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

库勒姆的桅杆升级托卡马克将是研究偏滤器分离物理的世界领先设备，偏滤器分离是一种高密度、低温(Te&lt；5 eV)的区域，被认为是减缓热核实验堆内外偏滤器热通量的主要手段。分离偏滤器中的等离子体条件引起了等离子体离子、燃料原子和分子(以及分子离子)之间的大量化学反应，这些化学反应可以增强等离子体中的能量和动量的耗散，但在计算模型中捕捉这些相互作用是一个严峻的挑战。例如，在聚变社区的最新代码中，假设分子离子等化学活性物种的传输是不存在的，需要解决这一问题。本项目旨在对MAST-U进行计算和实验研究，以表征偏滤器中发生的化学反应和化学活性物种的传输，包括偏滤器固有的H、D和C以及外部杂质如氮气。将应用光谱诊断和模型相结合的方法来识别偏滤器中发生的主要化学反应，并使用综合诊断来辅助数据解释。该项目的目的是测试并在必要时升级模型代码中使用的等离子体化学模型，以改进与实验观测的一致性及其预测能力。希望提供对球形托卡马克废气区域的更多了解，用于未来的原型装置。在本博士课程中，我将学习如何使用现有程序对复杂的等离子体化学进行建模，了解如何解释实验数据。我还将获得科学写作、公共演讲和网络方面的技能。

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.