Sökning: "modulational instability"

Visar resultat 1 - 5 av 6 avhandlingar innehållade orden modulational instability.

  1. 1. Aspects of Wave Interaction in Nonlinear Media

    Författare :Björn Hall; [2005]
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; nonlinear Schrödinger equation; incoherent solitons; partial incoherence; nonlinear wave interaction; Gross-Pitaevskii equation; modulational instability; collective dynamics; Wigner transform; nonlinear guided waves; Bose-Einstein condensation;

    Sammanfattning : Selected aspects of various types of nonlinear wave interaction are investigated. These aspects are studied in terms of models described by Nonlinear Schrödinger equations, mainly analytically and numerically, but also experimentally. LÄS MER

  2. 2. Nonlinear Dynamics of Coherent and Partially Coherent Optical Waves

    Författare :Tobias Hansson; [2009]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; soliton interaction; Wigner transform; logarithmically saturable media; Nonlinear Schrödinger equation; parabolic beams; partial coherence; quasilinear diffusion; modulational instability;

    Sammanfattning : In optics an important nonlinear effect is manifested by the fact that the refractive index, in addition to its frequency dependence, also depends on the intensity of the light. Nonlinear effects are present within a wide range of optical applications e.g. the fast growing fields of fiber-optic communication and all-optical signal processing. LÄS MER

  3. 3. Nonlinear Theory of Partially Coherent Optical Waves

    Författare :Tobias Hansson; [2011]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Nonlinear optics; partial coherence; beam collapse; saturable logarithmic media; soliton interaction; dressing method; parabolic beams; Wigner transform; invariants; modulational instability;

    Sammanfattning : Nonlinear effects arise in optics as a consequence of the medium properties being modified by the presence of light. Of particular interest are situations where the effect of the nonlinearity can be described by an intensity dependent refractive index and the subsequent interplay with dispersion and diffraction. LÄS MER

  4. 4. Nonlinear Propagation of Partially Incoherent Light

    Författare :Lukasz Helczynski-Wolf; [2005]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : This thesis deals with consequences of partial incoherence on light propagation in nonlinear media. A new approach, based on the Wigner transform method, has beed developed and used to investigate several important problems in nonlinear light propagation. LÄS MER

  5. 5. Waves and instabilities in quantum plasmas

    Detta är en avhandling från Umeå : Fysik

    Författare :Shahid Ali; Umeå universitet.; [2008]
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Quantum mechanical effects; dusty plasma; linear and nonlinear waves; instabilities; nonlinear wave interactions; density gradients; magnetoplasmas.; NATURAL SCIENCES Physics Geocosmophysics and plasma physics Plasma physics; NATURVETENSKAP Fysik Geokosmofysik och plasmafysik Plasmafysik;

    Sammanfattning : The study of waves and instabilities in quantum plasmas is of fundamental importance for understanding collective interactions in superdense astrophysical objects, in high intense laser-plasma/solid-matter interactions, in microelectronic devices and metallic nanostructures. In dense quantum plasmas, there are new pressure laws associated with the Fermi-Dirac distribution functions and new quantum forces associated with the quantum Bohm potential and the Bohr magnetization involving electron ½ spin. LÄS MER