Staff profile

I am a PhD student in the Durham University Superconductivity Group, studying Ginzburg-Landau and microscopic theory for high-field, high-temperature superconductors used in fusion applications. I hold a first class integrated master’s degree in Physics from Durham University and am part of the EPSRC Centre for Doctoral Training in Fusion Power. 

Fusion CDT

The Fusion CDT is an innovative and forward-looking programme where six universities (Durham, Liverpool, Manchester, Oxford, Sheffield and York) collaborate with over 20 partners in the private industry and national and international laboratories to ensure that students are well-equipped to contribute to the development of fusion and maintain the UK's sustained leadership in this critical field. The primary focus of the first six months of my PhD is the training programme provided by the Fusion CDT, where I am attending a series of modules delivered by academics and industry experts that focus on plasma physics, plasma-surface interactions and materials science.  

Research Interests

Fusion energy is being developed to provide a long-term, large-scale source of energy without the emission of greenhouse gases or the creation of radioactive waste, complementing renewable energy sources like wind and solar, to meet the rise in global energy demand sustainably. For fusion energy devices, and tokamaks in particular, superconductors are now a core enabling technology due to their ability to sustain large currents without dissipation to produce high magnetic fields. However, observed values of the critical current density (J_c) in superconductors are found to be orders of magnitude below the theoretical limit [1], offering the opportunity for a huge technological improvement and an essential cost saving in the development of fusion reactors. 

My current work focuses on developing an understanding of the current-carrying capacity of grain boundaries and internal interfaces in superconducting, polycrystalline, high-field, anisotropic materials, such as the REBCO (rare-earth barium copper oxide) coated superconductors used in fusion [2]. I am using time-dependent Ginzburg-Landau (TDGL) theory and numerical simulations to study the critical current density across REBCO grain boundaries using 2D anisotropic and d-wave SNS (superconductor-normal-superconductor) Josephson junctions in order to identify routes to improve the transmission of current across grain boundaries.

In my future work, I will be using computational techniques and TDGL theory to model polycrystalline low-temperature superconductors (LTS) and high-temperature superconductors (HTS) and LTS with inclusions, with particular focus on the mechanism of flux pinning and the modes of flux flow in high-field superconductors and the intention of increasing high-field critical current values in the superconductors used in fusion applications. I will also be using microscopic theory and analytic calculations to better understand and explain the empirical scaling laws that have been developed to describe the vast majority of high-field, high-temperature superconducting materials discovered since the development of the BCS theory, which cannot explain the HTS materials used in fusion applications, in order to improve understanding of the mechanism causing superconductivity.  

Simulations are carried out using a solver developed in the Julia programming language by Charles Haddon of the Durham University Superconductivity Group. The solver employs a non-linear geometric multigrid method to compute superconducting properties in discretised space and remains stable for arbitrary values of the Ginzburg–Landau parameter κ, unlike many other solvers that are restricted to the high-κ limit.

[1] G. Wang, M. J. Raine, and D. P. Hampshire, “How Resistive Must Grain-Boundaries be to Limit Jc in Polycrystalline Superconductors?,” Supercond. Sci. Technol., 30, 10, (2017). Art. no. 104001.

[2] Z. S. Hartwig et al., "The SPARC Toroidal Field Model Coil Program", IEEE Transactions on Applied Superconductivity, 34(2), 1-16, (2024).