Phenomenology of flute-like perturbations in the divertor region

A very strong squeezing of the flux-tube passing near the divertor X-point should make impossible existence of flute-like perturbations connecting the divertor plate and the median part of the SOL. On the other hand, some of the current experimental observations imply that such perturbations do exist. In the present paper we consider possible resolutions of this apparent paradox for some specific experimental situations: short divertor legs; presence of a cold plasma in the divertor legs; and excitation of the modes with small toroidal wave numbers.