Supervisors: Peter Hill (University of York), David Dickinson (University of York) & James Cook (UKAEA).
The edge region of tokamak devices is a crucial part of the plasma, as it includes the exhaust and essentially sets the boundary conditions for the whole device. Unfortunately it is also complex, often requiring multiple models to capture the physics of the bulk plasma, ionised and non-fully ionised impurities, and neutral species, all of which can interact over many spatial and time scales. These different models require different numerical techniques to simulate, for example particle-in-cell (PIC) for the charged impurity species and finite elements (FEM) for the bulk plasma. High fidelity simulations that can be used to inform the design of reactors also need uncertainty quantification (UQ). UQ is often computationally expensive, as it requires many simulations to cover the parameter space, but as we move into the exascale era this is becoming more feasible. This PhD project will benefit from interaction with the team working on the ExCALIBUR (https://excalibur.ac.uk) project, which draws upon all of these technologies.
The main objective of this project is to investigate coupling software to allow state of the art FEM-PIC simulations in a UQ framework that can be run on exascale machines. This will involve, among other things, helping develop algorithms for the FEM-PIC coupling, developing efficient off-loading onto GPUs, and integrating the FEM-PIC software into a UQ framework. The plasma physics applications of this PhD include, but are not limited to, ion cyclotron emission (ICE), which, for the next generation of studies requires FEM and PIC and UQ. ICE is a passive diagnostic for confined and leaving fast ions in toroidal fusion plasmas and is under consideration as a diagnostic for ITER. There may also be opportunities for linking with experiments.
This project is ideally suited to a student interested in software development and high performance computing. Experience in at least one programming language would be very beneficial. As part of this project there will be ample opportunities to develop software engineering, computational physics and mathematics skills. Training will include C++ and sustainable software development.
This project will be mainly based in York with the opportunity to spend time with the ExCALIBUR-NEPTUNE team in Culham (Oxfordshire).