Same as Fig. 4, but for a nitrogen-dominated atmosphere with no initial hydrogen content for 7, 10, and 20 XUV (from left to right panels). One can see that the inner atmosphere expands at high XUV fluxes. The yellow dots (N ions) indicate a region of enhanced ionization. The dark blue dots are the neutral hydrogen atoms produced due to charge exchange between neutral N atoms and incoming stellar wind protons, the light blue dots are neutral N atoms.