Magnetic field twisting by intergranular downdrafts

Youra Taroyan, Thomas Williams

Research output: Contribution to journalArticlepeer-review

4 Citations (SciVal)
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Abstract

The interaction of an intergranular downdraft with an embedded vertical magnetic field is examined. It is demonstrated that the downdraft may couple to small magnetic twists leading to an instability. The descending plasma exponentially amplifies the magnetic twists when it decelerates with depth due to increasing density. Most efficient amplification is found in the vicinity of the level, where the kinetic energy density of the downdraft reaches equipartition with the magnetic energy density. Continual extraction of energy from the decelerating plasma and growth in the total azimuthal energy occurs as a consequence of the wave-flow coupling along the downdraft. The presented mechanism may drive vortices and torsional motions that have been detected between granules and in simulations of magnetoconvection.
Original languageEnglish
Article number107
Pages (from-to)1-11
Number of pages11
JournalAstrophysical Journal
Volume829
Issue number2
Early online date28 Sept 2016
DOIs
Publication statusPublished - 01 Oct 2016

Keywords

  • instabilities
  • magnetohydrodynamics (MHD)
  • Sun: granulation
  • Sun: interior
  • Sun: magnetic fields
  • Sun: photosphere

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