The Distribution of the Quiet Sun Photospheric Magnetic Flux

Abstract

A gradient-based tessellating algorithm is used to study the magnetic field structure of the quiet Sun photosphere using SoRO full disk magnetograms. We find that the field is not uniformly distributed, but parcelled into flux concentrations. Both the flux and size of the concentrations are found to be described by broad, asymmetric distribution functions. Their mean absolute flux and size are found to be about 1.4 x 1018 m:x: and 6.1 Mm for both polarities in unsmoothed magnetogra.ms at Ii gauss threshold. These values represent a. weighted average for both network- and intra.network magnetic fields, since the present method cannot currently distinguish between the two regions. Both flux and size distributions become more symmetric and less peaked in response to smoothing of images. Extrapolating this trend to sub-resolution seale, we note a linear decrease in size but a rapid increase in the mean absolute field strength, with asymptotic values of about 400 km and 50 gauss. This exercise shows that the true field strengths of quiet magnetic elements are higher and their size smaller than usua.lly inferred from observa.tions. This is because observation of mixed polarity regions under finite resolution causes the observed flux to be smeared out and apparently modified. Therefore, this flux cannot be interpreted independently of the geometric structure and flux distribution of the concentrations.