Direct measurements of the gradual extreme ultraviolet emission from large solar flares

Abstract

Broadband sensors aboard the Naval Research Laboratory's SOLRAD 11 satellites measured solar emission in the 0.5 to 3 A, 1 to 8 A, 8 to 20 A, 100 to 500 A, 500 to 800 A, and 700 to 1030 A bands. Data from sixteen large flares show that the EUV emission is dominated by gradual emission which parallels the soft X-ray emission in duration and magnitude. The data are consistent with the separation of EUV and X-ray flare emission into two distinct components. A persistent component is made up of gradual EUV and gradual soft X-ray emissions. A brief component consists of hard X-rays, impulsive soft X-rays, and impulsive EUV emission.