OSCILLATING AND NONOSCILLATING CONTRIBUTIONS IN THE POROD LAW

Experimental Ih4 plots often show damped oscillating terms. The first non-oscillating term describing the interface curvature effects is giv en by the Kirste-Porod formula for regular surfaces. It provides a pos itive h-2 contribution to Ih4. In the presence of sharp edges and vert ices on otherwise planar interfaces an additional negative h-2 term oc curs. A cylinder cutted following a planar section parallel to its axi s provides the simplest situation where oscillating, positive and nega tive h-2 terms have to be simultaneously taken into account. The three additional asymptotic contributions to Ih4 are evaluated. The exact c orrelation function is calculated. The difference between its fourier transform and the asymptotic intensity yields an estimate of the negle cted contribution using the asymptotic expansion. The modification of the oscillating lh4 pattern resulting from the positive and negative h -2 contributions is examined.