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1.
Wei Fengsi Feng Xueshang Guo Jian-shan Fan Quanlin Wu Jian 《Space Science Reviews》2003,107(1-2):327-334
Recent progress in space weather research are briefly presented here from three aspects: establishment or improvement in observation
systems, such as extra-soft X-ray detector and γ-ray detector onboard the spacecraft ‘Shen Zhou 2’, new solar radio broad-band
spectrometer, magnetometer-chain, ionosonde and digisonde–chain, laser-lidar system and VHF radar; partial topic progresses
included in CMEs, multi-streamer structures, evolution of interplanetary magnetic field B
z component, regional properties of traveling ionospheric disturbances, a fully-nonlinear global dynamical model for the middle
and upper atmosphere, and a combined prediction method for geomagnetic disturbances; and space weather activity, such as ‘Meridian
Project’ — a national major scientific project, ‘International Space Weather Meridian Circle Program’ — a suggestion of internationalization
of ‘Meridian Project’, ‘Space Weather Research Plan’ — a major research plan from National Natural Science Foundation of China
(NNSFC) and other space weather activities.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
2.
Historical data of the geomagnetic activity records in St. Petersburg since 1841 do not show any ‘doubling’ of the total magnetic
field at the Sun as claimed recently by Lockwood et al. (1999). However, recurrent patterns of the geomagnetic activity variations display ‘secular’ trend of the solar wind near
ecliptic plane resulting from gradual change of the topological structure of the solar corona (Ponyavin, 1997). By comparing
geomagnetic and eclipse observations we found ‘typical’ coronal shapes, which correspond better to periods of extremely low
and high geomagnetic activity level rather than standard sunspot activity referencing as ‘Corona at Solar Maximum or Minimum’.
Using geomagnetic records as proxies it has been suggested that the maximum of the sunspot activity was in July 2000.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
3.
Reports of unpredicted lightning and its spatial association with mountains of possible volcanic origin are provocative features of the 1980's literature on Venus. These reports are based upon interpretation of low-frequency 100 Hz electric field noise observed from the Pioneer Venus Orbiter during 1978–1986. These speculations have been repeatedly challenged in the literature. Even though explosive volcanism, like lightning, is discounted in the literature, researchers have been prompted to believe in present-day eruptions by the suggestion that volcanic plumes might stimulate the otherwise unexpected lightning. Recent introductions of a distinct set of higher-frequency electric field noise has resulted in further claims for lightning, but these results, like those derived from the 100 Hz data are discounted be several independent studies. Commenting on the large body of 100 Hz data, Russell (1991) abandons earlier reports of the planetographic clustering of this noise, and states that active volcanoes are not the source of the Venus lightning. This welcome acknowledgement leaves unresolved problems. First, this brief comment is quite insufficient to correct the widespread and flawed perception that Venus is currently experiencing widespread lightning, stimulated by volcanic disturbances. Second, this admission leaves unexplained the origin of the voluminous 100 Hz data set. The foregoing problems, combined with negative results of recent independent studies, indicate strongly that the Pioneer Venus results provide no reliable evidence of either lightning or volcanism at Venus. 相似文献
4.
Chang Tom Tam Sunny W.Y. Wu Cheng-Chin Consolini Giuseppe 《Space Science Reviews》2003,107(1-2):425-445
The first definitive observation that provided convincing evidence indicating certain turbulent space plasma processes are
in states of ‘complexity’ was the discovery of the apparent power-law probability distribution of solar flare intensities.
Recent statistical studies of complexity in space plasmas came from the AE index, UVI auroral imagery, and in-situ measurements
related to the dynamics of the plasma sheet in the Earth's magnetotail and the auroral zone.
In this review, we describe a theory of dynamical ‘complexity’ for space plasma systems far from equilibrium. We demonstrate
that the sporadic and localized interactions of magnetic coherent structures are the origin of ‘complexity’ in space plasmas.
Such interactions generate the anomalous diffusion, transport, acceleration, and evolution of the macroscopic states of the
overall dynamical systems.
Several illustrative examples are considered. These include: the dynamical multi- and cross-scale interactions of the macro-and
kinetic coherent structures in a sheared magnetic field geometry, the preferential acceleration of the bursty bulk flows in
the plasma sheet, and the onset of ‘fluctuation induced nonlinear instabilities’ that can lead to magnetic reconfigurations.
