NUMERICAL-STUDIES OF LOCALIZED WAVE-FIELDS GOVERNED BY THE RAMAN-EXTENDED DERIVATIVE NONLINEAR SCHRODINGER-EQUATION

Using a stable pseudospectral multi-domain method we investigate the d ynamics of localized wavefields in the extended derivative nonlinear S chrodinger equation, with particular emphasis on the critical mass and structure of the initial conditions that promote wave collapse. The r esults are found to correspond well with theoretical observations base d on a Lagrangian approach and through comparison with solutions of th e critical nonlinear Schrodinger equation. Inclusion of high-order non linear dissipation due to the self-induced Raman effect, leading to th e Raman-extended derivative nonlinear Schrodinger equation, is found t o inhibit finite-time collapse in certain cases.