Phase shift of interacting algebraic solitary waves in a two-layer fluid system.

The interaction of interfacial solitary waves of algebraic type is investigated on the basis of a higherorder Benjamin-Ono equation. By developing a multisoliton perturbation theory, we show analytically that the overtaking collision between two solitary waves exhibits the phase shift but the amplitudes are not altered after interaction. The predication of the phase shift that takes place between algebraic solitary waves is the first example reported in the literature.