The technique of dynamical renormalization group is introduced and applied to the study of two-dimensional intermittent MHD
fluctuations and an analogous modified forest-fire model exhibiting forced and/or self-organized criticality [FSOC] and other
types of topological phase transitions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
5.
Nicholas W. Watkins Daniel Credgington Bogdan Hnat Sandra C. Chapman Mervyn P. Freeman John Greenhough 《Space Science Reviews》2005,121(1-4):271-284
Mandelbrot introduced the concept of fractals to describe the non-Euclidean shape of many aspects of the natural world. In
the time series context, he proposed the use of fractional Brownian motion (fBm) to model non-negligible temporal persistence,
the ‘Joseph Effect’; and Lévy flights to quantify large discontinuities, the ‘Noah Effect’. In space physics, both effects
are manifested in the intermittency and long-range correlation which are by now well-established features of geomagnetic indices
and their solar wind drivers. In order to capture and quantify the Noah and Joseph effects in one compact model, we propose
the application of the ‘bridging’ fractional Lévy motion (fLm) to space physics. We perform an initial evaluation of some
previous scaling results in this paradigm, and show how fLm can model the previously observed exponents. We suggest some new
directions for the future. 相似文献
6.
The ‘scintillations’ observed on signals received in the equatorial region from GPS satellites are due to plasma instabilities
in the F region of the ionosphere, also detected as spread F. These instabilities give rise to depletions of ionisation or
‘bubbles’. The occurrence of these events and their relation to the equatorial electrojet are reviewed. Possibilities of short-term
forecasting are examined with particular attention to problems encountered in modelling the equatorial electrojet.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
7.
First, high-frequency (HF) slowly drifting pulsating structures are interpreted as radio emissions of electron beams accelerated
in the magnetic reconnection volume and injected into magnetic islands (plasmoids). Then, the time evolution of plasma parameters
(density, magnetic field, etc.) in a 2-D MHD model of solar flare reconnection is computed numerically. Assuming plasma radio
emission from locations where the “double-resonance’’ instability generates upper-hybrid (UH) waves due to unstable distribution
function of suprathermal electrons, the radio spectra and spatial source structures in the reconnection region are modeled.
By comparison of the modeled and observed spectra a remarkable similarity has been found between the computed narrow-band
emission and the observed lace bursts. Finally, a new diagnostics of the reconnection process is proposed. 相似文献
8.
H. Noda T. Terasawa Y. Saito H. Hayakawa A. Matsuoka T. Mukai 《Space Science Reviews》2001,97(1-4):423-426
‘The Japanese Mars probe, NOZOMI, is staying in the interplanetary space (1–1.5 AU) until its Mars’ orbit insertion scheduled
in early 2004. Every 16 months on this interplanetary orbit the spacecraft crosses around 1 AU the ‘gravitational focusing
cone’ of the interstellar helium, which are penetrating into the inner heliosphere under the solar gravity. During the first
crossing of the cone in the season of March–May 2000, we observed these helium particles after the solar wind pickup process
with an E/q type ion detector aboard NOZOMI. We have estimated the original temperature of the interstellar helium as 11 000 K.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
9.
C. Ferrari F. Govoni S. Schindler A. M. Bykov Y. Rephaeli 《Space Science Reviews》2008,134(1-4):93-118
We review observations of extended regions of radio emission in clusters; these include diffuse emission in ‘relics’, and
the large central regions commonly referred to as ‘halos’. The spectral observations, as well as Faraday rotation measurements
of background and cluster radio sources, provide the main evidence for large-scale intracluster magnetic fields and significant
densities of relativistic electrons. Implications from these observations on acceleration mechanisms of these electrons are
reviewed, including turbulent and shock acceleration, and also the origin of some of the electrons in collisions of relativistic
protons by ambient protons in the (thermal) gas. Improved knowledge of non-thermal phenomena in clusters requires more extensive
and detailed radio measurements; we briefly review prospects for future observations. 相似文献
10.
Blanc M. Bolton S. Bradley J. Burton M. Cravens T.E. Dandouras I. Dougherty M.K. Festou M.C. Feynman J. Johnson R.E. Gombosi T.G. Kurth W.S. Liewer P.C. Mauk B.H. Maurice S. Mitchell D. Neubauer F.M. Richardson J.D. Shemansky D.E. Sittler E.C. Tsurutani B.T. Zarka Ph. Esposito L.W. Grün E. Gurnett D.A. Kliore A.J. Krimigis S.M. Southwood D. Waite J.H. Young D.T. 《Space Science Reviews》2002,104(1-4):253-346
Magnetospheric and plasma science studies at Saturn offer a unique opportunity to explore in-depth two types of magnetospheres.
