Measurements of magnetic fields in solar corona as based on the radio observations of the inversion of polarization of local sources at microwaves

The possibility of measuring magnetic fields of solar active regions at coronal heights up to 10¹⁰ cm by observing the inversion of circular polarization of local sources at microwaves is demonstrated. The observations by the radiotelescope RATAN-600 were accomplished with the angular resolution 17–34 in the wavelength range 2–4 cm. It is found that the inversion of polarization occured within a core of local source situated above the largest sunspot of Mc Math 14822. The inversion was followed during the period of June 30–July 3, 1977. The measured coronal magnetic field of 16 G is found to be at the height 12 × 10⁹ cm. This measured field proves to agree with a simulated potential structure of Mc Math 14822 coronal magnetic field. Our analysis of the inversion has been based on the theory of interaction (coupling) of the ordinary and extraordinary wave modes in the region of quasi-transverse propagation.     

Electron paramagnetic resonance of PO 2 2− and SO 2 − radicals in barite

Electron paramagnetic resonance (EPR) measurements of natural barite BaSO₄ have revealed the presence of PO ₂ ^2– and SO ₂ ^– ionic radicals. For the latter a hyperfine structure from the ³³S isotope has been detected and measured for the first time. The temperature dependence of the hyperfine interaction (HFI) constant of the PO ₂ ^2– and SO ₂ ^– radicals has been investigated in the 100–400 K range.     

Study of the Rapid Variability of the BL Lac Object MRK 421 in the Optical Range

Astrophysics - MRK 421 is a giant elliptical galaxy in the Ursa Major constellation whose core has all the properties of a BL Lac object. It manifests a high activity and variability from the radio...     

Paleomagnetism of trap basalts in the northwestern Siberian craton,from core data

We present new paleomagnetic data for continental flood basalts (Siberian traps) obtained from cores of two boreholes in the northwestern Noril'sk area, within the Kharaelakh and Vologochan basins. Paleomagnetic measurements of lava and tuff samples from KhS-59 and SSV-19 boreholes allowed reconstructing and correlating the polarity patterns. Thus multiple paleomagnetic anomalies (PMA) have been discovered as brief polarity changes in narrow intervals of the magnetostratigraphic section above the principle reversal at the boundary between the Ivakin and Syverma Formations.The most prominent anomalies are observed at the bases of the Morongo and Mokulai Formations. The samples from the anomalous intervals differ from those of other intervals neither in rock magnetic properties, nor in mineralogy and magnetic grain sizes. Therefore, the revealed PMA record excursions of the geomagnetic field. Comparison of the results with the Meishan Global Stratotype Section and Point (GSSP) of the Permian–Triassic boundary implies a revision to the P–T position in the trap basalt succession of the Noril'sk area. Judging by the EMF behavior, basalts in this part of the trap province erupted for at least 500 kyr during an interval of stable normal polarity.     

EPR study of chromium-doped forsterite crystals: Cr3+(M1) with associated trivalent ions Al3+ and Sc3+

Electron paramagnetic resonance (EPR) study of single crystals of forsterite co-doped with chromium and scandium has revealed, apart from the known paramagnetic centers Cr³⁺(M1) and Cr³⁺(M1)– $ V_{{{\text{Mg}}^{2 + } }} $ (M2) (Ryabov in Phys Chem Miner 38:177–184, 2011), a new center Cr³⁺(M1)– $ V_{{{\text{Mg}}^{2 + } }} $ (M2)–Sc³⁺ formed by a Cr³⁺ ion substituting for Mg²⁺ at the M1 structural position with a nearest-neighbor Mg²⁺ vacancy at the M2 position and a Sc³⁺ ion presumably at the nearest-neighbor M1 position. For this center, the conventional zero-field splitting parameters D and E and the principal g values have been determined as follows: D?=?33,172(29) MHz, E?=?8,482(13) MHz, g?=?[1.9808(2), 1.9778(2), 1.9739(2)]. The center has been compared with the known ion pair Cr³⁺(M1)–Al³⁺ (Bershov et al. in Phys Chem Miner 9:95–101, 1983), for which the refined EPR data have been obtained. Based on these data, the known sharp M1″ line at 13,967?cm^?1 (with the splitting of 1.8?cm^?1), observed in low-temperature luminescence spectra of chromium-doped forsterite crystals (Glynn et al. in J Lumin 48, 49:541–544, 1991), has been ascribed to the Cr³⁺(M1)–Al³⁺ center. It has been found that the concentration of the new center increases from 0 up to 4.4?×?10¹⁵?mg^?1, whereas that of the Cr³⁺(M1) and Cr³⁺(M1)– $ V_{{{\text{Mg}}^{2 + } }} $ (M2) centers quickly decreases from 7.4?×?10¹⁵?mg^?1 down to 3?×?10¹⁵?mg^?1 and from 2.7?×?10¹⁵?mg^?1 down to 0.5?×?10¹⁵?mg^?1, i.e., by a factor of 2.5 and 5.4, respectively, with an increase of the Sc content from 0 up to 0.22 wt?% (at the same Cr content 0.25 wt?%) in the melt. When the Sc content exceeds that of Cr, the concentration of the new center decreases most likely due to the formation of the Sc³⁺(M1)– $ V_{{{\text{Mg}}^{2 + } }} $ (M2)–Sc³⁺ complex instead of the Cr³⁺(M1)– $ V_{{{\text{Mg}}^{2 + } }} $ (M2)–Sc³⁺ center. The formation of such ordered neutral complex is in agreement with the experimental results, concerning the incorporation of Sc into olivine, recently obtained by Grant and Wood (Geochim Cosmochim Acta 74:2412–2428, 2010).     

