Vertical net Poynting flux into a field line versus the volumetric Ohmic heating integrated along that field line. Red data points show the absolute value of the Poynting flux wherever the Poynting flux is negative, dark blue dots show the data points where the Poynting flux is positive. The gray dashed line indicates the equality, where all of the incoming Poynting flux would be converted to Ohmic heat. We apply a least-absolute-deviation (LAD) fit to the positive net flux data points (black line). The green stars indicate the mean Ohmic heating within the corresponding bins in Poynting flux. See Sect. 4.1.1.