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Spring 2017, Number 10 Department of Physics Newsletter FROM OXFORD TO MARS The enigma of methane on Mars PAVING THE WAY TO THE IMPACT OF OUR A NEW GENERATION POWERED BY RESEARCH OF LIGHT SOURCES A STAR A new collaborative Plasma acceleration Astronomy off the grid initiative with Industry www.physics.ox.ac.uk PROUD WINNERS OF: SCIENCE NEWS SCIENCE NEWS www.physics.ox.ac.uk/research www.physics.ox.ac.uk/research being commisioned at the graduate training. The graduate course offered to JAI German Electron Synchrotron students is coordinated by Prof Emmanuel Tsesmelis PAVING THE WAY Centre (DESY, Hamburg) – but (CERN/JAI) and combines classic accelerator theory about a hundred times smaller, with plasma and laser physics, as well as real life thanks to advantages in plasma experiences such as lectures given to students via video TO A NEW GENERATION acceleration. from the heart of the LHC-CERN control room. Building an FEL based on The JAI graduate training is world renowned with its OF LIGHT SOURCES plasma acceleration requires trademark being the students’ design project. In this solving a number of challenges. project, all first-year JAI graduate students work as a For instance, if we scale up all One of the most spectacular phenomena, as we often hear Excited by the recent progress, we should also be vigilant team for two months to design an innovative accelerator, Professor Andrei Seryi, the phase space dimensions, from schoolchildren visiting our Physics Department, about the next steps. The time it takes to design and ensuring that all the major systems (optics, magnets, Director of the John the beam accelerated by plasma is a meteor shower – a wide glowing trail left by tiny build any new accelerator or collider, and the fact that accelerator systems) are self-consistent. The projects vary Adams Institute (JAI) looks like a sheet of A4 paper – grains of matter on the night sky. Even more amazing their sizes and costs tend to increase, slowing down each year, with recent projects ranging from a plasma IMAGES IN FIG. 2 COURTESY PROF ZULFIKAR very thin (in size) and wide (in (rare but still possible in Oxfordshire) are Aurorae progress in recent decades, indicates that a technological accelerator for proton therapy to the electron-positron NAJMUDING (IMPERIAL COLLEGE AND JAI), angular and energy spread). Our dream beam, however, Borealis, the result of interaction of ‘solar wind’ – the revolution is required to make further progress. Back in J. COLE ET AL, SCI REP. 2015 AUG 18;5:13244. DOI: option of the Future Circular Collider. 10.1038/SREP13244. would have the same volume but would be round, like accelerated subatomic elementary particles – with the 1940 Enrico Fermi dreamed about a giant accelerator a hazelnut. Creating a beam with proper phase space Earth’s atmosphere. on a stable orbit that circled the Earth. We now need The JAI students’ design project utilises a proven and suitable for FEL is a task we are currently working on. to be much more responsible and ensure that every effective hands-on approach. It allows students to Another challenge we have is the limitation imposed Cosmic rays – elementary particles of tiny masses, which technological advance is explored and exploited before master and put into practice the theoretical concepts by high power solid-state lasers needed for plasma enter the Earth’s atmosphere with the energy of a cricket we can propose to funding agencies a collider even two and methods they have learnt during the previous excitation which, unfortunately, have low repetition rates ball – are much more difficult to observe with a naked or three times larger than the LHC. terms’ lectures. eye and even their acceleration mechanism still remains (just a few Hz), and very low ‘wall-plug’ efficiency. The multi-pulse plasma acceleration technology developed a mystery. Yet we are often asked by schoolchildren; can Thinking about the next technological revolution in The JAI’s graduate training approach has been by our team and led by Prof Simon Hooker (JAI/Oxford) we create such cosmic rays in the laboratory, and if so, accelerators, we can recall that some plasma physicists successfully applied in 2016 at the US Particle could use high-repetition-rate fibre lasers to overcome why would we want to do this and how would we use have recently argued that the above-mentioned ultra- Accelerator School (USPAS) where Prof Andrei Seryi this difficulty. such scientific tools? high-energy cosmic