Effect of Alpha-Particle Transport on the Fusion Energy Gain in Burning Plasmas – Plasma strand project
Supervisors: Juan Ruiz Ruiz and David Dickinson (University of York), Michael Barnes (University of Oxford) & George Wilkie (Princeton Plasma Physics Laboratory).
Next-generation burning plasma experiments such as ITER, STEP, and SPARC will qualitatively differ from current magnetic confinement fusion experiments in the large populations of 3.5 MeV alpha particles generated by the deuterium-tritium (DT) reaction. In a burning plasma, alpha particles should remain confined for a long-enough time to heat the rest of the thermal plasma particles via collisions. One of the primary concerns for obtaining good alpha-particle confinement is the presence of Alfvénic instabilities, known as Alfvén eigenmodes (AEs). These modes are perturbations to the magnetic field, analogous to waves propagating on a string, and can be driven unstable by the alpha particles themselves. By perturbing the background magnetic field, AEs give rise to high transport of the alpha particles. Due to the large populations of alpha particles expected in a burning plasma, future burning plasmas will likely exhibit large AE activity. If the alpha-particle confinement degrades, alpha particles will not efficiently heat the thermal plasma, which will have a detrimental impact on the fusion energy gain (Q).
Current projections of the fusion energy gain in machines such as ITER, STEP, and SPARC are either based on 0-D empirical scalings, or assume no alpha-particle transport. Quantitatively assessing the effect of alpha-particle transport on the fusion energy gain is still an open question, and is the primary goal of this project. By using advanced analytical calculations, the student will derive the transport power-balance equations for a burning plasma, including the thermal and alpha particles, and will use state-of-the-art numerical tools (nonlinear gyrokinetic simulation) to calculate the thermal and alpha-particle transport expected in a burning plasma. The student will then numerically solve the power-balance equations to calculate the steady-state profiles of the temperature and alpha-particle pressure. This will allow calculation of the fusion power gain.
The student will present this work internally and in international conferences and workshops, and will produce publications in high-impact, internationally recognized journals. An emphasis will be placed on acquiring communication skills, both oral and writing, as well as in establishing collaborations with partner institutions, .e.g. UK Atomic Energy Authority (UKAEA), Tokamak Energy, or Princeton Plasma Physics Laboratory.
The project is expected to be primarily based at the University of York, with potential visits to collaborating institutions (e.g. UKAEA, Tokamak Energy, Princeton Plasma Physics Laboratory).
During the first six months of the PhD students will typically travel to undertake taught modules at all of the Fusion CDT partner universities.
This project is offered by University of York. For further information please contact: Juan Ruiz Ruiz (juan.ruizruiz@york.ac.uk), David Dickinson (d.dickinson@york.ac.uk) or Michael Barnes (michael.barnes@physics.ox.ac.uk).
For details on how to apply, please visit: Apply