DATA
The data are observations of the longitudinal magnetic
field of two large sunspots (AR NOAA 8375
and AR NOAA 8525) which were obtained at BBSO
on 1998 November 4 and 1999 May 05, respectively. During the
observations, the sunspots were located near the central meridian (AR
NOAA 8375 -- N18W06 and AR NOAA 8525 -- N18E02).
Clockwise twist of Halpha filaments around a sunspot in
AR NOAA 8375 implies positive helicity, while dark filaments and
fibrils in an AR NOAA 8525 indicate that the sunspot had a weak, but
noticeable counterclockwise twist (negative helicity).
©BBSO/NJIT Seminar on OCT 99, 2000