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Simultaneous measurements of sunspot umbral oscillations in the photosphere, chromosphere, and transition regionMeasurements of umbral oscillations in a sunspot were made simultaneously from space (with the SMM/UVSP instrument) in the C IV transition-region line and from the ground (with the tower telescope at NSO/sunspot) in spectral lines formed in the photosphere and chromosphere. The power spectra of velocity and intensity variations show multiple peaks in the 3 min band (4.5-10 mHz). A strong oscillation at 5.5 mHz is coherent between the chromosphere and transition region. Another strong oscillation mode at 7.5 mHz is coherent between the photosphere and transition region and appears to have a node in the chromosphere. The rms velocity in the 3 min band is a little over 12 km/sec in both the chromosphere and transition region, but the kinetic energy density is lower in the transition region (by a factor of 10 or more) due to the lower mass density there. These measurements of amplitude and phase of the waves at different heights provided a new, independent method of testing or fitting models of the vertical temperature distribution in the umbral chromosphere and transition regions.
Document ID
19870042273
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
External Source(s)
Authors
Thomas, John H.
(Rochester, University; C. E. K. Mees Observatory, Rochester, NY, United States)
Lites, Bruce W.
(High Altitude Observatory Boulder, CO, United States)
Gurman, Joseph B.
(NASA Goddard Space Flight Center Greenbelt, MD, United States)
Ladd, Edwin F.
(Rochester Univ. NY, United States)
Date Acquired
August 13, 2013
Publication Date
January 1, 1987
Publication Information
Publication: Astrophysical Journal, Part 1
Volume: 312
ISSN: 0004-637X
Subject Category
Solar Physics
Accession Number
87A29547
Funding Number(s)
CONTRACT_GRANT: NAG5-505
CONTRACT_GRANT: NSG-7562
Distribution Limits
Public
Copyright
Other

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