Sökning: "quasilinear diffusion"

Visar resultat 1 - 5 av 7 avhandlingar innehållade orden quasilinear diffusion.

  1. 1. Statistical Aspects of Diffusion in Turbulent Plasmas

    Författare :Igor Holod; Chalmers University of Technology; []
    Nyckelord :turbulent diffusion; fluctuations; fluid closure; Fokker-Plack equation; non-Markovian effects;

    Sammanfattning : In this work we address the closure issue in kinetic and fluid descriptions of turbulent plasmas. In fluid description contribution has been made to the nonlinear closure by Mattor and Parker [Phys. Rev. Lett. LÄS MER

  2. 2. Numerical solution of quasilinear kinetic diffusion equations in toroidal plasmas

    Författare :Lars Josef Höök; Torbjörn Hellsten; Thomas Johnson; Jukka Heikkinen; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES;

    Sammanfattning : One of the main challenges for the realization of a working fusion power plant is an increased detailed understanding of kinetic phenomena in toroidal plasmas. The tokamak is a toroidal, magnetically confined plasma device and is currently the main line towards a power plant. LÄS MER

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

    Författare :Tobias Hansson; Chalmers University of Technology; []
    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

  4. 4. The dynamics of Alfvén eigenmodes excited by energetic ions in toroidal plasmas

    Författare :Emmi Tholerus; Torbjörn Hellsten; Thomas Johnson; Lars-Göran Eriksson; KTH; []
    Nyckelord :NATURAL SCIENCES; NATURVETENSKAP; NATURVETENSKAP; NATURAL SCIENCES; Fusion plasma physics; tokamak; wave-particle interactions; toroidal Alfvén eigenmodes; bump-on-tail instabilities; magnetohydrodynamics; nonlinear dynamics; quasilinear dynamics; Hamiltonian mechanics; Monte Carlo method; Electrical Engineering; Elektro- och systemteknik;

    Sammanfattning : Experiments for the development of fusion power that are based on magnetic confinement deal with plasmas that inevitably contain energetic (non-thermal) particles. These particles come e.g. from fusion reactions or from external heating of the plasma. LÄS MER

  5. 5. Ion cyclotron resonance heating and current drive in tokamaks

    Författare :Johan Carlsson; KTH; []
    Nyckelord :;

    Sammanfattning : In this thesis numerical studies, performed with theMonte-Carlo code FIDO of the evolution of the resonant-iondistribution function in the presence of ion cyclotronresonance heating (ICRH) in toroidal geometry are presented. Inparticular it is pointed out how the absorption of toroidalmomentum from a wave field with finite parallel wave numberscauses spatial drift and diffusion, which together with thefinite orbit widths of the tail ions is shown to have a largeeffect on the temperature profile of the resonant ion speciesand also to cause losses of high-energy ions to the wall. LÄS MER