Electromagnetic sounding of the Kola Peninsula with a powerful extremely low frequency source

Experiment on electromagnetic sounding of the Kola Peninsula using unique mobile measuring complex of the low-frequency sounding was conducted, allowing to investigate a geoelectric section with a depth of several kilometers on distances up to 100 km from the stationary transmitting aerial. Excess on the order of amplitudes of the vertical component above the horizontal at all frequencies of sounding was registered in a number of points of measurements. This feature managed to be explained quantitatively by circulation of current on regional faults with the closure of current through the sea—before unknown galvanic coastal effect. Interpretation of the results of modeling and neural network solving of inverse problem essentially specifies the fault tectonics of the central part of the Kola Peninsula. Anomaly remote from the observation profile was found out—local pinch of a crustal conductive layer consisting of graphitized rocks and associated with the zone of overthrust.     

Electron oscillations in the induced martian magnetosphere

The Analyzer of Space Plasmas and Energetic Atoms (ASPERA-3) experiment flown on the Mars Express (MEX) spacecraft includes the Electron Spectrometer (ELS) as part of its complement. The ELS instrument measures the differential electron flux spectrum in a 128-level logarithmic energy sweep within a time period of 4 s. The orbital path of MEX traverses the martian sheath, cusps, and tail where ELS recorded periodic electron intensity oscillations. These oscillations comprised periodic variations of up to an order of magnitude (peak to valley) in energy flux, with the largest amplitudes in the tens to hundreds of eV range. The observed oscillations displayed periods ranging from minutes down to the instrument sweep resolution of 4 s. In the cases analyzed here, the frequency of the integrated electron energy flux typically peaked between 0.01 and 0.02 Hz. This frequency range is nearly the same as the typical O⁺ gyrofrequency in the magnetosheath, calculated using magnetometer data from Mars Global Surveyor. Due to the motion of the spacecraft, it is unclear if the wave structures observed were permanent standing waves or rather constituted waves propagating past the spacecraft.     

Comparative analysis of Venus and Mars magnetotails

We have an unique opportunity to compare the magnetospheres of two non-magnetic planets as Mars and Venus with identical instrument sets Aspera-3 and Aspera-4 on board of the Mars Express and Venus Express missions. We have performed both statistical and case studies of properties of the magnetosheath ion flows and the flows of planetary ions behind both planets. We have shown that the general morphology of both magnetotails is generally identical. In both cases the energy of the light (H⁺) and the heavy (O⁺, etc.) ions decreases from the tail periphery (several keV) down to few eV in the tail center. At the same time the wake center of both planets is occupied by plasma sheet coincident with the current sheet of the tail. Both plasma sheets are filled by accelerated (500-1000 eV) heavy planetary ions. We report also the discovery of a new feature never observed before in the tails of non-magnetic planets: the plasma sheet is enveloped by consecutive layers of He⁺ and H⁺ with decreasing energies.     

U–Th age of the Kazantsevo (MIS 5) Horizon of the Upper Neopleistocene Ust Oda reference section,Baikal Region

For the first time, the organic sediments of the Kazantsevo Horizon (Baikal Region) were characterized geochronometrically. The ²³⁰Th/U age of the buried gyttias from the Upper Neopleistocene Ust Oda stratotypical section on the Kitoi River was determined using a new version of isochronous approximation. The assemblage of all the ²³⁰Th/U age data, which were obtained taking into account the errors in the entire range from 136 to 86 kyr, indicates that most likely gyttia age is 115–104 kyr (MIS 5d). Thus, the paleontological conclusions on the Kazantsevo age of the Ust Oda Formation with buried gyttias are confirmed. Our geochronometric data supplement and make more reliable the age model of the formation of sedimentary rocks of the Ust Oda section.     

Age of a Cross-Layered Sand Sequence of the Yar Sredny Reference Section (Central Kamchatka): Data on Combined 230Th/238U and 14С Dating of Peat

Doklady Earth Sciences - The first quantitative data on the radio-isotope age are presented for a sequence of cross-layered sands abundant in the Neopleistocene reference sections of loose...     

Studying instrumental linear polarization at the Large Solar Vacuum Telescope (LSVT)

Impact linear polarization in solar flares is studied with the Large Solar Vacuum Telescope (LSVT) using the spectral polarimetric method. This method makes it possible to minimize the effect of instrumental polarization with an error of up to 10⁻² owing to the normalization of the spectral line intensity to the continuum spectrum intensity with negligible linear polarization. As a result, the Hα line intensity in two orthogonally polarized spectral stripes coincides in the absence of solar polarization. However, in the presence of linear polarization in a flare, the spectral polarimetric method does not rule out that the error can be present in determining the Stokes parameters Q and U because of their possible relative “leakage.” Linear instrumental polarization of LSVT has been performed using polaroid rotation before the major mirror. Twelve elements of a telescope matrix, characterizing linear polarization, have been determined. The usage of a matrix makes it possible to specify the observed Q and U values accurate to 10⁻³ of their magnitude.     

Dynamics of the Mesosphere and Lower Thermosphere Based on Results of Observations on the SURA Facility

Geomagnetism and Aeronomy - The results of studies of atmospheric dynamics in the altitude range of 60–130 km are presented based on measurements of the velocity of vertical plasma motion,...     

Shipboard Flow-Through Complex for Measuring Bio-Optical and Hydrological Seawater Characteristics

Oceanology - A flow-through measuring complex has been created for continuous underway measurements of bio-optical characteristics (fluorescence intensities of chlorophyll a and dissolved organic...