By using the method presented by Isobe et al .
( 2002 ) , the non-dimensional reconnection rate v _ { in } / v _ { A } has been determined for the impulsive phase of three two-ribbon flares , where v _ { in } is the velocity of the reconnection inflow and v _ { A } is the Alfvén velocity .
The non-dimensional reconnection rate is important to make a constraint on the theoretical models of magnetic reconnection .
In order to reduce the uncertainty of the reconnection rate , it is important to determine the energy release rate of the flares from observational data as accurately as possible .
To this end , we have carried out one dimensional hydrodynamic simulations of a flare loop and synthesized the count rate detected by the soft X-ray telescope ( SXT ) aboard Yohkoh satellite .
We found that the time derivative of the thermal energy contents in a flare arcade derived from SXT data is smaller than the real energy release rate by a factor of 0.3 – 0.8 , depending on the loop length and the energy release rate .
The result of simulation is presented in the paper and used to calculate the reconnection rate .
We found that reconnection rate is 0.047 for the X2.3 flare on 2000 November 24 , 0.015 for the M3.7 flare on 2000 July 14 , and 0.071 for the C8.9 flare on 2000 November 16 .
These values are similar to that derived from the direct observation of the reconnection inflow by Yokoyama et al .
( 65 ) , and consistent with the fast reconnection models such as that of Petschek ( 41 ) .