Observations of solar X-ray bursts in the energy range 5–15 keV

✍ Scribed by D. W. Datlowe; H. S. Hudson; L. E. Peterson

• Publisher: Springer
• Year: 1974
• Tongue: English
• Weight: 737 KB
• Volume: 35
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00156967

✦ Synopsis

Bursts of solar X-rays in the energy range 5-15 keV are associated with flares and are due to thermal emission from a hot coronal plasma. In this paper we present the results of the first study of a large sample of separate bursts, 197 events associated with subftares and a few importance 1 events. The observations were made by a proportional counter on the satellite OSO-7 from October 1971 to June 1972. In most cases the temperature characterizing the X-ray spectrum rises impulsively at the onset of the burst and then declines slowly throughout the remainder of the burst. The emission measure rises exponentially with a time scale of 30-100 s and then declines slowly, on a time scale of the order of 103 s. From these observations we show that the growth of the thermal energy in the flare plasma throughout the burst can be due to the heating of new cool material.