The Spray-Like Eruptive Prominence and Its Velocity Distribution on March 5,1991

An optical flare of 3N magnitude erupted at 0255 UT on the solar limb (S23°, E90°) on March 5,1991.It reached the maximum at 0312UT and ended at 0325UT.The active region in which the flare appeared is assigned by NOAA/USAF serial Number 6538.At 0320UT,a Spray—like eruptive prominence appeared at the place where the flare located, and the prominence was in company with the flare and disappeared at 0346UT.The scanning data of Hα spectral photographs and Hα filtergrams were obtained for the active event from 0255UT to 0346UT.The partial Hα filtergrams and the spectral scan pictures are given in Figure 1.#br#The eruptive duration of the prominence lased about 50 minutes.It ascended to a maximum project height of 15.9×10⁴km at 0330UT.The features of the prominence are found as follows: #br#a) The prominence coexisted with the active phenomena of flare, surge.It is probably induced by the flare and may be a complicated eruptive process in chromosphere;#br#b) There are some intermittences in project height during the ascending and descending (see Figure 3).It may be a reflection of expansion in the ascending.The interval between two intermittences is about 6 minutes;#br#c) The prominence moved towards the observer with a relative high veloctiy, the maximum velocity is 120 km/s, the velocity near the solar limb is higher and decreases gradually with the increase of the height (Figure 2).