High-Field Superconductors under Strain that Enable Tokamaks for Fusion Power Generation (Experimental PhD).

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,) measurements as a function of magnetic field (B), temperature (T) and strain 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),T,). 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 first class 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.

Identifying a sustainable energy supply is one of the biggest challenges facing humanity. Fusion energy has great potential to make a major contribution to the baseload supply - it produces no greenhouse gases, has abundant fuel and limited waste. Furthermore, the UK is amongst the world leaders in the endeavour to commercialise fusion, with a rapidly growing fusion technology and physics programme undertaken at UKAEA within the Culham Centre for Fusion Energy (CCFE). With the construction of ITER - the 15Bn Euro international fusion energy research facility - expected to be completed in the middle of the 2020's, we are taking a huge step towards fusion power. ITER is designed to address all the science and many of the technology issues required to inform the design of the first demonstration reactors, called DEMO. It is also providing a vehicle to upskill industry through the multi-million pound high-tech contracts it places, including in the UK.
ITER embodies the magnetic confinement approach to fusion (MCF). An alternative approach is inertial fusion energy (IFE), where small pellets of fuel are compressed and heated to fusion conditions by an intense driver, typically high-power lasers. While ignition was anticipated on the world's most advanced laser fusion facility, NIF (US), it did not happen; the research effort is now focused on understanding why not and the consequences for IFE, as well as alternative IFE schemes to that employed on NIF.

Our CDT is designed to ensure that the UK is well positioned to exploit ITER and next generation laser facilities to maximise their benefit to the UK and indeed international fusion effort. There are a number of beneficiaries to our training programme: (1) CCFE and the national fusion programme will benefit by employing our trained students who will be well- equipped to play leading roles in the international exploitation of ITER and DEMO design; (2) industry will be able to recruit our students, providing companies with fusion experience as part of the evolution necessary to prepare to build the first demonstration power plants; (3) Government will benefit from a cadre of fusion experts to advise on its role in the international fusion programme, as well as to deliver that programme; (4) the UK requires laser plasma physicists to understand why NIF has not achieved ignition and identify a pathway to inertial fusion energy.

As well as these core fusion impacts, there are impacts in related disciplines. (1) Some of our students will be trained in low temperature plasmas, which also have technological applications in a wide range of sectors including advanced manufacturing and spacecraft/satellite propulsion; (2) our training in materials science has close synergies with the advances in the fission programme and so has impacts there; (3) AWE require expertise in materials science and high energy density plasma physics as part of the national security and non-proliferation strategy; (4) the students we train in socio-economic aspects of fusion will be in a position to help guide policy across a range of areas that fusion science and technology touches; (5) those students involved in inertial fusion will be equipped to advance basic science understanding across a range of applications involving extreme states of matter, such as laboratory astrophysics and equations of state at extreme pressures, positioning the UK to win time on the emerging next generation of international laser facilities; (6) our training in advanced instrumentation and control impacts many sectors in industry as well as academia (eg astrophysics); (7) finally, high performance computing underpins much of our plasma and materials science, and our students' skills in advanced software are valued by many companies in sectors such as nuclear, fluid dynamics and finance.