The energy, transported from the photosphere through countless energy tunnels to the chromosphere and the corona, drives the solar activity and the eruption as well as heats the corona. Manifestations of these tunnels in the photosphere provide the key information for understanding the physics of the process of the energy transportation.

In the photosphere, numerous bright and point-like features are frequently observed and are known as the magnetic bright point (MBP), or bright point (BP). They are the intersection of and are considered as the reliable tracer of the energy tunnel. Tracking MBPs and investigating their kinematic and dynamic properties are important to learn where the energy comes from and how it is stored, which helps to solve the problem of the corona heating and predict solar activities.

LIU Yanxiao and the collaborators at the Yunnan Observatories of 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 study, published in The Astrophysical Journal, provided an essential evidence for how the solar corona is heated, a century-long puzzle in the field of the solar physics.

The researchers 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, they 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 study provided brand new observational evidence for studying features and physical properties of the energy tunnels, which further opens a new window to the behavior of the energy transportation as the energy tunnel deforms, and offers observational constraints for theories and models of the corona heating, as well as the energy storage prior to the major solar eruption.