We apply differential affine velocity estimator (DAVE) to the Solar Dynamics Observatory (SDO)/Helioseismic and Magnetic Imager (HMI) 12-min line-of-sight magnetograms, and separately cal- culate the injected magnetic helicity for the leading and the following polarities of nine emerging bipolar active regions (ARs). Comparing magnetic helicity ux of the leading polarity with the following polarity, we nd that six ARs studied in this paper have the following polarity that injected more magnetic helicity ux than that of the leading polarity. We also measure the mean area of each polarity in all the nine ARs, and nd that the compact polarity tend to possess more magnetic helicity ux than the fragmented one. Our results conrm the previous studies on asymmetry of magnetic helicity that emerging bipolar ARs have a polarity preference in injecting magnetic helicity. Based on the changes of unsigned magnetic ux, we divide the emergence process into two evolutionary stages: (1) an increasing stage before the peak ux and (2) a constant or decreasing stage after the peak ux. Obvious changes on magnetic helicity ux can be seen during transition from one stage to another. Seven ARs have one or both polarity that changed the sign of magnetic helicity ux. Additionally, the prevailing polarity of the two ARs, which injects more magnetic helicity, changes form the following polarity to the leading one.

A necessary condition for the formation of a filament is magnetic helicity. In the present paper we seek the origin of magnetic helicity of intermediate filaments. We observed the formation of a sinistral filament at the boundary of a decaying active region using full-disk Hα images obtained from Big Bear Solar Observatory. We have measured the rate of helicity injection during the formation of the filament using full-disk 96 minute-cadence magnetograms taken by SOHO MDI. As a result we found that 1) no significant helicity was injected around the region (polarity inversion line; PIL) of filament formation and 2) negative helicity was injected in the decaying active region. The negative sign of the injected helicity was opposite to that of the filament helicity. On the other hand, at earlier times when the associated active region emerged and grew, positive helicity was intensively injected. Our results suggest that the magnetic helicity of the intermediate filament may have originated from the helicity accumulated during the period of the growth of its associated active region.

Recently a big progress has been made on the measurements of magnetic helicity of solar active regions based on photospheric magnetograms . In this paper, we present the details of Chae's method of determining the rate of helicity transfer using line-of-sight magnetograms such as taken by SORO /MDI. The method is specifically applied to full-disk magnetograms that are routinely taken at 96-minute cadence.