LIU Yanxiao, the PhD candidate of the Solar Physics Group at the Yunnan Observatories, Chinese Academy of Sciences, discovered splitting and merging phenomenon of the tunnel for the energy transportation in the solar atmosphere from the photosphere to the corona. This finding provides an essential evidence for helping answer the question how the solar corona is heated, a century-long puzzle in the field of the solar physics. The result has been published in The Astrophysical Journal recently.

The solar atmosphere consists of three parts. The inmost layer is the photosphere, the middle layer is the chromosphere, and outmost one is the corona. The energy driving the solar activity and the eruption, as well as heating the corona, is transported from the photosphere through countless energy tunnels to the chromosphere and the corona. Part of the energy is dissipated during transportation for heating the corona, and other parts of energy is eventually stored in the coronal magnetic field for driving the eruption. Therefore, manifestations of these tunnels in the photosphere provide us the key information for learning and understanding the physics of the process of the energy transportation.

Numerous bright and point-like features are frequently observed in the photosphere, they are also known as the magnetic bright point (MBP), or bright point (BP) for short. They are the intersection of the energy tunnel with the photosphere, and are considered as the reliable tracer of the energy tunnel in the photosphere. Tracking MBPs and investigating their kinematic and dynamic properties are very important for learning where the energy comes from and how the energy is stored. The former one is the key to solving the problem of the corona heating, and the latter is essential for predicting solar activities.

LIU Yanxiao developed a novel algorithm for identifying and tracking BPs automatically. This algorithm could recognize and identify the BPs that experienced splitting and/or merging, distinguish them from those that did not split or merge, and track them for a long time.

By analyzing the data of high quality and resolution observed with the wonderful and stable seeing by the New Vacuum Solar Telescope (NVST) of Yunnan Observatories located by the Fuxian Lake, LIU found that although most of the energy tunnels remained unchanging topologically during their lifetime, quite many of them still experienced splitting and merging as the energy propagates through them, which have not been reported yet.

This provides a brand new observational evidence for studying features and physical properties of the energy tunnels, which further opens a new window to looking into the behavior of the energy transportation as the energy tunnel deforms, and also offers observational constraints for theories and models of the corona heating, as well as the energy storage prior to the major solar eruption.

Contact:

LIU Yanxiao

liuyanxiao@ynao.ac.cn

Yunnan Observatories