Keeping heat and particle fluxes to the surrounding wall structures of magnetically confined fusion plasmas within engineering limits and simultaneously ensuring high core plasma confinement constitutes one of the main challenges for the success of fusion energy. Plasmas with a negative triangularity (NT) core shape have recently emerged as a very promising option, featuring high core performance without the need of an edge transport barrier that is generally accompanied by violent transient events called ELMs.
However, the dynamics in the boundary plasma region of NT plasmas and in particular the access to a detached regime are mostly unexplored to date. In this 1-year project, we propose to perform first-principles, real-size turbulence simulations of the boundary plasma in the Tokamak à Configuration Variable (TCV) at EPFL, with a specific focus on the effect of triangularity on turbulence, transport and the detachment characteristics.
The simulations will be performed with the three-dimensional turbulence code GBS that evolves in time the electromagnetic drift-reduced Braginskii equations coupled to a kinetic, multispecies neutral model. These simulations and their analysis and in-depth validation against an extensive set of experimental measurements will constitute an important step in developing reliable, theory-based predictive capabilities of NT for future devices.
EPFL, Switzerland.