REVERSED-POLARITY STRUCTURES OF CHROMOSPHERIC MAGNETIC-FIELD

Reversed-polarity structures of chromospheric magnetic fields are magn etic gulfs and islands of opposite polarity relative to the underlying photospheric fields. In this paper data measured with the Solar Magne tic Field Telescope of the Huairou Solar Observing Station in Beijing were analyzed. From more than 300 pairs of photospheric magnetograms ( in Fe I lambda5324.19 angstrom) and relevant chromospheric magnetogram s (Hbeta lambda4861.34 angstrom), the reality of the reversed-polarity structures is demonstrated. According to an analysis of the fine stru cture of the magnetic field in the two layers of active regions, we fo und that there are probably four different types as follows: Type A: m agnetic islands of opposite polarity corresponding to photospheric fie lds appear in the chromospheric magnetogram. Type B: magnetic gulfs of opposite polarity corresponding to photospheric fields appear in the chromospheric magnetogram. Type C is the reverse of type B. That is, a magnetic gulf of opposite polarity corresponding to the chromospheric field appears in the photospheric magnetogram. Type D is the reverse of type A.