Takashi Sakurai

The fine structure in solar filaments has been known to show the chiral nature depending on the hemisphere, and it is presumed to be a manifestation of the helicity in the magnetic field generated by the solar dynamo. To investigate the chirality of the filament magnetic field, we carried out a statistical study of the magnetic field orientation in solar filaments based on our daily full-Sun, full-Stokes spectropolarimetric observations with the He I 10830 line. The analysis of more than 400 filaments revealed that the average direction of the magnetic field in filaments generally deviates from their axis by 10-30 degrees, and the direction of the deviation strongly depends on the hemisphere where the filaments appear. This hemispheric pattern is consistent with the well-known chirality pattern of the fine structure seen in filaments, and for some of the filaments we can confirm that the magnetic field direction is parallel to their fine structure.