The height dependence of intensity and velocity structures in the solar photosphere

Details The height dependence of intensity and velocity structures in the solar photosphere The height dependence of intensity and velocity structures in the solar photosphere

May 1994

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1994a%26a...285..322s&link_type=abstract

Astronomy and Astrophysics 285, 322-332 (1994)

Astronomy and Astrophysics

Astrophysics

24

Sun: Photosphere, Convection

Scientific paper

Results about a statistical analysis of the solar granulation, obtained by analyzing a series of narrow band (20 mA FWHM) images in the 6162.18 A CaI photospheric line, are presented. The observations have been performed at the Vacuum Solar Tower of the National Solar Observatory at Sac. Peak (NM-USA) in 1988, using a Fabry-Perot interferometer and a Universal Birefringent Filter mounted in tandem. We computed coherence, phase and power spectra of intensity and velocity fields in a 27"x27" quiet region at the disk center. Energy spectra, plotted in the usual log-log coordinates, clearly show a linear shape for wavenumbers between 3 and 10 Mm^-1^. The exponent is -17/3: it does not significatively vary within the considered photospheric layers and largely differs from both the theoretical value and the results of previous 1-D observations. This result indicates that in the photosphere we are in presence of a redistribution of the convective energy through a cascade from larger granules to smaller ones, although the size distribution does not follow the Kolmogorov law. The physical processes involved in the granulation have been investigated by studying the height dependence of coherence and phase spectra of Velocity-Velocity (V-V) and Velocity-Intensity (V-I) fields. We find that the photosphere is divided in two regions: the velocity structures existing in the lower layers (first region) are convective and extend up to about 170 km. The decay of these granular motions generates well correlated velocity structures in the second region (height range 170-400 km), at spatial frequencies 5-10 Mm^-1^. In this region, moreover, the coherence moderately increases with height, while the phase is stable around +/-180°. This means that velocity and intensity fields are predominantly anticorrelated, as expected for gravity waves.

Affiliated with

Also associated with

No associations

Rating

The height dependence of intensity and velocity structures in the solar photosphere does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with The height dependence of intensity and velocity structures in the solar photosphere, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The height dependence of intensity and velocity structures in the solar photosphere will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-879806