| Izvleček: | <p>Nuclear fusion has the potential to be the reliable, clean, safe, and fuel-abundant source of baseload power necessary to meet the ever-increasing global energy demand. One technological roadblock is dealing with the heat load that escapes the core confinement region and must be exhausted within the vessel on a component known as the divertor, without causing it excessive damage. A thin liquid metal film covering a solid divertor substrate is one promising direction that may be capable of sustaining the predicted heat loads. It is therefore of great scientific and industrial interest to study the dynamics and stability of a thin liquid metal film within a tokamak (toroidal plasma confinement device).</p> <p>In this thesis we develop a model of the liquid-metal divertor. We derive the equations governing the flow of a liquid metal on a substrate in the presence of a strong magnetic field. Focusing on the asymptotic limit in which the film is thin compared to its length, and the induced magnetic fields are relatively weak, we derive a generalised thin-film equation governing the film thickness and study the stability of such flows in configurations not previously analysed.</p> <p>We extend the model to capture the transfer of heat and momentum to the fluid film as the core plasma is exhausted onto the divertor. This allows us to study how the free surface of the fluid is displaced, and whether it may be maintained in a sufficiently stable state. In particular, we analyse the effect on the liquid film of an oscillating plasma jet, and determine how operating parameters may be tuned to minimise the resulting free-surface displacements. We also show how the cooling channels within the divertor may be designed so as to minimise displacements.</p>
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