The Motion of the Flare Loop prominence On April 27 in 1981

The asensional motion chracteristics and some initial results of the flare loop prominence which appeared above the sunspot group (B. R. 3049) on the western solar limb on April 27 in 1981 are given.The results show that the motion state and characteristics of the flare loop prominence had close relation to the variations in its brightness. The loop prominence constantly ascended and accelerated before the maximum brightness. The.maximum average velocity and acceleration were 17.5 km/sec and 0.023 km/sec² respectively. After the maximum brightness it decelerated. There was the expansional motion in the top part of the loop prominence, its maximum transverse expansion velocity was about 10.6km/sec, the expansion velocity decreased with the increase in the height, the demarcation between the expansional acceleration and the expansional deceleration was also nearby the maximum brightness.There was the radial motion in the top part and two legs of the loop prominence, the rotational motion in its two legs was in the same direction, the southern legs like a rigid body had the spiral motion.The correlation between the loop preminence and its corresponding active region is also brifely analysed.