`Solitoff' Solutions of Nonlinear Evolution Equations

Abstract

Dromions are exact, localized solutions of (2+1) dimensional evolution equations and decay exponentially in all directions. `Solitoffs' of the Davey-Stewartson equations constitute an intermediate state between dromions and plane solitons, since they decay exponentially in all directions except a preferred one. Here solitoffs are rederived by the Hirota bilinear operator and extended to a variety of nonlinear evolution equations.