Shock heating in numerical simulations of kink-unstable coronal loops

M. R. Bareford*, A. W. Hood

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)
12 Downloads (Pure)

Abstract

An analysis of the importance of shock heating within coronal magnetic fields has hitherto been a neglected area of study. We present new results obtained from nonlinear magnetohydrodynamic simulations of straight coronal loops. This work shows how the energy released from the magnetic field, following an ideal instability, can be converted into thermal energy, thereby heating the solar corona. Fast dissipation of magnetic energy is necessary for coronal heating and this requirement is compatible with the time scales associated with ideal instabilities. Therefore, we choose an initial loop configuration that is susceptible to the fast-growing kink, an instability that is likely to be created by convectively driven vortices, occurring where the loop field intersects the photosphere (i.e. the loop footpoints). The large-scale deformation of the field caused by the kinking creates the conditions for the formation of strong current sheets and magnetic reconnection, which have previously been considered as sites of heating, under the assumption of an enhanced resistivity. However, our simulations indicate that slow mode shocks are the primary heating mechanism, since, as well as creating current sheets, magnetic reconnection also generates plasma flows that are faster than the slow magnetoacoustic wave speed.
Original languageEnglish
Article number20140266
Pages (from-to)1-14
Number of pages14
JournalPhilosophical Transactions of the Royal Society. A, Mathematical, Physical and Engineering Sciences
Volume373
Issue number2042
Early online date28 May 2015
DOIs
Publication statusPublished - May 2015

Keywords

  • Coronal heating
  • Magnetic kink instability
  • Slow mode shocks

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