Section: New Results
Full wave modeling of lower hybrid current drive in tokamaks
Participants : Pierre Bertrand, Simon Labrunie, Takashi Hattori, Jean Rodolphe Roche.
This work is performed in collaboration with Yves Peysson (DRFC, CEA Cadarrache).
The aim of this project is to develop a finite element numerical method for the full-wave simulation of electromagnetic wave propagation in aplasma. Full-wave calculations of the LH wave propagation is a challenging issue because of the short wave length with respect to the machine size. In the continuation of the works previously led in cylindrical geometry, a full toroidal description for an arbitrary poloidal cross-section of the plasma has been developed.
Since its wavelength
With such a description, usual limitations of the conventional ray tracing related to the approximation
The domain considered is as near as possible of the cavity filled by a tokomak plasma. Toroidal coordinates are introduced. In our approach we consider Fourier decomposition in the angular coordinate to obtain stationary Maxwell equations in a cross-section of the tokamak cavity.
A finite element method is proposed for the simulation of time-harmonic electromagnetic waves in a plasma, which is an anisotropic medium. The approach chosen here is sometimes referred to as full-wave modeling in the literature: the original Maxwell's equations are used to obtain a second order equation for the time-harmonic electric field. These are written in a weak form using an augmented variational formulation (AVF), which takes into account the divergence. The variational formulation is then discretized using modified Taylor-Hood (nodal) elements.
During 2011 we introduced a new boundary condition in order to take account of the antenna and essential condition are considered in the code "FullWaveFEM" and new real case was considered.