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171.
Alexander S. Kovtyukh 《Space Science Reviews》2018,214(8):124
Spatial, energy and angular distributions of ion fluxes in the Earth’s radiation belts (ERB) near the equatorial plane, at middle geomagnetic latitudes and at low altitudes are systematically reviewed herein. Distributions of all main ion components, from protons to Fe (including hydrogen and helium isotopes), and their variations under the action of solar and geomagnetic activity are considered. For ions with \(Z\geq 2\) and especially for ions with \(Z \geq 9\), these variations are much more than for protons, and these have no direct connection with the intensity of magnetic storms (\(Z\) is the charge of the atomic nucleus with respect to the charge of the proton). The main physical mechanisms for the generation of ion fluxes in the ERB and the losses of these ions are considered. Solar wind, Solar Cosmic Rays (SCR), Galactic Cosmic Rays (GCR), and Anomalous component of Cosmic Rays (ACR) as sources of ions in the ERB are considered. 相似文献
172.
Andrew W. Stephan R. R. Meier Scott L. England Stephen B. Mende Harald U. Frey Thomas J. Immel 《Space Science Reviews》2018,214(1):42
The NASA Ionospheric Connection Explorer Far-Ultraviolet spectrometer, ICON FUV, will measure altitude profiles of the daytime far-ultraviolet (FUV) OI 135.6 nm and N2 Lyman-Birge-Hopfield (LBH) band emissions that are used to determine thermospheric density profiles and state parameters related to thermospheric composition; specifically the thermospheric column O/N2 ratio (symbolized as \(\Sigma\)O/N2). This paper describes the algorithm concept that has been adapted and updated from one previously applied with success to limb data from the Global Ultraviolet Imager (GUVI) on the NASA Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) mission. We also describe the requirements that are imposed on the ICON FUV to measure \(\Sigma\)O/N2 over any 500-km sample in daytime with a precision of better than 8.7%. We present results from orbit-simulation testing that demonstrates that the ICON FUV and our thermospheric composition retrieval algorithm can meet these requirements and provide the measurements necessary to address ICON science objectives. 相似文献
173.
Pulsars are natural cosmic clocks. On long timescales they rival the precision of terrestrial atomic clocks. Using a technique called pulsar timing, the exact measurement of pulse arrival times allows a number of applications, ranging from testing theories of gravity to detecting gravitational waves. Also an external reference system suitable for autonomous space navigation can be defined by pulsars, using them as natural navigation beacons, not unlike the use of GPS satellites for navigation on Earth. By comparing pulse arrival times measured on-board a spacecraft with predicted pulse arrivals at a reference location (e.g. the solar system barycenter), the spacecraft position can be determined autonomously and with high accuracy everywhere in the solar system and beyond. We describe the unique properties of pulsars that suggest that such a navigation system will certainly have its application in future astronautics. We also describe the on-going experiments to use the clock-like nature of pulsars to “construct” a galactic-sized gravitational wave detector for low-frequency (\(f_{GW}\sim 10^{-9} \text{--} 10^{-7}\) Hz) gravitational waves. We present the current status and provide an outlook for the future. 相似文献
174.
T. Beuselinck C. Van Bavinchove V. I. Abrashkin A. E. Kazakova V. V. Sazonov 《Cosmic Research》2010,48(3):246-259
The results of reconstruction of rotational motion of the Foton M-3 satellite during its uncontrolled flight in September 2007 are presented. The reconstruction was performed by processing
the data of onboard measurements of the Earth’s magnetic field obtained by the DIMAC instruments. The measurements were carried
out continuously throughout the flight, but the processing technique dealt with the data portions covering time intervals
of a few orbital revolutions. The data obtained on each such interval were processed jointly by the least squares method with
using integration of the equations of satellite motion relative to its center of mass. When processing, the initial conditions
of motion and the used mathematical model’s parameters were estimated. The results of processing 16 data sets gave us complete
information about the satellite motion. This motion, which began at a low angular velocity, had gradually accelerated and
in five days became close to the regular Euler precession of an axisymmetric solid body. At the end of uncontrolled flight
the angular velocity of the satellite relative to its lengthwise axis was 0.5 deg/s; the angular velocity projection onto
the plane perpendicular to this axis had a magnitude of about 0.18 deg/s. 相似文献
175.