发表机构
Max-Planck-Institut für Sonnensystemforschung; Kyung Hee University; Queen’s University Belfast（马克斯·普朗克太阳系统研究所; 庆熙大学; 贝尔法斯特女王大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过Sunrise观测数据，分析了宁静太阳区域中与弱磁场相关的217个Ca II H增亮事件，发现约半数位于磁冠中，其余与磁亮点或磁浮现/对消相关，并揭示相反极性磁场相互作用对最亮峰值的贡献。
AI 中文摘要
背景：在Ca II H和K共振线中观测到的色球发射通常与光球磁场呈正相关。然而，发现一部分强烈的Ca II H&K增亮现象发生在低光球磁通量密度的区域。目的：我们旨在理解宁静太阳区域中与弱磁场相关的这些色球增亮现象的起源。方法：我们使用了气球载天文台Sunrise首次飞行中搭载的SuFI仪器获取的Ca II H观测数据，以及IMaX仪器记录的光球磁图。我们还使用了SPINOR代码从IMaX数据反演得到的大气物理参数。结果：共识别出217个与弱磁场相关的Ca II H增亮事件。其中111个位于强磁场区域的边缘，处于由kG磁通量管膨胀形成的磁冠中。其余增亮事件与弱单极磁斑、弱混合极性磁场之间的相互作用有关，或位于无明显磁特征的位置。对于后两种情况，Ca II H强度以3-5分钟的周期变化，同时视线速度、温度和磁通量也以相似周期变化。结论：与弱磁场相关的强烈Ca II H增亮事件中，约有一半位于覆盖极弱光球磁场的磁冠中。约10-12%与磁场可能未被空间分辨的磁亮点相关。其余似乎是Ca II H颗粒，这些颗粒绝大多数与磁浮现或磁对消事件相关。我们得出结论，尽管Ca II H颗粒主要由（磁）声冲击波驱动，但相反极性磁场之间的相互作用也促进了最亮峰值的形成。
英文摘要
Context. Chromospheric emission observed in the Ca II H and K resonance lines is generally positively correlated with photospheric magnetic fields. However, a fraction of strong Ca II H&K brightenings are found to occur over regions of low photospheric magnetic flux density. Aims. We aim to understand the origin of these chromospheric brightenings associated with weak fields in quiet Sun regions. Methods. We use Ca II H observations taken by the SuFI along with the photospheric magnetograms recorded by the IMaX, instruments onboard the first flight of the balloon-borne observatory Sunrise. We also use the atmospheric physical parameters inverted from IMaX data by the SPINOR code. Results. 217 Ca II H brightenings associated with weak fields are identified. 111 of these are located at the peripheries of strong field regions, in the magnetic canopies formed by the expansion of the kG flux tube. The other brightenings are associated with either weak unipolar magnetic patches, with interactions between weak mixed-polarity magnetic fields, or at locations with no clear magnetic features. For the latter two situations, the Ca II H intensity varies with a period of 3-5 mins, accompanied by variations in the line-of-sight velocity, the temperature, and the magnetic flux with a similar period. Conclusions. About half of the strong Ca II H brightenings associated with weak fields are located in magnetic canopies overlying very weak photospheric fields. About 10-12% are associated with magnetic bright points where the magnetic field is probably not spatially resolved. The remainder appears to be Ca II H grains, which are overwhelmingly associated with magnetic emergence or cancellation events. We conclude that although Ca II grains are mainly driven by (magneto-)acoustic shock waves, interactions between opposite-polarity magnetic fields also contribute to the formation of the brightest peaks.
Comments16 pages, 15 figures, accepted for publication in Astronomy & Astrophysics
