Period, damping time, and damping ratio as a function of the density in the evacuated part of the tube for prominence threads with ρ_f/ρ_c = 200, a = 1, R_m = 10⁶, l_z = a, and l/a = 0.2 and three values of the length of the thread. The main plots are for ρ_c ≤ ρ_ev ≤ ρ_f, while the inset plots correspond to the range 0.1ρ_c ≤ ρ_ev ≤ ρ_c. Times are shown in units of the internal filament Alfvén crossing time, τ_Af = a/v_Af. All computations have been performed in a two-dimensional grid with N_r = 401 and N_z = 51 points, with 250 grid-points in the resonant layer. Lengths are normalised to a = 1 and L = 50a.