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Observations of the horizontal velocity field surrounding sunspots

โœ Scribed by N. R. Sheeley

Publisher
Springer
Year
1972
Tongue
English
Weight
676 KB
Volume
25
Category
Article
ISSN
0038-0938

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โœฆ Synopsis

During the summer and fall of 1971, Doppler spectroheliograms were obtained for several sunspots located near the solar limb. These observations confirm a previous result based on the study of only a few sunspots that in the plage-free photosphere surrounding sunspots the spatiallyaveraged, horizontal flow tends to be outward at 0.5-1.0 km s -1 for distances typically 10000-20000 km beyond the outer boundary of the penumbra. It is suggested that these material motions are the means by which small-scale fragments of magnetic flux are carried away from sunspots.

๐Ÿ“œ SIMILAR VOLUMES

The oscillatory velocity field observed
The oscillatory velocity field observed in a unipolar sunspot region
โœ J. B. Rice; V. Gaizauskas ๐Ÿ“‚ Article ๐Ÿ“… 1973 ๐Ÿ› Springer ๐ŸŒ English โš– 640 KB

The velocity field has been mapped for 42 min in an area 80" by 85" containing a unipolar sunspot. Apparent shifts of Fe 1 2 5233 were measured photoelectrically using a rectangular scanning aperture 1.6" โ€ข 4.0". The sunspot did not exert a marked influence on the generally random pattern of oscilla

Observations of sunspot umbral velocity
Observations of sunspot umbral velocity oscillations
โœ Arvind Bhatnagar; W. C. Livingston; J. W. Harvey ๐Ÿ“‚ Article ๐Ÿ“… 1972 ๐Ÿ› Springer ๐ŸŒ English โš– 383 KB

Sunspot umbral molecular lines have been used to look for the oscillatory velocities in the umbra. Power spectrum analysis showed conspicuous power for periods in the range between 448 and 310 s. The maximum peak-to-peak amplitude of the umbral oscillatory velocity component is observed to be in the