Second-order two- and three-point structure functions for the polarised intensity of the southern region. The blue and grey vertical dashed lines indicate the telescopeâs resolution, l_b, and coherence length, l_s, respectively. The black and blue dashed horizontal lines mark 2σ² and 2${\sigma }_s^2$, corresponding to the variance for initial polarised intensity (large-scale gradients) and small-scale fluctuations, respectively. The unit of the y-axis is in squares of intensity.