Amplitude modulation of VLF emission and absorption of cosmic noise by <Emphasis Type="Italic">Pc</Emphasis>5 geomagnetic pulsations in the period of geomagnetic storms on October 30–31, 2003

Modulation of the VLF emission and riometric absorption by Pc5 geomagnetic pulsations is studied in the period of strong geomagnetic disturbances on October 30–31, 2003. Some conclusions about the regime of pitch-angular diffusion into the loss cone are made. The better coincidence of VLF emission modulation with geomagnetic pulsations in other longitude sectors is explained by the global character of excitation of the pulsations and by damping of their amplitudes at the meridian of observation of the VLF emission, which is associated with intensification of auroral electrojets.Translated from Kosmicheskie Issledovaniya, Vol. 42, No. 6, 2004, pp. 632–639.Original Russian Text Copyright © 2004 by Solovyev, Mullayarov, Baishev, Barkova, Samsonov.     

Structure of the earth’s magnetosheath at small fluctuations in the interplanetary magnetic field direction

Spatial structure of the magnetosheath of the Earth was studied under the conditions when no sharp (more than 40° during 5 min) changes in the interplanetary magnetic field direction were observed. On the basis of 24 flights of the Interball-1 satellite through the magnetosheath, it is found that three regions differing from each other by parameters of the field and plasma can be observed in the magnetosheath under the above-indicated conditions. These regions also differ from the solar wind region before front of the Earth’s magnetospheric bow shock. Empirical distributions of parameters were studied in each region. Taking into account the influence of the interplanetary magnetic field direction on the processes in the magnetosheath, the cases of quasi-perpendicular and quasi-parallel shock waves were considered separately. The study showed that the distribution of parameters in the selected regions (in the solar wind before front of the bow shock, in the magnetosheath behind the bow shock (post-shock), in the region of the magnetosheath with minimal fluctuations in the field, and in the inner magnetosheath) differ from each other at any interplanetary magnetic field direction.     

On the problem of lunar radiation environment

In connection with projects of manned bases on the Moon it becomes topical to estimate radiation danger for their inhabitants. In this paper we describe a method of evaluation of the radiation environment on the lunar surface produced by galactic and solar cosmic rays. The roles of both primary and secondary radiations generated in the depth of the lunar soil under the action of high-energy protons and nuclei are taken into account. Calculated fluxes of particles are used in order to estimate annual averaged absorbed and equivalent local dose rates in tissues. It is established that in the lunar rock the contribution of secondary neutrons to the dose rate exceeds that of protons. The contribution of the secondary particles generated by nuclei of galactic cosmic rays to the dose rate is estimated.     

An algorithm for computer-aided design calculation of aircraft stability and controllability parameters

An algorithm is proposed for computer-aided calculation of required values of aircraft controlling moments and aerodynamic moment coefficients for stable fulfillment of flight trajectories specified by design flight performance.     

Antideuteron based dark matter search with GAPS: Current progress and future prospects

The General Antiparticle Spectrometer (GAPS) is a new approach to the indirect detection of dark matter. It relies on searching for primary antideuterons produced in the annihilation of dark matter in the galactic halo. Low energy antideuterons produced through Standard Model processes, such as collisions of cosmic-rays with interstellar baryons, are greatly suppressed compared to primary antideuterons. Thus a low energy antideuteron search provides a clean signature of dark matter. In GAPS antiparticles are slowed down and captured in target atoms. The resultant exotic atom deexcites with the emission of X-rays and annihilation pions, protons and other particles. A tracking geometry allows for the detection of the X-rays and particles, providing a unique signature to identify the mass of the antiparticle. A prototype detector was successfully tested at the KEK accelerator in 2005, and a prototype GAPS balloon flight is scheduled for 2011. This will be followed by a full scale experiment on a long duration balloon from Antarctica in 2014. We discuss the status and future plans for GAPS.     

A Parallel Adaptive 3D MHD Scheme for Modeling Coronal and Solar Wind Plasma Flows

A parallel adaptive mesh refinement (AMR) scheme is described for solving the governing equations of ideal magnetohydrodynamics (MHD) in three space dimensions. This solution algorithm makes use of modern finite-volume numerical methodology to provide a combination of high solution accuracy and computational robustness. Efficient and scalable implementations of the method have been developed for massively parallel computer architectures and high performance achieved. Numerical results are discussed for a simplified model of the initiation and evolution of coronal mass ejections (CMEs) in the inner heliosphere. The results demonstrate the potential of this numerical tool for enhancing our understanding of coronal and solar wind plasma processes. This revised version was published online in June 2006 with corrections to the Cover Date.     

