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991.
The Magnetospheric Multiscale Magnetometers 总被引:2,自引:0,他引:2
C. T. Russell B. J. Anderson W. Baumjohann K. R. Bromund D. Dearborn D. Fischer G. Le H. K. Leinweber D. Leneman W. Magnes J. D. Means M. B. Moldwin R. Nakamura D. Pierce F. Plaschke K. M. Rowe J. A. Slavin R. J. Strangeway R. Torbert C. Hagen I. Jernej A. Valavanoglou I. Richter 《Space Science Reviews》2016,199(1-4):189-256
The success of the Magnetospheric Multiscale mission depends on the accurate measurement of the magnetic field on all four spacecraft. To ensure this success, two independently designed and built fluxgate magnetometers were developed, avoiding single-point failures. The magnetometers were dubbed the digital fluxgate (DFG), which uses an ASIC implementation and was supplied by the Space Research Institute of the Austrian Academy of Sciences and the analogue magnetometer (AFG) with a more traditional circuit board design supplied by the University of California, Los Angeles. A stringent magnetic cleanliness program was executed under the supervision of the Johns Hopkins University’s Applied Physics Laboratory. To achieve mission objectives, the calibration determined on the ground will be refined in space to ensure all eight magnetometers are precisely inter-calibrated. Near real-time data plays a key role in the transmission of high-resolution observations stored on board so rapid processing of the low-resolution data is required. This article describes these instruments, the magnetic cleanliness program, and the instrument pre-launch calibrations, the planned in-flight calibration program, and the information flow that provides the data on the rapid time scale needed for mission success. 相似文献
992.
993.
994.
Johnson R. L. Mason J. L. Petrou N. V. Woll H. J. Hansen G. L. Regan D. C. 《IEEE transactions on aerospace and electronic systems》1966,(1):121-136
A panel session held at the 1965 Aerospace Conference, Houston,Tex., June 23, 1965. Panelists discussed Life-Suppport interfaces with Electric Power; Communications; Navigation; System Integration for Future Space Programs; and Reliability. 相似文献
995.
We compare the results of analyzing the stress strain state for the tubular skid landing gear with regard for the physically and geometrically nonlinear scheme of deformation; the analysis is carried out by the finite element method and with the aid of a special beam-type design model. The analysis has been performed for a real helicopter design. The peculiarities of deforming the aircraft structures of the type under study are shown based on the comparison results. 相似文献
996.
Ground level events (GLEs) occupy the high-energy end of gradual solar energetic particle (SEP) events. They are associated with coronal mass ejections (CMEs) and solar flares, but we still do not clearly understand the special conditions that produce these rare events. During Solar Cycle 23, a total of 16 GLEs were registered, by ground-based neutron monitors. We first ask if these GLEs are clearly distinguishable from other SEP events observed from space. Setting aside possible difficulties in identifying all GLEs consistently, we then try to find observables which may unmistakably isolate these GLEs by studying the basic properties of the associated eruptions and the active regions (ARs) that produced them. It is found that neither the magnitudes of the CMEs and flares nor the complexities of the ARs give sufficient conditions for GLEs. It is possible to find CMEs, flares or ARs that are not associated with GLEs but that have more extreme properties than those associated with GLEs. We also try to evaluate the importance of magnetic field connection of the AR with Earth on the detection of GLEs and their onset times. Using the potential field source surface (PFSS) model, a half of the GLEs are found to be well-connected. However, the GLE onset time with respect to the onset of the associated flare and CME does not strongly depend on how well-connected the AR is. The GLE onset behavior may be largely determined by when and where the CME-driven shock develops. We could not relate the shocks responsible for the onsets of past GLEs with features in solar images, but the combined data from the Solar TErrestrial RElations Observatory (STEREO) and the Solar Dynamics Observatory (SDO) have the potential to change this for GLEs that may occur in the rising phase of Solar Cycle 24. 相似文献
997.
