Tracking a magnetic flux tube: from the Sun to the interplanetary medium

M. S. NAKWACKI; DASSO, S.; DÉMOULIN, P.; MANDRINI, C. H.; GULISANO, A. M.

Mar del Plata

Congreso; 55va Reunión Anual de la Asociación Argentina de Astronomía; 2012

The interplanetary medium is filled with a low density plasma, thesolar wind, that flows from the Sun. This wind transports the magneticstructures that are ejected from the solar corona (e.g. coronal mass ejec-tions, CMEs). We study from a theoretical and observational point of viewsome aspects of the evolution of a particular CME in the interplanetarymedium, a magnetic cloud observed in 1998 at 1 astronomical unit (AU)and at 5.4 AU. We model the dynamical evolution of this event based on amagnetohydrodynamic description of the plasma proposing a self similarevolution with different expansion rates in each of their main directions.We quantify their expansion and we compute the global invariant quan-tities (flux, magnetic helicity and magnetic energy) that are relevant to acombined analysis of solar events and their interplanetary counterparts.From solar observations of the sources, we quantify the magnetic flux in-volved in the ejection and the magnetic helicity variation of the sourceactive region. We follow the evolution of the above mentioned MC fromits solar source, until farther than 5 AU providing an interpretation forthe distorsion of the structure due to its interaction with the solar windfar from the Sun.