排序方式: 共有30条查询结果,搜索用时 15 毫秒
21.
Three ways of the energy transfer in the Earth's magnetosphere are studied. The solar wind MHD generator is an unique energy
source for all magnetospheric processes. Field-aligned currents directly transport the energy and momentum of the solar wind
plasma to the Earth's ionosphere. The magnetospheric lobe and plasma sheet convection generated by the solar wind is another
magnetospheric energy source. Plasma sheet particles and cold ionospheric polar wind ions are accelerated by convection electric
field. After energetic particle precipitation into the upper atmosphere the solar wind energy is transferred into the ionosphere
and atmosphere. This way of the energy transfer can include the tail lobe magnetic field energy storage connected with the
increase of the tail current during the southward IMF. After that the magnetospheric substorm occurs. The model calculations
of the magnetospheric energy give possibility to determine the ground state of the magnetosphere, and to calculate relative
contributions of the tail current, ring current and field-aligned currents to the magnetospheric energy. The magnetospheric
substorms and storms manifest that the permanent solar wind energy transfer ways are not enough for the covering of the solar
wind energy input into the magnetosphere. Nonlinear explosive processes are necessary for the energy transmission into the
ionosphere and atmosphere. For understanding a relation between substorm and storm it is necessary to take into account that
they are the concurrent energy transferring ways.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
22.
Edwards Christopher S. Christensen Philip R. Mehall Greg L. Anwar Saadat Tunaiji Eman Al Badri Khalid Bowles Heather Chase Stillman Farkas Zoltan Fisher Tara Janiczek John Kubik Ian Harris-Laurila Kelly Holmes Andrew Lazbin Igor Madril Edgar McAdam Mark Miner Mark O’Donnell William Ortiz Carlos Pelham Daniel Patel Mehul Powell Kathryn Shamordola Ken Tourville Tom Smith Michael D. Smith Nathan Woodward Rob Weintraub Aaron Reed Heather Pilinski Emily B. 《Space Science Reviews》2021,217(7):1-37
Space Science Reviews - Modern observatories have revealed the ubiquitous presence of magnetohydrodynamic waves in the solar corona. The propagating waves (in contrast to the standing waves) are... 相似文献
23.
Baliukin Igor Bertaux Jean-Loup Bzowski Maciej Izmodenov Vladislav Lallement Rosine Provornikova Elena Quémerais Eric 《Space Science Reviews》2022,218(6):1-33
Space Science Reviews - The Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) is a robotic arm-mounted instrument onboard NASA’s Perseverance... 相似文献
24.
Petr Ammosov Galina GavrilyevaAnastasia Ammosova Igor Koltovskoi 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2014
OH(6-2) rotational temperature trends and solar cycle effects are studied. Observations were carried out at the Maimaga station (63.04°N, 129.51°E) for the period August 1999 to March 2013. Measurements were conducted with an infrared spectrograph. Temperatures were determined from intensity ratios in the P branch of the OH band. The monthly average residuals of temperature after the subtraction of the mean seasonal variation were used for a search for the solar component of temperature response. The dependence of temperatures on solar activity has been investigated using the Ottawa 10.7 cm flux as a proxy. A linear regression fitting on residual temperatures yields a solar cycle coefficient of 4.24 ± 1.39 K/100 solar flux units (SFU). The cross-correlation analyses showed that changes of the residual temperature follow changes of solar activity with a quasi-two year delay (25 months). The temperature response at the delay of 25 months reaches 7 K/100 SFU. The possible reason of the observed delay can be an influence of quasi-biennial oscillations (QBO) of the atmosphere on the relation of temperature and solar activity. The value of the temperature trend after the subtraction of seasonal and solar components is not statistically significant. 相似文献
25.
The Lunar Orbiter Laser Altimeter Investigation on the Lunar Reconnaissance Orbiter Mission 总被引:3,自引:0,他引:3
David E. Smith Maria T. Zuber Glenn B. Jackson John F. Cavanaugh Gregory A. Neumann Haris Riris Xiaoli Sun Ronald S. Zellar Craig Coltharp Joseph Connelly Richard B. Katz Igor Kleyner Peter Liiva Adam Matuszeski Erwan M. Mazarico Jan F. McGarry Anne-Marie Novo-Gradac Melanie N. Ott Carlton Peters Luis A. Ramos-Izquierdo Lawrence Ramsey David D. Rowlands Stephen Schmidt V. Stanley Scott III George B. Shaw James C. Smith Joseph-Paul Swinski Mark H. Torrence Glenn Unger Anthony W. Yu Thomas W. Zagwodzki 《Space Science Reviews》2010,150(1-4):209-241
The Lunar Orbiter Laser Altimeter (LOLA) is an instrument on the payload of NASA’s Lunar Reconnaissance Orbiter spacecraft (LRO) (Chin et al., in Space Sci. Rev. 129:391–419, 2007). The instrument is designed to measure the shape of the Moon by measuring precisely the range from the spacecraft to the lunar surface, and incorporating precision orbit determination of LRO, referencing surface ranges to the Moon’s center of mass. LOLA has 5 beams and operates at 28 Hz, with a nominal accuracy of 10 cm. Its primary objective is to produce a global geodetic grid for the Moon to which all other observations can be precisely referenced. 相似文献
26.
