The link between CME-associated dimmings and interplanetary magnetic clouds

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

Universal Heliophysical Processes

Cambridge University Press

Año: 2009; p. 265 - 270

Coronal dimmings often develop in the vicinity of erupting magnetic configurations.It has been suggested that they mark the location of the footpoints of ejected flux ropes and,thus, their magnetic flux can be used as a proxy for the ejected flux. If so, this quantity can becompared to the flux in the associated interplanetary magnetic cloud (MC) to find clues aboutthe origin of the ejected flux rope. In the context of this interpretation, we present several eventsfor which we have done a comparative solar-interplanetary analysis.We combine SOHO/ExtremeUltraviolet Imaging Telescope (EIT) data and Michelson Doppler Imager (MDI) magnetic mapsto identify and measure the flux in the dimmed regions. We model the associated MCs andcompute their magnetic flux using in situ observations. We find that the magnetic fluxes in thedimmings and MCs are compatible in some events; though this is not the case for large-scale andintense eruptions that occur in regions that are not isolated from others. We conclude that, inthese particular cases, a fraction of the dimmed regions can be formed by reconnection betweenthe erupting field and the surrounding magnetic structures, via a stepping process that can alsoexplain other CME associated events.