This proposal describes a programme of research on single-particle and collective radiation-beam-plasma interactions at high field intensities, production of high-brightness particle beams with femtosecond to attosecond duration, new sources of coherent and incoherent radiation that are both compact and inexpensive, new methods of accelerating particles which could make them widely available and, by extending their parameter range, stimulate new application areas. An important adjunct to the proposal will be a programme to apply the sources to demonstrate their usefulness and also provide a way to involve industry and other end-users. The project builds on previous experiments and theoretical investigations of the Advanced Laser Plasma High-energy Accelerators towards X-rays (ALPHA-X) project, which has demonstrated controlled acceleration in a laser-plasma wakefield accelerator (LWFA), initial applications of beams from the LWFA and demonstrations of gamma ray production due to resonant betatron motion in the LWFA. The programme will have broad relevance, through developing an understanding of the highly nonlinear and collective physics of radiation-matter interactions, to fields ranging from astrophysics, fusion and nuclear physics, to the interaction of radiation with biological matter. It will also touch on several basic problems in physics, such as radiation reaction in plasma media and the development of coherence in nonlinear coupled systems.

The lab in a bubble project is a timely investigation of the interaction of charged particles with radiation inside and in the vicinity of relativistic plasma bubbles created by intense ultra-short laser pulses propagating in plasma. It builds on recent studies carried out by the ALPHA-X team of coherent X-ray radiation from the laser-plasma wakefield accelerator and high field effects where radiation reaction becomes important. The experimental programme will be carried out using high power lasers and investigate new areas of physics where single-particle and collective radiation reaction and quantum effects become important, and where non-linear coupling and instabilities between beams, laser, plasma and induced fields develop, which result in radiation and particle beams with unique properties. Laser-plasma interactions are central to all problems studied and understanding their complex and often highly non-linear interactions gives a way of controlling the bubble and beams therein. To investigate the rich range of physical processes, advanced theoretical and experimental methods will be applied and advantage will be taken of know-how and techniques developed by the teams. New analytical and numerical methods will be developed to enable planning and interpreting results from experiments. Advanced experimental methods and diagnostics will be developed to probe the bubble and characterise the beams and radiation. An important objective will be to apply the radiation and beams in selected proof-of-concept applications to the benefit of society. The project is involves a large group of Collaborators and Partners, who will contribute to both theoretical and experimental work. The diverse programme is managed through a synergistic approach where there is strong linkage between work-packages, and both theoretical and experiential methodologies are applied bilaterally: experiments are informed by theory at planning and data interpretation stages, and theory is steered by the outcome of experimental studies, which results in a virtuous circle that advances understanding of the physics inside and outside the lab in a bubble. We also expect to make major advances in high field physics and the development of a new generation of compact coherent X-ray sources.

In a consortium led by Heriot-Watt with St Andrews, Glasgow, Strathclyde, Edinburgh and Dundee, this proposal for an "EPSRC CDT in Industry-Inspired Photonic Imaging, Sensing and Analysis" responds to the priority area in Imaging, Sensing and Analysis. It recognises the foundational role of photonics in many imaging and sensing technologies, while also noting the exciting opportunities to enhance their performance using emerging computational techniques like machine learning. Photonics' role in sensing and imaging is hard to overstate. Smart and autonomous systems are driving growth in lasers for automotive lidar and smartphone gesture recognition; photonic structural-health monitoring protects our road, rail, air and energy infrastructure; and spectroscopy continues to find new applications from identifying forgeries to detecting chemical-warfare agents. UK photonics companies addressing the sensing and imaging market are vital to our economy (see CfS) but their success is threatened by a lack of doctoral-level researchers with a breadth of knowledge and understanding of photonic imaging, sensing and analysis, coupled with high-level business, management and communication skills. By ensuring a supply of these individuals, our CDT will consolidate the UK industrial knowledge base, driving the high-growth export-led sectors of the economy whose photonics-enabled products and services have far-reaching impacts on society, from consumer technology and mobile computing devices to healthcare and security. Building on the success of our CDT in Applied Photonics, the proposed CDT will be configured with most (40) students pursuing an EngD degree, characterised by a research project originated by a company and hosted on their site. Recognizing that companies' interests span all technology readiness levels, we are introducing a PhD stream where some (15) students will pursue industrially relevant research in university labs, with more flexibility and technical risk than would be possible in an EngD project. Overwhelming industry commitment for over 100 projects represents a nearly 100% industrial oversubscription, with £4.38M cash and £5.56M in-kind support offered by major stakeholders including Fraunhofer UK, NPL, Renishaw, Thales, Gooch and Housego and Leonardo, as well as a number of SMEs. Our request to EPSRC for £4.86M will support 35 students, from a total of 40 EngD and 15 PhD researchers. The remaining students will be funded by industrial (£2.3M) and university (£0.93M) contributions, giving an exceptional 2:3 cash gearing of EPSRC funding, with more students trained and at a lower cost / head to the taxpayer than in our current CDT. For our centre to be reactive to industry's needs a diverse pool of supervisors is required. Across the consortium we have identified 72 core supervisors and a further 58 available for project supervision, whose 1679 papers since 2013 include 154 in Science / Nature / PRL, and whose active RCUK PI funding is £97M. All academics are experienced supervisors, with many current or former CDT supervisors. An 8-month frontloaded residential phase in St Andrews and Edinburgh will ensure the cohort gels strongly, and will equip students with the knowledge and skills they need before beginning their research projects. Business modules (x3) will bring each cohort back to Heriot-Watt for 1-week periods, and weekend skills workshops will be used to regularly reunite the cohort, further consolidating the peer-to-peer network. Core taught courses augmented with specialist options will total 120 credits, and will be supplemented by professional skills and responsible innovation training delivered by our industry partners and external providers. Governance will follow our current model, with a mixed academic-industry Management Committee and an independent International Advisory Board of world-leading experts.

Ultrasonics, the science and technology of sound at frequencies above the audible range, has a huge range of applications in sensing and remote delivery of energy. In sensing, 20% of medical scans rely on ultrasonics for increasingly diverse procedures. Ultrasonics is pervasive in underwater sensing and communication and a key technology for non-destructive evaluation. Ultrasonic devices are essential components in every mobile phone and are being developed for enhanced biometric security. Ultrasound is also important in remote delivery of energy. In medical therapy, it is used to treat neural dysfunction and cancer. Many surgical tools are actuated with ultrasound. As the best way to clean surfaces and bond interconnects, ultrasound is pervasive in semiconductor and electronics fabrication; it is also being explored for power delivery to implants and to give a contactless sense of touch. Such a broad range of applications predicts an exciting future: new materials will emerge into applications; semiconductor circuits will deliver smaller, more convenient instrumentation systems; autonomy and robotics will call for better sensors; and data analysis will benefit from machine learning. To maintain competitive advantage in this dynamic and multidisciplinary topic, companies worldwide rely on ambitious, innovative engineers to provide their unique knowledge of ultrasonics. As a significant contribution to address this need, Medical & Industrial Ultrasonics at the University of Glasgow and the Centre for Ultrasonic Engineering at the University of Strathclyde will combine to form the Centre for Doctoral Training in Future Ultrasonic Engineering (FUSE), the largest academic ultrasonic engineering unit in the world. Working with more than 30 external organisations, from microcompanies to multinationals, this will, for the first time, enable systematic training of a new generation of leaders in ultrasonics research, engineering and product development. This training will take place in the world-class research environment provided by two of the UK's pre-eminent universities with its partners, creating a training and research powerhouse in ultrasonics that will attract the best students and put them at the global forefront of the field.