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Title: Slow rise and partial eruption of a double-decker filament. II. A double flux rope model

Force-free equilibria containing two vertically arranged magnetic flux ropes of like chirality and current direction are considered as a model for split filaments/prominences and filament-sigmoid systems. Such equilibria are constructed analytically through an extension of the methods developed in Titov and Démoulin and numerically through an evolutionary sequence including shear flows, flux emergence, and flux cancellation in the photospheric boundary. It is demonstrated that the analytical equilibria are stable if an external toroidal (shear) field component exceeding a threshold value is included. If this component decreases sufficiently, then both flux ropes turn unstable for conditions typical of solar active regions, with the lower rope typically becoming unstable first. Either both flux ropes erupt upward, or only the upper rope erupts while the lower rope reconnects with the ambient flux low in the corona and is destroyed. However, for shear field strengths staying somewhat above the threshold value, the configuration also admits evolutions which lead to partial eruptions with only the upper flux rope becoming unstable and the lower one remaining in place. This can be triggered by a transfer of flux and current from the lower to the upper rope, as suggested by the observations of a split filament inmore » Paper I. It can also result from tether-cutting reconnection with the ambient flux at the X-type structure between the flux ropes, which similarly influences their stability properties in opposite ways. This is demonstrated for the numerically constructed equilibrium.« less
Authors:
 [1] ; ; ; ;  [2] ;  [3] ; ;  [4]
  1. Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Strasse 24, D-14476 Potsdam (Germany)
  2. Predictive Science, Inc., San Diego, CA 92121 (United States)
  3. CAS Key Laboratory of Geospace Environment, University of Science and Technology of China, Hefei 230026 (China)
  4. Space Weather Research Laboratory, Center for Solar-Terrestrial Research, NJIT, Newark, NJ 07102 (United States)
Publication Date:
OSTI Identifier:
22365123
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 792; 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; CHIRALITY; CONFIGURATION; DATA; EQUILIBRIUM; ERUPTION; FILAMENTS; INSTABILITY; MAGNETIC FLUX; MAGNETOHYDRODYNAMICS; MASS; STABILITY; STAR EVOLUTION; SUN