The Magnetic Helicity Sign from Flux Emergence

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

Mérida

Conferencia; VIII Conferencia Latinoamericana de Geofísica Espacial (VIII COLAGE); 2007

Asociación Latinoamericana de Geofísica Espacial

Recent studies have suggested that active regions containing X-ray sigmoidal structures are more likely to produce eruptive events. These events eject huge amounts of plasma and magnetic field into the interplanetary medium and can affect the Earth magnetosphere. The shape of soft X-ray sigmoids is associated with the sign of the active region magnetic helicity. In this work, we discuss how photospheric magnetic field observations can be used to predictthe magnetic helicity sign of an active region. We use coronal observations of sigmoidal structure to confirm our helicity sign prediction. Since the magnetic helicity sign has been often used to identify the source region of an interplanetary event, our study provides a useful tool to determine this sign from the first appearance of the flux concentration forming an active region.