Shaping turbulence – building a framework for turbulence optimisation of fusion reactors


Plasma turbulence is a hindrance to the successful exploitation of nuclear fusion for power generation. The stellarator concept is presently seeing the successful operation of the Wendelstein 7-X (W7-X) experiment. In W7-X the magnetic field geometry is optimised for good confinement. However, due to the computational expense of direct numerical turbulence simulation in 3D stellarator geometry, and the lack of accurate reduced predictive models, turbulence could not be incorporated in the optimisation of the design. But it should, if the stellarator concept is to be a power plant candidate.
We aim at building a framework for turbulence optimisation in stellarators. The key enabling component is a reduced turbulence model sufficiently tractable to incorporate into an optimisation process. This demands understanding the “saturation mechanisms” by which the underlying linear instabilities nonlinearly couple to define the turbulent state. By means of analytical calculations as well as simulations using the advanced gyrokinetics code GENE, we will study and classify the different saturation mechanisms available, and model how both drive and saturation depend on the magnetic geometry. This knowledge is critical for building an accurate turbulence model based on cheap linear calculations, allowing fast simulations of turbulence-driven heat loss. In that way we can explore the large stellarator design-space and tailor a low-turbulence confinement regime.





Dr. J.H.E. Proll

Verbonden aan

Technische Universiteit Eindhoven, Faculteit Technische Natuurkunde


01/01/2019 tot 31/12/2022