We investigate the turbulent velocity field and its interaction with the granular flow as a function of height in the photosphere and over one turn-over time of the granule. We are using a series of spectrograms which includes absorption lines of different strengths. The spectrograms were taken at the center of the solar disk with the German Vacuum Tower Telescope (VTT) in Izana (Tenerife, Spain) in 1994. The processing of the 7 best spectrograms from a series covering 12 min shows that the intergranular space is always turbulent whereas the granule reveals a practically pure laminar convective flow. In the deep photosphere, the turbulence in the intergranular space is concentrated predominantly near the granular border. At higher layers, however, the turbulence spreads out over the entire intergranular space. Remarkable is the decay of the turbulence with the height in the photosphere.
Cool Stars, Stellar Systems, and the Sun
- Pub Date:
- SUN: PHOTOSPHEREW;
- SUN: GRANULATION;