Magnetic clouds properties at 1AU: Analysis using different models

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

Río de Janeiro

Simposio; 11th Quadrienial Solar Terrestrial Physics Symposium - CAWSES; 2006

SCOSTEP

Interplanetary Magnetic Clouds (MCs) are a particular kind of solar ejecta that travel through the interplanetary medium, modifying the solar wind conditions. At 1 AU, MCs present an intense magnetic field (higher than the sorrounding one), a large and coherent rotation (along approximately one day), and a lower (than the typical solar wind) proton temperature. In this work we present a study of 20 MCs, observed by the Wind spacecraft during a solar minimum from August 22, 1995 to November 7, 1997. We reconstruct the 3D structure of the clouds from in situ magnetic data (in 1D) assuming a cylindrical symmetry and a given model for their magnetic configuration. We use two force free and two non-force free models to carry out our study. We follow two procedures to determine the orientation for the clouds and the physical parameters. From the fitted parameters we estimate their large scale magnetic helicity per unit length and their magnetic fluxes.