Sciences Naturelles et de l'Ingénieur

Local and global gyrokinetic simulations of microturbulence in magnetic fusion relevant plasmas using an Eulerian approach

This project deals with the problem of turbulent transport of particles, heat and momentum in magnetically confined plasmas. Such systems are considered as a possible way to tap a virtually inexhaustible, environmentally benign source of primary energy, namely through fusion of hydrogen isotopes. In particular, the ITER project, now under construction in southern France, will address crucial issues regarding this approach, based on the "tokamak" concept.
The most complete model used to describe such turbulent phenomena is based on the so-called gyrokinetic theory. The problem is nonlinear in a 5-dimensional phase space and is solved with advanced numerical methods involving massively parallel algorithms.
The ORB5 code is a truly global gyrokinetic turbulence simulation code based on the Lagrangian approach (PIC) and finite elements. It has been developed at CRPP-EPFL and with major contributions from the Max-Planck IPP in Garching and Greifswald under a longstanding collaboration. It features magnetic coordinates, field-aligned Fourier filtering, non-adiabatic trapped electron response, sources and noise-control algorithms that allow for true statistical steady state to be reached in long simulations. The ORB5 code has demonstrated excellent scalability up to 32768 processors on a BlueGene/P. The present project is an extension of the project that has been running since more than 4 years on the old BlueGene/L at EPFL. It aims at studying shaping, collisional and current profile effects (in particular relevant for internal transport barriers) on electrostatic turbulence in tokamak fusion plasmas.