical optics approximation in the vicinity of scattering angles of 0–10є (the vicinity of forward direction scattering). However, to solve the problem of light scattering in the vicinity of the backward scattering direction, which is important for the interpretation of lidar data, it is necessary to continue the calculations to sizes of the order of 20 μm. The results obtained are necessary for constructing algorithms for the interpretation of lidar data obtained by sounding cirrus clouds

SOME FEATURES OF CURRENT TECHNOGENIC MOVEMENTS OF THE EARTH’S CRUST

We describe the history of studying the current crustal movements by various methods and discuss technogenic effects recorded at large water-reservoir zones and mineral deposits in Siberia. Initially, classical surveying techniques aimed to obtain high-accuracy ground-based measurements of height, tilt and direction. Modern geodesy techniques and methods for measuring absolute gravity are now available to investigate displacement, deformation, tilt and other phenomena taking place on the Earth’s surface. These methods are used to estimate kinematic parameters of the crust areas (e.g. rates of subsidence and horizontal movements) and to monitor fluid motions in mineral deposits. Such data are critical for ensuring a proper management of the mineral deposits. In this article, we analyse technogenic processes observed in the Ust Balyk oil-gas field, the Zapolyarny gas deposit, the water-reservoir zone at the Sayano-Shushenskaya hydroelectric power station (SSHPS) on the Yenisei river, and large open-pit mines in the Kuzbass basin. Our analysis is based on surface displacement rates estimated from the data collected in different periods of observations at large man-made facilities. In the study of the hydro technical objects, we estimated the displacement rates at 5.0 mm per year. In the northern areas of the West Siberian petroleum basin, subsidence rates amounted to 20–25 mm per year in the early 2000s. These estimates were supported by the high-accuracy gravity measurements showing an increase up to 6–7 microGal per year in the oil-gas field development areas. We assess a possibility of triggering effects related to weak seismicity due to a high stress accumulation rate (1 KPa per hour) in the SSHPS area. A connection between earth tides and catastrophic events, such as gas emissions in high amounts on mining sites, is discussed. Having analysed the surface monitoring records taken in South Primorye in September 2017, we conclude that underground nuclear explosions in North Korea in this period did not cause any significant displacement of the surface in this most southerly region of the Russian Far East territories

Передача информации в рентгеновском диапазоне частот электромагнитного излучения

Introduction.  Data transmission systems using the  X-ray frequency range of electromagnetic radiation  –  X-ray communication system (XCS) have a number of advantages in comparison with radio or optical communication systems. The most significant advantages for practical use are their higher stealth and external interferences resistance, as well as stability against interception and decryption. It is of importance to develop a method for calculating the main parameters of an X-ray communication system: the range and speed of data transmission. In addition, the construction design and results of experimental research of the current X-ray communication system should be provided.Aim.  To develop physical and technical foundations of data transmission systems using the X-ray frequency range of electromagnetic radiation.Materials and methods.  We used an original method of calculating the X-ray emission spectrum, taking into account the attenuation coefficient in the propagation medium.Results.  A technique for data transmission using the X-ray frequency range of electromagnetic radiation was suggested, including a method for calculating basic parameters e.g. the transmission range and speed, as well as the construction design of the current X-ray communication system model. Relations between these parameters and the operating modes of the X-ray tube were shown. The calculated and experimental data were in good agreement, sufficient for practical use. On their basis, it can be expected that at a voltage across the X-ray tube of 200 kV and the tube current of 1A in a 1-μs pulse, data transmission range in free air will be about 250 m. The maximum possible data transmission rate when using the developed X-ray tube will be 5 Mbit/s.Conclusions.  The results of analytical and experimental investigations showed that the range and rate of data transmission of the XCS are exclusively determined by the transmitter energetic capabilities: by voltage and average the X-ray tube current during the generation of packages  (series) of the X-ray pulses, as well as by the duration of a single X-ray pulse. It is concluded that the prospects of XCS depend on the development of specialized X-ray sources generating a series of pulses with the minimum possible duration of every single pulse in a series. Taking into account the specific features, XCS can become an alternative to conventional radio and optical systems for communication and navigation.Введение.  Системы передачи информации в рентгеновском диапазоне частот электромагнитного излучения – рентгеновские системы связи (РСС) обладают рядом преимуществ по сравнению с радио- и оптическими системами связи. Наиболее существенными из них с точки зрения практического использования являются: более высокая скрытность и устойчивость к внешним помехам, а также к перехвату и дешифровке. Актуальна разработка методики расчета основных параметров системы рентгеновской связи дальности и скорости передачи информации, а также описание конструкции и результатов экспериментальных исследований действующего макета системы рентгеновской связи.Цель работы. Разработка физико-технических основ систем передачи информации в рентгеновском диапазоне частот электромагнитного излучения.Материалы и методы.  Использована оригинальная методика расчета спектров рентгеновского излучения с учетом коэффициента ослабления в среде распространения.Результаты.  Предложена технология передачи информации в рентгеновском диапазоне частот электромагнитного излучения, включая методику расчета основных параметров: дальности  и скорости передачи, а также конструкцию действующего макета системы рентгеновской связи. Показана зависимость между этими параметрами и режимами работы рентгеновской трубки. Расчетные и экспериментальные данные совпадают с удовлетворительной для практического использования точностью. На их основании можно ожидать, что при напряжении на рентгеновской трубке 200 кВ и токе трубки 1 А в импульсе длительностью 1 мкс дальность передачи информации на воздухе составит около 250 м. Максимально возможная скорость  передачи  информации  при  использовании  разработанной  рентгеновской  трубки  составит 5 Мбит/с.Заключение. Результаты аналитической оценки и экспериментальных исследований показали, что дальность и скорость передачи информации РСС определяются исключительно энергетическими возможностями передатчика: напряжением и средним током рентгеновской трубки во время генерирования пакета (серии) импульсов рентгеновского излучения, а также длительностью отдельного импульса рентгеновского излучения. Сделан вывод о том, что дальнейшее развитие РСС обусловлено, в первую очередь, разработкой специализированных источников рентгеновского излучения, генерирующих серии импульсов с минимально возможной длительностью каждого импульса в серии. С учетом специфических особенностей РСС могут составить реальную конкуренцию традиционным радио-  и оптическим системам связи для связи и навигации