OBSERVATIONS OF FE I LINES IN THE QUIET SOLAR PHOTOSPHERE

We investigate three sets of spectra with high spatial and spectral re solution. Each set consists of four spectra taken simultaneously with the Vacuum Tower Telescope at Izana, Tenerife. The main spectral chara cteristics (continuum intensity I-c; full width at half maximum FWHM; residual intensity I-o) were computed for 5 magnetic and non-magnetic Fe I lines (5434.543 Angstrom, 5576.099 Angstrom, 6301.497 Angstrom, 6 302.499 Angstrom, 6494.994 Angstrom). Our results allow a diagnosis of the solar atmosphere in the vertical (two main levels of line formati on) and horizontal directions (71 arcseconds). The spectra cover both interior parts of supergranular cells (purely quiet regions, PQR) and cell boundaries (moderate active regions, MAR). The main results are: (1) We find a different continuum intensity distribution for PQRs and MARs, which reflects the existence of different patterns in these regi ons. The difference is also evident in the rms residual intensity fluc tuation. (2) A significant minimum of the residual intensity fluctuati ons (delta I-o/($) over bar I-c)(rms) occurs at a height of about 300 km. (3) At all heights of the PQRs the line widths FWHM in the intergr anular lanes are larger than the mean line width; those in the granule s are smaller. This variation of the FWHM is influenced by a magnetic effect near the centres of the intergranular lanes (reduced FWHM), and by the effect of convection in granules (enhanced FWHM). (4) The corr elation < I-c, I-o > reverses its sign at a height of about 250 km. Th e anticorrelation in the range 300 - 500 km indicates a non-convective structure, different from the photospheric granular pattern found ear lier.