排序方式: 共有51条查询结果,搜索用时 375 毫秒
41.
L. F. Burlaga N. F. Ness J. W. Belcher A. J. Lazarus J. D. Richardson 《Space Science Reviews》1996,78(1-2):33-42
Voyagers 1 and 2 are now observing the latitudinal structure of the heliospheric magnetic field in the distant heliosphere (the legion between - 30 AU and the termination shock). Voyager 2 is observing the influence of the interstellar medium on the solar wind. The pressure of the interstellar pickup protons, measured by their contribution to pressure balanced structures, is greater than or equal to the magnetic pressure and much greater than the thermal pressures of the solar wind protons and electrons in the distant heliosphere. The solar wind speed is observed to decrease and the proton temperature increase with increasing distance from the sun. This may result from the production of pickup ions by the charge exchange process with the interstellar neutrals. The introduction of the pickup ions into the dynamics of the magnetized solar wind plasma appears to be an important new process which must be considered in future theoretical studies of the termination shock and boundary with the local interstellar medium. 相似文献
42.
G. M. Martínez C. N. Newman A. De Vicente-Retortillo E. Fischer N. O. Renno M. I. Richardson A. G. Fairén M. Genzer S. D. Guzewich R. M. Haberle A.-M. Harri O. Kemppinen M. T. Lemmon M. D. Smith M. de la Torre-Juárez A. R. Vasavada 《Space Science Reviews》2017,212(1-2):295-338
We analyze the complete set of in-situ meteorological data obtained from the Viking landers in the 1970s to today’s Curiosity rover to review our understanding of the modern near-surface climate of Mars, with focus on the dust, CO2 and H2O cycles and their impact on the radiative and thermodynamic conditions near the surface. In particular, we provide values of the highest confidence possible for atmospheric opacity, atmospheric pressure, near-surface air temperature, ground temperature, near-surface wind speed and direction, and near-surface air relative humidity and water vapor content. Then, we study the diurnal, seasonal and interannual variability of these quantities over a span of more than twenty Martian years. Finally, we propose measurements to improve our understanding of the Martian dust and H2O cycles, and discuss the potential for liquid water formation under Mars’ present day conditions and its implications for future Mars missions. Understanding the modern Martian climate is important to determine if Mars could have the conditions to support life and to prepare for future human exploration. 相似文献
43.
R. J. Forsyth V. Bothmer C. Cid N. U. Crooker T. S. Horbury K. Kecskemety B. Klecker J. A. Linker D. Odstrcil M. J. Reiner I. G. Richardson J. Rodriguez-Pacheco J. M. Schmidt R. F. Wimmer-Schweingruber 《Space Science Reviews》2006,123(1-3):383-416
This report assesses the current status of research relating the origin at the Sun, the evolution through the inner heliosphere and the effects on the inner heliosphere of the interplanetary counterparts of coronal mass ejections (ICMEs). The signatures of ICMEs measured by in-situ spacecraft are determined both by the physical processes associated with their origin in the low corona, as observed by space-borne coronagraphs, and by the physical processes occurring as the ICMEs propagate out through the inner heliosphere, interacting with the ambient solar wind. The solar and in-situ observations are discussed as are efforts to model the evolution of ICMEs from the Sun out to 1 AU. 相似文献
44.
An estimation of the value and orientation of the inclination of middle-scale structures in the solar wind plasma is obtained on the basis of time lags of simultaneous correlated measurements on three spacecraft: INTERBALL-1, IMP-8, and WIND. It is shown that middle-scale plasma structures, in the majority of cases, are not perpendicular to the Sun–Earth line, but inclined to it (presumably, in the ecliptic plane), on average, at an angle of approximately 63° (or 27° to the Y
SE axis). However, this inclination is significantly less than the inclination of the Parker spiral for the interplanetary magnetic field (45° at the Earth's orbit). 相似文献
45.
James E. Richardson H. Jay Melosh Natasha A. Artemeiva Elisabetta Pierazzo 《Space Science Reviews》2005,117(1-2):241-267
The cratering event produced by the Deep Impact mission is a unique experimental opportunity, beyond the capability of Earth-based
laboratories with regard to the impacting energy, target material, space environment, and extremely low-gravity field. Consequently,
impact cratering theory and modeling play an important role in this mission, from initial inception to final data analysis.
