a) Total integrated heating, H, as a function of the hydrogen ionization ratio, ξ_i, when the velocity amplitude of the incident waves is 10 km s^-1. The black line indicates the full result, the red line indicates the contribution of short periods (0.1 s ≤ P ≤ 1 s), and the blue line indicates the contribution of intermediate periods (1 s ≤ P ≤ 100 s). b) Same as panel a) but for the velocity power law of Hillier et al. (2013).