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Pekka Janhunen Annika Olsson Christopher T. Russell Harri Laakso 《Space Science Reviews》2006,122(1-4):89-95
Auroral emission caused by electron precipitation (Hardy et al., 1987, J. Geophys. Res. 92, 12275–12294) is powered by magnetospheric driving processes. It is not yet fully understood how the energy transfer mechanisms
are responsible for the electron precipitation. It has been proposed (Hasegawa, 1976, J. Geophys. Res. 81, 5083–5090) that Alfvén waves coming from the magnetosphere play some role in powering the aurora (Wygant et al., 2000, J. Geophys. Res. 105, 18675–18692, Keiling et al., 2003, Science
299, 383–386). Alfvén-wave-induced electron acceleration is shown to be confined in a rather narrow radial distance range of
4–5 R
E
(Earth radii) and its importance, relative to other electron acceleration mechanisms, depends strongly on the magnetic disturbance
level so that it represents 10% of all electron precipitation power during quiet conditions and increased to 40% during disturbed
conditions. Our observations suggest that an electron Landau resonance mechanism operating in the “Alfvén resonosphere” is
responsible for the energy transfer. 相似文献
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Fulchignoni M. Ferri F. Angrilli F. Bar-Nun A. Barucci M.A. Bianchini G. Borucki W. Coradini M. Coustenis A. Falkner P. Flamini E. Grard R. Hamelin M. Harri A.M. Leppelmeier G.W. Lopez-Moreno J.J. McDonnell J.A.M. McKay C.P. Neubauer F.H. Pedersen A. Picardi G. Pirronello V. Rodrigo R. Schwingenschuh K. Seiff A. Svedhem H. Vanzani V. Zarnecki J. 《Space Science Reviews》2002,104(1-4):395-431
The Huygens Atmospheric Structure Instrument (HASI) is a multi-sensor package which has been designed to measure the physical
quantities characterising the atmosphere of Titan during the Huygens probe descent on Titan and at the surface. HASI sensors
are devoted to the study of Titan's atmospheric structure and electric properties, and to provide information on its surface,
whether solid or liquid.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Certain meteoritical inclusions contain evidence for the existence of short-lived radioactivities such as 26Al and 41Ca at the time of their formation 4.566 billion years ago. Because the half-lives of these nuclides are so short, this evidence
requires that no more than about a million years elapsed between their nucleosynthesis and their inclusion in cm-sized solids
in the solar nebula. This abbreviated time span can be explained if these nuclides were synthesized in a stellar source such
as a supernova, and were then transported across the interstellar medium by the resulting shock wave, which then triggered
the gravitational collapse of the presolar molecular cloud core. Detailed 2D and 3D numerical hydrodynamical models are reviewed
and show that such a scenario is consistent with the time scale constraint, and with the need to both trigger collapse and
to inject shock-wave matter into the collapsing protostellar cloud and onto the protoplanetary disk formed by the collapse.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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J. Gómez-Elvira C. Armiens L. Casta?er M. Domínguez M. Genzer F. Gómez R. Haberle A.-M. Harri V. Jiménez H. Kahanp?? L. Kowalski A. Lepinette J. Martín J. Martínez-Frías I. McEwan L. Mora J. Moreno S. Navarro M. A. de Pablo V. Peinado A. Pe?a J. Polkko M. Ramos N. O. Renno J. Ricart M. Richardson J. Rodríguez-Manfredi J. Romeral E. Sebastián J. Serrano M. de?la Torre Juárez J. Torres F. Torrero R. Urquí L. Vázquez T. Velasco J. Verdasca M.-P. Zorzano J. Martín-Torres 《Space Science Reviews》2012,170(1-4):583-640
The Rover Environmental Monitoring Station (REMS) will investigate environmental factors directly tied to current habitability at the Martian surface during the Mars Science Laboratory (MSL) mission. Three major habitability factors are addressed by REMS: the thermal environment, ultraviolet irradiation, and water cycling. The thermal environment is determined by a mixture of processes, chief amongst these being the meteorological. Accordingly, the REMS sensors have been designed to record air and ground temperatures, pressure, relative humidity, wind speed in the horizontal and vertical directions, as well as ultraviolet radiation in different bands. These sensors are distributed over the rover in four places: two booms located on the MSL Remote Sensing Mast, the ultraviolet sensor on the rover deck, and the pressure sensor inside the rover body. Typical daily REMS observations will collect 180 minutes of data from all sensors simultaneously (arranged in 5 minute hourly samples plus 60 additional minutes taken at times to be decided during the course of the mission). REMS will add significantly to the environmental record collected by prior missions through the range of simultaneous observations including water vapor; the ability to take measurements routinely through the night; the intended minimum of one Martian year of observations; and the first measurement of surface UV irradiation. In this paper, we describe the scientific potential of REMS measurements and describe in detail the sensors that constitute REMS and the calibration procedures. 相似文献
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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
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