Structure of Thermal Radio Emission from the Atmosphere in the Middle Part of the Submillimeter Wavelength Range

We present the results of theoretical studies of the structure of thermal radio emission from the Earth's atmosphere in the middle part of the submillimeter wavelength range (wave numbers 1/ 20–50 cm^-1). Absorption spectra of the atmosphere, heights at which the radiation is formed, and other physical factors, which determine the features of the inverse problems of remote sensing in the band considered, are analyzed.     

Spectra of the Brightness Temperature of a Linearly Polarized Component of the Background Radio Emission from the Galaxy

We calculate the Stokes parameters of synchrotron radiation of the interstellar medium for the model of radiation source consisting of N homogeneous layers. The calculations take into account the variance of the Faraday rotation. The results of polarization measurements of the North Spur and a region of strong linear polarization of radio emission with coordinates ₁₉₅₀=4 h 30 m and ₁₉₅₀=61°, performed at the Radiophysical Research Institute (NIRFI) at 25 frequencies in the interval 195-1250 MHz, are presented. Based on the models considered, we discuss the spectra of polarization temperature of these regions.     

Effects of Ionospheric Radio Wave Scattering in the Decameter Interferometry

We consider some theoretical issues concerning diffraction of radio waves in a randomly irregular ionosphere with application to the problems of long-wavelength interferometry of cosmic objects. The statistical characteristics of intensity fluctuations of the decameter radio emission from discrete sources in the case of ground-based observations by two-element interferometers with very long and small baselines are analyzed. Analytical expressions are obtained for the autocorrelation function of the radiation intensity and for the scintillation spectrum of a point source in the limiting cases of large and small phase increments in an irregular ionospheric plasma. We find that in the case of radio interferometric reception, the scintillation spectrum corresponding to observations of a source by a single antenna is transferred from the zero-frequency region to the region of the Doppler frequency of the interferometer. It is shown that decameter ground-based and space-borne radio interferometers can be used to study the angular distribution of the radio brightness of cosmic sources under conditions of both quiet and disturbed ionosphere.     

New Possibilities of Radioastronomical Diagnostics of the Jovian Magnetosphere Using the Observed Polarization of its Decameter Radio Emission

We discuss possibilities of diagnostics of the Jovian magnetosphere based on the results of measurements of the polarization characteristics of the decameter radio emission. It is shown that the essentially elliptical polarization of that radiation and its generation at frequencies near the local electron gyrofrequency opens new possibilities for radioastronomical diagnostics of the Jovian magnetosphere. The plasma distribution can be studied not only along the radiation path but also in the transverse direction, i.e., over latitudes. Moreover, since the relative position of the source and observer during a decameter noise storm is rather stable, it is possible to perform tomography of the magnetosphere (its diagnostics at different longitudes) using the planet rotation. We present the examples of diagnostics of different regions in the Jovian magnetosphere, such as sources of decameter radio emission, i.e., lower-magnetosphere regions located at a distance of about 1.5-2 R_J from the center of the planet, and the Io plasma torus located at a distance of about 6R_J from the center of the planet. It is pointed out that the number density of the magnetospheric plasma outside the Io magnetic flux tube is small (n 1 cm^-3 at the height of the gyroresonance level f_Be 30 MHz) while it is higher inside this flux tube at the same height: n 3 cm^-3. We estimate the variations in the number density of the plasma along the Io magnetic flux tube (n B, 1-1.8), determine the rate at which the integral plasma density varies over latitudes (d( n dz)/dh 2· 10³ cm^-3), and find the average number density of the plasma in the region where the radiation crosses the Io torus ( n 2· 10³ cm^-3).     

On the Distribution of Radio Pulsars Above the Galaxy Plane

A mechanism of pulsar accumulation over the galaxy plane, caused by deceleration in the gravitational field and stopping at a certain distance of z from the plane is proposed. For pulsars with velocities close to the average observed velocity of about 300 km/s, the consideration of kinematics of such motion estimates the age of stopped pulsars of the order of ten millions years and the average distance from the galaxy plane of about 2 kpc. The consistency in the pulsar longitude distribution at |z| = 0.45–4.5 kpc and the distribution of the formation regions of massive stars in the galaxy disk was found.     

Constraints on Cosmic Rays Population in the Radio Halo of the M87 Galaxy from Gamma-Ray Observations

JETP Letters - We present results of our search for extended high-energy emission around the M87 galaxy, which is the central galaxy in the Virgo cluster. The M87 galaxy harbors extremely heavy...     

