Damping rate (the imaginary part of the normalized frequency ϖ = ω/k_zv_A) of fast (upper panel) and slow (lower panel) magneto-acoustic waves vs. the normalized wavenumber a = k_zv_A/ν_in. Red asterisks are the solutions of the two-fluid dispersion relation. Blue lines correspond to the solutions of Braginskii. The values are calculated for 50% of neutral hydrogen and c_sn/v_A = 0.1. The damping rates are calculated for the waves that propagate along the magnetic field.