List of Participants

The possibility of obtaining information about small-scale inhomogenities of the electron component of the local interstellar medium (ISM) is investigated using interstellar scintillation of extragalactic radio sources. We analyze Culgoora array variability data at 80 and 160 MHz for 190 extragalactic radio sources distributed over most of the sky. The variability on time-scales of 1 month-15 years is interpreted as interstellar scintillations in rapidly-moving nearby (less than 150 pc) hot gas near shock waves in the local ISM. All-sky maps of scintillation index m averaged over 3-5 neighbouring sources and over m for time-scales of 1 month (m1) and one or several years (m12) show several maximum values for m. Locations of the maxima are insensitive to the method and number of points used for averaging. The positions of the maxima obtained in different ways agree to within 15-30 degrees on the sky; this is the angular resolution of this method. Two of the three most certain maxima are probably associated with Loop I, and the third coincides with a soft X-ray (0.1 - 0.3 keV) background maximum near the South Galactic Pole. Other less certain scintillation index maxima probably correspond to the Orion starformation region and to a soft X-ray maximum near the North Galactic Pole. A tunnel that is free of gas in the direction l = 240° is indicated by low values of m. The estimated time-scale for interstellar scintillations in these structures in the local ISM is in agreement with the time-scale for the observed radio source variations.     

Electron paramagnetic resonance of the SO 4 3- radical in barite and celestite

The electron paramagnetic resonance (EPR) study of gammaor x-ray-irradiated natural barite and celestite has revealed the presence of a radiation center with principal values of the g tensor and the A tensor [MHz] of hyperfine interaction (from the ³³S isotope): g_xx=1.9963, g_yy=2.0073, g_zz=2.0025, A_xx=434, A_yy=447, A_zz=528 in BaSO₄, g_xx=1.9990, g_yy=2.0075, g_zz=2.0027, A_xx=426, A_yy=439, A_zz=520 in SrSO₄. The center has been identified as SO _3- ⁴ radical. The electron centers SO ₄ ^3- in barite have been found to be produced along with the hole centers SO ₄ ^3- , and maximum concentration of both centers is reached at a gamma-ray-radiation dose of about 5·10⁵ Gy. UV or thermal treatment causes both centers to disappear. The SO ₄ ^3- radicals proved to be more thermally stable than the SO ₄ ^3- radicals: within about 0.5 h the latter disappear at 125° C, whereas the former do so at 180° C.     

太湖平原碟形洼地沉积物记录的距今8000年以来植被、气候与地貌演变

利用DGY孔沉积物的岩性、粒度及孢粉分析资料,探讨了太湖平原碟形洼地沉积物记录的8000年以来植被演化、气候波动,流域地貌环境的演变及其对海平面波动的响应。孢粉记录表明:本区距今8000~5000年木本植被由以落叶阔叶乔木和针叶乔木为主变为落叶阔叶乔木和常绿阔叶乔木为主,气候由温和略干转为暖热湿润;距今5000~4000年森林退缩,气候温和偏干;距今4000年左右出现低温事件;距今4000~3,000年木本植被以常绿阔叶乔木为主,气候温暖湿润;距今3000年以来木本植被主要为常绿阔叶乔木、落叶阔叶乔木和针叶乔木,气候总体温暖湿润,有波动变凉干趋势。岩性、粒度及孢粉记录综合显示本区距今8000~5000年发育潟湖相泥质粉砂,反映流域环境开放、与海连通;距今5000~4000年发育淡水沼泽,未受海水作用,反映水域缩小、流域环境封闭;距今4000~3000年水域扩大,并出现海水倒灌,反映内低外高的碟形洼地已经形成;距今3000年以来,发育湖沼平原,发生数次海水倒灌,反映碟形洼地地貌的进一步发育。     

Decametric survey of discrete sources in the Northern sky

A new method was developed for comparing absolute flux scales of the decametric surveys. The absolute scales of the new survey performed with the UTR-2 in the 10 to 25 MHz frequency range are compared with UTR-1 data and surveys at 10.03, 22.25, 26.3 and 38 MHz operating frequencies.