We present the Solar Dynamics Observatory observations of two flux ropes respectively tracked out by material from a surge and a failed filament eruption on 2012 July 29 and August 04 .
For the first event , the interaction between the erupting surge and a loop-shaped filament in the east seems to “ peel off ” the filament and add bright mass into the flux rope body .
The second event is associated with a C-class flare that occurs several minutes before the filament activation .
The two flux ropes are respectively composed of 85 \pm 12 and 102 \pm 15 fine-scale structures , with an average width of about 1 \arcsec .6 .
Our observations show that two extreme ends of the flux rope are rooted in the opposite polarity fields and each end is composed of multiple footpoints ( FPs ) of the fine-scale structures .
The FPs of the fine-scale structures are located at network magnetic fields , with magnetic fluxes from 5.6 \times 10 ^ { 18 } Mx to 8.6 \times 10 ^ { 19 } Mx .
Moreover , almost half of the FPs show converging motion of smaller magnetic structures over 10 hr before the appearance of the flux rope .
By calculating the magnetic fields of the FPs , we deduce that the two flux ropes occupy at least 4.3 \times 10 ^ { 20 } Mx and 7.6 \times 10 ^ { 20 } Mx magnetic fluxes , respectively .