Ejection and descent of matter in the solar atmosphere

Abstract

The descent and ejection of matter in the solar atmosphere observed in the CaII 8498-A line have been studied. In the NOAA active region no. 10 792 on July 30, 2005 before the flare, the dense cold gas cloud descended with a ray velocity of ∼8 km/s and then ascended in the impulsive phase. The plasma ascended with an acceleration reaching 0.4 km/s2 in the flare maximum. The acceleration of the matter likely continued after the flare maximum, because an acceleration of higher than 0.5 km/s2 was required for the appearance of the ejection at the edge of the occulting disk of the LASCO C2 coronagraph at 0557 UT. The descent of the matter resulting in the local heating of the chromosphere was also observed in the NOAA active region no. 10656 on August 9, 2004 before the flare. The maximum descent velocity was no more than 24.7 km/s.