Experimental study of parameters of X-ray radiation from solar flares using the PENGUIN-M instrument aboard the CORONAS-PHOTON spacecraft

The main characteristics of the PENGUIN-M instrument are given. The instrument has been operating aboard the CORONAS-PHOTON spacecraft (SC) launched into orbit on January 30, 2009. The instrument includes the PENGUIN-MD detector unit (PMD) and the PENGUIN-ME electronic unit (PMD). The purpose of the experiment is to measure the degree of linear polarization of X-ray radiation from solar flares in the energy range of 20–150 keV and to obtain energy spectra of X-ray radiation from solar flares in the energy range of 2–500 keV. The paper describes the instrument, calibration procedure, and in-flight adjustment, and contains the first results of measurements.     

Methods for reconstructing harmonic functions from the magnetic field ΔT and V.N. Strakhov’s function ΔS: A review

We give an overview of the methods designed for reconstructing close-to-harmonic functions from the magnetic field ΔT. The formula of Yu.P. Tafeev is refined. It is shown that this refined formula directly leads to the relation derived by V.M. Gordin and his colleagues that allows isolating the harmonic component in the function ΔT. V.N. Strakhov’s linearized representation of the function ΔT is immediately derived from the main approximate Tafeev formula for Q ΔT. The experience of using Strakhov’s ΔS function in the interpretation of the magnetic anomaly ΔT generated by the Krivoi Rog structure is described. It is noted that the problem of reconstructing the corresponding harmonic functions from the data of magnetic and gravity surveys has much in common. The specific features of measuring the magnetic field H and magnetic induction B in the material media are considered, and the physical interpretation of these fields is presented.     

Energy Exchange between Jets of the Antarctic Circumpolar Current and Synoptic Eddies in the Drake Passage and Scotia Sea

We study the energy exchange between jets of the Antarctic Circumpolar Current (ACC) and synoptic eddies generated by them in the surface layer of the ocean in the Drake Passage and Scotia Sea based on 22-year-long satellite altimetry time series from the French CLS Agency (DT Global–MADT–Upd product, http://www.aviso.altimetry.fr) under the assumption, based on observations, that each of the jets is confined between two fixed contour lines of the absolute dynamic topography of the ocean. We calculate and analyze the 22-year evolution of the kinetic energy of each ACC jet and cyclonic and anticyclonic eddies generated by it. We demonstrate the fundamental dependence of fluctuations in jet energy on the phase of their meander and eddy formation, as well as their back absorption by jets. We calculate the mean and extreme energetic characteristics of jets and eddies and compare the jets in terms of the intensity of the generated eddies.     

PGM in chromite ore of the Sopcheozero deposit, Kola Peninsula

The Sopcheozero chromite deposit is hosted in dunite of the Monchegorsk layered intrusion as a sheetlike body of disseminated ore with a chromite grade varying from 20 to 60%. The total PGM content in the ore attains 0.5–0.8 g/t. The composition of host rocks varies from plagioclase peridotite to dunite, but PGM were found only in chromite-bearing dunite. PGM inclusions were detected in the interstices of chromite and olivine grains and within grains themselves. The data obtained confirm the known tendency toward variation in PGM composition with increasing sulfur and light PGE contents in the residual magmatic melt. The first particles of refractory Ir, Os, and Ru intermetallides appeared at the final stage of olivine crystallization, whereas laurite (Ru,Os,Ir)S₂ and pentlandite (Fe,Ni)₉S₈ were formed at the final stage of chromite crystallization, when the sulfur concentration in the residual melt became sufficient.     

Metamorphic evolution of the archean eclogite-like rocks of the Shirokaya and Uzkaya Salma area (Kola Peninsula): Geochemical features of zircon,composition of inclusions,and age

Zircon from the eclogite-like rocks of the Shirokaya and Uzkaya Salma area (Kola Peninsula) was studied using a complex of mineralogical and geochemical methods (CL, BSE, microprobe, and REE distribution). Different zones distinguished within zircon crystals were dated on a SHRIMP-II mass spectrometer. Mineral and chemical compositions of inclusions in the zircons were analyzed. Based on these studies, the following stages of the formation and transformation of the rocks were determined: (1) formation of basic protolith of the eclogite-like rocks of the Shirokaya and Uzkaya Salma area 2.94–2.93 Ga ago; (2) the granulite-facies metamorphism of the eclogite-like rocks of the Shirokaya Salma 2.72 Ga ago; (3) the onset of decompressional cooling with formation of Cpx-Pl symplectites at 2.70 Ga ago; and (4) final metamorphic reworking together with surrounding TTG under the amphibolite-facies conditions at 1.89 Ga ago. The studied rocks and minerals revealed no isotope-geochemical or geochronological signs of eclogite metamorphism. Geochemistry of the primary magmatic zircons showed that the protolith of eclogite-like rocks was gabbro rather than MOR basalts. The formation of garnet in the rocks of the Uzkaya and Shirokaya Salma area is dated at 2.70 and 1.89 Ga ago, which is consistent with petrological observations of later formation of garnet relative to omphacite. Obtained data led us to prefer a magmatogenic model, which suggests that omphacite in the rocks of the Shirokaya and Uzkaya Salma was presumably formed during crystallization from basic melt, rather than during eclogite-facies metamorphism.     

Solar flares registered by the IRIS spectrometer onboard the CORONAS-F satellite: Peculiarities of the X-ray emission

The X-ray spectrometer IRIS was designed to register the fluxes of quanta with energies ranging from 2 to 250 keV in various time-resolution modes: 0.01, 1.0, and 2.5 s in 4, 64, and 12 channels, respectively. Owing to the high instrument sensitivity, individual spikes of tens of milliseconds can be distinguished in the time structure of the X-ray flare emission. The time spectral analysis carried out for the X-ray emission of a number of registered flares points to the presence of a quasiperiodic structure with characteristic times of the same order. For the flares of December 19, 2001, and August 10, 2002, the process of energy release has been considered with a 1-s time resolution, and its periodic character has been revealed. For the flare of December 19, 2001, the energy spectra of the hard X-ray emission have been simulated by thermal and nonthermal models. It has been shown that the both models can describe this emission.     

Time structure and energy spectrum evolution of the solar flare X-rays measured by the IRIS spectrometer onboard the CORONAS-F spacecraft

The time structure and energy spectrum evolution of the X-ray emission of solar flares, observed by the IRIS spectrometer onboard the CORONAS-F spacecraft, are investigated. It has been found out that one or two quasi-periodic components with periods of 1–20 s, which are absent in the background preflare emission, appear in the flare soft X rays. It has been indicated that the variation in the shape of the energetic spectra of the C-class flare hard X rays reflects the evolution of the accelerated electron distribution function.     

Generation of magnetic-field perturbations in underwater explosion

In this paper we study the inertial and induction mechanisms of electric-current generation in sea-water motions. The problem of calculating the magnetic field induced by these currents is considered. For the induction generation mechanism, if self-induction is disregarded, the fields arising in central-symmetric motions of sea water (like underwater explosions) are calculated.