ELASKAR sergio Amado
Simulation of dark lanes in post-flare supra-arcades III. A 2D simulation
MAGLIONE, LIVIO; SCHNEITER, E. M; COSTA, ANDREA; ELASKAR, SERGIO
ASTRONOMY AND ASTROPHYSICS
EDP SCIENCES S A
Año: 2011 vol. 527 p. 5 - 10
Context. Using two simulations of 1.5D, for the first time, in Costa et al. (2009) and Shulz et al. (2010) we numerically reproduce theobservational dark inflows described in Verwichte et al. (2005). We show that the dark tracks can be explained as hot plasma vacuumsgenerated upstream of a slow magnetoacoustic shock wave produced by a localized deposition of energy.Aims. To confirm the later ?dark lane? interpretation and to identify specific 2D contributions to the description of the phenomenon.Methods. To solve the ideal and non?stationary MHD equations we used a 2D Riemann solver Eulerian code specially designed tocapture supersonic flow discontinuities.Results. The numerical 2D results are in agreement with the observational behaviour however they show a slight shift in the charac-teristic parameter with respect to those found previously.Conclusions. We confirm qualitatively the behaviour found in the previous papers. For a given numerical domain the period of thekink?like structure is a function of the magnetic field intensity: larger periods are associated with lower magnetic field intensities.Contrary to the 1D result -where the sunward dynamic is independent of the magnetic field intensity due to its exclusively waveguiderole- in the 2D simulation the sunward speed is larger for larger values of the magnetic field. This can be interpreted as the capabilityof the low coronal plasma to collimate the deposition of energy into the magnetic field direction. The moving features consistentof low?density and high?temperature plasma cavities have larger inside values of the structuring parameter β than the neighboringmedia. Thus, the voids seem to be the emergence structures of a whole nonlinear interacting plasma context of shocks and wavesmore than voided plasma loops magnetically structured.