The Solar Interface Region

• Applicant: Dr. Thomas Wiegelmann
• Subject Area: Astrophysics and Astronomy
• Term: from 2016 to 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 317231409

• Final Report Year: 2021

Final Report Abstract

Within this project we have established a nonlinear magnetohydrostatic (MHS) extrapolation code which is applicable for investigations of the solar interface region. The work done in this project included improving the algorithm of the MHS extrapolation and testing the code with both a semi-analytical model and a radiative magnetohydrodynamic simulation model. Finally the code was applied to data from SUNRISE/IMaX. The magnetic field and plasma structure in the solar interface region was studied regarding the magnetic topology and phenomena like current sheets and concentrations of the Lorentz-force and plasma forces. Investigated was also the transition from the non-force-free lower solar atmosphere (photosphere and chromosphere) to the force-free corona. As nonlinear magnetohydrostatic modelling is computational way more expensive than a nonlinear force-free approach, it was important to investigate the details of this transition to find out above which height plasma effects can be neglected and where force-free computations are justified in lowest order. Further research in the framework of international collaborations was to use our magnetic field models to guide the analysis of spectroscopic observations in the solar interface region, e.g., to study heating and small scale eruptions.

Publications

• On the Extrapolation of Magnetohydrostatic Equilibria on the Sun, ApJ, 2018, 866, 130
  Zhu, X., & Wiegelmann, T.
  
• Testing magnetohydrostatic extrapolation with radiative MHD simulation of a solar flare, A&A, 2019, 631, 162
  Zhu, X., & Wiegelmann, T.
  
• Magnetohydrostatic modeling of AR11768 based on a SUN- RISE/IMaX vector magnetogram, A&A, 2020, 640, 103
  Zhu, X., Wiegelmann, T., Solanki, S. K.
  
• Preprocessing of vector magnetograms for magnetohydrostatic extrapolations, A&A, 2020, 644, 57
  Zhu, X., Wiegelmann, T., Inhester, B.