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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-24 23:07 |
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Conference: Bucharest University Faculty of Physics 2003 Meeting
Section: Theoretical Physics and Applied Mathematics Seminar
Title:
Higher order dispersion effects on the modulational instability of NLS equation.
Authors:
Anca Visinescu, D. Grecu
Affiliation:
Department of Theoretical Physics
National Institute of Physics and Nuclear Engineering "Horia Hulubei"
Bucharest, Magurele
e-mail: avisin@theor1.theory.nipne.ro
E-mail
Keywords:
Abstract:
The influence of a higher order dispersive term (fourth order derivative) on the modulational instability of the nonlinear Schroedinger equation (NLS) is studied using a statistical approach. An integral stability equation is found, which is solved for two initial conditions, a delta-spectrum and a Lorentzian one. A restriction for the coefficients describing the higher order dispersion, nonlineariry and the initial mean square amplitude is obtained. Two distinct regions of instability are possible, one in the long wave region and another for short waves. For the Lorentzian initial conditions, as for the usual NLS equation, a critical value of the distribution parameters exists, beyond which the instability cannot develop.
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