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Numerical simulation of dark lanes in post-flare supra-arcade
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andrea costa Submitted: 2009-10-02 17:14
We integrate the MHD ideal equations to simulate dark void sun wardly moving structures in post-flare supra-arcades. We study the onset and evolution of the internal plasma instability to
compare with observations and to gain insight into physical processes and characteristic parameters
of these phenomena. The numerical approach uses a finite-volume Harten-Yee TVD scheme to integrate the 1D½ MHD equations specially designed to capture supersonic flow discontinuities.
The integration is performed in both directions, the sunward radial one and the transverse to the
magnetic field. For the first time, we numerically reproduce observational dark voids described
in Verwichte et al. (2005). We show that the dark tracks are plasma vacuums generated by the
bouncing and interfering of shocks and expansion waves, upstream an initial slow magnetoacoustic
shock produced by a localized deposition of energy modeled with a pressure perturbation. The same
pressure perturbation produces a transverse to the field or perpendicular magnetic shock giving rise
to nonlinear waves that compose the kink-like plasma void structures, with the same functional
sunward decreasing phase speed and constancy with height of the period, as those determined by
the observations.
Authors: Costa, Andrea, Elaskar, Sergio, Fernández, Carlos, Martínez, Guadalupe
Projects: TRACE
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Publication Status: Accepted MNRAS
Last Modified: 2009-10-05 09:42
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