Ljubisa Stankovic Igor Djurovic Thayananthan Thayaparan 《IEEE transactions on aerospace and electronic systems》2006,42(4):1496-1506
Micro-Doppler (m-D) effect is caused by moving parts of the radar target. It can cover rigid parts of a target and degrade the inverse synthetic aperture radar (ISAR) image. Separation of the patterns caused by stationary parts of the target from those caused by moving (rotating or vibrating) parts is the topic of this paper. Two techniques for separation of the rigid part from the rotating parts have been proposed. The first technique is based on time-frequency (TF) representation with sliding window and order statistics techniques. The first step in this technique is recognition of rigid parts in the range/cross-range plane. In the second step, reviewed TF representation and order statistics setup are employed to obtain signals caused by moving parts. The second technique can be applied in the case of very emphatic m-D effect. In the first step the rotating parts are recognized, based on the inverse Radon transform (RT). After masking these patterns, a radar image with the rigid body reflection can be obtained. The proposed methods are illustrated by examples 相似文献
27.
Igor E. Kozlov Vladimir N. Kudryavtsev Johnny A. Johannessen Bertrand Chapron Inga Dailidienė Alexander G. Myasoedov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2012
Analysis of Envisat Advanced Synthetic Aperture Radar (ASAR) and Aqua/Terra Moderate Imaging Spectrometer (MODIS) infrared (IR) imagery of coastal upwelling in the southeastern Baltic Sea is presented. It is found that upwelling features are well distinct in the SAR images, and the leading imaging mechanism appears to be the change of the marine atmospheric boundary layer (MABL) stratification over the sea surface temperature (SST) front. This finding is supported by model calculations of the MABL transformation supplemented with the SAR backscatter calculations based on the CMOD4 model. In addition an empirical dependence of the SAR contrasts over the upwelling region on the wind speed and the SST drop is suggested. Finally, surface slicks accumulated in the sea surface current convergence zones generate additional distinct features in SAR imagery. This effect is interpreted within the framework of the coastal current circulation model based on analysis of the SST snapshot. 相似文献
28.
Tim Van Hoolst Frank Sohl Igor Holin Olivier Verhoeven Véronique Dehant Tilman Spohn 《Space Science Reviews》2007,132(2-4):203-227
This review addresses the deep interior structure of Mercury. Mercury is thought to consist of similar chemical reservoirs
(core, mantle, crust) as the other terrestrial planets, but with a relatively much larger core. Constraints on Mercury’s composition
and internal structure are reviewed, and possible interior models are described. Large advances in our knowledge of Mercury’s
interior are not only expected from imaging of characteristic surface features but particularly from geodetic observations
of the gravity field, the rotation, and the tides of Mercury. The low-degree gravity field of Mercury gives information on
the differences of the principal moments of inertia, which are a measure of the mass concentration toward the center of the
planet. Mercury’s unique rotation presents several clues to the deep interior. From observations of the mean obliquity of
Mercury and the low-degree gravity data, the moments of inertia can be obtained, and deviations from the mean rotation speed
(librations) offer an exciting possibility to determine the moment of inertia of the mantle. Due to its proximity to the Sun,
Mercury has the largest tides of the Solar System planets. Since tides are sensitive to the existence and location of liquid
layers, tidal observations are ideally suited to study the physical state and size of the core of Mercury. 相似文献
29.
The Lunar Reconnaissance Orbiter Laser Ranging Investigation 总被引:1,自引:0,他引:1
Maria T. Zuber David E. Smith Ronald S. Zellar Gregory A. Neumann Xiaoli Sun Richard B. Katz Igor Kleyner Adam Matuszeski Jan F. McGarry Melanie N. Ott Luis A. Ramos-Izquierdo David D. Rowlands Mark H. Torrence Thomas W. Zagwodzki 《Space Science Reviews》2010,150(1-4):63-80
The objective of the Lunar Reconnaissance Orbiter (LRO) Laser Ranging (LR) system is to collect precise measurements of range that allow the spacecraft to achieve its requirement for precision orbit determination. The LR will make one-way range measurements via laser pulse time-of-flight from Earth to LRO, and will determine the position of the spacecraft at a sub-meter level with respect to ground stations on Earth and the center of mass of the Moon. Ranging will occur whenever LRO is visible in the line of sight from participating Earth ground tracking stations. The LR consists of two primary components, a flight system and ground system. The flight system consists of a small receiver telescope mounted on the LRO high-gain antenna that captures the uplinked laser signal, and a fiber optic cable that routes the signal to the Lunar Orbiter Laser Altimeter (LOLA) instrument on LRO. The LOLA instrument receiver records the time of the laser signal based on an ultrastable crystal oscillator, and provides the information to the onboard LRO data system for storage and/or transmittal to the ground through the spacecraft radio frequency link. The LR ground system consists of a network of satellite laser ranging stations, a data reception and distribution facility, and the LOLA Science Operations Center. LR measurements will enable the determination of a three-dimensional geodetic grid for the Moon based on the precise seleno-location of ground spots from LOLA. 相似文献
30.
Igor G. Mitrofanov 《Space Science Reviews》1995,74(3-4):417-426
The paper is devoted to the present crisis in the field of cosmic gamma-ray bursts. There are two different paradigms of the phenomenon, which have practically equal numbers of supporters. The cosmological one associates bursts with collisions of compact objects at distances up to those with red-shifts of about 1–2. The galactic paradigm assumes that bursts are generated by neutron stars in the extended galactic halo. The present situation is shown to be very close to the ultimate establishment of the paradigm of the origin of cosmic gamma-ray bursts. 相似文献