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341.
E.B. Romanova O.M. Pirog N.M. Polekh A.V. Tashchilin G.A. Zherebtsov J.K. Shi X. Wang 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(4):569-578
The results of modeling of ionospheric disturbances observed in the East Asian region during moderate storms are presented. The numerical model for ionosphere–plasmasphere coupling developed at the ISTP SB RAS is used to interpret the data of observations at ionospheric stations located in the longitudinal sector of 90–130°E at latitudes from auroral zone to equator. There is obtained a reasonable agreement between measurements and modeling results for winter and equinox. In the summer ionosphere, at the background of high ionization by the solar EUV radiation in the quiet geomagnetic period the meridional thermospheric wind strongly impacts the electron concentration in the middle and auroral ionosphere. The consistent calculations of the thermospheric wind permit to obtain the model results which are closer to summer observations. The actual information about the space-time variations of thermosphere and magnetosphere parameters should be taken into account during storms. 相似文献
342.
G. I. Pugacheva A. A. Gusev U. B. Jayanthi I. M. Martin W. N. Spjeldvik 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2001,28(12):1759-1762
We report a study of the numeric solution to the diffusive transport equation for energetic protons magnetically trapped in the Earth's equatorial magnetosphere. The analysis takes into account the pertinent physical processes in this region, including deceleration of protons by Coulomb collisional interactions with free and bound electrons, the charge exchange process, cosmic ray albedo neutron decay source, and electric and magnetic radial diffusion. These results were obtained using the Finite Element Method with magnetic moment and geomagnetic L-shell as free variables. Steady state boundary conditions were imposed at L=1 as zero distribution function and at L=7 with proton distribution function extracted from ATS 6 satellite observations. The FEM-code yields unidirectional proton flux in the energy range of 0.1–1000 MeV at the equatorial top of the geomagnetic lines, and the results are found to be in satisfactorily agreement with the empirical NASA AP-8 model proton flux within the energy range of 0.5–100 MeV. Below 500 keV, the empirical AP-8 model proton fluxes are several orders of magnitude greater than those computed with the FEM-code at L<3. This discrepancy is difficult to explain by uncertainties of boundary spectrum parameters or transport coefficients. 相似文献
343.
R Facius K Scherer G Reitz H Bucker L V Nevzgodina E N Maximova 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1994,14(10):93-103
The potentially specific importance of the heavy ions of the galactic cosmic radiation for radiation protection in manned spaceflight continues to stimulate in situ, i.e., spaceflight experiments to investigate their radiobiological properties. Chromosome aberrations as an expression of a direct assault on the genome are of particular interest in view of cancerogenesis being the primary radiation risk for man in space. In such investigations the establishment of the geometrical correlation between heavy ions' trajectories and the location of radiation sensitive biological substructures is an essential task. The overall qualitative and quantitative precision achieved for the identification of particle trajectories in the order of approximately 10 micrometers as well as the contributing sources of uncertainties are discussed. We describe how this was achieved for seeds of Lactuca sativa as biological test organisms, whose location and orientation had to be derived from contact photographies displaying their outlines and those of the holder plates only. The incidence of chromosome aberrations in cells exposed during the COSMOS 1887 (Biosatellite 8) and the COSMOS 2044 (Biosatellite 9) mission was determined for seeds hit by cosmic heavy ions. In those seeds the incidence of both single and multiple chromosome aberrations was enhanced. The results of the Biosatellite 9 experiment, however, are confounded by spaceflight effects unrelated to the passage of heavy ions. 相似文献
344.
N. Langer 《Space Science Reviews》1993,66(1-4):365-372
Taking as example a 60M ⊙ star of solar metallicity, the state of the art of model calculations for very massive, from the main sequence to the supernova stage, is reviewed. It is argued that — due to the simple internal structure of Wolf-Rayet stars — the post main sequence evolutionary phases are currently those which are better understood. A brief discussion of the supernova outcome from very massive stars is given. Then, the more uncertain main sequence evolution is discussed. A first attempt to incorporate results about pulsational instabilities of very massive stars in stellar evolutionary calculations is performed. On its basis, a new type of evolutionary sequence for very massive stars is obtained, namely O-star → Of-star → H-rich WNL → LBV → H-poor WNL → WNE → WC → SN. This scenario is shown to correspond better to many observed properties of very massive stars than the standard one. It includes a model for the prototype LBV P Cygni. 相似文献
345.
346.
K. Kudela V. N. Lutsenko D. G. Sibeck M. Slivka T. V. Gretchko E. T. Sarris 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2002,30(12):2849-2854
Time period from October 1996 until January 1998 was checked on high energy resolution DOK2 energetic particle instrument measurements on Interball-1 and Interball-2 for the ion (> 20 keV) dispersive events (EDIS) with the exclusion of Interball-1 orbit parts in the tail. A variety of energy dispersive events, both in ion and electron spectra with different duration is found in the auroral regions, in the outer magnetosphere and near the cusp. While EDIS were observed in all sectors of MLT, the best conditions for their observation were in the afternoon local time. The characteristics of dispersive events observed by DOK2 are consistent with their explanation by the gradient-curvature drift of particles from the injection point(s) in the night local time sector given in Lutsenko at al., 2000a, b. 相似文献
347.
S. Seetha M.C. Ramadevi V.C. Babu M.R. Sharma N.S.R. Murthy B.N. Ashoka K.C. Shyama R. Kulkarni G. Meena P. Sreekumar 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2006,38(12):2995-2998
The Scanning Sky Monitor is one of the experiments onboard the ASTROSAT, an Indian multiwavelength astronomy satellite mission. This experiment will detect and monitor X-ray transients in the energy band 2–10 keV. It is similar in design to the ASM on RXTE. It consists of position-sensitive proportional counters with one-dimensional mask. We describe the configuration of the experiment. We also discuss some of the results obtained using a detector which has already been fabricated and tested in our laboratory. 相似文献
348.
349.
Information Support for Space Experiments Based on a Numerical-Analytical Theory of Satellite Motion
A software tool for application in calculations of the position and velocity vectors of spacecraft is presented. These vectors are necessary at the stage of processing the data of space experiments and analyzing the results of ground-based observations. A new theory of satellite motion, in a numerical-analytical form, is the basis of this software application. The model of disturbing forces corresponds to recommendations of the International Laser Ranging Service. The reliability of the software tool is confirmed by the results of processing of high-precision laser satellite observations. 相似文献
350.
Oxygen Isotopes in the Solar System 总被引:1,自引:0,他引:1
The oxygen three-isotope system has major advantages over the two-isotope systems of hydrogen, carbon, and nitrogen because
different fractionation laws govern intraplanetary and interplanetary processes. This permits discriminating between solar
nebular processes and parent-body processes. Oxygen isotopes also serve as a sensitive natural tracer for meteorite classification.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献