Multi-wavelength observations of an M 2.0 flare event on 2000 March 23 in NOAA active region 8910 provide us a good chance to study the detailed structure and dynamics of the magnetic reconnection region .
In the process of the flare , extreme ultraviolet ( EUV ) loops displayed two times of sideward motions upon a loop-top hard X-ray source with average velocities of 75 and 25.6 km s ^ { -1 } , respectively .
Meanwhile part of the loops disappeared and new post-flare loops formed .
We consider these two motions to be the observational evidence of reconnection inflow , and find an X-shaped structure upon the post-flare loops during the period of the second motion .
Two separations of the flare ribbons are associated with these two sideward motions , with average velocities of 3.3 and 1.3 km s ^ { -1 } , separately .
The sideward motions of the EUV loops and the separations of the flare ribbons are temporally consistent with two peaks of the X-ray flux .
This indicates that there are two times of magnetic reconnection in the process of the flare .
Using the observation of photospheric magnetic field , the velocities of the sideward motions and the separations , we deduce the corresponding coronal magnetic field strength to be about 13.2-15.2 G , and estimate the reconnection rates to be 0.05 and 0.02 for these two magnetic reconnection process , respectively .
Besides the sideward motions of EUV loops and the separations of flare ribbons , we also observe motions of bright points upward and downward along the EUV loops with velocities ranging from 45.4 to 556.7 km s ^ { -1 } , which are thought to be the plasmoids accelerated in the current sheet and ejected upward and downward when magnetic reconnection occurs and energy releases .
A cloud of bright material flowing outward from the loop-top hard X-ray source with an average velocity of 51 km s ^ { -1 } in the process of the flare may be accelerated by the tension force of the newly reconnected magnetic field lines .
All the observations can be explained by schematic diagrams of magnetic reconnection .