Ionisation rate due to EPs (ζ_EP) compared to the total ionisation rate ζ_tot = ζ_XR + ζ_GCR + ζ_EP, for the reference case κ = 0.1, where ζ_XR and ζ_GCR are the ionisation rates due to X-rays and GCRs, respectfully. The solid black contours mark regions where ionisation from EPs dominates over all other ionisation sources, while the dashed black line indicates where the EP ionisation is 5% of the total ionisation rate. The red contour outlines regions dominated by GCRs. The region in between is dominated by X-ray ionisation.