Adhesion between self-affine rough surfaces: Possible large effects in small deviations from the nominally Gaussian case

It is shown that even small deviations from the ideal Gaussian random roughness case seem to lead to dramatic increase in adhesion of rough surfaces: this could be due to a finite number of asperities, or to a finite tail in the height distribution, particularly realistic at low fractal dimensions D, which is the case of most practical interest. It is emphasized that the assumption of a perfect Gaussian heigth distribution, including infinite tails, may be a strong one when studying adhesion in rough surfaces.