The oscillatory velocity field observed in a unipolar sunspot region

✍ Scribed by J. B. Rice; V. Gaizauskas

• Publisher: Springer
• Year: 1973
• Tongue: English
• Weight: 640 KB
• Volume: 32
• Category: Article
• ISSN: 0038-0938
• DOI: 10.1007/bf00154954

✦ Synopsis

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" • 4.0". The sunspot did not exert a marked influence on the generally random pattern of oscillations at a period of 300 s. Discrete periods of oscillation both longer and shorter than 300 s were excited within the enhanced magnetic field boundaries of this spot. Umbral oscillations at periods near 180 s were detected in agreement with independent observations of the same spot during the previous solar rotation.