Observation and analysis of intensity oscillations in the solar K-line
Abstract
Chromospheric oscillations are investigated with a time sequence of filtergrams of the sun taken in the core of the Ca II K-line at the Sacramento Peak Observatory. The relations between oscillation frequency and wavenumber are analyzed, as are those between frequency and mean intensity. Intensity analysis reveals that low frequency waves are associated mainly with bright (chromospheric network) regions, while the '3-min' oscillation dominates in cell interiors. As the mean brightness of the observed region increases, the high frequency limit of oscillatory power decreases. This is interpreted as the decrease of the resonance frequency of the chromospheric cavity with increasing temperatures, which confirms the chromospheric origin of the 3-min oscillations. Diagnostic diagrams suggest that both acoustic and internal gravity waves occur in the chromosphere and appear to have a modal structure.
- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- January 1984
- Bibcode:
- 1984A&A...130..331D
- Keywords:
-
- Chromosphere;
- K Lines;
- Solar Oscillations;
- Solar Spectra;
- Evanescence;
- Filtergrams;
- Fine Structure;
- Gravity Waves;
- Sound Waves;
- Specific Heat;
- Solar Physics