High-Field Superconductors under Strain that Enable Spherical Tokamaks for Fusion Power Generation (Materials Strand Project)

Supervisor/s – Prof. D. P Hampshire (Durham University)

Materials Strand project – an experimental PhD project.

Background to the PhD Research Project:
The ITER (International Thermonuclear Experimental Reactor) Tokomak that is being built in Cadarache in France is one of the most exciting scientific projects at the beginning of the 21st century (http://www.iter.org/). It will produce 500 MW which is about ten times the power needed to run the machine. Superconductivity is the enabling technology for this project since without it, the magnets that hold the plasma would either melt or consume more energy than the tokamak produces. Approximately one third of the cost of ITER comes from the superconducting magnets which use low temperature superconductors. Recent work has demonstrated that the next generation of fusion tokamaks may be most effective at higher fields than ITER – more than ~ 16 Tesla – which opens the question of whether we can develop high-temperature superconductors, that have higher current densities and upper critical fields, to enable commercial fusion energy http://www.superpower-inc.com/content/2g-hts-wire. The current density in these high temperature superconductors is still typically less than 1 % of the theoretical limit in high magnetic fields and there is no agreement about why it is so pitifully low. In Durham, we have developed purpose-built facilities to make transport critical current density JC(B,T,ε) measurements as a function of magnetic field (B), temperature (T) and strain (ε) on 2G tapes. This PhD is directed at measuring the best available conductors, using our state-of-the-art horizontal Helmholtz-like 15 Tesla magnet system in Durham, as well as using the magnets at the International high-field facilities in Grenoble. The timescale for first-plasma at ITER (2025) offers a wonderful opportunity for early career Physicists to help pioneer our understanding of high field superconducting materials for fusion applications.

PhD Research Project and Supervision :
In this PhD research programme, the student will measure both the fundamental and extrinsic properties of superconducting materials including the critical current density JC(B(θ),T, ε,). Important research questions include: What is the mechanism that determines the critical current in high magnetic fields of high temperature superconductors? How can we optimise HTS materials to enable commercial fusion energy ? What is the role of anisotropy/reduced dimensionality in these materials? Why is the critical current density in state-of-the-art materials 2 or 3 orders of magnitude lower than the theoretical limit in high magnetic fields? Can we understand the nature of flux pinning and flux flow in high Jc materials under strain? This is a fabulous PhD project that is ideal for a student with a good degree in Physics and a broad interest in materials and applied Physics. They will be expected to network with scientists throughout the world working on fusion.

The PhD supervisory team will include Prof. Damian Hampshire who is an experienced member of the high-field applied superconductivity and fusion energy community. The 4 year PhD is funded through the Fusion CDT partnership which gives an excellent exposure to many of the best Universities in the UK, an excellent taught course in fusion energy and exposure to the fusion community across Europe. The PhD is formally based at Durham for access to high magnetic fields and cryogenic facilities, but the training in the fusion CDT means you spend about 6-8 months during the first year of your PhD at CDT partner Universities and will include regular visits to CCFE. It will also probably involve working in an International laboratory (usually the USA, Japan or EU) for at least one collaborative project in the 2nd or 3rd year. The Research Groups are committed to developing an environment that produces world-class science and is inclusive, flexible and family-friendly.

Skills the student will learn during the PhD:
Transferable Skills:
Communication: Presentations at conferences and developing collaboration.
Personnel: Networking skills. Working with expert senior staff, junior staff and staff providing services.
Writing: Reports, Conference and Journal publications.
Computerised Data Acquisition and Analysis.
Technical Design: CAD Design of hardware with new functionality and understanding materials
Knowledge: Understanding magnetically confined fusion and high field superconductors.
Time management.

Specialist Skills and Know-how:
Knowledge: High field superconductors for fusion applications.
Use of: High magnetic fields; Cryogenic liquids; High performance computers; High current power supplies; Low voltages; materials at high and at cryogenic temperatures.
Design of new experiments.

The project will be mainly based in Durham University, but will include regular visits to CCFE. It will involve overseas travel to: Japan or the US for a collaboratory for 6 – 8 weeks; the USA and/or Japan and/or Europe for conferences and collaborations; Japan or France to use International High Field Facilities.

This project is offered by Durham University. For further information please contact: Prof. Damian Hampshire (d.p.hampshire@durham.ac.uk)

Send your CV, a covering e-mail that includes a brief explanation of why you are interested in Superconductivity and Fusion Energy and your availability for interview. Web-pages: http://www.ccfe.ac.uk/JET.aspx and http://community.dur.ac.uk/superconductivity.durham/personnel.html. CCFE is the fusion research arm of UKAEA.

This project may be compatible with part time study, please contact the project supervisors if you are interested in exploring this.

Image above: P.O. Branch, Y. Tsui, K. Osamura and D. P. Hampshire. Weakly-Emergent Strain-Dependent Properties of High Field Superconductors. Nature Scientific Reports 9:13998 (2019).