Simulating and optimising turbulence in stellarators.
Speaker: Josefine Proll (Science and Technology of Nuclear Fusion, TU/e)
Time: May 24, 2018, 10:00–11:00
Location: Differ, Alexander-zaal
Stellarators, the twisted siblings of the axisymmetric fusion experiments called tokamaks, have historically suffered from confining the heat of the plasma insufficiently compared with tokamaks and were therefore considered to be less promising candidates for a fusion reactor.
This has changed, however, with the advent of stellarators in which the laminar transport is reduced by shaping the magnetic field accordingly. As in tokamaks, the turbulent transport remains as the now dominant transport channel. In this talk I want to present the state of the art of modelling turbulence in the - rather complicated - geometry of stellarator plasmas. I will discuss the challenges that need to be overcome - from the choice of coordinates to the limitations in the simulation domain and why we need to learn more about turbulence saturation before quasi-linear models, which are so successfully used for tokamaks, can be applied to stellarators. In the long run, optimising the next generation of fusion devices also for reduced turbulent transport would be the holy grail. I will briefly outline how the STELLOPT code used for the optimisation approaches the multiple-variable optimisation, what has been achieved so far in terms of reducing turbulence, and what is still missing.