Numerical simulation of dark inflow in post–flare supra–arcade

ANDREA COSTA, SERGIO ELASKAR, CARLOS A. FERNÁNDEZ, GUADALUPE MARTÍNEZ

ASTRONOMY AND ASTROPHYSICS

EDP Sciences

Lugar: Les Ulis - Francia; Año: 2009

0004-6361

Context. We integrate the MHD ideal equations to simulate dark tadpole–like sunward moving structures in post–flare supra–arcades.Aims. We study the onset and evolution of the internal plasma instability to compare with observational tadpole structures and to gaininsight into physical processes and characteristic parameters of these structures.Methods. The numerical approach uses a finite-volume Harten-Yee TVD scheme to integrate the 1D1/2 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 line of sight direction.Results. For the first time, we numerically reproduce observational dark inflows described in Verwichte et al. (2005).Conclusions. We show that the dark tracks are produced by plasma vacuum generated upstream a slow magnetoacoustic shock waveproduced by a localized deposition of energy modeled with a pressure perturbation. The same perturbation produces a transverse to the field or perpendicular magnetic shock giving rise to the kink–like plasma voids structures, with the same functional sunward decreasing amplitude and constancy with height of the period, as those determined by the observations.