Helicity-conserving relaxation in unstable and merging twisted magnetic flux ropes

Philippa K. Browning, Mykola Gordovskyy, Alan W. Hood

Research output: Chapter in Book/Report/Conference proceedingChapter


Twisted magnetic flux ropes are reservoirs of free magnetic energy. In a highly conducting plasma such as the solar corona, energy release through multiple magnetic reconnections can be modeled as a helicity-conserving relaxation to a minimum energy state. One possible trigger for this relaxation is the ideal kink instability in a twisted flux rope. We show that this provides a good description for confined solar flares and we develop the approach from idealized cylindrical models to realistic models of coronal loops. Using 3D magnetohydrodynamic simulations combined with test-particle simulations of nonthermal electrons and ions, we predict multiple observational signatures of such flares. We then show how interactions and mergers of flux ropes can release free magnetic energy, using relaxation theory to complement simulations of merging-compression formation in spherical tokamaks and heating avalanches in the solar corona.

Original languageEnglish
Title of host publicationHelicities in geophysics, astrophysics, and beyond
EditorsKirill Kuzanyan, Nobumitsu Yokoi, Manolis K. Georgoulis, Rodion Stepanov
Place of PublicationHoboken, NJ
Number of pages14
ISBN (Electronic)9781119841715
ISBN (Print)9781119841685
Publication statusPublished - 15 Dec 2023

Publication series

NameGeophysical monograph series


  • Flux ropes
  • Helicity
  • Relaxation
  • Solar flares


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