Dissipation cut at time t = 1/3t_turnover for OT initial conditions with P_m = 1. Lower and upper thresholds have been applied to the 3% pixels with smallest and largest dissipation, the intensity scaling of the pixels is logarithmic, while the colour-code is as follows. Red: ohmic dissipation ε_η = 4πηJ²; blue: compressive viscous heating ε_comp = 4/3pv (∇ · u)²; green: solenoidal viscous heating ε_sol = ρv (∇ × u)². We warn the reader that , both locally and globally (because we used a uniform v and not a uniform pv; see Lesaffre et al. 2020). We note that there is very little compressive heating (blue).