Filamentary plasma eruptions and their control on the route to fusion energy

Filamentary plasma eruptions and their control on the route to fusion energy

Filamentary plasma eruptions and their control on the route to fusion energy 150 150 UKAEA Opendata
UKAEA-CCFE-PR(19)39

Filamentary plasma eruptions and their control on the route to fusion energy

Fusion is one of very few options for sustainable, baseload power to the grid that is necessary to meet the energy needs of future generations. The tokamak is the most advanced approach to fusion and, with the construction of ITER, we are approaching power plant conditions. While commercialisation of this key technology is a main driver for tokamak plasma physics research, it is nevertheless a field that is rich in fundamental science, including complex phenomena such as self-organisation and bifurcations. For example, as the heating power is increased above a threshold, the tokamak plasma suddenly bifurcates to a state of high confinement, creating a region of high plasma pressure gradient at its edge. This is a fascinating piece of plasma physics, but the focus here is on the consequence of this bifurcation, rather than the cause – understanding the repetitive sequence of explosive filamentary plasma eruptions called Edge Localised Modes (ELMs). ELMs on next step tokamaks, such as ITER, will cause excessive erosion to plasma facing components, and therefore must be controlled. There are several options, but one is the use of a system of current-carrying coils positioned around the plasma. The idea is to use them to fine-tune the quality of the confinement in the edge plasma region, reducing the pressure gradient there below the threshold required to drive ELMs.

Collection:
Journals
Journal:
Nature Reviews Physics
Publisher:
Nature
Published date:
14/02/2020