Ionisation rate, ζ, as a function of height in the early Earth atmosphere at 200 Myr due to Galactic and solar cosmic rays. Dotted lines show ζ due to Galactic cosmic rays only, dashed lines show ζ due to solar cosmic rays only, solid lines show the total ζ from Galactic cosmic rays and solar cosmic rays combined. The ζ values for the slow, medium, and fast solar rotation rates are shown by black, red, and blue lines, respectively. For the fast solar rotation rate, ζ_GCR has been multiplied by 10² to allow ζ_GCR and ζ_SCR for all rotation rates to be shown within a reasonable range on the same axes.