Analysis of large scale MHD magnitudes in radial expanding magnetic clouds

NAKWACKI M.S.; DASSO S.; MANDRINI C.H.; DÉMOULIN P.

JOURNAL OF ATMOSPHERIC AND SOLAR-TERRESTRIAL PHYSICS

Año: 2008 vol. 70 p. 1318 - 1326

1364-6826

Magnetic clouds (MCs) transport the magnetic flux and helicity released by the Sun.They are generally modeled as a static flux rope traveling in the solar wind, thoughthey can present signatures of expansion. We analyze three expanding MCs using aself-similar free radial expansion model with a cylindrical linear force-free field (i.e.Lundquist solution) as the initial condition. We derive expressions for the magneticfluxes, the magnetic helicity and the magnetic energy per unit length along the fluxtube. We find that these quantities do not differ more than 25% when using thestatic or expansion model.