Estimating the Rate of Field Line Braiding in the Solar Corona by Photospheric Flows

Simon Candelaresi (Lead / Corresponding author), David Pontin, Anthony R. Yeates, P J Bushby, Gunnar Hornig

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)
141 Downloads (Pure)


In this paper, we seek to understand the timescale in which the photospheric motions on the Sun braid coronal magnetic field lines. This is a crucial ingredient for determining the viability of the braiding mechanism for explaining the high temperatures observed in the corona. We study the topological complexity induced in the coronal magnetic field, primarily using plasma motions extracted from magneto-convection simulations. This topological complexity is quantified using the field line winding, finite time topological entropy (FTTE), and passive scalar mixing. With these measures, we contrast mixing efficiencies of the magneto-convection simulation, a benchmark flow known as a "blinking vortex", and finally photospheric flows inferred from sequences of observed magnetograms using local correlation tracking. While the highly resolved magneto-convection simulations induce a strong degree of field line winding and FTTE, the values obtained from the observations from the plage region are around an order of magnitude smaller. This behavior is carried over to the FTTE. Nevertheless, the results suggest that the photospheric motions induce complex tangling of the coronal field on a timescale of hours.

Original languageEnglish
Article number157
Number of pages9
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 12 Sept 2018


  • chaos
  • convection
  • hydrodynamics
  • Sun: magnetic fields
  • Sun: photosphere
  • turbulence

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Estimating the Rate of Field Line Braiding in the Solar Corona by Photospheric Flows'. Together they form a unique fingerprint.

Cite this