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The flares of August 1972Observations of the August, 1972 flares at Big Bear and Tel Aviv, involving monochromatic movies, magnetograms, and spectra, are analyzed. The region (McMath 11976) showed inverted polarity from its inception on July 11; the great activity was due to extremely high shear and gradients in the magnetic field, as well as a constant invasion of one polarity into the opposite; observations in lambda 3835 show remarkable fast flashes in the impulsive flare of 18:38 UT on Aug. 2 with lifetimes of 5 sec, which may be due to dumping of particles in the lower chromosphere. Flare loops show evolutionary increases of their tilts to the neutral line in the flares of Aug. 4 and 7. Spectroscopic observations show red asymmetry and red shift of the H alpha emission in the flash phase of the Aug. 7 flare, as well as substantial velocity shear in the photosphere during the flare, somewhat like earthquake movement along a fault. Finally the total H alpha emission of the Aug. 7 flare could be measured accurately as about 2.5 x 10 to the 30th power erg, considerably less than coarser previous estimates for great flares.
Document ID
19740033094
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Zirin, H.
Tanaka, K.
(Big Bear Solar Observatory Washington, D.C., United States)
Date Acquired
August 7, 2013
Publication Date
September 1, 1973
Publication Information
Publication: Solar Physics
Volume: 32
Subject Category
Space Radiation
Accession Number
74A15844
Funding Number(s)
CONTRACT_GRANT: NSF GA-24015
CONTRACT_GRANT: F19628-73-C-0085
CONTRACT_GRANT: NGR-05-002-034
Distribution Limits
Public
Copyright
Other

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