arXivDaily arXiv每日学术速递 周一至周五更新
北美退伍军人节(Veterans Day),12 日无更新
arXiv 1301.3141astro-ph.SR
收藏

磁色球加热:Ca II 8542谱的观测约束

Heating of the magnetic chromosphere: observational constraints from Ca II 8542 spectra

J. de la Cruz Rodríguez, B. De Pontieu, M. Carlsson, L. H. M. Rouppe van der Voort

摘要:

太阳色球层的加热仍然知之甚少。虽然在了解是什么驱动了平静的太阳网络色球层方面取得了进展,但强磁场区域的色球层加热仍然是一个困难的挑战,主要是因为缺乏观测限制。我们使用瑞典1米太阳望远镜的高分辨率光谱偏振数据,以确定在磁色球加热的位置和时空特性。特别是,我们报告的存在下,提高核心谱线配置文件中的钙II 8542线。这些剖面的特点是没有吸收线芯,在+/- 0.5 μ m之间显示出准平坦的剖面,并且在磁亮点和磁斑附近丰富。与3D MHD模拟的比较表明,当视线穿过与通量集中的磁场的高度相关的膨胀的“高温冠”时,会发生这样的配置文件。模拟中的这种温度冠是由存在强磁场梯度的欧姆耗散引起的。因此,凸起的核心轮廓是色球加热增加的位置的指标。我们在我们的观察,这样的配置文件的位置和时间和空间特性的特征,从而提供更严格的限制色球加热机制的理论模型比以前。

英文摘要:

The heating of the Sun's chromosphere remains poorly understood. While progress has been made on understanding what drives the quiet Sun internetwork chromosphere, chromospheric heating in strong magnetic field regions continues to present a difficult challenge, mostly because of a lack of observational constraints. We use high-resolution spectropolarimetric data from the Swedish 1-m Solar Telescope to identify the location and spatio-temporal properties of heating in the magnetic chromosphere. In particular, we report the existence of raised-core spectral line profiles in the Ca II 8542 line. These profiles are characterized by the absence of an absorption line core, showing a quasi-flat profile between +/- 0.5 Å, and are abundant close to magnetic bright-points and plage. Comparison with 3D MHD simulations indicates that such profiles occur when the line-of-sight goes through an "elevated temperature canopy" associated with the expansion with height of the magnetic field of flux concentrations. This temperature canopy in the simulations is caused by ohmic dissipation where there are strong magnetic field gradients. The raised-core profiles are thus indicators of locations of increased chromospheric heating. We characterize the location and temporal and spatial properties of such profiles in our observations, thus providing much stricter constraints on theoretical models of chromospheric heating mechanisms than before.

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。

↑