Journal of The Korean Astronomical Society (천문학회지)

The Korean Astronomical Society (한국천문학회)
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DYNAMIC FORMATION AND ASSOCIATED HEATING OF A MAGNETIC LOOP ON THE SUN

  • Tetsuya, Magara (Department of Astronomy and Space Science, Kyung Hee University) ;
  • Yeonwoo, Jang (School of Space Research, Kyung Hee University) ;
  • Donghui, Son (School of Space Research, Kyung Hee University)
  • Received : 2022.11.03
  • Accepted : 2022.11.25
  • Published : 2022.12.31
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Abstract

To seek an atmospheric heating mechanism operating on the Sun we investigated a heating source generated by a downflow, both of which may arise in a magnetic loop dynamically formed on the Sun via flux emergence. Since an observation shows that the illumination of evolving magnetic loops under the dynamic formation occurs sporadically and intermittently, we performed a magnetohydrodynamic simulation of flux emergence to obtain a high-cadence simulated data, where temperature enhancement was identified at the footpoint of an evolving magnetic loop. Unlike a rigid magnetic loop with a confined flow in it, the evolving loop in a low plasma β atmosphere is subjected to local compression by the magnetic field surrounding the loop, which drives a strong supersonic downflow generating an effective footpoint heating source in it. This may introduce an energy conversion system to the magnetized atmosphere of the Sun, in which the free magnetic energy causing the compression via Lorentz force is converted to the flow energy, and eventually reduced to the thermal energy. Dynamic and thermodynamic states involved in the system are explained.

Keywords

Acknowledgement

T.M. deeply appreciates the referee's useful comments on the paper. The authors wish to thank the Kyung Hee University for general support of this work. Part of Figure 1 was made using images obtained by the Transition Region and Coronal Explorer (TRACE). TRACE is a mission of the Stanford-Lockheed Institute for Space Research, and part of the NASA Small Explorer program. The main panel of Figure 2 was made using VAPOR (Clyne et al. 2007). This work was financially supported by a research program (NRF2021R1A2C1010310, PI: T. Magara) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology.

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