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101.
102.
J.B.L. Jones R.D. Bentley R. Hunter R.H.A. Iles G.C. Taylor D.J. Thomas 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2005,36(12):2258-2267
Space weather phenomena can effect many areas of commercial airline operations including avionics, communications and GPS navigation systems. Of particular importance at present is the recently introduced EU legislation requiring the monitoring of aircrew radiation exposure, including any variations at aircraft altitudes due to solar activity. With the introduction of new ultra-long-haul “over-the-pole” routes, “more-electric” aircraft in the future, and the increasing use of satellites in the operation, the need for a better understanding of the space weather impacts on future airline operations becomes all the more compelling. This paper will present the various space weather effects, some provisional results of an ongoing 3-year study to monitor cosmic radiation in aircraft, and conclude by summarising some of the identified key operational issues, which must be addressed, with the help of the science community, if the airlines want to benefit from the availability of space weather services. 相似文献
103.
D.K. Callebaut V.I. Makarov A.G. Tlatov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2007,40(12):1917-1920
After a polar reversal in one hemisphere the Sun has two polar caps of the same sign, leaving it in a kind of monopolar state. It may take months before a polar reversal occurs in the other hemisphere. The situation may have been extreme in the Maunder Minimum where the northern hemisphere most probably did not have polar reversals during several cycles, while the southern hemisphere may have had some. This may affect the interplanetary field and thus the cosmic rays reaching the Earth. Using the relation between the Wolf number and the speed of the global magnetic field regions the yearly mean Wolf number has to exceed 40 in order to have polar reversals, hence per hemisphere we expect that it must exceed 20. This may be used to give a definition of a deep minimum. 相似文献
104.
M. Storini P. Metteo G. Moreno 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,41(1):70-75
Taking advantage of the cutoff computations performed for more than a hundred locations from 1955 to 1995 [every 5 years; Shea, M.A., Smart, D.F. Vertical cutoff rigidities for cosmic ray stations since 1955, in: Proceedings of the ICRC 2001, Hamburg, Copernicus Gesellschaft, vol. 10, pp. 4063–4066, 2001], we carefully checked the relationship between the vertical cutoff rigidity and the McIlwain parameter introduced by Shea et al. [Shea, M.A., Smart, D.F., Gentile, L.C. Estimating cosmic ray vertical cutoff rigidities as a function of the McIlwain L-parameter for different epochs of the geomagnetic field. Phys. Earth Planet. Int., 48, 200–205, 1987]. We derived an updated algorithm that can be used outside the polar and equatorial regions, avoiding time consuming computations. Results for the European area and 1990 epoch suggest that the fast evaluation is accurate within 0.1 GV in 26 out of the 30 considered locations. 相似文献
105.
I. Büsching O.C. de Jager 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008
In this study, we investigate how restrictive the γ-ray emission from the Galactic center region, as seen by HESS and other Cherenkov air shower arrays, is against various models for cosmic ray injection. We derive diffusion coefficients which fit the observed spatial scales of diffuse γ-ray emission from the extended emission associated with the molecular clouds SgrA, B and C. Using these diffusion coefficients, we then obtain a limit for time scale of assumed recent proton acceleration near the SMBH, as the spatial size of SgrA∗ in VHE γ-rays has to be consistent with the observed unresolved HESS point source size at this position. The signal from this hadronic component may be mixed with the expected VHE inverse Compton emission from the nearby unresolved pulsar wind nebula. 相似文献
106.
J. G. Trotignon J. L. Michau D. Lagoutte M. Chabassière G. Chalumeau F. Colin P. M. E. Décréau J. Geiswiller P. Gille R. Grard T. Hachemi M. Hamelin A. Eriksson H. Laakso J. P. Lebreton C. Mazelle O. Randriamboarison W. Schmidt A. Smit U. Telljohann P. Zamora 《Space Science Reviews》2007,128(1-4):713-728
The main objective of the Mutual Impedance Probe (MIP), part of the Rosetta Plasma Consortium (RPC), is to measure the electron
density and temperature of Comet 67P/Churyumov-Gerasimenko’s coma, in particular inside the contact surface. Furthermore,
MIP will determine the bulk velocity of the ionised outflowing atmosphere, define the spectral distribution of natural plasma
waves, and monitor dust and gas activities around the nucleus. The MIP instrumentation consists of an electronics board for
signal processing in the 7 kHz to 3.5 MHz range and a sensor unit of two receiving and two transmitting electrodes mounted
on a 1-m long bar. In addition, the Langmuir probe of the RPC/LAP instrument that is at about 4 m from the MIP sensor can
be used as a transmitter (in place of the MIP ones) and MIP as a receiver in order to have access to the density and temperature
of plasmas at higher Debye lengths than those for which the MIP is originally designed. 相似文献
107.
108.
S.A. Elwakil M.A. Zahran E.K. El-Shewy A.E. Mowafy 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
A theoretical investigation has been made for adiabatic positive and negative dust charge fluctuations on the propagation of dust-ion acoustic waves (DIAWs) in a weakly inhomogeneous, collisionless, unmagnetized dusty plasmas consisting of cold positive ions, stationary positively and negatively charged dust particles and isothermal electrons. The reductive perturbation method is employed to reduce the basic set of fluid equations to the variable coefficients Korteweg–de Vries (KdV) equation. Either compressive or rarefactive solitons are shown to exist depending on the critical value of the ion density, which in turn, depends on the inhomogeneous distribution of the ion. The dissipative effects of non-adiabatic dust charge variation has been studied which cause generation of dust ion acoustic shock waves governed by KdV-Burger (KdVB) equation. The results of the present investigation may be applicable to some dusty plasma environments, such as dusty plasma existing in polar mesosphere region. 相似文献
109.
110.
Emmanuel Dartois 《Space Science Reviews》2005,119(1-4):293-310
The instruments on board the Infrared Space Observatory have for the first time allowed a complete low (PHOT, CVF) to medium
resolution (SWS) spectroscopic harvest, from 2.5 to 45 μm, of interstellar dust. Amongst the detected solids present in starless
molecular clouds surrounding recently born stellar and still embedded objects or products of the chemistry in some mass loss
envelopes, the so-called “ice mantles” are of specific interest. They represent an interface between the very refractory carbonaceous
and silicates materials that built the first grains with the rich chemistry taking place in the gas phase. Molecules condense,
react on ices, are subjected to UV and cosmic ray irradiation at low temperatures, participating efficiently to the evolution
toward more complex molecules, being in constant interaction in an ice layer. They also play an important role in the radiative
transfer of molecular clouds and strongly affect the gas phase chemistry. ISO results shed light on many other species than
H2O ice. The detection of these van der Waal's solids is mainly performed in absorption. Each ice feature observed by ISO spectrometer
is an important species, with abundance in the 10−4–10−7 range with respect to H2. Such high abundances represent a substantial reservoir of matter that, once released later on, replenishes the gas phase
and feeds the ladder of molecular complexity. Medium resolution spectroscopy also offers the opportunity to look at individual
line profiles of the ice features, and therefore to progressively reveal the interactions taking place in the mantles.
This article will give a view on selected results to avoid to overlap with the numerous reviews the reader is invited to consult
(e.g. van Dishoeck, in press; Gibb et al., 2004.).
Based on observations with ISO, an ESA project with instruments funded by ESA Member States (especially the PI countries:
France, Germany, The Netherlands, and the United Kingdom), and with the participation of ISAS and NASA. 相似文献