Sökning: "Fokker-Planck"

Visar resultat 6 - 10 av 28 avhandlingar innehållade ordet Fokker-Planck.

  1. 6. Kinetic modelling of runaways in plasmas

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

    Sammanfattning : The phenomenon of runaway occurs in plasmas in the presence of a strong electric field, when the accelerating force overcomes the collisional friction acting on the charged particles moving through the plasma. Electron runaway is observed in both laboratory and space plasmas, and is of great importance in fusion-energy research, where the energetic electrons can damage the plasma-facing components of fusion reactors. LÄS MER

  3. 7. Eulerian Numerical Study of the Sedimentation of Fibre Suspensions

    Författare :Feng Zhang; Anders Dahlkild; Fredrik Lundell; Staffan Lundström; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fokker-Planck equation; particle fluid flow; suspension; instability;

    Sammanfattning :  Sedimenting suspensions exist in a varity of natural phenomena and industrial applications. It is already observed in experiments that the dilute fibre suspensions experience a hydrodynamics instability under gravity at low Reynolds numbers. Initially well-mixed suspensions become inhomogeneous and anisotropic due to this instability. LÄS MER

  4. 8. 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

  5. 9. Diffusion-Induced Nonlinear Dynamics in Carbon Nanomechanical Resonators

    Författare :Christin Edblom; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; mass sensing; graphene; stochastic differential equations; diffusion; carbon nanotubes; resonators; nanoelectromechanical systems; equations of motion; nonlinear dynamics; dissipation; Fokker-Planck equation; noise; nonequilibrium dynamics;

    Sammanfattning : The emergence of nanoelectromechanical systems has enabled the development of sensors capable of detecting mass, charge, force, position, and spin with an unprecedented precision. In particular, the low mass, high resonant frequency, and high quality factor of carbon nanomechanical resonators make them ideal for the creation of a high sensitivity mass sensor. LÄS MER

  7. 10. Effect of Partial Screening on Runaway-Electron Dynamics

    Författare :Linnea Hesslow; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Fokker-Planck equation; runaway electrons; tokamak; fusion; plasma physics;

    Sammanfattning : One of the essential results of kinetic plasma physics is the runaway phenomenon: sufficiently large electric fields can accelerate a fraction of an electron population to relativistic energies. While such runaway electrons are fundamentally interesting objects of study in astrophysical settings, they are also of great practical relevance to fusion research. LÄS MER