the corrugation is modified and it reaches its maximum when $R\cong
r_s$ (see Figs.\[fig6\] and \[fig7\]).

This is expected, since the rigid shift around the resonance of the sinusoidal perturbation is equivalent to a change in the phase $\alpha$ in in the slab model. Furthermore, the comparison between the solid ($A=5\times 10^{-5}$) and dashed lines ($A=2.5\times
10^{-5}$) in Figs.\[fig6\] and \[fig7\] confirm also in cylindrical geometry the linear dependence of $\delta\Delta'$ on the perturbation amplitude, as given in Eq.\[9\]. Similarly, also the scaling in the cube of the corrugation wavelength is verified by measuring the maximum amplitude of the solid ($K=40$) and the dash-dot ($K=30$) lines.

Finally, it is interesting to evaluate the constant $C$ for the cylindrical equilibrium investigated. In order to do that, we divide the maximum value of $\delta\Delta'$ (obtained at $R=r_s$) by the amplitude of the corrugation and the cube of its wavelength. With this procedure we find that $C\cong 2.5$ for $m=2$, $n=1$ and $C\cong 1.7$ for $m=3$, $n=2$. While both values are pretty close to the slab estimate, this result suggest a dependence of the effect of the corrugation on the wave-vector of the driven perturbation. This dependence is easily explained by the presence 