一个拱桥状爆发日珥的运动情况

Movement of an Arch-like Eruptive Prominence

分析了1991年3月7日太阳东北边缘一个拱桥状爆发日珥上升、下降和半径膨胀的运动情况。该日珥的上升阶段和下降的开始阶段高度随时间的变化比较迅速,而且基本是线性的变化,但在下降的结束阶段则比较缓慢,也基本是线性的变化。它的下降运动不仅受到重力作用自由下落,而且还受到不均匀的大气阻力,磁场等力的共同作用而下落。而速度,喷射出以后总的在逐渐减弱,上升阶段减弱较快。下降阶段初期有一次跳跃式的变化,先迅速减弱,然后又很快增加,在下降后期速度减弱较慢。日珥到达最大高度的时间比日珥半径膨胀到达最大尺度的时间早4min左右。上升下降速度最大时半径膨胀速度最小,而上升下降速度最小时半径膨胀的速度最大。

The motions of ascending, descending and expanding in radius of an arch-like eruptive prominence are analyzed in this paper.The variations of the height of the prominence versus time were relative fast during the stages of its ascending and the beginning of the descending,and were linear basically.But the height variation was slow and linear basically during the end stage of its descending.The prominence did not free fall down under the action of gravity,it falled down under an united actions of not only the gravity but also inhomogeneous atmospheric resistance and magnetic force.The ejection velocity of the prominence weaken gradually,it weaken rapidly during its ascending.However,during the descending there was a leap-like change: the velocity decreased rapidly at first,then increased fast,during the late stage of descending it decreased slowly.The time when the prominence ascended to its maximum height was earlier about 4 minutes than that time while the radius of prominence expanded to the maximum.The expanding velocity of its radius reached the minimum when the ascending or descending velocity was in the maximum and vice versa.