Understanding the role of chemical interactions on detached divertors in MAST-Upgrade

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The MAST Upgrade tokamak in Culham will be a world-leading facility to study the physics of divertor detachment, a high density, low temperature (Te < 5eV) regime which is envisaged to be the primary means of moderating divertor heat fluxes in ITER and beyond. The plasma conditions in detached divertors give rise to a plethora of chemical reactions between plasma ions, fuel atoms and molecules (and molecular ions) that can enhance the dissipation of power and momentum from the plasma but presents a serious challenge to capture these interactions in computational models. For example, the transport of chemically reactive species, such as molecular ions, is assumed to be non-existent in state-of-the-art codes in the fusion community, and needs to be addressed.This project aims to perform computational and experimental research on MAST-U to characterise the chemical interactions that take place and the transport of chemically reactive species in the divertor, including H, D & C intrinsic to the divertor, and extrinsic impurities such as N2. A combination of spectroscopic diagnostics and models will be applied to identify the dominant chemical reactions taking place in the divertor, with synthetic diagnostics to aid data interpretation. The aim of this project is to test, and if necessary upgrade, the plasma chemistry models used in modelling codes to improve agreement with experimental observations and their predictive capability. In hopes of providing additional understanding of the exhaust region of spherical tokamaks for use in future prototype devices.During the course of this PhD I will learn how to model complex plasma chemistries using existing codes, understand how to interpret experimental data. I will also gain skills in scientific writing, public speaking and networking.