Three Kinds of Optical Flow Technique: LCT, DAVE and DAVE4VM

Abstract

Abstract. Photospheric velocity field is an important parameter in studying solar eruptions. This parameter can be deduced by three kinds of optical flow techniques, i.e., LCT [1] , DAVE and DAVE4VM [2] . By using an example of active region (AR) NOAA 12017, we have compared the distribution of the velocity field and magnetic helicity transport rate which calculated from the velocity field by these three methods. It is found that, the velocity fields are very similar for the results from LCT and DAVE method, while much different for those from DAVE4VM. However, the helicity transport rates are in similar trend for the results from all methods.