Analysis of 20 magnetic clouds at 1 AU during a solar minimum

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

La Plata, Buenos Aires, Argentina

Congreso; 48 Reunión de la Asociación Argentina de Astronomía; 2005

We study 20 magnetic clouds, observed in situ by thespacecraft Wind, at the Lagrangian point L1, from 22 August, 1995,to 7 November, 1997. In previous works, assuming a cylindrical symmetryfor the local magnetic configuration and a satellite trajectorycrossing the axis of the cloud, we obtained their orientations usinga minimum variance analysis. In this work we compute the orientationsand magnetic configurations using a non-linear simultaneous fitof the geometric and physical parameters for a linear force-free model,including the possibility of a not null impact parameter. We quantifyglobal magnitudes such as the relative magnetic helicity per unitlength and compare the values found with both methods (minimumvariance and the simultaneous fit).