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The umbral flash as a magneto-acoustic wave phenomenon

โœ Scribed by Ove Havnes

Book ID
104645273
Publisher
Springer
Year
1970
Tongue
English
Weight
388 KB
Volume
13
Category
Article
ISSN
0038-0938

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โœฆ Synopsis

The suggestion that an 'umbra flash' may be caused by a magneto-acoustic wave phenomenon is examined. It is suggested that the flash in Call lines is formed during the compressional stage in a magneto-acoustic wave. The compression which is assumed to be adiabatic will produce a rise in temperature and a corresponding increase in number of CaiI atoms. The variations in line emission (absorption) coefficient of the Cali K-line are calculated on this assumption and are found to be in general agreement with the observed variations. Other observed quantities as proper motion, magnitude of line shift etc., also agree with the wave hypothesis. Further observations which may serve as tests on the wave hypothesis are suggested.

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