Can we determine the magnetic helicity sign of solar active regions from observations?

LUONI, M.L.; MANDRINI, C.H.; DÉMOULIN, P.; VAN DRIEL-GESZTELYI, L.; KHOVARI, ZS.

San Juan, Argentina

Congreso; 47 Reunión de la Asociación Argentina de Astronomía; 2004

Asociación Argentina de Astronomía

To improve space weather prediction it is important to know the characteristics of the solar active event responsable for the observed disturbances in the interplanetary (IP)medium. The comparison of the magnetic helicity sign of the active region (AR) and the interplanetary magnetic cloud, observed after a coronal mass ejection (CME), is a useful tool to link solar and interplanetary events. However, the determination of the coronal helicity sign requires the analysis of loop observations which is not promptly available (and, sometimes, non-conclusive), vector magnetograms that are not obtained in a routine way, and/or coronal magnetic field modeling. In this preliminary work, we show that it is possible to determine the magnetic helicity sign of an AR using only observations of the photospheric line of sight component of the magnetic field (Bl) during its emergence and early life-time stages.