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排序方式: 共有255条查询结果,搜索用时 31 毫秒
21.
We consider the kinetic problem of charged-particle acceleration in a magnetic trap with converging magnetic mirrors. We show that for a positive electrostatic potential of the trap plasma relative to the mirrors, the efficiency of confinement and acceleration increases for electrons and decreases for ions. 相似文献
22.
I. A. Zhitnik S. V. Kuzin A. M. Urnov I. L. Beigman S. A. Bozhenkov I. Yu. Tolstikhina 《Astronomy Letters》2005,31(1):37-56
We present a catalog of 100 lines in the wavelength range 280–330 Å detected by the RES-C spectroheliograph in solar active regions and flares during the SPIRIT experiment aboard the CORONAS-F orbital station. We identified 54 lines. The line intensities recorded during the X3.4 (GOES) solar flare of December 28, 2001, are given. The data reduction procedure is discussed. 相似文献
23.
为了观测太阳耀斑高速电子轰击色球,紫金山天文台赣榆观测站将原精细结构望远镜改造为高速CCD精细结构望远镜,拍摄到局部H_α活动区.在光学系统里增加缩焦器,引进干涉偏振滤光片后,高速CCD就能记录H_α各波段的单色像.经过1999年至2004年的反复试验和改进,目前H_α图像的空间分辨率己达1个角秒,时间分辨率为每秒钟30至40帧图像.2004年11月观测到一个M1.1级耀斑,我们将H_α紫移(H_α-0.5(?))高速图像和硬X-射线暴、射电微波暴比较,结果发现:初始的耀斑成对亮点在上升相相互靠近,特别是微波暴源也显出类似的靠近运动,以前从未观测到这种现象,它可解释为磁弧脚根沿中性线的剪切运动. 相似文献
24.
The most rapid and dramatic evolution in the solar corona occurs in events now known as Coronal Mass Ejections (CMEs). There have considerable importance for our understanding of the evolution of the mass and energy injected into the interplanetary medium. In this work, we have studied the relation of CMEs with geomagnetic activity for the period of 1988 to 1993. Not all CMEs are capable of producing geomagnetic disturbances. Our study indicates that the maximum chance of a geomagnetic disturbance occurs two to three days after a CME in association with B-type solar flares. 相似文献
25.
经典的太阳光谱观测是一维的,它有很大的局限性。从50年代起,天文工作者采用多种方法开展二维太阳光谱观测,已经研制出一系列仪器,建立完整的资料归算程序,取得优良成果。在二维观测资料的基础上,用理论方法推出深度分布,可以得出三维的立体图像,这会成为太阳研究的主要方法之一。 相似文献
26.
We describe solar observations carried out for the first time jointly with Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) and Aalto University Metshovi Radio Observatory (MRO). KAIRA is new radio antenna array observing the decimeter and meter wavelength range. It is located near Kilpisjärvi, Finland, and operated by the SodankyläGeophysical Observatory, University of Oulu. We investigate the feasibility of KAIRA for solar observations, and the additional benefits of carrying out multi‐instrument solar observations with KAIRA and the MRO facilities, which are already used for regular solar observations. The data measured with three instruments at MRO, and with KAIRA during time period 2014 April–October were analyzed. One solar radio event, measured on 2014 April 18, was studied in detail. Seven solar flares were recorded with at least two of the three instruments at MRO, and with KAIRA during the chosen time period. KAIRA is a great versatile asset as a new Finnish instrument that can also be used for solar observations. Collaboration observations with MRO instruments and KAIRA enable detailed multi‐frequency solar flare analysis. Flare pulsations, flare statistics and radio spectra of single flares can be investigated due to the broad frequency range observations. The Northern locations of both MRO and KAIRA make as long as 15‐hour unique solar observations possible during summer time. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
27.
Hui Zhao Jing-Xiu Wang Jun Zhang Chi-Jie Xiao National Astronomical Observatories Chinese Academy of Sciences Beijing 《中国天文和天体物理学报》2005,5(5):443-447
Employing the Poincare index of isolated null-points in a vector field, we worked out a mathematical method of searching for 3D null-points in coronal magnetic fields. After introducing the relevant differential topology, we test the method by using the analytical model of Brown & Priest. The location of null-point identified by our method coincides precisely with the analytical solution. Finally we apply the method to the 3D coronal magnetic fields reconstructed from an observed MDI magnetogram of a super-active region (NOAA 10488). We find that the 3D null-point seems to be a key element in the magnetic topology associated with flare occurrence. 相似文献
28.
We show that our original suggestion that gamma-ray bursts (GRB) may be flares on Magnetically Active Stellar Systems (MASS) namely flare stars, RS CVn binaries and Cataclysmic variables agrees well with the new observations of CGRO. We make a multi component fit to the log(N) - log(S) distribution and the high degree of isotropy as observed by the previous generation of satellites as well as BATSE/CGRO using the second BATSE catalogue. We then discuss individual source association and optical transient observations and show that they favor the present suggestion. We discuss the physical mechanisms and gamma-ray production processes that can occur on such systems giving the GRB their characteristics. We predict increase of anisotropy in the BATSE/CGRO observations for bright GRB. 相似文献
29.
A statistical analysis of the contemporary (1954-1975) solar flare particle events has been made for the parametersF (integrated, proton fluence in cm-2 in an event with kinetic energy above 10 MeV) andR
0 (the characteristic rigidity). These data are compared with the long-term averaged values determined from stable- and radio-nuclide
measurements of lunar samples. The analysis shows that the ancient solar flare proton spectrum was harder (higher R0 values) compared to that observed in contemporary flares. A similar analysis can not be made for the mean long-term averaged
flux (ˉJ, cm-2 S-1), since the contemporary averages suffer from an uncertainty due to the statistics of a single event. However, the average
flux estimates for time durations 〈T〉 exceeding 103 yr, are free from such uncertainties. The long-term averaged ˉJ values obtained over different time scales (104 - 106 yr) suggest a possible periodic variation in solar flare activity, with enhanced flux level during the last 105 yr. The available data rule out the occurrence of giant flares, with proton fluence exceeding 1015 cm-2 during the last million years. 相似文献
30.