Effect of the magnetic field geometry on the flute-like perturbations near the divertor X point

It is shown that a very strong squeezing of the magnetic flux tube passing near the divertor X point imposes stringent limitations on the longitudinal correlation length of the flute-like perturbations near the divertor X point, and leads to a decoupling of the perturbations in the main part of the scrape-off layer from possible effects of the boundary conditions on the surface of the divertor plates.