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671.
Giuseppe Nisticò Spiros Patsourakos Volker Bothmer Gaetano Zimbardo 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
Coronal hole jets are fast ejections of plasma occurring within coronal holes, observed at Extreme-UltraViolet (EUV) and X-ray wavelengths. Recent observations of jets by the STEREO and Hinode missions show that they are transient phenomena which occur at much higher rates than large-scale impulsive phenomena like flares and Coronal Mass Ejections (CMEs). In this paper we describe some typical characteristics of coronal jets observed by the SECCHI instruments of STEREO spacecraft. We show an example of 3D reconstruction of the helical structure for a south pole jet, and present how the angular distribution of the jet position angles changes from the Extreme-UltraViolet-Imager (EUVI) field of view to the CORonagraph1 (COR1) (height ∼2.0 R⊙ heliocentric distance) field of view. Then we discuss a preliminary temperature determination for the jet plasma by using the filter ratio method at 171 and 195 Å and applying a technique for subtracting the EUV background radiation. The results show that jets are characterized by electron temperatures ranging between 0.8 and 1.3 MK. We present the thermal structure of the jet as temperature maps and we describe its thermal evolution. 相似文献
672.
Ts.N. Gogosheva V.N. Grigorieva Ts.T. Evgenieva B.D. Mendeva N.I. Kolev D.G. Krastev B.H. Petkov 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
This presentation deals with the recent investigations of the dynamics of the total ozone content (TOC) and of the lower troposphere ozone over Bulgaria, South-Eastern Europe. 相似文献
673.
Gyula Greschik 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
In order to assess space tow solar sail stability and control feasibility, slew simulations are performed for a simplified but dynamically representative km-class tow-like sail of sixteen 25 m square units (10,000 m2 total area and 110 kg gross mass) with a 250 kg payload. It is seen that, for the dimensions considered, the space tow concept is structurally sound and its control is feasible. While observed instabilities are identified as numeric in nature and are eliminated accordingly, their very occurrence highlights the need for a refinement of the model for future studies. The analyses are carried out with custom software implementing non-standard implicit-iterative time integration with innovative elements. A new damping model, specifically tailored for the analysis of truly gossamer systems such as solar sails, is also proposed. 相似文献
674.
Mariano Poisson Marcelo López Fuentes Cristina H. Mandrini Pascal Démoulin Etienne Pariat 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
We study the extremely complex active region (AR) NOAA 10314, that was observed from March 13–19, 2003. This AR was the source of several energetic events, among them two major (X class) flares, along a few days. We follow the evolution of this AR since the very first stages of its emergence. From the photospheric evolution of the magnetic polarities observed with SOHO/MDI we infer the morphology of the flux tube that originates the AR. Using a computation technique that combines Local Correlation Tracking with magnetic induction constrains, we compute the rate of magnetic helicity injection at the photosphere during the observed evolution. From our results we conclude that the AR originated by the emergence of a severely deformed magnetic flux tube having a dominantly positive magnetic helicity. 相似文献
675.
Daniel Gómez Luis N. Martín Pablo Dmitruk 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Because of its proximity, our Sun provides a unique opportunity to perform high resolution observations of its outer layers throughout the whole electromagnetic spectrum. We can also theoretically model most of the fascinating physical phenomena taking place on the Sun, as well as their impact on the solar system. 相似文献
676.
