Normalised power spectral density kP_k plots for time-averaged datasets of mm brightness temperatures with both definitions of linewidth at 3.0 mm and 0.8 mm. The solid lines represent the original-resolution data and the dashed lines show the spatially degraded data, green for the Leenaarts et al. (2012) linewidth, red for the Molnar et al. (2019) definition of linewidth, and blue for the corresponding mm wavelength. The vertical lines represent the dominant spatial scales (in arcsec) for the original-resolution data with the (Leenaarts et al. 2012) definition of linewidth and the Molnar et al. (2019) definition of linewidth. The black dashed line represents the PSF corresponding to the mm wavelength, showing the resolution limit for the degraded dataset. In the left panel, the spatial power spectral density for the Band 3 ALMA observations (ADS/NRAO.ALMA#2016.1.01129.S) as used by Molnar et al. (2019) and shown in Fig. 11 are plotted as the black solid line. The power spectral density was calculated for all time steps in the time range considered by Molnar et al. (2019) and then averaged in time.