Journal article · Preprint article
Modulational instability in nonlocal nonlinear Kerr media
Australian National University1
Department of Informatics and Mathematical Modeling, Technical University of Denmark2
Plasma Physics and Technology Programme, Risø National Laboratory for Sustainable Energy, Technical University of Denmark3
Risø National Laboratory for Sustainable Energy, Technical University of Denmark4
Agricultural University of Norway5
We study modulational instability (MI) of plane waves in nonlocal nonlinear Kerr media. For a focusing nonlinearity we show that, although the nonlocality tends to suppress MI, it can never remove it completely, irrespective of the particular profile of the nonlocal response function. For a defocusing nonlinearity the stability properties depend sensitively on the response function profile: for a smooth profile (e.g., a Gaussian) plane waves are always stable, but MI may occur for a rectangular response.
We also find that the reduced model for a weak nonlocality predicts MI in defocusing media for arbitrary response profiles, as long as the intensity exceeds a certain critical value. However, it appears that this regime of MI is beyond the validity of the reduced model, if it is to represent the weakly nonlocal limit of a general nonlocal nonlinearity, as in optics and the theory of Bose-Einstein condensates.
Language: | English |
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Year: | 2001 |
Pages: | 016612 |
ISSN: | 24700053 , 24700045 , 1063651x , 15502376 , 15393755 and 10953787 |
Types: | Journal article and Preprint article |
DOI: | 10.1103/PhysRevE.64.016612 |
ORCIDs: | Bang, Ole and Juul Rasmussen, Jens |