等离子体发射光谱仪分类与"全谱直读"一词

本文从仪器结构原理上讨论了当前国内在新型等离子体发射光谱仪分类仪命名上的问题。指出“全谱直读”一词用于仪分类的不严谨性，提仪使用固态检测器等离子体发射光谱仪作为分类词。     

Prevalence of the Ordinary Mode in Microwave Radio Emission from Solar Active Regions

We propose an interpretation of some observations of the ordinary (o) mode in the microwave emission of slowly-varying (s) radio sources associated with active regions in the solar atmosphere. As a rule, the extraordinary (e) mode dominates in the s-component, which is fully explained by the generally accepted theory of its origin. This theory is based on the cyclotron and bremsstrahlung mechanisms of radiation of thermal electrons in an inhomogeneous plasma of the solar atmosphere above sunspots, where the magnetic field decreases and the kinetic temperature increases with height. It is shown in this work that the prevalence of the ordinary mode is due most probably to the presence of a region with a negative gradient of the kinetic temperature in the atmosphere above the sunspot. We analyze the qualitative frequency dependences of the brightness temperature and polarization of the radiation of a hot and cold (compared to the ambient plasma) filament in the s-component source, as well as the possible reasons for the polarization reversal at a certain frequency. Special attention is paid to the active region NOAA 4741 with the unipolar sunspot described in [1, 2]. Criteria permitting one to judge which of two effects (linear wave coupling or presence of a region with a negative temperature gradient) is responsible for the o-mode in the s-component are discussed.     

High-Frequency Radio Emission of the Lightning Discharge

A special system created to register short electromagnetic pulses has been used to study high-frequency (0.1–30 MHz) radio emission of lightning discharges. It has been shown that the emission is a sequence of short pulses. The shape, width, and amplitude of the first (bipolar) pulse agree with those predicted by theory with account for the combined action of the effect of the runaway electron breakdown and an extensive atmospheric shower for the energy of the initial particle of the order of 10¹⁶ eV. __________ Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Radiofizika, Vol. 48, No. 9, pp. 800–809, September 2005.     

Time Integrated Measurements of the Spectral Line Emission of a Neon Pinch Plasma Radiation Source in the 0.9–1.4 nm Wavelength Range

Time integrated measurements of the line emission of hydrogen-like and helium-like neon from a dense plasma focus device were performed. Relative intensities of Lyman-series emission from Ne X were measured end-on and side-on showing strong deviation from thermal equilibrium and indicating substantial population inversion between levels n = 5 and n = 2.     

Calculating the Parameters of the Biphoton Radiation Source in a Wide Wavelength Range

Optics and Spectroscopy - In this paper, we develop a constructive algorithm to determine the parameters of a nonlinear crystal for generating correlated photons in a given wavelength range using...     

Spectroscopic Observations in the 3-mm Wavelength Range at CrAO RT-22 Radiotelescope Using an Acousto-Optical Spectrum Analyzer

Within the framework of a multi-year program of dense interstellar gas studies, we performed a new series of observations at the CrAO RT-22 radiotelescope in July 1998 using an improved 3-mm wavelength receiving facility. An acousto-optical spectrum analyzer (AOS) was used for the first time for the spectral analysis of incoming radiation. The AOS has larger bandwidth compared to the filter spectrum analyzer used previously and simplifies tuning SIS-mixer circuits and frequency converters. Using this facility, we observed a number of star-forming regions including clouds associated with bright IR sources and ultracompact HII regions as well as clouds with high-velocity outflows in the HCO⁺, ¹³CO, HCN, and CS molecule lines.     

Wavelength Shift Investigation of Optical Emission from Nanosecond Pulsed Laser Ablated Metal Al

The wavelength shift of optical emission from pulsed laser ablation of metal Al in 1atm air has been investigated by using the time-resolved optical emission spectroscopy (OES). The wavelength shift of OES has a second order exponential decay with time and was also found to be significantly influenced by the laser ablated pulse energy. By taking account of the shielding effect of free electrons inside of the plasma plume, the relation between the electron density and wavelength shift has been discussed.     

Radio Emission of Rydberg Atoms in the Upper Atmosphere Modified by High-Power HF Radio Waves

Radiophysics and Quantum Electronics - We report on the results of studying the radio emission of the Rydberg states of atoms and molecules in the Earth’s upper atmosphere at ionospheric...     

Monte Carlo Simulation of Near Infrared Reflectance Spectroscopy in the Wavelength Range from 1000 nm to 1900 nm

We have calculated the characteristics of reflected near infrared light, which is incident on the skin surface, scattered in the skin tissue and detected, in the wavelength range from 1000 nm to 1900 nm. We have used a Monte Carlo method to calculate the propagation path, the average photon visit depth, the average photon path length, etc. for the cases of short source-detector distances, to which the isotropic scattering approximation cannot be applied. An experiment to validate the simulation results was also conducted using a liquid phantom.     

C72O3的结构和光谱的理论研究

采用AM 1方法理论研究了C70 五元环酸酐衍生物C72 O3 的 8种可能异构体的结构和稳定性 ;以各异构体稳定构型为基础 ,分别用AM 1和ZINDO/CI方法计算了它们的振动光谱和电子光谱。结果表明 ,酸酐基团—C2 O3 主要加成在CⅠ CⅡ(异构体A)和CⅢ CⅢ(异构体B)键上形成闭环结构 ,异构体B的稳定性与实验已证实存在的异构体A十分相近 ;异构体A的振动光谱理论计算值与实验值符合较好 ,B的振动光谱理论计算值与A相似 ;对C72 O3 各异构体的电子跃迁进行了理论指认 ,讨论了其电子光谱的红移现象 ;其他异构体的振动和电子光谱属于理论预测。