排序方式： 共有8条查询结果，搜索用时 15 毫秒
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Martin Füllekrug Declan Diver Jean-Louis Pinçon Alan D. R. Phelps Anne Bourdon Christiane Helling Elisabeth Blanc Farideh Honary R. Giles Harrison Jean-André Sauvaud Jean-Baptiste Renard Mark Lester Michael Rycroft Mike Kosch Richard B. Horne Serge Soula Stéphane Gaffet 《Surveys in Geophysics》2013,34(1):1-41
The French government has committed to launch the satellite TARANIS to study transient coupling processes between the Earth’s atmosphere and near-Earth space. The prime objective of TARANIS is to detect energetic charged particles and hard radiation emanating from thunderclouds. The British Nobel prize winner C.T.R. Wilson predicted lightning discharges from the top of thunderclouds into space almost a century ago. However, new experiments have only recently confirmed energetic discharge processes which transfer energy from the top of thunderclouds into the upper atmosphere and near-Earth space; they are now denoted as transient luminous events, terrestrial gamma-ray flashes and relativistic electron beams. This meeting report builds on the current state of scientific knowledge on the physics of plasmas in the laboratory and naturally occurring plasmas in the Earth’s atmosphere to propose areas of future research. The report specifically reflects presentations delivered by the members of a novel Franco-British collaboration during a meeting at the French Embassy in London held in November 2011. The scientific subjects of the report tackle ionization processes leading to electrical discharge processes, observations of transient luminous events, electromagnetic emissions, energetic charged particles and their impact on the Earth’s atmosphere. The importance of future research in this area for science and society, and towards spacecraft protection, is emphasized. 相似文献
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We describe an archive of high-precision MDI flat fields that can be used to refine most MDI high-resolution continuum data.
The archive consists of many flat-field images representing different time ranges over the full operating period of SOHO.
The residual flat-field error on the standard level 1.5/1.8 calibrated continuum images represents a significant proportion
(25% – 100%) of the true data variation data on the quiet sun. Using the flat fields in this archive will reduce that error
by a factor of 10 – 30, greatly increasing the accuracy of any tracking or photometric operations. The access, use and accuracy
of these flat fields are described in this paper. 相似文献
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Christiane Helling R. Giles Harrison Farideh Honary Declan A. Diver Karen Aplin Ian Dobbs-Dixon Ute Ebert Shu-ichiro Inutsuka Francisco J. Gordillo-Vazquez Stuart Littlefair 《Surveys in Geophysics》2016,37(4):705-756
Detailed observations of the solar system planets reveal a wide variety of local atmospheric conditions. Astronomical observations have revealed a variety of extrasolar planets none of which resembles any of the solar system planets in full. Instead, the most massive amongst the extrasolar planets, the gas giants, appear very similar to the class of (young) brown dwarfs which are amongst the oldest objects in the Universe. Despite this diversity, solar system planets, extrasolar planets and brown dwarfs have broadly similar global temperatures between 300 and 2500 K. In consequence, clouds of different chemical species form in their atmospheres. While the details of these clouds differ, the fundamental physical processes are the same. Further to this, all these objects were observed to produce radio and X-ray emissions. While both kinds of radiation are well studied on Earth and to a lesser extent on the solar system planets, the occurrence of emissions that potentially originate from accelerated electrons on brown dwarfs, extrasolar planets and protoplanetary disks is not well understood yet. This paper offers an interdisciplinary view on electrification processes and their feedback on their hosting environment in meteorology, volcanology, planetology and research on extrasolar planets and planet formation. 相似文献
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Local correlation tracking (LCT) is a commonly used motion tracking technique, particularly in solar physics. When used to track motions smaller than one pixel per time sample, interpolation of the original data is required. We demonstrate that it is possible to introduce large systematic errors by using an inappropriate interpolation method, and describe how to avoid these errors. The effect of these errors on the calculated velocity field is demonstrated on simulated solar granulation data. 相似文献
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We present data and modelling for the quiet Sun that strongly suggest a ubiquitous small-scale atmospheric heating mechanism
that is driven solely by converging supergranular flows. A possible energy source for such events is the power transfer to
the plasma via the work done on the magnetic field by photospheric convective flows, which exert drag on the footpoints of
magnetic structures. We present evidence of small-scale energy release events driven directly by the hydrodynamic forces that
act on the magnetic elements in the photosphere, as a result of supergranular-scale flows. We show strong spatial and temporal
correlation between quiet-Sun soft X-ray emission (from Yohkoh SXT) and SOHO MDI-derived flux removal events driven by deduced photospheric flows. We also present a simple model of heating
generated by flux submergence, based on particle acceleration by converging magnetic mirrors. In the near future, high resolution
soft X-ray images from XRT on the Hinode satellite will allow definitive, quantitative verification of our results.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
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We have developed an exceptionally noise-resistant method for accurate and automatic identification of supergranular cell
boundaries from velocity measurements. Because of its high noise tolerance the algorithm can produce reliable cell patterns
with only very small amounts of smoothing of the source data in comparison to conventional methods. In this paper we describe
the method and test it with simulated data. We then apply it to the analysis of velocity fields derived from high-resolution
continuum data from MDI (Michelson Doppler Imager) on SOHO. From this, we can identify with high spatial resolution certain
basic properties of supergranulation cells, such as their characteristic sizes, the flow speeds within cells, and their dependence
on cell areas. The effect of the noise and smoothing on the derived cell boundaries is investigated and quantified by using
simulated data. We show in detail the evolution of supergranular cells over their lifetime, including observations of emerging,
splitting, and coalescing cells. A key result of our analysis of cell internal velocities is that there is a simple linear
relation between cell size and cell internal velocity, rather than the power law usually suggested.
Electronic Supplementary Material The online version of this article () contains supplementary material, which is available to authorized users. 相似文献
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A hydrodynamic-magnetofluid hybrid analysis of lower chromospheric shear flows in the Sun may explain the occurrence and time development of Ellerman bombs. The analysis assumes that the erupting material forming the bomb is driven initially by the Kelvin-Helmholtz fluid instability applied to the interface between two atmospheric fluid layers, characterized by a steep density change across the boundary and driven by flow fields around sunspots. The ensuing instability eventually evolves into a magnetofluid phenomenon by virtue of the trapping and bending of the interfacial magnetic field, giving rise to a dense globule of material entering, and persisting in, the upper layers and due to Ohmic dissipation having a significantly enhanced temperature compared with ambient material. 相似文献
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