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31.
C. Debi Prasad Ashok Ambastha Nandita Srivastava Sushanta C. Tripathy Mona J. Hagyard 《Journal of Astrophysics and Astronomy》1997,18(1):39-55
Super-active region NOAA 6555 was highly flare productive during the period March 21st–27th, 1991 of its disk passage. We
have st udied its chromospheric activity using high spatial resolution Hα filtergrams taken at Udaipur along with MSFC vector
magnetograms. A possible relationship of flare productivity and the variation in shear has been explored. Flares were generally
seen in those subareas of the active region which possessed closed magnetic field configuration, whereas only minor flares
and/or surges occurred in subareas showing open magnetic field configuration. Physical mechanisms responsible for the observed
surges are also discussed. 相似文献
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在太阳活动区的物理研究中,特别是在二维动力学光谱分析中,迫切需要相应活动区的磁图资料。本文介绍了在太阳光谱仪的入射狭缝后安装一种新型偏振器进行活动区二维磁场观测的新方法。这种方法不仅能获得日面上任一点的磁场强度,且可快速获得活动区的纵向场磁图。除此之外,还可利用多条谱线的同时观测,获得有关磁力线管结构等方面的资料。 相似文献
34.
M. Sereno 《Monthly notices of the Royal Astronomical Society》2005,356(3):937-943
Constraints on an exact quintessence scalar-field model with an exponential potential are derived from gravitational lens statistics. An exponential potential can account for data from both optical quasar surveys and radio-selected sources. Based on the Cosmic Lens All-Sky Survey (CLASS) sample, lensing statistics provides, for the pressureless matter density parameter, an estimate of ΩM0 = 0.31+0.12 −0.14 . 相似文献
35.
Motivated by recent high-resolution observations of the solar surface, we investigate the problem of non-linear magnetoconvection in a three-dimensional compressible layer. We present results from a set of numerical simulations which model the situation in which there is a weak imposed magnetic field. This weak-field regime is characterized by vigorous granular convection and spatially intermittent magnetic field structures. When the imposed field is very weak, magnetic flux tends to accumulate at the edges of the convective cells, where it forms compact, almost 'point-like' structures which are reminiscent of those observed in the quiet Sun. If the imposed field is slightly stronger, there is a tendency for magnetic flux to become concentrated into 'ribbon-like' structures which are comparable to those observed in solar plages. The dependence of these simulations upon the strength of the imposed magnetic field is analysed in detail, and the concept of the fractal dimension is used to make a further, more quantitative comparison between these simulations and photospheric observations. 相似文献
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The process of non-linear ambipolar diffusion in the region overlying the solar surface can be an effective mechanism for producing sharp magnetic structures and current sheets. These may be the sites responsible for the occurrence of connectivity of magnetic field lines, and the subsequent explosive input of energy for heating of some of the features in the atmosphere of the Sun.. 相似文献
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