Measurements of magnetic fluxes and field strengths in the photospheric network

Digital pictures of an active-region network cell are presented in five quantities measured simultaneously: continuum intensity, line-center intensity, equivalent width, magnetogram signal, and magnetic-field strength. These maps are derived from computer analysis of circularly polarized line profiles of Fe I 5250.2-A; spectral and spatial resolution are 1/40 A and 1.5 arcsec, respectively. Measured Zeeman splittings show the existence of strong magnetic fields (1000-1800 G) at nearly all points with a magnetogram signal exceeding 125 G. The mean and rms deviation of the field strengths change by less than 20% over a factor-of-four range of fluxes. From the significant disparity between measured fluxes and field strengths, it is concluded that large flux patches (up to 4 arcsec across) consist of closely-packed unresolved filaments. The smallest filaments must be less than 0.7 arcsec in diameter. The dark component of the photospheric network, which appears to contain sizable transverse fields, is also observed.