Comparison of the variation of period of these oscillations against longitudinal wavelength in the slab and cylindrical cases, both curves have values of α = 6 and δ = 0.5, the dotted line represents the cylindrical case (Nakariakov et al. 2012), the solid line represents the slab. The thick straight line shows P = λ/C_A∞, that is the cutoff separating the trapped and leaky regimes. The thinner straight line shows P = λ/C_A0 which corresponds to the short wavelength asymptote.