The ARTEMIS Mission 总被引:2,自引:0,他引:2
V. Angelopoulos 《Space Science Reviews》2011,165(1-4):3-25
The Acceleration, Reconnection, Turbulence, and Electrodynamics of the Moon??s Interaction with the Sun (ARTEMIS) mission is a spin-off from NASA??s Medium-class Explorer (MIDEX) mission THEMIS, a five identical micro-satellite (hereafter termed ??probe??) constellation in high altitude Earth-orbit since 17 February 2007. By repositioning two of the five THEMIS probes (P1 and P2) in coordinated, lunar equatorial orbits, at distances of ??55?C65 R E geocentric (??1.1?C12 R L selenocentric), ARTEMIS will perform the first systematic, two-point observations of the distant magnetotail, the solar wind, and the lunar space and planetary environment. The primary heliophysics science objectives of the mission are to study from such unprecedented vantage points and inter-probe separations how particles are accelerated at reconnection sites and shocks, and how turbulence develops and evolves in Earth??s magnetotail and in the solar wind. Additionally, the mission will determine the structure, formation, refilling, and downstream evolution of the lunar wake and explore particle acceleration processes within it. ARTEMIS??s orbits and instrumentation will also address key lunar planetary science objectives: the evolution of lunar exospheric and sputtered ions, the origin of electric fields contributing to dust charging and circulation, the structure of the lunar interior as inferred by electromagnetic sounding, and the lunar surface properties as revealed by studies of crustal magnetism. ARTEMIS is synergistic with concurrent NASA missions LRO and LADEE and the anticipated deployment of the International Lunar Network. It is expected to be a key element in the NASA Heliophysics Great Observatory and to play an important role in international plans for lunar exploration. 相似文献
998.
Colangeli L. Mennella V. Brucato J.R. Palumbo P. Rotundi A. 《Space Science Reviews》1999,90(1-2):341-354
One of the main objectives of modern astrophysics is the characterisation of properties and evolution of materials present
in space. Production, processing and analysis of cosmic dust analogues in the laboratory represents a powerful tool to interpret
astronomical observations and to contribute to the solution of puzzling problems which are so far unsolved. In the present
paper we summarize recent results obtained in our laboratory on carbon-based and silicate materials able to simulate various
types of cosmic grains. The laboratory data are applied to discuss the nature of spectral features observed in the interstellar
medium and in comets.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
999.
W. I. Axford J. F. McKenzie G. V. Sukhorukova M. Banaszkiewicz A. Czechowski R. Ratkiewicz 《Space Science Reviews》1999,87(1-2):25-41
We outline a theory for the origin and acceleration of the fast solar wind as a consequence of network microflares releasing
a spectrum of high frequency Alfvén waves which heat (by cyclotron absorption) the corona close to the Sun. The significant
features of our model of the fast wind are that the acceleration is rapid with the sonic point at around two solar radii,
the proton temperatures are high (~ 5 million degrees) and the minor ions are correspondingly hotter, roughly in proportion
to their mass. Moreover we argue that since the energy flux needed to power the quiet corona in closed field regions is about
the same as that needed to drive the fast solar wind, and also because at deeper levels (< 2 × 105 K) there is no great difference in the properties of supergranules and network in closed and open field regions, the heating
process (i.e., dissipation of high frequency waves) must be the same in both cases.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
1000.
Vasiliev I.A. Ivashov S.I. Makarenkov V.I. Sablin V.N. Sheyko A.P. 《Aerospace and Electronic Systems Magazine, IEEE》1999,14(5):25-29
A subsurface radar using a multi-frequency signal has been developed. It is designated for surveying building structures and works. The characteristic feature of this device is the possibility of obtaining sounding plane radio images featuring a high resolution attaining 1…2 cm. The main applications of this device includes the survey of building structures to reveal their heterogeneities and defects and the investigation of premises to detect bugging devices 相似文献