Intensity oscillations in the calcium - K line
Abstract
An analysis is undertaken of a time sequence of quiet sun filtergrams taken in the core of the K line, in order to investigate the oscillatory properties of the chromosphere. The physical significance of these intensity variations and their diagnostic capabilities are discussed, and an oscillatory power vs. frequency and mean intensity diagram is noted to indicate the different behaviors of bright regions dominated by low frequency waves and darker regions dominated by high frequency waves. A diagnostic wavenumber-frequency diagram indicates two oscillatory power concentrations which approximately correspond to acoustic and gravity waves, in chromospheric conditions. A theoretical diagnostic diagram computed on the basis of a solar atmosphere model exhibits a 'g-1' chromospheric mode; this corresponds almost exactly to the location of the observed ridge.
- Publication:
-
Memorie della Societa Astronomica Italiana
- Pub Date:
- June 1984
- Bibcode:
- 1984MmSAI..55..245G
- Keywords:
-
- Calcium;
- Chromosphere;
- K Lines;
- Solar Oscillations;
- Vibration Mode;
- Bandpass Filters;
- Brightness Distribution;
- Filtergrams;
- Solar Atmosphere;
- Solar Physics