Arsenocolusite in Pyrite Ores of the Saum Copper–Zinc Massive Sulfide Deposit,North Urals

Geology of Ore Deposits - Pyrite ores on the flanks of the Saum copper–zinc massive sulfide deposit are clastic sediments intensely transformed under conditions of acid diagenesis. Colusite...     

Ballooning instability and oscillations of coronal loops

The excitation of the ballooning instability by the eigenoscillations of coronal loops is analyzed using the energy method. The second variation of the potential energy for the case of a plasma—plasma boundary is obtained via the linearized ideal MHD equations. It is shown that the eigenmodes of a magnetic tube and of a toroidal coronal loop coincide in a first approximation. The bending oscillations of the loops are able to excite the ballooning instability when β ? 1. The effects of the instability in solar coronal loops are discussed.     

Modification of “Pressed” Atmospheres in Active Regions of Ultracool Stars

Ultracool stars usually have active regions, which is confirmed by their high-power radiofrequency emission modulated by the star axial rotation. The interpretation of this emission is commonly based on the electron cyclotron maser mechanism realized in the active regions. A plasma mechanism of radiofrequency emission is not considered, because ultracool star atmospheres are tightly “pressed” against the star surface, and the plasma frequency is much lower than the electron gyrofrequency (f_L ? f_B) at the coronal levels. This paper explores active regions of ultracool stars for the possible existence of a system of coronal magnetic loops carrying electric current generated by photospheric convection. It is shown that current dissipation induces a temperature increase inside the loops to about 10⁷ K, which causes an increase in the scale of height of the inhomogeneous atmosphere and, at the coronal levels, effectuates condition f_L ? f_B, at which the plasma mechanism of radiofrequency emission prevails over the electron cyclotron maser mechanism. The magnetic loop parameters, intensity of electric currents generated by the photospheric convection, and efficiency of plasma heating inside the magnetic loops are evaluated on the example of the brown dwarf TVLM513-46546. The scale of the height of the modified atmosphere, which appears to be comparable to the star radius, is calculated; it is shown that the soft X-ray flow created by the hot modified atmosphere inside a coronal magnetic loop is about equal to that observed for brown dwarf TVLM513-46546.     

Slowly Varying Component of Radio Emission from TVLM 513-46546 and Continuous Sources of High Energy Electrons in the Coronae of UltraCool Stars

Geomagnetism and Aeronomy - It is shown that a source generating a slowly varying or quiet component of radio emission from ultracool stars such as the brown dwarf TVLM 513-46546 can be the...     

ANALYSIS OF THE CHEMICAL POLLUTION OF BUFFER ZONES BY MODELING AND SUB-SATELLITE EXPERIMENTS

Principles are outlined for the use of sub-satellite soil, air, water, and vegetation samples as an auxiliary source of information in remote sensing studies of vegetation stress caused by air pollution. More specifically, procedures for satellite-synchronous aerial overflights, vegetation transects, water quality measurements, and soil tests are described as a basis for delineating boundaries between areas of vegetation stress and unpolluted areas in an industrialized area in the central Urals. Translated from: Kosmicheskiy monitoring biosfery, Yu. A. Izrael', V. V. Bugrovskiy, and Yu. V. Novikov, eds. Leningrad: Gidrometeoizdat, 1985, pp. 93-99.     

Position variations of the polarization jet and injection boundary of energetic ions during substorms

The comparison of selected cases of polarization jet observation at ground stations and measurements of energetic ions at the AMPTE/CCE satellite shows that these phenomena occur simultaneously and on the same L shells. Polarization jet observations at DMSP satellites make it possible to statistically determine the dependence of its equatorial boundary position on the AE-index value. It is also shown that, in the case of isolated magnetic disturbances, the position of the inner boundary of injection of energetic ions measured at the AMPTE/CCE satellite depends on the AE index. It was found that the dependences of both boundaries on the AE index match over a wide range of AE variations. This is evidence that the equatorial boundary polarization jet band and the inner boundary of the injection of energetic ions are physically interconnected and are formed on the same L shells during substorms.     

Dynamics of accelerated electron beams and X rays in solar flares with sub-THz radiation

Unique measurements by a solar submillimeter radio telescope (SST) have been carried out in the sub-THz radiation at 212 and 405 THz over the past decade. The spectrum of RF radiation in this region increased with frequency for the three flares of November 2 and 4, 2003, and December 6, 2006, and the flux value reached 5 × 10³?2 × 10⁴ sfu at 405 GHz (Kaufman et al., 2009). In this work, we consider a set of nonlinear equations for an accelerated electrons beam and the Langmuir wave energy density. The distribution functions of the accelerated electron beam and wave energy density are calculated taking into account Coulomb collisions, electron scattering by waves, and wave scattering by plasma ions. In addition, the source of accelerated particles and the heat level of the Langmuir turbulence are specified. The beam and plasma parameters are chosen based on the aims of a problem. The plasma concentration varies from n = 10¹³ to 10¹⁵ cm^?3, the electron plasma frequency f _p = (3 × 10¹⁰?3 × 10¹¹) Hz in this case. The ratio of plasma and beam concentrations, sufficient to explain the value of the radio flux at a frequency of 300 GHz, is n _b/n = 10^?3. The Langmuir turbulence is excited due to the instability of the accelerated electron beam with an initial distribution function of the ??bump-in-tail?? type. Then, the parameters of radiowaves are calculated in the sub-THz range under the assumption of coalescence of two plasma waves. The calculation results show that a sub-THz radio flux can be obtained under the condition of injection of accelerated electrons. The fine time structure of radio flux observed is easily simulated based on this statement by the pulsed time structure of electron beams and their dynamics in overdense plasma. X-ray and gamma radiation was recorded during the events under study. Hard X-ray radiation is bremsstrahlung radiation from accelerated electron beams.