These are an ‘induced’ magnetosphere generated by the interaction of Titan with the surrounding plasma flow and Saturn's ‘intrinsic’
magnetosphere, the magnetic cavity Saturn's planetary magnetic field creates inside the solar wind flow. These two objects
will be explored using the most advanced and diverse package of instruments for the analysis of plasmas, energetic particles
and fields ever flown to a planet. These instruments will make it possible to address and solve a series of key scientific
questions concerning the interaction of these two magnetospheres with their environment.
The flow of magnetospheric plasma around the obstacle, caused by Titan's atmosphere/ionosphere, produces an elongated cavity
and wake, which we call an ‘induced magnetosphere’. The Mach number characteristics of this interaction make it unique in
the solar system. We first describe Titan's ionosphere, which is the obstacle to the external plasma flow. We then study Titan's
induced magnetosphere, its structure, dynamics and variability, and discuss the possible existence of a small intrinsic magnetic
field of Titan.
Saturn's magnetosphere, which is dynamically and chemically coupled to all other components of Saturn's environment in addition
to Titan, is then described. We start with a summary of the morphology of magnetospheric plasma and fields. Then we discuss
what we know of the magnetospheric interactions in each region. Beginning with the innermost regions and moving outwards,
we first describe the region of the main rings and their connection to the low-latitude ionosphere. Next the icy satellites,
which develop specific magnetospheric interactions, are imbedded in a relatively dense neutral gas cloud which also overlaps
the spatial extent of the diffuse E ring. This region constitutes a very interesting case of direct and mutual coupling between
dust, neutral gas and plasma populations. Beyond about twelve Saturn radii is the outer magnetosphere, where the dynamics
is dominated by its coupling with the solar wind and a large hydrogen torus. It is a region of intense coupling between the
magnetosphere and Saturn's upper atmosphere, and the source of Saturn's auroral emissions, including the kilometric radiation.
For each of these regions we identify the key scientific questions and propose an investigation strategy to address them.
Finally, we show how the unique characteristics of the CASSINI spacecraft, instruments and mission profile make it possible
to address, and hopefully solve, many of these questions. While the CASSINI orbital tour gives access to most, if not all,
of the regions that need to be explored, the unique capabilities of the MAPS instrument suite make it possible to define an
efficient strategy in which in situ measurements and remote sensing observations complement each other.
Saturn's magnetosphere will be extensively studied from the microphysical to the global scale over the four years of the mission.
All phases present in this unique environment — extended solid surfaces, dust and gas clouds, plasma and energetic particles
— are coupled in an intricate way, very much as they are in planetary formation environments. This is one of the most interesting
aspects of Magnetospheric and Plasma Science studies at Saturn. It provides us with a unique opportunity to conduct an in situ investigation of a dynamical system that is in some ways analogous to the dusty plasma environments in which planetary systems
form.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
11.
V: SEA LEVEL: Benefits of GRACE and GOCE to sea level studies 总被引:1,自引:0,他引:1
The recently published Third Assessment Reports of the Intergovernmental Panel on Climate Change have underlined the scientific
interest in, and practical importance of past and potential future sea level changes. Space gravity missions will provide
major benefits to the understanding of the past, and, thereby, in the prediction of future, sea level changes in many ways.
The proposal for the GOCE mission described well the improvements to be expected from improved gravity field and geoid models
in oceanography (for example, in the measurement of the time-averaged, or ‘steady state’, ocean surface circulation and better
estimation of ocean transports), in geophysics (in the improvement of geodynamic models for vertical land movements), in geodesy
(in positioning of tide gauge data into the same reference frame as altimeter data, and in improvement of altimeter satellite
orbits), and possibly in glaciology (in improved knowledge of bedrock topography and ice sheet mass fluxes). GRACE will make
many important steps towards these ‘steady state’ aims. However, its main purpose is the provision of oceanographic (and hydrological
and meteorological) temporally-varying gravity information, and should in effect function as a global ‘bottom pressure recorder’,
providing further insight into the 3-D temporal variation of the ocean circulation, and of the global water budget in general.
This paper summaries several of these issues, pointing the way towards improved accuracy of prediction of future sea level
change.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
12.
