Sökning: "density peaking"

Visar resultat 1 - 5 av 11 avhandlingar innehållade orden density peaking.

  1. 1. Fast ions and turbulent particle transport in tokamaks

    Författare :Frida Eriksson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NBI; numerical modelling; turbulence; drift waves; bump-on-tail; density peaking; Fusion plasma physics; wave-particle interaction;

    Sammanfattning : The presence of highly energetic (fast) ions, be it fusion born alpha particles or ions accelerated by auxiliary heating schemes, can affect the heating and transport of all particles in the plasma through two main mechanisms. First, fast ions may excite fast ion driven instabilities. LÄS MER

  3. 2. On Monte Carlo Operators for Studying Collisional Relaxation in Toroidal Plasmas

    Författare :Qaisar Mukhtar; Torbjörn Hellsten; Tainia Kurki-Suonio; KTH; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fusion plasma; thermonuclear fusion; tokamak; Coulomb collisions; stochastic differential equations with singular diffusion coefficients; Monte Carlo schemes; spatial diffusion; modelling; Fokker-Planck equation; RF-heating.;

    Sammanfattning : This thesis concerns modelling of Coulomb collisions in toroidal plasma with Monte Carlo operators, which is important for many applications such as heating, current drive and collisional transport in fusion plasmas. Collisions relax the distribution functions towards local isotropic ones and transfer power to the background species when they are perturbed e. LÄS MER

  4. 3. Gyrokinetic simulations of turbulent transport in tokamak plasmas

    Författare :Andreas Skyman; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; fusion; TEM; ITG; tokamaks; e-science; Joint European Torus; turbulence; gyrokinetics; plasma physics; impurity transport;

    Sammanfattning : With the enormous growth of high performance computing (HPC) over the last few decades, plasma physicists have gained access to a valuable instrument for investigating turbulent plasma behaviour. In this thesis, these tools are utilised for the study of particle transport in fusion devices of the tokamak variety. LÄS MER

  5. 4. Turbulent impurity transport in tokamak fusion plasmas

    Författare :Andreas Skyman; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; tokamaks; fluid theory; ion temperature gradient mode; impurity transport; trapped electron mode; fusion plasma physics; turbulence; e-science; Joint European Torus; gyrokinetic theory;

    Sammanfattning : With the enormous growth of high performance computing (HPC) over the last few decades, plasma physicists have gained access to a valuable instrument for investigating turbulent plasma behaviour. In this thesis, these tools are utilised for the study of particle transport in fusion devices of the tokamak variety, focusing in particular on the transport of impurities. LÄS MER

  7. 5. Atomic Spectroscopy on Fusion Relevant Ions and Studies of Light Impurities in the JET Tokamak

    Författare :Magnus Tunklev; Partikel- och kärnfysik; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Active and Passive Charge Exchange; Transport; Diffusion; Convection; Neutral Background Densities; Ion temperatures; Fusion; Isoelectronic sequences; Plasma; Atom- och molekylärfysik; Fysicumarkivet A:1999:Tunklev; Ritz formalism; Plume; Atomic and molecular physics;

    Sammanfattning : The spectrum and energy levels C IV and the 3l4l' system of the Mg-like ions in the iron group elements has been investigated. This has led to several hundred identified transitions, many of them previously unknown. LÄS MER