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Title: RAYLEIGH-TAYLOR TYPE INSTABILITIES IN THE RECONNECTION EXHAUST JET AS A MECHANISM FOR SUPRA-ARCADE DOWNFLOWS IN THE SUN

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.
Authors:
; ;  [1] ;  [2]
  1. Space Science Center, University of New Hampshire, Durham, NH 03824 (United States)
  2. Max Planck/Princeton Center for Plasma Physics, Princeton, NJ 08540 (United States)
Publication Date:
OSTI Identifier:
22364885
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 796; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; COMPARATIVE EVALUATIONS; COMPUTERIZED SIMULATION; DENSITY; JETS; MAGNETIC RECONNECTION; RAYLEIGH-TAYLOR INSTABILITY; SOLAR CORONA; STAR EVOLUTION; SUN; THREE-DIMENSIONAL CALCULATIONS