The Center-to-Limb Variation of the Photospheric Wave Spectrum
Abstract
Using photoelectric observations in the Fe 5576 Å line we obtained line-of-sight velocities at nine different positions on the solar disk, as functions of one horizontal co-ordinate and time. With the help of the Fast Fourier Transform algorithm we calculated two-dimensional power spectra (horizontal wave number and frequency). Special attention was given to the possible existence of horizontal sound waves. We find only very little power in these waves; thus the excitation of the solar atmosphere to oscillations by locally overshooting granules, which should be accompanied by horizontal sound waves with large amplitudes, can play only a minor role.
- Publication:
-
Solar Physics
- Pub Date:
- July 1974
- DOI:
- 10.1007/BF00157844
- Bibcode:
- 1974SoPh...37...63S
- Keywords:
-
- Atmosphere;
- Fourier;
- Fourier Transform;
- Power Spectrum;
- Fast Fourier Transform