Hannover 2016 – wissenschaftliches Programm

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P: Fachverband Plasmaphysik

P 5: Poster Session- Helmholtz Graduate School for Plasma Physics

P 5.14: Poster

Montag, 29. Februar 2016, 16:30–19:00, Empore Lichthof

A Monte-Carlo scheme for cross-polarization scattering of diffracting wave beams in random media. — •Lorenzo Guidi^{1, 2}, Omar Maj¹, and Emanuele Poli¹ — ¹Max Planck Institute for Plasma Physics, Garching, Germany — ²Technische Universität München, Numerical Methods for Plasmaphysics (M16), Garching, Germany

Asymptotic methods are widely used in studying the evolution of high frequency waves in plasmas. In this framework singularities in the configuration space can arise, and a phase-space representation of the model is one of the possible ways to overcome such difficulties; the result is a description of waves in terms of the kinetic wave equation. Fluctuations of the medium and consequent scattering phenomena can be taken into account, allowing the analysis of problems which are considered extremely relevant in the prediction of wave beam performances for the next-generation tokamak machines. The WKBeam code provides a numerical solution of the kinetic wave equation in the phase-space, taking into account random density fluctuations by means of a statistic average and assuming that scattering between different modes, i.e. cross-polarization scattering, can be neglected. The idea of this work is to include cross-polarization scattering phenomena into the WKBeam code, allowing simulations of a wider class of experimental scenarios. In order to obtain this, the Monte-Carlo scheme implemented in WKBeam is extended, providing a description of random jumps of both the refractive index (a continuous process) and the wave mode (a discrete process), due to fluctuations of the medium.