Stationary parts of an EIT and Moreton wave: a topological model

¹ Royal Observatory of Belgium, Brussels, Belgium e-mail: ceaulanier@wanadoo.fr
² LESIA, Meudon observatory, Meudon, France

Received: 16 June 2006
Accepted: 30 August 2006

Abstract

Context.EIT and Moreton waves came into focus in 1997, when a propagating disturbance on a large area of the solar disc was discovered. The process generating the EIT and Moreton waves has been frequently discussed.

Aims.On May 2, 1998, a halo CME was observed related to an EIT wave, a Moreton wave, a X1 flare, radio emission sources, and dimmings. We studied this event to find the relation between all these structures.

Methods.We use and co-align multi-wavelength observations and the online potential field source surface (pfss) package.

Results.The observed EIT and Moreton waves present some brightenings that remain at the same location. We relate the connectivity of the coronal potential magnetic field to the stationary brightenings. We find that the areas where the magnetic field lines have drastic jumps of connectivity are cospatial to the stationary brightenings of the waves.

Conclusions.We conclude that the EIT and Moreton waves may be due to Joule heating resulting from the generation of electric currents in the neighboring area of the drastic jumps of magnetic connectivity, while the magnetic field lines are opening during a CME.