H. Shimazu K. Kitamura T. Tanaka S. Fujita M.S. Nakamura T. Obara 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2008,42(9):1504-1509
We have developed a real-time global MHD (magnetohydrodynamics) simulation of the solar wind interaction with the earth’s magnetosphere. By adopting the real-time solar wind parameters and interplanetary magnetic field (IMF) observed routinely by the ACE (Advanced Composition Explorer) spacecraft, responses of the magnetosphere are calculated with MHD code. The simulation is carried out routinely on the super computer system at National Institute of Information and Communications Technology (NICT), Japan. The visualized images of the magnetic field lines around the earth, pressure distribution on the meridian plane, and the conductivity of the polar ionosphere, can be referred to on the web site (http://www2.nict.go.jp/y/y223/simulation/realtime/).The results show that various magnetospheric activities are almost reproduced qualitatively. They also give us information how geomagnetic disturbances develop in the magnetosphere in relation with the ionosphere. From the viewpoint of space weather, the real-time simulation helps us to understand the whole image in the current condition of the magnetosphere. To evaluate the simulation results, we compare the AE indices derived from the simulation and observations. The simulation and observation agree well for quiet days and isolated substorm cases in general. 相似文献
677.
Stefano Casadio Olivier Arino 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2011
The South Atlantic Anomaly (SAA) has been monitored for 19 years using the Along Track Scanning Radiometer (ATSR) series of instruments onboard the ERS-1, ERS-2 and ENVISAT ESA satellites. The time evolution of the night-time particle induced noise in the short wavelength infrared (SWIR, 1.6 μm) and visible (VIS, 0.55 μm) channels of the ATSR instrument series have been analysed. The monthly location and extension of the SAA are inferred by fitting a two-dimensional, elliptical Gaussian function to the coordinates of the night-time hot spots detected over the SAA region. The location of the centre of the SAA is found to drift westwards with an average drift rate of about 0.24 deg/year and northward with an average drift rate of about 0.12 deg/year. Irregularities are found where the drift speed is inverted and the SAA moves eastward and southward. Results indicate that, as expected, the retrieved values of SAA’s strength and extension are anti-correlated with the solar activity expressed by the solar flux at 10.7 cm (F10.7). Finally, the peak-to-peak amplitude of the seasonal variation of the SAA strength, estimated from monthly VIS data, is found to be 30% of the average value with the annual to semiannual amplitude ratio of 1.38. 相似文献
678.
Adolfo L. Méndez Berhondo Ramón E. Rodríguez Taboada Paolo Zlobec Ana K. Díaz Rodríguez 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2013
Source length scales are estimated for the September 14, 2005 solar noise storm from the spectral and temporal observed characteristics of the background continuum fluctuations and clusters of Type I bursts. The characteristic height of the magnetic structure where the noise storm source is located and the size of the source where Type I bursts clustering takes place were calculated. A lower limit for the height of the magnetic structure supporting the noise storm at 237 MHz was estimated too. 相似文献
679.
Athena Coustenis 《Space Science Reviews》2005,116(1-2):171-184
The origin and evolution of Titan’s enigmatic atmosphere is reviewed. Starting with the present-day volatile inventory, the
question of what was the original composition on Titan and how a satellite of similar size to other Galilean moons managed
to acquire and hold on to the required material is discussed. In particular the possible sources and sinks of the main mother
molecules (nitrogen, methane and oxygen) are investigated in view of the most recent models and laboratory experiments. The
answers expected to be provided by the instruments aboard the Cassini-Huygens mission to some of the most prominent current
questions regarding Titan’s atmosphere are defined. 相似文献
680.
J.F. Valdés-Galicia Y. Muraki K. Watanabe Y. Matsubara T. Sako L.X. Gonzalez O. Musalem A. Hurtado 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》2009
The Sun provides unique opportunities to study particle acceleration mechanisms using data from detectors placed on the Earth’s surface and on board spacecrafts. Particles may gain high energies by several physical mechanisms. Differentiating between these possibilities is a fundamental problem of cosmic ray physics. Energetic neutrons provide us with information that keeps the signatures of the acceleration site. A summary of some representative solar neutron events observed on the Earth’s surface, including associated X and γ-ray observations from spacecrafts is presented. We discuss evidence of acceleration of particles by the Sun to energies up to several tens of GeV. In addition, a recent solar neutron event that occurred on September 7th 2005 and detected by several observatories at Earth is analyzed in detail. 相似文献