arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0810.1020astro-ph
收藏

从Hinode、SoHO和TRACE看亮点的结构和动力学

The structure and dynamics of a bright point as seen with Hinode, SoHO and TRACE

D. Pérez-Suárez, R. C. Maclean, J. G. Doyle, M. S. Madjarska

摘要:

我们的目的是确定日冕亮点的等离子体特性,并将其磁图数据外推的磁拓扑结构与其在X射线图像中的外观进行比较。我们分析获得的光谱数据与EIS/Hinode,钙II H和G-波段图像从SOT/Hinode,紫外图像从TRACE,X射线图像从XRT/Hinode和高分辨率/高节奏的磁图数据从MDI/SoHO。BP由几个日冕环组成,如X射线图像所示,而色球结构由数十个小亮点组成,如Ca II H所示。在Ca II BP和磁场增加之间存在良好的相关性,这意味着Ca II H通带是磁通量浓度的良好指标。BP区的多普勒速度在6至15 km/s之间,来自Fe XII和Fe XIII线,而Fe XIV和Si VII的多普勒速度在-15至+15 km/s之间。日冕电子密度为3.7 × 10^9 cm^-3。发现正磁通量与X射线光变曲线之间有很好的相关性。外推的磁场配置与X射线图像中所见的组成BP的一些环之间的显著一致性表明,亮点中的大部分磁场接近电势。正磁通量和X射线辐射之间的密切相关性表明,磁重联释放的能量是由磁通量的出现或消除所激发的。

英文摘要:

Our aim is to determine the plasma properties of a coronal bright point and compare its magnetic topology extrapolated from magnetogram data with its appearance in X-ray images. We analyse spectroscopic data obtained with EIS/Hinode, Ca II H and G-band images from SOT/Hinode, UV images from TRACE, X-ray images from XRT/Hinode and high-resolution/high-cadence magnetogram data from MDI/SoHO. The BP comprises several coronal loops as seen in the X-ray images, while the chromospheric structure consists of tens of small bright points as seen in Ca II H. An excellent correlation exists between the Ca II BPs and increases in the magnetic field, implying that the Ca II H passband is a good indicator for the concentration of magnetic flux. Doppler velocities between 6 and 15 km/s are derived from the Fe XII and Fe XIII lines for the BP region, while for Fe XIV and Si VII they are in the range from -15 to +15 km/s. The coronal electron density is 3.7x10^9 cm^-3. An excellent correlation is found between the positive magnetic flux and the X-ray light-curves. The remarkable agreement between the extrapolated magnetic field configuration and some of the loops composing the BP as seen in the X-ray images suggests that a large fraction of the magnetic field in the bright point is close to potential. The close correlation between the positive magnetic flux and the X-ray emission suggests that energy released by magnetic reconnection is stimulated by flux emergence or cancellation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

↑