New observational support for the role of magnetic field line braiding in solar coronal heating
Abstract
We present here new work that links models of magnetic field line braiding in coronal loops to observations of the photosphere and corona. We describe analysis of photospheric flows that quantifies the rate at which coronal magnetic field lines are braided. The results suggest that the photospheric motions induce complex tangling of the coronal field on a timescale of minutes to hours. New data from DKIST promises to further improve such estimates. Theoretical models show that this persistent tangling inevitably leads to the onset of reconnection and a turbulent heating of the plasma in the corona. We go on to describe synthetic emissions in a 3D magnetohydrodynamic model of the turbulent decay of an initially-braided magnetic field. We discuss how previously unexplained key features of observed emission line profiles in coronal loops - such as non-thermal widths and non-Gaussian profiles - are reproduced in the synthesised spectra.
- Publication:
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43rd COSPAR Scientific Assembly. Held 28 January - 4 February
- Pub Date:
- January 2021
- Bibcode:
- 2021cosp...43E1796P