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 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.
- OSTI ID:
- 22342255
- Journal Information:
- Astrophysical Journal, Vol. 756, Issue 1; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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