Simulations of the plasma edge

Figure 1: Simulation of turbulence at the edge of a tokamak using BOUT++. The region to the left of the vertical line is inside the plasma, Plasma "filaments" are ejected from the plasma into the edge.

At the edge of the plasma in tokamaks and other machines, hot plasma leaking from the core meets relatively cool gas, and is channelled towards regions of the wall designed to handle high heat loads (the divertor). Turbulence in this region is important for determining how this heat is spread, and so how much the walls will have to withstand.

At York we develop and use computational tools to simulate the complex dynamics close to the plasma edge region, in particular turbulence and plasma filaments. We lead development of BOUT++ (http://boutproject.github.io/), which is used around the world to study the edge of tokamaks and other devices.

Using these simulations, we aim to understand the characteristics of this turbulence, how it interacts with flows in the plasma, and how the resulting plasma structures move (“filaments” or “blobs” visible on the right of the figure). We aim to use this understanding to improve predictions of how the heat and plasma particles will behave in large fusion devices like ITER.

A topic of particular interest at the moment is the interaction between the plasma turbulence, and the gas which surrounds the plasma. This interaction is currently poorly understood, but could have a significant impact on predictions for future fusion devices. Understanding this involves a complicated combination of plasma, atomic and molecular physics.

Selected publications

J.Leddy, B.Dudson, H.Willett , Simulation of the interaction between plasma turbulence and neutrals in linear devices, Nuclear Materials and Energy, 12, (2017)

B.Dudson, J.Leddy, Hermes: Global plasma edge fluid turbulence simulations, Plasma Phys., 1, (2016)

L.Easy, F.Militello, J.Omotani, N.Walkden, B.Dudson, Investigation of the Effect of Resistivity on Scrape Off Layer Filaments using Three Dimensional Simulations, Plasma Phys., 1 (2015)