Perturbation analysis of single Langmuir solitons

An investigation is made of the effects of perturbations on single solitary wave solutions to the Zakharov equations. The main results are expressions, to first order in the perturbation, for the time evolution of the soliton parameters. It is shown that an adiabatically perturbed solitary Langmuir wave generally emits free ion-sound waves in the form of shelves at zero frequency and wavenumber. The evolution equations for the solition parameters include frequency and velocity shifts induced by the radiated ion sound