Histograms showing the distribution of ∫ j_∥ ds where the corresponding field-line-integrated parallel electric field is zero (blue) or non-zero (red) at (a) t = 200, (b) t = 325, and (c) t = 400; and scatter plots of ∫ E_∥ ds against ∫ j_∥ ds in the mid-plane at (d) t = 200, (e) t = 325, and (f) t = 400. The histograms are normalized such that the two histograms for each time have a combined area of unity. Both histograms and scatter plots are drawn on logarithmic axes.