Putative graviperception mechanisms of protists.

Many (if not all) free-living cells use the gravity vector for their spatial orientation (gravitaxis). Additional responses may include gravikinesis as well as changes in morphological and physiological parameters. Though using essentially different modes of locomotion, ameboid and ciliated cells seem to rely on common fundamental graviperception mechanisms. Uniquely in the ciliate family Loxodidae a specialized intracellular gravireceptor organelle has been developed, whereas in all other cells common cell structures seem to be responsible for gravisensing. Changes in direction or magnitude of acceleration (from 0 to 5 g) as well as experiments in density-adjusted media strongly indicate that either the whole cytoplasm or dense organelles like nuclei act as statoliths and open directly or via cytoskeletal elements mechano-sensitive ion channels in the cell membrane. A recent spaceflight experiment (S/MM-06) demonstrated that prolonged (9 d) actual weightlessness did not affect the ability of Loxodes to respond to acceleration stimuli. However, prolonged cooling (> or = l4 d, 4-10 degrees C) destroyed the ability for gravitactic orientation of Paramecium. This may reflect a profound effect either on the gravireceptor itself or on the gravity-signal processing. In gravity signalling the ubiquitous second messenger cAMP may be involved in acceleration-stimulus transduction.     

Optical properties of the undisturbed mesosphere from wide-angle twilight sky polarimetry

The paper describes the first results of all-sky polarization measurements of the twilight background started in central Russia in the very beginning of summer 2011. Time-frequency data of the sky intensity and polarization over a wide range of sky point zenith distances are used to separate single and multiple scattering and construct the altitude dependence of the scattering coefficient and polarization in the mesosphere (altitudes from 60 to 90 km) at different angles. The undisturbed structure of the mesosphere without noticeable aerosol stratification on observation days makes it possible to estimate the temperature of the atmosphere at these altitudes.     

Spectroscopic Constraints on Models of Ion-cyclotron Resonance Heating in the Polar Solar Corona

Using empirical velocity distributions derived from UVCS and SUMER ultraviolet spectroscopy, we construct theoretical models of anisotropic ion temperatures in the polar solar corona. The primary energy deposition mechanism we investigate is the dissipation of high frequency (10-10000 Hz) ion-cyclotron resonant Alfvén waves which can heat and accelerate ions differently depending on their charge and mass. We find that it is possible to explain the observed high perpendicular temperatures and strong anisotropies with relatively small amplitudes for the resonant waves. There is suggestive evidence for steepening of the Alfvén wave spectrum between the coronal base and the largest heights observed spectroscopically. Because the ion-cyclotron wave dissipation is rapid, even for minor ions like O⁵⁺, the observed extended heating seems to demand a constantly replenished population of waves over several solar radii. This indicates that the waves are generated gradually throughout the wind rather than propagated up from the base of the corona. This revised version was published online in June 2006 with corrections to the Cover Date.     

Does mental arithmetic before head up tilt have an effect on the orthostatic cardiovascular and hormonal responses?

Passive head up tilt (HUT) and mental arithmetic (MA) are commonly used for providing mental and orthostatic challenges, respectively. In animal experiments, even a single exposure to a stressor has been shown to modify the response to subsequent stress stimulus. We investigated whether MA applied before HUT elicits synergistic responses in orthostatic heart rate (HR), cardiac output (CO), heart rate variability and arterial blood pressure. The 15 healthy young males were subjected to two randomized protocols: (a) HUT and (b) HUT preceded by MA, with sessions randomized and ≥2 weeks apart. Beat to beat continuous hemodynamic variables were measured and saliva samples taken for hormonal assay. HUT alone increased HR from 59±7 (baseline) to 80±10 bpm (mean±SD) and mean blood pressure (MBP) from 88±10 to 91±14 mmHg. HUT results after MA were not different from those with HUT alone. The activity of alpha amylase showed differences during the experiments irrespective of the protocols. We conclude that mental challenge does not affect orthostatic cardiovascular responses when applied before; the timing of mental loading seems to be critical if it is intended to alter cardiovascular responses to upright standing.