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61.
M. R. James L. Wilson S. J. Lane J. S. Gilbert T. A. Mather R. G. Harrison R. S. Martin 《Space Science Reviews》2008,137(1-4):399-418
Many explosive terrestrial volcanic eruptions are accompanied by lightning and other atmospheric electrical phenomena. The plumes produced generate large perturbations in the surface atmospheric electric potential gradient and high charge densities have been measured on falling volcanic ash particles. The complex nature of volcanic plumes (which contain gases, solid particles, and liquid drops) provides several possible charging mechanisms. For plumes rich in solid silicate particles, fractoemission (the ejection of ions and atomic particles during fracture events) is probably the dominant source of charge generation. In other plumes, such as those created when lava enters the sea, different mechanisms, such as boiling, may be important. Further charging mechanisms may also subsequently operate, downwind of the vent. Other solar system bodies also show evidence for volcanism, with activity ongoing on Io. Consequently, volcanic electrification under different planetary scenarios (on Venus, Mars, Io, Moon, Enceladus, Tethys, Dione and Triton) is also discussed. 相似文献
62.
G. Randall Gladstone Steven C. Persyn John S. Eterno Brandon C. Walther David C. Slater Michael W. Davis Maarten H. Versteeg Kristian B. Persson Michael K. Young Gregory J. Dirks Anthony O. Sawka Jessica Tumlinson Henry Sykes John Beshears Cherie L. Rhoad James P. Cravens Gregory S. Winters Robert A. Klar Walter Lockhart Benjamin M. Piepgrass Thomas K. Greathouse Bradley J. Trantham Philip M. Wilcox Matthew W. Jackson Oswald H. W. Siegmund John V. Vallerga Rick Raffanti Adrian Martin J.-C. Gérard Denis C. Grodent Bertrand Bonfond Benoit Marquet François Denis 《Space Science Reviews》2017,213(1-4):447-473
The ultraviolet spectrograph instrument on the Juno mission (Juno-UVS) is a long-slit imaging spectrograph designed to observe and characterize Jupiter’s far-ultraviolet (FUV) auroral emissions. These observations will be coordinated and correlated with those from Juno’s other remote sensing instruments and used to place in situ measurements made by Juno’s particles and fields instruments into a global context, relating the local data with events occurring in more distant regions of Jupiter’s magnetosphere. Juno-UVS is based on a series of imaging FUV spectrographs currently in flight—the two Alice instruments on the Rosetta and New Horizons missions, and the Lyman Alpha Mapping Project on the Lunar Reconnaissance Orbiter mission. However, Juno-UVS has several important modifications, including (1) a scan mirror (for targeting specific auroral features), (2) extensive shielding (for mitigation of electronics and data quality degradation by energetic particles), and (3) a cross delay line microchannel plate detector (for both faster photon counting and improved spatial resolution). This paper describes the science objectives, design, and initial performance of the Juno-UVS. 相似文献
63.
64.
Bozdağ Ebru Ruan Youyi Metthez Nathan Khan Amir Leng Kuangdai van Driel Martin Wieczorek Mark Rivoldini Attilio Larmat Carène S. Giardini Domenico Tromp Jeroen Lognonné Philippe Banerdt Bruce W. 《Space Science Reviews》2017,211(1-4):571-594
Space Science Reviews - We present global and regional synthetic seismograms computed for 1D and 3D Mars models based on the spectral-element method. For global simulations, we implemented a... 相似文献
65.
The Wiener-Hopf equation is developed using only a knowledge of elementary calculus and the definition of ensemble average from statistics. Then using the Leibniz equation for differentiating an integral, the Kalman filter and its relation to orthogonal projection is presented. 相似文献
66.
Synthetic Aperture Radar (SAR) is an airborne (or spaceborne) radar mapping technique for generating high resolution maps of surface target areas including terrain. High resolution is achieved by coherently combining the returns from a number of radar transmissions. The resolution of the images is determined by the parameters of the emissions, with more data giving greater resolution. A requirement of the Microwave Radar Division's SAR radar is to provide classification of targets. This paper presents a technique for enhancing slant range resolution in SAR images by dithering the carrier centre frequency of the transmitted signal. The procedure controls the radar waveforms so they will optimally perform the classification function, rather than provide an image of best quality. It is shown that a Knowledge-Based engineering approach to determining the waveform of the radar gives considerably improved performance as a classifier of targets (of large radar cross-section), even though the corresponding image is degraded 相似文献
67.
This paper reproduces the Symposium Summary presentation at the 28th ESLAB Symposium on The High Latitude Heliosphere. The summary is not comprehensive but with considerable latitude covers the highlights of the conference. Featured are the observations of the high-speed wind from the growing southern polar coronal hole, new measurements of the interstellar gas and pickup ions, new measurements of cosmic ray modulation at high latitude, and our growing awareness of the three-dimensional heliosphere. 相似文献
68.
Donald L. Hampton James W. Baer Martin A. Huisjen Chris C. Varner Alan Delamere Dennis D. Wellnitz Michael F. A’Hearn Kenneth P. Klaasen 《Space Science Reviews》2005,117(1-2):43-93
A suite of three optical instruments has been developed to observe Comet 9P/Tempel 1, the impact of a dedicated impactor spacecraft,
and the resulting crater formation for the Deep Impact mission. The high-resolution instrument (HRI) consists of an f/35 telescope with 10.5 m focal length, and a combined filtered CCD camera and IR spectrometer. The medium-resolution instrument
(MRI) consists of an f/17.5 telescope with a 2.1 m focal length feeding a filtered CCD camera. The HRI and MRI are mounted on an instrument platform
on the flyby spacecraft, along with the spacecraft star trackers and inertial reference unit. The third instrument is a simple
unfiltered CCD camera with the same telescope as MRI, mounted within the impactor spacecraft. All three instruments use a
Fairchild split-frame-transfer CCD with 1,024× 1,024 active pixels. The IR spectrometer is a two-prism (CaF2 and ZnSe) imaging spectrometer imaged on a Rockwell HAWAII-1R HgCdTe MWIR array. The CCDs and IR FPA are read out and digitized
to 14 bits by a set of dedicated instrument electronics, one set per instrument. Each electronics box is controlled by a radiation-hard
TSC695F microprocessor. Software running on the microprocessor executes imaging commands from a sequence engine on the spacecraft.
Commands and telemetry are transmitted via a MIL-STD-1553 interface, while image data are transmitted to the spacecraft via a low-voltage differential signaling (LVDS) interface standard. The instruments are used as the science instruments and are
used for the optical navigation of both spacecraft. This paper presents an overview of the instrument suite designs, functionality,
calibration and operational considerations. 相似文献
69.
J. Martin Laming 《Space Science Reviews》1994,70(1-2):107-110
The ultraviolet spectrum of a redshifted plasma flow appearing over a sunspot observed during the first flight of the High Resolution Telescope Spectrograph (HRTS I) is analysed, and interpreted as a radiatively cooling plasma. For most of the lines emitted from this plasma, the assumption of ionization equilibrium during the cooling is good. However for He II (and other ions with a single electron outside of closed shells), this is not the case. Integrating differential equations for the various ionization fractions of helium and the temperature allows an approximate determination of the abundance of helium relative to other elements whose lines appear in the spectrum of the plasma flow. 相似文献
70.
刘柱:首先,请您简单介绍一下柯马公司.目前,柯马在航空领域的业务范围主要包括哪些内容?
约翰·纳克斯:柯马(COMAU)是一家隶属于FIAT(菲亚特)集团的全球化企业. 相似文献