CME-related dimmings as a signature of interplanetary magnetic cloud footpoints

MANDRINI, C.H.; NAKWACKI, M.S.; ATTRILL, G.; VAN DRIEL-GESZTELYI, L.; DASSO, S.; DÉMOULIN, P.

Montreal

Congreso; 37th COSPAR Scientific Assembly; 2008

COSPAR

Coronal dimmings are often present on both sides of erupting magnetic configurations. It has been suggested that dimmings mark the location of the footpoints of ejected flux ropes and, thus, their magnetic flux can be used as a proxy for the flux involved in the ejection. If so, this quantity can be compared to the flux in the associated interplanetary magnetic cloud to find clues about the origin of the ejected flux rope. In the context of this physical interpretation, we analyse several events, flares and coronal mass ejections (CMEs), for which we can find their interplanetary counterpart. We combine SOHO/Extreme Ultraviolet Imaging Telescope data and Michelson Doppler Imager magnetic maps to identify and measure the flux in the dimming regions. We model the associated clouds and compute their magnetic flux using in situ observations. We find that the magnetic fluxes of the dimmings and magnetic clouds are compatible in some cases; though this is not the case for large-scale events and eruptions that occur in regions that are not isolated from other flux concentrations. We conclude that the interpretation of dimmings requires a deeper analysis of the global magnetic field configuration, since at least a fraction of the dimmed regions could be formed by reconnection between the erupting field and the surrounding magnetic structures.