As. Gadun et al., Two-dimensional simulation of solar granulation: description of technique and comparison with observations, ASTRON ASTR, 350(3), 1999, pp. 1018-1034
The physical properties of the solar granulation are analyzed on the basis
of 2-D fully compressible, radiation-hydrodynamic simulations and the synth
etic spectra they produce. The basic physical and numerical treatment of th
e problem as well as tests of this treatment are described. The simulations
are compared with spatially averaged spectral observations made near disk
centre and high resolution spectra recorded near the solar limb. The presen
t simulations reproduce a significant number of observed features, both at
the centre of the solar disc and near the solar limb. Reproduced observable
s include the magnitude of continuum and line-core intensity fluctuations,
line bisectors and correlations between different line parameters. Spatiall
y averaged line shifts near disc centre, however, are not so well reproduce
d, as are individual correlations between line parameters near the solar li
mb. Possible causes of these discrepancies are discussed.
The present models predict the existence of two photospheric layers at whic
h the temperature fluctuations change sign. We point out a diagnostic of th
e hitherto undetected upper sign reversal based on high spatial resolution
spectral observations of a sample of lines formed over a wide range of heig
hts in the photosphere.