A simple model has been developed that demonstrates that heliospheric X-ray emission can account for about 25%–50% of observed
soft X-ray background intensities. Similar to cometary soft X-ray emission, these X-rays are thought to be produced in the
heliosphere due to charge transfer collisions between heavy solar wind ions and interstellar neutrals. A more complex model
has now been developed to take into account temporal and spatial variations of the solar wind and interstellar neutrals. Measured
time histories of the solar wind proton flux are used in the model and the results are compared with the ‘long-term enhancements’
in the soft X-ray background measured by ROSAT for the same time period.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
13.
Charles E. Schlemm II Richard D. Starr George C. Ho Kathryn E. Bechtold Sarah A. Hamilton John D. Boldt William V. Boynton Walter Bradley Martin E. Fraeman Robert E. Gold John O. Goldsten John R. Hayes Stephen E. Jaskulek Egidio Rossano Robert A. Rumpf Edward D. Schaefer Kim Strohbehn Richard G. Shelton Raymond E. Thompson Jacob I. Trombka Bruce D. Williams 《Space Science Reviews》2007,131(1-4):393-415
NASA’s MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) mission will further the understanding of
the formation of the planets by examining the least studied of the terrestrial planets, Mercury. During the one-year orbital
phase (beginning in 2011) and three earlier flybys (2008 and 2009), the X-Ray Spectrometer (XRS) onboard the MESSENGER spacecraft
will measure the surface elemental composition. XRS will measure the characteristic X-ray emissions induced on the surface
of Mercury by the incident solar flux. The Kα lines for the elements Mg, Al, Si, S, Ca, Ti, and Fe will be detected. The 12°
field-of-view of the instrument will allow a spatial resolution that ranges from 42 km at periapsis to 3200 km at apoapsis
due to the spacecraft’s highly elliptical orbit. XRS will provide elemental composition measurements covering the majority
of Mercury’s surface, as well as potential high-spatial-resolution measurements of features of interest. This paper summarizes
XRS’s science objectives, technical design, calibration, and mission observation strategy. 相似文献
14.
Lightning activity in Venus has been a mystery for a long period, although many studies based on observations both by spacecraft and by ground-based telescope have been carried out. This situation may be attributed to the ambiguity of these evidential measurements. In order to conclude this controversial subject, we are developing a new type of lightning detector, LAC (Lightning and Airglow Camera), which will be onboard Planet-C (Venus Climate Orbiter: VCO). Planet-C will be launched in 2010 by JAXA. To distinguish an optical lightning flash from other pulsing noises, high-speed sampling at 50 kHz for each pixel, that enables us to investigate the time variation of each lightning flash phenomenon, is adopted. On the other hand, spatial resolution is not the first priority. For this purpose we developed a new type of APD (avalanche photo diode) array with a format of 8×8. A narrow band interference filter at wavelength of 777.4 nm (OI), which is the expected lightning color based on laboratory discharge experiment, is chosen for lightning measurement. LAC detects lightning flash with an optical intensity of average of Earth’s lightning or less at a distance of 3 Rv. In this paper, firstly we describe the background of the Venus lightning study to locate our spacecraft project, and then introduce the mission details. 相似文献
15.
C. M. Lisse M. F. A’Hearn T. L. Farnham O. Groussin K. J. Meech U. Fink D. G. Schleicher 《Space Science Reviews》2005,117(1-2):161-192
As comet 9P/Tempel 1 approaches the Sun in 2004–2005, a temporary atmosphere, or “coma,” will form, composed of molecules
and dust expelled from the nucleus as its component icy volatiles sublimate. Driven mainly by water ice sublimation at surface
temperatures T > 200 K, this coma is a gravitationally unbound atmosphere in free adiabatic expansion. Near the nucleus (≤ 102 km), it is in collisional equilibrium, at larger distances (≥104 km) it is in free molecular flow. Ultimately the coma components are swept into the comet’s plasma and dust tails or simply
dissipate into interplanetary space. Clues to the nature of the cometary nucleus are contained in the chemistry and physics
of the coma, as well as with its variability with time, orbital position, and heliocentric distance.
The DI instrument payload includes CCD cameras with broadband filters covering the optical spectrum, allowing for sensitive
measurement of dust in the comet’s coma, and a number of narrowband filters for studying the spatial distribution of several
gas species. DI also carries the first near-infrared spectrometer to a comet flyby since the VEGA mission to Halley in 1986.
