Revivals of a Coronal Arch

The giant post-flare arch of 6 November 1980 revived 11 hr and 25 hr after its formation. Both these revivals were caused by two-ribbon flares with growing systems of loops. The first two brightenings of the arch were homologous events with brightness maxima moving upwards through the corona with rather constant speed; during all three brightenings the arch showed a velocity pattern with two components: a slow one (8-12 km⁻¹), related to the moving maxima of brightness, and a fast one (∼ 35 km s⁻¹), the source of which is unknown.