Abstract of FWTOR Project

In the field of electromagnetic wave propagation in tokamak plasmas, the mainstream in theory and applications is oriented to frequency-domain asymptotic methods assuming linear plasma response, where the solution of the wave-plasma system is more feasible. However, in many cases of interest (O-X-B mode conversion, high-power ECRH, mm-diagnostics) this approach typically breaks down. In such cases, asymptotic methods are in principle robust in still providing a meaningful solution, however the results are questionable and one should resort to a full-wave solution for validation. FWTOR is a full-wave code, written in Fortran 95, which solves Maxwell's equations for the propagation and absorption of electromagnetic wave beams in tokamak plasmas implementing the FDTD method. The plasma response is formulated in terms of the linear plasma dielectric tensor, the magnetic equilibrium can be analytic or experimental, including non-axisymmetric magnetic perturbations (e.g. due to NTMs) and density fluctuations (e.g. due to edge turbulence), while the wave beam profile can have arbitrary shape. The code purpose is to conduct thorough investigations of the electromagnetic wave propagation and absorption in plasma geometry relevant to EC/IC/LH applications in ITER H&CD, mm-diagnostics and MHD control, as well as to perform benchmarks with the currently established tools in the field. A caveat of the current version of the code is that it is not parallelized optimally (only auto-parallelization has been attempted, which provides a very small improvement in the performance). The central aim of this project (in collaboration with the HLST team) is to conduct code parallelization in a mixed OpenMP-MPI scheme and include check-point/restart functionality in the code.