RELATION BETWEEN MAGNETIC-FIELD AND INTENSITY ON THE SOLAR PHOTOSPHERE

We have analysed a time series of high resolution spectra of Fe I line s 6301.5 Angstrom and 6302.5 Angstrom, near an active region, obtained at the Sacramento Peak Tower Telescope. The derived spectroheliograms and spectromagnetograms have been used to investigate the statistical relation between magnetic fields and. the associated intensities and velocities. We found that two kinds of magnetic structures coexist : t iny bright flux tubes, located in the intergranular lanes, which expla in the increase of the brightness of week magnetic fields, (from 0 to 400 Gauss) and magnetic features of larger sizes which should be darke r than the average photosphere. Downflows up to 200 m.s(-1) are measur ed for magnetic signal values between 80 and 400 Gauss; they are certa inly due to the presence of several tiny bright flux tubes in the reso lution element. We also confirm that the contrast of granulation is re duced in magnetic field areas.