On the existence and stability of solitary-wave solutions to a class of evolution equations of Whitham type

摘要

We consider a class of pseudodifferential evolution equations of the form u _t + (n(u) + Lu) _x = 0, in which L is a linear smoothing operator and n is at least quadratic near the origin; this class includes in particular the Whitham equation. A family of solitary-wave solutions is found using a constrained minimization principle and concentration-compactness methods for noncoercive functionals. The solitary waves are approximated by (scalings of) the corresponding solutions to partial differential equations arising as weakly nonlinear approximations; in the case of the Whitham equation the approximation is the KortewegdeVries equation. We also demonstrate that the family of solitary-wave solutions is conditionally energetically stable.