Resonant radiation from Peregrine solitons

We investigate the phenomenon of resonant radiation emitted by Peregrine solitons. We show that, unlike bright or dark solitons of the nonlinear Schrödinger equation, the radiation process is affected by the intrinsic local longitudinal variation of the soliton wavenumber. We give a phase-matching condition that allows the prediction of the multiple spectral peaks of the resonant radiation.