Numerical Experiments of Wave-Like Phenomena Caused by the Disruption of an Unstable Magnetic Configuration

Abstract

The origin of the Moreton wave observed in the chromosphere and the EIT wave observed in the corona during the eruption remains being an active research subject for a while. We investigate numerically in this work the evolutionary features of the magnetic configuration that includes a current-carrying flux rope, which is used to model the filament, after the loss of equilibrium in the system takes place in a catastrophic fashion. Rapid motions of the flux rope following the catastrophe invokes the velocity vortices behind the rope, and may invoke as well slow and fast mode shocks in front of the rope. The velocity vortices at each side of the flux rope propagate roughly horizontally away from the area where it is produced, and both shocks expand toward the flank of the flux rope. The fast one may eventually reach the bottom boundary and produces two echoes moving back into the corona, but the slow one and the vortices totally decay somewhere in the lower corona before arriving the bottom boundary. The interaction of the fast shock with the boundary leads to disturbance that accounts for the Moreton wave observed in Hα, and the disturbance in the corona caused by the slow shock and the velocity vortices should account for the EIT wave whose speed is about 40% that of the Moreton wave. Implication of these results to the observed correlation of the type II radio burst to the fast and the slow mode shocks, and that of EIT waves to CMEs and flares have also been discussed.

Large-scale Globally Propagating Coronal Waves

“…In these events, the apex of the dome could be traced to heights beyond one solar radius. Such wave domes have been predicted by numerical simulations of fast-mode waves or shocks (e.g., Uchida, 1968;Wang et al, 2009;Afanasyev and Uralov, 2011;Selwa et al, 2012;Downs et al, 2012, see Section 6.1). Harra and Sterling (2003) first reported evidence for two distinct wavefronts in an event observed with TRACE.…”

“…MHD simulations, fast-mode waves that were launched by eruptions were found to be consistent with many aspects of coronal EUV waves (e.g., Wang, 2000;Wu et al, 2001Wu et al, , 2005Pomoell et al, 2008;Wang et al, 2009;Cohen et al, 2009;Schmidt and Ofman, 2010, see middle panel in Figure 41 for an example). Of course, the results of numerical models must be interpreted with care, since all of them have to make some simplifying assumptions.…”

Large-scale Bright Fronts in the Solar Corona: A Review of “EIT waves”

“…It appears from this and other work (e.g., Zhukov & Auchère 2004) that both wave and non-wave models may be required to explain the observational properties of CBFs. The simulations of Wang et al (2009) introduce an additional degree of complexity to the wave versus non-wave argument. Rapid motions of the erupting flux rope in their simulations produce velocity vortices behind the rope, together with slow-and fast-mode shocks in front of the rope (see Figure 19).…”

SDO/AIA and Hinode/EIS observations of interaction between an EUV wave and active region loops

“…Such bright signal might be the result of the AR loop oscillation. Previously, propagating disturbances in AR loops were reported by many researchers (e.g., De Moortel et al 2000;Wang et al 2009a;McIntosh & De Pontieu 2009;Tian et al 2011). Such propagating disturbances were similar to our observed disturbance except that they were periodic.…”

“…Several models have been proposed that can be grouped into wave, non-wave and hybrid wave interpretations. The wave interpretation considers that EUV waves are real waves, including fast-mode magnetohydrodynamic (MHD) waves or shock waves (e.g., Wang 2000;Wu 2001;Schmidt & Ofman 2010), slow-mode MHD waves (Wang et al 2009a) and soliton waves (Wills-Davey et al 2007). Among them, the fast-mode MHD wave model is the most popular and supported by many observations (Warmuth et al 2001;Veronig et al 2008;Kienreich et al 2009;Gopalswamy et al 2009;Patsourakos & Vourlidas 2009;Liu et al 2011;Zheng et al 2011;Asai et al 2012).…”