This spectrograph will allow detection of gas emission lines from the coma in unprecedented detail. Here we discuss the current
state of understanding of the 9P/Tempel 1 coma, our expectations for the measurements DI will obtain, and the predicted hazards
that the coma presents for the spacecraft.
An erratum to this article is available at . 相似文献
16.
Jurewicz A.J.G. Burnett D.S. Wiens R.C. Friedmann T.A. Hays C.C. Hohlfelder R.J. Nishiizumi K. Stone J.A. Woolum D.S. Becker R. Butterworth A.L. Campbell A.J. Ebihara M. Franchi I.A. Heber V. Hohenberg C.M. Humayun M. McKeegan K.D. McNamara K. Meshik A. Pepin R.O. Schlutter D. Wieler R. 《Space Science Reviews》2003,105(3-4):535-560
Genesis (NASA Discovery Mission #5) is a sample return mission. Collectors comprised of ultra-high purity materials will be
exposed to the solar wind and then returned to Earth for laboratory analysis. There is a suite of fifteen types of ultra-pure
materials distributed among several locations. Most of the materials are mounted on deployable panels (‘collector arrays’),
with some as targets in the focal spot of an electrostatic mirror (the ‘concentrator’). Other materials are strategically
placed on the spacecraft as additional targets of opportunity to maximize the area for solar-wind collection.
Most of the collection area consists of hexagonal collectors in the arrays; approximately half are silicon, the rest are for
solar-wind components not retained and/or not easily measured in silicon. There are a variety of materials both in collector
arrays and elsewhere targeted for the analyses of specific solar-wind components.
Engineering and science factors drove the selection process. Engineering required testing of physical properties such as the
ability to withstand shaking on launch and thermal cycling during deployment. Science constraints included bulk purity, surface
and interface cleanliness, retentiveness with respect to individual solar-wind components, and availability.
A detailed report of material parameters planned as a resource for choosing materials for study will be published on a Genesis
website, and will be updated as additional information is obtained. Some material is already linked to the Genesis plasma
data website (genesis.lanl.gov). Genesis should provide a reservoir of materials for allocation to the scientific community
throughout the 21st Century.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
17.
De Keyser Johan Roth Michel De Sterck Hans Poedts Stefaan 《Space Science Reviews》2001,97(1-4):201-204
We have surveyed solar wind plasma beta and field-aligned Alfvénic Mach number using Ulysses and Wind data. We show the characteristic
timescale and occurrence frequency of ‘magnetically dominated’ solar wind, whose interaction with a planetary magnetosphere
may produce a bow shock with multiple shock fronts. We discuss radial, latitudinal, and solar cycle effects.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
18.
During the years 1996–2000 solar activity has been gradually rising and is now close to maximum. At the same time the Ulysses spacecraft has performed a north to south traverse of the low latitude regions of the heliosphere and is now once again travelling
through high southerly latitudes. We show some examples and report on the occurence rates of transient solar wind disturbances
which have been identified by their magnetic field signatures. ‘Magnetic clouds’ remain more common at low (compared to high)
latitudes despite the rise in solar activity. However, more events were observed at high latitudes than at solar minimum.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
19.
We review some of the new results for suprathermal electrons obtained with the 3-D Plasma and Energetic Particle Instrument
on the WIND spacecraft, which provides high sensitivity electron and ion measurements from solar wind thermal plasma up to
≳MeV energies. These results include: (1) the observation of solar impulsive electron events extending down to ∼0.5 keV energy;
(2) the observation of a turnover at ∼12 keV for electrons in a gradual large solar energetic particle (LSEP) event; (3) the
detection of a quiet-time population (the ‘superhalo’) of electrons extending up to ∼100 keV energy; and (4) the probing of
the magnetic topology and source region for magnetic clouds, using electrons. These unique WIND measurements are highly complementary
to the particle composition measurements which will be made by ACE.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
20.
I. Kimura 《Space Science Reviews》1974,16(3):389-411
Observations and theoretical works so far made are reviewed in regard to the interrelation of VLF and ULF emissions. Quasi-periodic VLF emissions are one of the typical examples showing the interrelation between the two phenomena. The term modulation may be more appropriate to explain these phenomena. Tentative interpretations will be given of the VLF and ULF emissions which are closely associated through a modulation of the electron distributions. 相似文献