Rayleigh-Taylor type instabilities in the reconnection exhaust jet as a mechanism for supra-arcade downflows in the sun

L. J. Guo, Y. M. Huang, A. Bhattacharjee, D. E. Innes

Research output: Contribution to journalArticlepeer-review

22 Scopus citations

Abstract

Supra-arcade downflows (hereafter referred to as SADs) are low-emission, elongated, finger-like features observed in active region coronae above post-eruption flare arcades. Observations exhibit downward moving SADs intertwined with bright upward growing spikes. Whereas SADs are dark voids, spikes are brighter, denser structures. Although SADs have been observed for more than a decade, the mechanism of the formation of SADs remains an open issue. Using three-dimensional resistive magnetohydrodynamic simulations, we demonstrate that Rayleigh - Taylor-type instabilities develop in the downstream region of a reconnecting current sheet. The instabilities result in the formation of low-density coherent structures that resemble SADs, and high-density structures that appear to be spike-like. Comparison between the simulation results and observations suggests that Rayleigh - Taylor-type instabilities in the exhaust of reconnecting current sheets provide a plausible mechanism for observed SADs.

Original languageEnglish (US)
Article numberL29
JournalAstrophysical Journal Letters
Volume796
Issue number2
DOIs
StatePublished - Dec 1 2014

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • Instabilities
  • Magnetic reconnection
  • Sun: flares

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