Effects of the Absorption of Solar XUV Radiation by the Earth's Upper Atmosphere at Altitudes of 100–500 km in the X-ray Solar Images Obtained Onboard the Coronas-I (TEREK Telescope) and Coronas-F (SPIRIT X-ray Complex) Satellites

We consider the effects of the absorption of solar XUV radiation by the Earth's atmosphere that were observed in the solar images obtained with the TEREK-K telescope onboard the Coronas-I satellite in May–June 1994 at low solar activity and with the SPIRIT instrumentation onboard the Coronas-F satellite in October–November 2001 at maximum solar activity. The solar images were recorded during the satellite occultation: in the 175- and 304-A spectral ranges onboard Coronas-I with the TEREK-K telescope and in the 175-, 304-, and 8.42-A ranges onboard Coronas-F with the SPIRIT instrumentation. Based on the XUV solar images obtained during atmospheric sounding, apart from the total absorption, we can determine the direction of the atmospheric density gradient and study the local absorption variations with altitude on spatial scales of less than 1 km. The described method can significantly supplement the data obtained in studies of the upper atmosphere by the methods of mass spectrometry, incoherent radar scattering, and the drag of orbital spacecraft.     

Alarm-Seismo 3 automated monitoring station

An automated hardware-software station was designed at the Institute of Physics of the Earth (Moscow, Russia) for the continuous monitoring of a low-frequency electromagnetic background in a low atmosphere. The electromagnetic signal is processed in real time and an attempt is made to find and confirm the possible precursors of earthquakes. The basic concepts of electromagnetic earthquake precursors are described, as well as a technique of data recording and processing for obtaining the most accurate prediction. The design of the station is based on up-to-date hardware components and can be integrated with additional detectors if necessary. It is assumed that stations can be combined within monitoring networks of different scales. The net cost of the station is relatively low because only mainstream components are used.     

Geological structure, composition of ores and age of the Bamsk gold deposit, Amur region, Russia

The Bamsk gold-ore deposit is located in the Amur region, the Far East of Russia. It is confined to the Early Cretaceous volcanic-plutonic uplift of central type, located in the Stanov folded-clumpy Pre-Cambrian system. The deposit is presented by a series of gold-bearing quartz and carbonate-quartz vein-stringer zones. They are confined to the super-intrusive zone of the Nevachansk subvolcanic intrusion of sienite-porphyric composition. The mineralization is being controlled by zone of fractures developed in the autochthone ofthe Bamsk fault. Quartz, carbonates and sericite prevail in the composition of ores. The quantity of ore minerals doesn't exceed 1%～5%. Pyrite, chalcopyrite, galena and native gold are widely spread. Sheelite, gold and silver tellurides, sulphobismuthites, acanthite, sphalerite and cinnabar are less developed. Four stages of mineralization have been distinguished. Gold-sulphide-sulphosalt ore with tellurides of gold and silver is productive for gold. The following set of elements is typomorphic for the ores of the deposit: Au, Ag, Cu, Bi,Mo, Pb and Sb (W1, Pb1, Mo) -Cu- (Ag, Bi, Sb, Mn, W1, Pb2) form the vertical series of zoning. Rocks, enclosing the mineralization are exposed to the processes of listvenitization-beresitization. The processes of gumbeization and argillization are less manifested. The age of the gold mineralization, determined by Rb-Sr method on ore-accompanying minerals, is 130.6 Ma.     

Tokur gold ore–placer cluster in Amur Province: Geological–structural features and perspective of its development

The geological–structural features and gold-potential perspective of the Tokur ore–placer cluster in the Amur Province have been studied. This ore–placer cluster is a syncline composed of Paleozoic blackshale sequence, which is cut through by Late Paleozoic and Late Mesozoic intrusions. A granitoid massif is suggested at the depth on the basis of geophysical data. The cluster is distinguished by high productivity. Approximately 37 t gold from ore deposits, primarily from the Tokur deposit, and 60 t from placers have been mined out. The Tokur deposit is compared with the Natalka and Degdekan deposits from the Yana–Kolyma Province. Perspectives of the cluster area for large gold–quartz deposits and technogenic gold placers have been estimated.     

Ambipolar diffusion and magnetic reconnection

Some mechanisms for Joule dissipation of electric currents flowing in partially ionized hydrogen plasmas are analyzed in a three-fluid approximation. It is shown that ambipolar diffusion can be responsible for the annihilation of magnetic flux during collisions of ions with neutral atoms. The relative influences of the electron conductivity and the Cowling conductivity on the magnetic-field annihilation rate are examined in the frameworks of the Sweet-Parker reconnection model. The escape of plasma is an efficient mechanism for cooling current sheetswith thicknesses of hundreds of kilometers in the solar chromosphere. The origin of the solar chromospheric jets observed by the Hinode spacecraft is discussed.     

Pulsations of type IV solar radio emission: The bounce-resonance effects

A mechanism of excitation of radial oscillations of a magnetic tube is proposed for the interpretation of a periodic modulation of type IV radio burst intensity in the meter and decimeter range. After the flare a configuration with denser plasma extended along the magnetic field can be formed in the corona. Eigenoscillations of such a system are damped by MHD-wave emission into the external coronal plasma. However, if high energy protons with 0.2 are trapped by this configuration, the damping of oscillations can be made up for by an amplification due to bounce-resonant plasma instability. The regularity of the pulse period is explained by presence of a maximum in the wave growth rate dependence on the frequency.     

Estimating the baroclinic Rossby radius of deformation in the Sea of Okhotsk

The first baroclinic Rossby radius of deformation (R ₁) in the Sea of Okhotsk is estimated using the hydrological datasets from the World Ocean Atlas (WOA) 2001 and WOA 2013. It is established that the maximum values of R ₁ are observed over the Kuril Basin (18–20 km), and its minimum values (1.5–2 km), over the northern shelf of the Sea of Okhotsk. In the central part of the sea R1 varies from 8 to 10 km. The seasonal variability of R1 for both datasets is characterized by the minima in winter and by the maxima in summer. It was found that on the eastern shelf of Sakhalin Island R ₁ reaches the maximum both in November (～6 km) and in April (～4-5 km). According to the obtained estimates of R ₁, the model grid resolution of 3 to 8 km should be used for the eddy-permitting numerical simulation of circulation in the Sea of Okhotsk, and the model grid resolution from 1.5 to 2 km, for the explicit simulation of mesoscale variability.