Abstract of REFMUL2P Project

Simulation of reflectomentry using a Finite-difference Time-domain (FDTD) code is one the most popular numerical techniques used, as it offers a comprehensive description of the plasma phenomena. This method requires however, to keep error to a minimum, a fine spatial grid discretization, which also implies a high-resolution time discretization to comply with CFL stability condition. As a consequence, simulations, especially in 2D for x-mode, can become quite demanding in computational time. Also, as the size requirements increase in an effort to simulate large devices as JET or ASDEX Upgrade or next generation machines like ITER, memory demands become constringent. While true for o-mode, these constraints are worse for x-mode simulations. To circumvent these questions a parallel version of an x-mode code is a most welcome improvement. REFMULX, a code developed at Instituto de Plasmas e Fusão Nuclear (IPFN) for x-mode reflectometry is a two-dimensional full-wave Maxwell code, using a FDTD Yee scheme [1] where a transversal electric (TE) propagation mode is considered. The 1D parallelization of REFMULX was already implemented successfully within the ongoing HLST-REFMULXP project. The proposed workplan follows along the same lines by envisaging the extension of the parellization to both spatial dimensions. Further, using the knowledge thus obtained, parallelize a new code being developed at IPFN, namely, REFMULF. REFMULF is a 2D full-wave code with full polarization able to cope simultaneous with o- and x-mode and supports a general external magnetic field. It will be able to cope with a wider range of scenarios than the present day codes can. Apart from the added value that a 2D full polarization code brings to reflectometry simulations, this code has all the needed ingredients for an extension to a 3D full-wave code (which has forcibly to be a parallel code). Therefore, the solutions found will also apply to an envisaged 3D code that is much needed in the EU fusion programme.