Statistical analysis of magnetic twist properties of ARs from magnetic tongues

POISSON, M.; LÓPEZ FUENTES, M.C.; MANDRINI, C.H.; DÉMOULIN, P.

Cuzco

Congreso; X Conferencia Latinoamericana de Geofísica Espacial; 2014

Asociación Latinoamericana de Geofísica Espacial - International Space Weather Initiative

We analyze the distribution of the magnetic helicity properties of almost 200 active regions (ARs) during one and a half solar cycles (full Cycle 23 and half Cycle 24). We base our study in the magnetic twist inferred from the observed effects of magnetic tongues in SOHO/MDI photospheric magnetograms of bipolar ARs. Magnetic tongues are produced by the photospheric projection of the azimuthal component of the magnetic field around the axis of the emerging twisted flux-tubes that form ARs. We use a recently developed technique to characterize the tongues that is based in the computation of the polarity inversion line of the regions (see also the oral presentation "Active regions twist from magnetic tongues and force-free coronal models" by López Fuentes et al., in this meeting). We analyze if the the degree of twist of ARs is cycle dependent and if it is related to other AR properties, such as the maximum magnetic flux and their latitude. We also compare our results with other known helicity properties of ARs from the literature. We discuss our results in the frame of the mechanisms of magnetic field and helicity generation in the Sun and the observed distribution of activity events such as flares and coronal mass ejections along the cycle.