Ionospheric modification by intense radio waves is known to produce energetic tails on the electron velocity distribution function, resulting in enhanced airglow. We demonstrate that these energetic tails may be due to quasi-linear velocity space diffusion in the presence of the background magnetic field. The waves responsible for the diffusion are produced by the parametric decay instability. The magnetic quasi-linear diffusion considered here may often be more important than the unmagnetized resonance broadened diffusion considered by Weinstock; however, the two effects are additive, so that the predictions of either theory by itself are conservative.