Quasi-periodic geomagnetic secular variation (from 1985–2005 world observatory data)

We have discovered a 2–4 year periodicity in geomagnetic secular variation (SV) from data of 110 world magnetic observatories. The periodicity in the horizontal component (H) is most prominent and appears to be globally uniform in different regions, on all continents, and in both hemispheres. The quasi-periodic short-wavelength variations show up in the vertical component (Z) as well but locally superpose on long-wavelength regional anomalies. We presume that the short-period fluctuations may be produced by instability of the eccentric dipole (ED) axis proceeding from the analysis of the SV field and optimization modeling of the dipole field with varied ED parameters.     

Assessment of possible expansion of the climatic range of Italian locust (<Emphasis Type="Italic">Calliptamus italicus</Emphasis> L.) in Russia in the 21st century at simulated climate changes

The areas of distribution, high pest damage, and mass reproduction of Italian locust are mainly limited by climatic factors. It is demonstrated that under conditions of the RCP4.5 moderate scenario of anthropogenic impact on the global climate system in Russia in the 21st century the climatic range of Italian locust will be expanded mainly northward and, to a smaller extent, eastward. The expansion of the range by the middle of the 21st century as compared with the end of the 20th century will be more significant that at the end of the 21st century versus its middle.     

A low-mode dynamo with meridional circulation and dipolar symmetry of the magnetic field

A dynamic system for the Parker dynamo including meridional circulation that is applicable to astrophysical objects is constructed. The meridional circulation is able to control the regimes for the generation of magnetic fields. If the meridional flows are weak, regimes with steady oscillations, dynamo bursts, fluctuations, and chaotic components are possible. When the meridional circulation is strengthened, the range of dynamo numbers required for fluctuations and dynamo bursts is reduced, and gradually vanishes; at the same time, the range required for oscillations is increased and raised to higher dynamo numbers. The latitude-time distributions of the toroidal and poloidal magnetic fields for steady oscillations are presented.     

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.     

Stibiomicrolite from granitic pegmatite in the Dzhabyk-Karagai pluton of the South Urals

Stibiomicrolite has been identified in the Lepidolite Vein (53°06.8′N, 60°15.4′E) as metasomatic veinlets with tantite replacing stibiotantalite along fractures. The mineral is light gray-yellow, isotropic, and with reflectance of ～12%. The average chemical composition of two stibiomicrolite samples is as follows, wt %: Sb₂O₃ 23.34, CaO 4.91, Na₂O 0.96, MnO 0.17, Ta₂O₅ 58.97, Nb₂O₅ 6.64, total 94.99; H₂O_calc 3.4. The empirical formula is (Sb_1.02Ca_0.55Na_0.20Mn_0.02)_1.79(Ta_1.68Nb_0.32)_2.0O₆(OH)_1.18. Trilithionite, polylithionite, albite, manganotantalite, beryl (goshenite), elbaite, stibiotantalite, and tantite are associated with stibiomicrolite in the central zone of the Lepidolite Vein.     

The quasi-biennial cycle of solar activity and dynamo theory

We have investigated the behavior of dynamo waves within the framework of a nonlinear αω-dynamo by taking into account the thickness of the convective zone, turbulent diffusivity, and meridional circulation. We show that there exists a regime in the model where short and longer patterns are simultaneously observed in the butterfly diagrams for the magnetic field. This regime is similar to the mixed cycle of the Sun, when fast quasi-biennial oscillations are observed against the background of the 22-year cycle.     

Magnetic and electric-current helicities in very simple models of the solar dynamo

The behavior of the electric-current and magnetic helicities in the course of the solar-activity cycle is studied in the framework of Parker’s very simple model for the solar dynamo. A polarity rule is formulated for the helicities, which generalizes the well-known Hale polarity rule.     

Effects of various types of solar meridional circulation on the propagation of dynamo waves

We examine the effects of solar meridional circulation on the propagation of dynamo waves depending on the type of matter motion in a Parker approximation. The meridional circulation can lengthen the solar-activity cycle, with the dynamo-wave behavior depending on the latitude variations in the velocity of the moving material. The results obtained can qualitatively explain the Maunder minimum.