ON THE NATURE OF THE EXTREME-ULTRAVIOLET LATE PHASE OF SOLAR FLARES
ON THE NATURE OF THE EXTREME-ULTRAVIOLET LATE PHASE OF SOLAR FLARES
复制标题
太阳耀斑极紫外晚相的性质
DOI：
10.1088/0004-637x/793/2/85
复制
发表时间：
2014-07
影响因子：
4.9
通讯作者：
Dai, Y.
中科院分区：
文献类型：
--
作者：
Li, Y.;Ding, M. D.;Guo, Y.;Dai, Y.
太阳耀斑的极紫外（EUV）后期是温暖日冕辐射的第二个峰值（例如Fe xvi），在GOES软x射线峰值之后的几分钟到几小时。它首先是由太阳动力学观测站（SDO）上的EUV变异性实验观测到的。后期发射来自第二组较长的环（后期环），它比主燃烧环高。这可能是由于额外加热或长时间冷却造成的。在本文中，我们使用基于焓的循环热演化模型研究了长时间冷却和额外加热在产生EUV后期的作用。我们发现，在后期循环中长时间的冷却过程可以很好地解释EUV后期发射的存在，但我们不能排除在衰变阶段额外加热的可能性。此外，我们提供了两种基于SDO上大气成像组件的UV和EUV发射的初步方法来确定额外加热是否在后期发射中起作用。利用非线性无力场模型，研究了EUV后期的磁组态。发现后期相位既可以在与磁零点相关的热脊场线中产生，也可以在多极磁场的大尺度磁环中产生。在本文中，我们还讨论了为什么在温暖的日冕辐射中通常观察到极紫外后期，以及为什么大多数耀斑不表现出极紫外后期。
The extreme-ultraviolet (EUV) late phase of solar flares is a second peak of warm coronal emissions (e.g., Fe xvi) for many minutes to a few hours after the GOES soft X-ray peak. It was first observed by the EUV Variability Experiment on board the Solar Dynamics Observatory (SDO). The late-phase emission originates from a second set of longer loops (late-phase loops) that are higher than the main flaring loops. It is suggested to be caused by either additional heating or long-lasting cooling. In this paper, we study the role of long-lasting cooling and additional heating in producing the EUV late phase using the enthalpy based thermal evolution of loops model. We find that a long cooling process in late-phase loops can well explain the presence of the EUV late-phase emission, but we cannot exclude the possibility of additional heating in the decay phase. Moreover, we provide two preliminary methods based on the UV and EUV emissions from the Atmospheric Imaging Assembly on board SDO to determine whether or not additional heating plays a role in the late-phase emission. Using nonlinear force-free field modeling, we study the magnetic configuration of the EUV late phase. It is found that the late phase can be generated either in hot spine field lines associated with a magnetic null point or in large-scale magnetic loops of multipolar magnetic fields. In this paper, we also discuss why the EUV late phase is usually observed in warm coronal emissions and why the majority of flares do not exhibit an EUV late phase.
DOI：
--
发表时间：
2001
期刊：
--
影响因子：
--
作者：
A. Poland;R. Fisher
通讯作者：
A. Poland;R. Fisher