Study of the duration of the solar flare of the 23 and 24 solar cycles

Studying solar flares and their characteristics is significant for understanding the dynamics of the sun. In this work, a new view for studying the  duration time of solar flares is presented. Regarding the analysis of the duration time, one of the solar flares parameters is introduced for the solar cycles 23 and 24. This is done by ordering the duration time of solar flares into five groups of minutes (<30, 30-60, 60 90, 90-120, >120) and calculating the total annual duration time of solar flares for each group. The total annual duration time is also calculated for each class of solar flare classification (B, C, M, X). Their relationship with both F10.7 and Kp-index are also studied. We found that approximately 41% of solar flares occur within 6-12 minutes for both solar cycles. Additionally, the total average of their duration time is 19.1 and 19.6 minutes, respectively.Also, the average duration time of the ascending phase is less than the descending phase of both  solar cycles for all classes of solar flares, except for B-class, which is vice versa. The relationship between the duration time of solar  flares with F10.7 is strong. In contrast, the relationship with the Earth’s magnetic field is weak.