Confined and ejective eruptions of kink-unstable flux ropes |
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Tibor Toeroek Submitted: 2005-07-13 09:20
The ideal helical kink instability of a force-free coronal magnetic flux
rope, anchored in the photosphere, is studied as a model for solar
eruptions. Using the flux rope model of Titov and Démoulin (1999) as the initial
condition in MHD simulations, both the development of helical shape and
the rise profile of a confined (or failed) filament eruption (on 2002 May
27) are reproduced in excellent agreement with the observations. By
modifying the model such that the magnetic field decreases more rapidly
with height above the photosphere, a full (or ejective) eruption of the
flux rope is obtained in excellent agreement with the developing helical
shape and the exponential-to-linear rise profile of a fast coronal mass
ejection (CME) (on 2001 May 15). This confirms that the helical kink
instability of a twisted magnetic flux rope can be the mechanism of the
initiation and the initial driver of solar eruptions. The agreement of
the simulations with properties that are characteristic of many eruptions
suggests that they are often triggered by the kink instability. The
decrease of the overlying field with height is a main factor in deciding
whether the instability leads to a confined event or to a CME.
Authors: Tibor Toeroek and Bernhard Kliem
Projects: None
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Publication Status: ApJL (submitted)
Last Modified: 2005-07-13 09:20
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