Quantum effects in cyclotron plasma absorption

It is shown that X-ray radiation of neutron stars with magnetic fieldsB=10¹¹–10¹³ G near cyclotron resonances=s _B (s=1,2,...) is deeply affected by such quantum effects as electron-positron vacuum polarization (significant at V=3×10²⁸ n _e ^–1 (B/B _C ⁴)1, whereB _C =4.4×10¹³G), the quantizing character of the magnetic field (significant atV=3 x 10²⁸ n _e ^–1 (B/B _c)⁴1 whereB _c =4.4 x 10¹³G), the non-harmonic character of the Landau levels, and the quantum recoil of electrons. The latter two factors shift the resonances by the frequency –s ² _B (B/2B _c )sin², being the angle between the direction of radiation propagation and the magnetic field. IfVV ₀ (for 1,V ₀^–1=(mc ²/2T)^1/2), the normal mode (NM) polarizations, as well as the absorption coefficientk ₁ of the extraordinary NM in the Doppler core of the first resonance (|–| _B cos ), is only slightly affected by varyingb and/orV, whereas for the ordinary NM (at 1)k ₂k ₁ ²[b + (3 + tan²–2V)²]k ₁. For sufficiently largeb and/orV the quantum effects amplify resonant absorption of the ordinary NM at _B , with spin-flip transitions playing a major role atb1+V ². IfVV ₀, the coefficientsk ₁ andk ₂ in the Doppler core of the resonance are of the same order and acquire some peculiar features (shifts, intersections, etc.), with the NM polarizations depending sharply on and being strongly non-orthogonal. AtVV ₀,k ₂=k ₁(cos² +B/2B _C ) and the polarizations are almost linear. Near high resonances (s2), as a rule,k _1,2(1 + b) ^{s–1 2s–3} i.e., absorption increases withb due to replacement of the thermal energy of the transverse motion of electron,T, by the magnetic energy _B . The above effects should be taken into account for an interpretation of observational data on X-ray pulsars (e.g., Her X-1) and other X-ray sources associated with neutron stars.     

The creation of a geophysical observatory at the Aleksandrovka research base of the geological faculty of Moscow State University in the Kaluga region

Since May 2011, long-period magnetotelluric (MT) data have been collected in the non-magnetic pavilion at the geophysical base of Moscow University in the Kaluga Region. The non-magnetic pavilion was constructed in compliance with the following conditions: selection of non-magnetic materials, control of local magnetic field anomalies, and setting the basement for magnetometers separately from the main building. Recording equipment with fluxgate and optomechanical magnetometers with three sets of electric lines with different electrodes was installed. The parallel testing of channels was performed. Currently, the seismo-logical equipment and meteorological station are being prepared for installation.     

Cooling of magnetars with internal layer heating

We model thermal evolution of magnetars with a phenomenological heat source in a spherical internal layer and compare the results with observations of persistent thermal radiation from magnetars. We show that the heat source should be located in the outer magnetar’s crust, at densities ρ≲5×10¹¹ g cm⁻³, and the heating rate should be ∼10²⁰ erg cm⁻³ s⁻¹. Heating deeper layers is extremely inefficient because the thermal energy is mainly radiated away by neutrinos and does not warm up the surface to the magnetar’s level. This deep heating requires too much energy; it is inconsistent with the energy budget of neutron stars.      

A new stage in the development of ablative pulsed plasma thrusters at the RIAME

This paper presents an overview of the works on ablative pulsed plasma thrusters (APPTs) carried out at the Research Institute of Applied Mechanics and Electrodynamics (RIAME). The main features of next generation thrusters developed at the RIAME in the 2000s are discussed together with the optimization criteria for APPTs intended for use in correction propulsion systems of small spacecraft, e.g., MKA-FKI (developed by the Lavochkin Association) and Soyuz-Sat-O (developed by Maksimov Space Systems Research Institute and the Production Corporation Polyot).     

Burial and thermal history of the West Bashkirian sedimentary basins

The GALO system is applied to the numerical reconstruction of burial and thermal histories of the West Bashkirian lithosphere from the Riphean to the present. An analysis of the variation in tectonic subsidence of the basin during its development is utilized to estimate approximately the mantle heat flow variations. Our variant of basin evolution suggests that after cooling in the Early Riphean, the rather weak thermal reactivations have not led to considerable heating of the lithosphere in the study region. Surface heat flow decreased from relatively high values in the Early Riphean (60–70 mW/m² in the eastern area and 40–50 mW/m² in the western part) to present-day values of 32–40 mW/m². In spite of the relatively low temperature regime of the basin as a whole, a syn-rifting deposition of more than 10 km of limestone, shale and sandstone in the Riphean resulted in rather high temperatures (180–190 °C) at the base of present-day sedimentary blanket in the eastern area. In agreement with the observed data, computed present-day heat flow through the sediment surface increases slightly from 32 to 34 mW/m² near the west boundary of the region to 42 mW/m² near the boundary of the Ural Foldbelt, whereas the heat flow through the basement surface decreases slightly from 28–32 to 24–26 mW/m² in the same direction. The mantle heat flow is only 11.3–12.7 mW/m², which is considerable lower than mean heat flow of the Russian Platform (16–18 mW/m²) and comparable with the low heat flow of Precambrian shields.     

Physics and Chemistry of Impacts

Earth, Moon, and Planets -     

On the Legitimacy of Using Plane-Wave Model and Two-Component Measurement Systems when Performing MT Soundings in Polar Regions

Izvestiya, Physics of the Solid Earth - Abstract—The paper addresses two issues. The first is the validity of the plane wave model when applied in the MT soundings (MT) collected in polar...