The interaction of creeping waves on a smooth anisotropic impedance surface

Electromagnetic creeping waves running along a smooth convex anisotropic impedance surface are studied. The adiabatic expansion for creeping waves works if attenuations of modes do not coincide. The leading order term of the expansion may have the TE or TM polarization. We consider the case where the adiabatic approach fails near the points of coincidence of attenuation parameters of the modes with different polarizations. We assume that this coincidence takes place on a curve on the surface. We have found the asymptotic expansion which works near this curve. This expansion is matched with the adiabatic expansions, and the effect of the initiation of the new mode is described.