Ohmic heating contributions from separate current structures in the spine and fan. We show the mean ohmic heating contributions from the spines (dotted) and current-vortex sheet (dashed) and their sum (solid) for η = 10⁻³ (a) and η = 10⁻⁴ (b) in only the isotropic cases at t = 10. The value of η dictates how rapidly the balance of contributions shifts from fan to spine with ν, resulting in different trends in total ohmic heating.