Observation of a New Type of Flare

Abstract

The importance of chromospheric flares from both the astrophysical and geophysical points of view is now generally recognized, but, in spite of the extensive observational material collected by Ellison, Dodson, and others, it must be admitted that the mechanism of their origin is still little understood. In this paper we present observations of a hitherto unobserved phenomenon, namely, the ejection of a mass of very bright material from a flare some 28° from the limb of the Sun. The ejection occurred several minutes before flare maximum. It was approximately 10,000 by 30,000 km in size and moved outwards with a velocity across the line-of-sight of 300 km/sec. As it did so, it brightened appreciably, reaching maximum intensity 3½ min after expulsion, its height then being 25,000 km. The ejection was quite unlike the dark surge prominences often emitted from flares, and in fact, except for its motion, possessed all the properties of a small flare.