Sökning: "collisional transport"

Visar resultat 6 - 10 av 12 avhandlingar innehållade orden collisional transport.

  1. 6. 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

  3. 7. Drift waves in non-circular tokamak geometry

    Författare :Johan Anderson; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; tokamak geometry; instabilities; drift waves; fusion plasmas;

    Sammanfattning : One of the main concerns in fusion research is to understand the anomalously high transport in magnetically confined plasmas. In recent years, substantial progress in the understanding of transport in terms of drift waves in tokamaks has been achieved. LÄS MER

  4. 8. Kinetic modelling of runaway in plasmas

    Författare :Ola Embréus; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fokker-Planck equation; synchrotron radiation; plasma; runaway; bremsstrahlung; Boltzmann equation;

    Sammanfattning : The phenomenon of runaway occurs in plasmas in the presence of a strong electric field, which overcomes the collisional friction acting on the charged particles moving through the plasma. A subpopulation of particles can then be accelerated to energies significantly higher than the thermal energy. LÄS MER

  5. 9. Momentum-space dynamics of runaway electrons in plasmas

    Författare :Adam Stahl; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; synchrotron radiation; tokamak; critical electric field; non-linear collision operator; slide-away; runaway electrons; fusion-plasma physics;

    Sammanfattning : Fast electrons in a plasma experience a friction force that decreases with increasing particle speed, and may therefore be continuously accelerated by sufficiently strong electric fields. These so-called runaway electrons may quickly reach relativistic speeds. LÄS MER

  7. 10. Modelling and Applications of the Hollow Cathode Plasma

    Författare :Daniel Söderström; Hana Baránková; Ladislav Bárdos; Zoltán Donkó; Uppsala universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Engineering physics; hollow cathode; hybrid plasma; vibrational temperature; atmospheric pressure; fluid modelling; radio frequency; pulsed power; Teknisk fysik; Engineering physics; Teknisk fysik;

    Sammanfattning : This thesis presents experimental and modelling research on atmospheric pressure hollow cathodes and hollow electrodes. Experiments with the hybrid hollow electrode activated discharge (H-HEAD), which is a combination of a hollow cathode and a microwave plasma source, is presented. LÄS MER