Experimentally derived impact cratering scaling laws provide us with our best estimates for the crater diameter, depth, and
formation time: critical in the mission planning stage for producing the flight plan and instrument specifications. Cratering
theory has strongly influenced the impactor design, producing a probe that should produce the largest possible crater on the
surface of Tempel 1 under a wide range of scenarios. Numerical hydrocode modeling allows us to estimate the volume and thermodynamic
characteristics of the material vaporized in the early stages of the impact. Hydrocode modeling will also aid us in understanding
the observed crater excavation process, especially in the area of impacts into porous materials. Finally, experimentally derived
ejecta scaling laws and modeling provide us with a means to predict and analyze the observed behavior of the material launched
from the comet during crater excavation, and may provide us with a unique means of estimating the magnitude of the comet’s
gravity field and by extension the mass and density of comet Tempel 1. 相似文献
46.
N. N. Shevyrev G. N. Zastenker J. Safrankova Z. Nemecek M. Gaiosh J. D. Richardson 《Cosmic Research》2002,40(4):335-346
We present the results of experimental studies of high frequency (with periods of seconds and tens of seconds) and low frequency (with periods of minutes and tens of minutes) large variations of the ion flux and magnetic field magnitude in the magnetosheath. It is shown that, on average, the relative amplitudes of these variations are approximately two times higher than similar values characteristic for the undisturbed solar wind. The averaged spatial profile of these values and their variations across the magnetosheath is obtained, as are the dependencies of normalized plasma fluxes and their variations on the place of entrance of a given plasma element into the magnetosheath. Using one particular example, a good coincidence between the time profiles of ion fluxes measured aboard two spacecraft separated by a distance of 10R
E along the magnetosheath is demonstrated. 相似文献
47.
Chetty P.R.K. Richardson R. Sherwood R. 《Aerospace and Electronic Systems Magazine, IEEE》1997,12(6):18-24
The main objective of the TOPEX/Poseidon Spacecraft is to monitor the world's oceans for scientific study of weather and climate prediction, coastal storm warning and maritime safety. The operational conditions of this satellite imposed challenging requirements for the on-board Electrical Power System (EPS), Going through various phases of its development and on-orbit performance verifications, there were certain events and/or circumstances we would have liked to avoid. Some circumstances were avoided with preventative measures, other potentially detrimental events were not. Thus, a number of valuable lessons were learned which are presented in this paper 相似文献
48.
The heliospheric counterparts of coronal mass ejections (CMEs) at the Sun, interplanetary coronal mass ejections (ICMEs),
can be identified in situ based on a number of magnetic field, plasma, compositional and energetic particle signatures as
well as combinations thereof. We summarize these signatures and their implications for understanding the nature of these structures
and the physical properties of coronal mass ejections. We conclude that our understanding of ICMEs is far from complete and
formulate several challenges that, if addressed, would substantially improve our knowledge of the relationship between CMEs
at the Sun and in the heliosphere. 相似文献
49.
We present here a brief summary of the rich heritage of observational and theoretical research leading to the development
of our current understanding of the initiation, structure, and evolution of Coronal Mass Ejections. 相似文献
50.
G.M. Mason R. Von Steiger R.B. Decker M.I. Desai J.R. Dwyer L.A. Fisk G. Gloeckler J.T. Gosling M. Hilchenbach R. Kallenbach E. Keppler B. Klecker H. Kunow G. Mann I.G. Richardson T.R. Sanderson G.M. Simnett Y.-M. Wang R.F. Wimmer-Schweingruber M. Fränz J.E. Mazur 《Space Science Reviews》1999,89(1-2):327-367
This report emphasizes new observational aspects of CIR ions revealed by advanced instruments launched on the Ulysses, WIND,
SOHO, and ACE spacecraft, and by the unique vantage point of Ulysses which carried out the first survey of Corotating Interaction
Region (CIR) properties over a very wide range of heliolatitudes. With this more complete observational picture established,
this review is the basis to consider the status of theoretical models on origin, injection, and acceleration of CIR particles
reported by Scholer, Mann et al. (1999) in this volume.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献