SPATIAL STRUCTURE OF SUNSPOT OSCILLATIONS OBSERVED WITH SDO/AIA

The spatial structure of sunspot oscillations and its variation with frequency and height have been studied using data from SDO/AIA for two well-developed sunspots observed in 2010. Computation of potential magnetic fields together with line-of-sight and vector magnetograms from SDO/HMI allowed us t...

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Bibliographic Details
Published in:The Astrophysical journal 2012-09, Vol.756 (1), p.1-10
Main Authors: Reznikova, V E, Shibasaki, K
Format: Article
Language:English
Subjects:
ASTROPHYSICS, COSMOLOGY AND ASTRONOMY
COMPUTERIZED SIMULATION
DISTANCE
EXPANSION
INCLINATION
Line of sight
MAGNETIC FIELDS
OSCILLATIONS
Pulsation
PULSATIONS
SPATIAL DISTRIBUTION
SUN
SUNSPOTS
TRANSFORMATIONS
ULTRAVIOLET RADIATION
Umbras
VARIATIONS
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Summary:The spatial structure of sunspot oscillations and its variation with frequency and height have been studied using data from SDO/AIA for two well-developed sunspots observed in 2010. Computation of potential magnetic fields together with line-of-sight and vector magnetograms from SDO/HMI allowed us to interpret discovered features of spatial structure. Namely, we have found that (1) expansion of the magnetic field lines above the sunspot causes a gradual broadening of the area occupied by the 3 minute oscillations with height, and (2) variation of magnetic field inclination across the sunspot causes a decrease in the pulsation frequency with distance from the center of the umbra. We have shown that the transformation from 3 minute umbral oscillations to 5 minute penumbral waves can be explained by variation of the acoustic cutoff frequency across the sunspot.
ISSN:0004-637X
1538-4357
DOI:10.1088/0004-637X/756/1/35