Gradual enhancements which repeatedly appeared 20-50 min after the onset of an impulsive burst were observed in microwaves and hard X-rays. The observed characteristics of the gradual enhancements are (i) the similarity of time profiles in both the frequency range of 17 GHz to 160 MHz and the energ
Gradual hard X-ray events and second phase particle acceleration
β Scribed by S. W. Kahler
- Publisher
- Springer
- Year
- 1984
- Tongue
- English
- Weight
- 464 KB
- Volume
- 90
- Category
- Article
- ISSN
- 0038-0938
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β¦ Synopsis
In the second phase acceleration process the close time coincidence between the gradual hard X-ray burst and the type II shock wave is presumed due to shock acceleration of the electrons producing the gradual phase burst. We point out that recent studies of gradual hard X-ray bursts place the source heights well below the heights of 2-10 x 103 km traversed by the shock. Gradual phase energetic electrons therefore cannot be accelerated in the shock but must be produced elsewhere. We propose the loop systems of long decay X-ray events (LDEs) as the sites of the gradual phase electron production.
π SIMILAR VOLUMES
Requirements for the number of nonthermal electrons which must be accelerated in the impulsive phase of a flare are reviewed. These are uncertain by two orders of magnitude depending on whether hard X-rays above 25 keV are produced primarily by hot thermal electron.,; which contain a small fraction
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