Talk abstract

We simulated a fast expanding twisted flux rope. We found that around the flux rope a current shell develops that propagates ahead of the flux rope at velocities, at first time, much less than the ambient Alfvèn speed and, at later time, much faster than the ambient Alfvèn speed. The integration along the line of sight of this current shell is compared to propagating coronal waves and show very similar properties with the laters. However very few examples of coronal wave are fully moving: some brightenings produced during their propagation lay for several 10s of minutes. The locations of those stationary brightenings match the locations of the magnetic field (quasi-)spearatrixes. We therefore believe that the coronal waves are not magnetosonic waves but the manifestations of the pertubation of the coronal magnetic field during CMEs.