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Steady flows in the chromosphere and transition-zone above active regions as observed by OSO-8Two years of data from the University of Colorado ultraviolet spectrometer aboard OSO-8 were searched for steady line-of-sight flows in the chromosphere and transition-zone above active regions. The most conspicuous pattern that emerges from this data set is that many sunspots show persistent blueshifts of transition-zone lines indicating velocities of about 20 km/s with respect to the surrounding plage areas. The data show much smaller shifts in ultraviolet emission lines arising from the chromosphere: the shifts are frequently to the blue, but sometimes redshifts do occur. Plage areas often show a redshift of the transition-zone lines relative to the surrounding quiet areas, and a strong gradient of the vertical component of the velocity is evident in many plages. One area of persistent blueshift was observed in the transition-zone above an active region filament. The energy requirement of these steady flows over sunspots is discussed.
Document ID
19810035480
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Lites, B. W. (Colorado, University Boulder, Colo., United States)
Date Acquired
August 11, 2013
Publication Date
December 1, 1980
Publication Information
Publication: Solar Physics
Volume: 68
Subject Category
SOLAR PHYSICS
Funding Number(s)
CONTRACT_GRANT: NAS5-11363
Distribution Limits
Public
Copyright
Other