Evolution of Magnetic Helicity During Eruptive Flares and Coronal Mass Ejections

E. R. Priest, D. W. Longcope, M. Janvier

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)


During eruptive solar flares and coronal mass ejections, a non-potential magnetic arcade with much excess magnetic energy goes unstable and reconnects. It produces a twisted erupting flux rope and leaves behind a sheared arcade of hot coronal loops. We suggest that the twist of the erupting flux rope can be determined from conservation of magnetic flux and magnetic helicity and equipartition of magnetic helicity. It depends on the geometry of the initial pre-eruptive structure. Two cases are considered, in the first of which a flux rope is not present initially but is created during the eruption by the reconnection. In the second case, a flux rope is present under the arcade in the pre-eruptive state, and the effect of the eruption and reconnection is to add an amount of magnetic helicity that depends on the fluxes of the rope and arcade and the geometry.

Original languageEnglish
Pages (from-to)2017-2036
Number of pages20
JournalSolar Physics
Issue number7
Publication statusPublished - 1 Aug 2016


  • Helicity
  • Magnetic reconnection
  • Sun: flares
  • Sun: magnetic topology

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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