Simulating and optimising turbulence in stellarators

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 give a brief overview of what we know about turbulence and the underlying instabilities in the - rather complicated - geometry of stellarator plasmas. I will show that some stellarators with a particular magnetic field are more stable towards the turbulence-causing instabilities than others, and discuss what is still missing before these findings can be translated into accurate turbulence predictions for general geometry. Ultimately, these predictions will be necessary to allow us to optimise stellarators not only for laminar, but also for turbulent transport.

Thursday, February 14, 2019 -
11:15 to 12:15
seminar room
Josefine Proll