Transition-Region Network Boundaries in the Quiet Sun: Width Variation with Temperature as Observed with CDS on SOHO

Abstract

We report here the results of a study of the temperature variation of the network boundary thicknesses in the quiet-Sun transition region. A Fourier-based two-dimensional autocorrelation method has been applied to 240^''×240^'' rasters obtained in several transition-region lines by the CDS spectrometer on SOHO. The quantitative variation of the network boundary width with temperature has been obtained for the first time in a full two-dimensional field. It appears that network boundaries have an almost constant width up to a temperature of about 10^5.4 K and then fan out rapidly at coronal temperatures. This expansion of the transition-region network boundaries with temperature is found to be quantitatively in agreement with earlier theoretical models of the transition region.