rays are, in fact, the result of plasma (JAI/Oxford) and Dr Aakash Sahai (JAI/ICL) taught acceleration happening far away in our Galaxy. These a one-week class on ‘Unifying physics of accelerators, Following Freeman Dyson, who refuted the idea While the plasma acceleration FEL is being actively same processes may drive the technology to create the lasers and plasma’. Here the design project had to be of concept-driven scientific revolution and instead developed, a compact incoherent light source based on next breakthrough here on Earth. And even though we completed in just one week, so detailed simulations argued that creation of scientific tools drives progress, plasma acceleration (see Fig. 1) is already possible and do not directly study cosmic rays at the John Adams were replaced by estimations of the parameters of the we are well armed to answer these questions. We can can actually be quite bright. In fact, it is comparable in Institute (JAI) for accelerator science, we are looking key systems. point schoolchildren to the many tens of thousands into this technology as a possible workhorse for next peak brightness with the third generation synchrotron of accelerators used in science and industry. We can generation colliders and various other accelerators. light sources. The x-rays produced by such sources have describe how physicists and engineers can, in fact, already been used in trials conducted in consultation The results of this JAI-led USPAS class exceeded our compete with nature. Even though the elementary Conventional accelerators operate on the principle with medical experts. For example, the team led by Prof expectations; the students were able to develop a novel particle energies achieved in accelerators are less of particle acceleration in resonators, these are metal Zulfikar Najmudin of JAI/Imperial College London design of an x-ray source based on a compact storage than a millionth of those of the most energetic space containers of a certain shape that have a limited ability (ICL), is studying microscopic bone damage caused ring of an electron beam with on-orbit and on-energy particles, we can accelerate billions and billions of to withstand strong electromagnetic fields due to by osteoporosis – see Fig. 2. injection by a laser plasma acceleration system. Based particles simultaneously. Moreover, we have found possible electric breakdowns and destruction of the on their successful design, the team of students were ways to focus the particle flux and compress it to a tiny resonator walls. However, the wave produced in plasma, invited to present their concept at the prestigious A BOLD NEW APPROACH TO TRAINING North American Particle Accelerator Conference size. For instance, one of the most ambitious modern a material which is already ‘broken-down’, can create Figure 1 (opposite below): ACCELERATOR SCIENTISTS (NAPAC 2016) where the USPAS leadership praised accelerators – the Large Hadron Collider (LHC) an accelerating gradient a thousand times larger, which Concept of an incoherent x-ray their achievement. at CERN – accelerates proton beams to an energy would allow us to reduce the size of the accelerators. source based on laser-plasma Work on novel technologies such as plasma acceleration equivalent to that of a Boeing 747 at take-off, and this accelerator. FEL and light sources requires a new approach to energy is concentrated within a ‘point’ less than a human Following the research and training principles outlined hair in diameter. PLASMA-BASED COLLIDERS: FROM CONCEPT TO Figure 2 (opposite above): above, the JAI is determined to bring its basic research REALITY Tomographic reconstruction of to industrial, medical and societal applications in trabecular bone sample: the near future. We hope that our research will help PAVING THE WAY FOR NEW ACCELERATORS We are often asked the question: ‘when will plasma acceleration-based colliders become a reality?’ The a) a raw image of the bone to design compact sources of synchrotron radiation Discoveries such as those enabled by accelerated beams answer is, certainly not tomorrow: the research and sample recorded on the x-ray that are based on synergy between lasers and new can shake our imagination and amaze us, both with the development roadmaps toward plasma acceleration camera; accelerators. We believe that these sources will be able ability of modern physics to predict them, and with colliders created by US and European communities b) 2D reconstruction of a one- to revolutionise the world of accelerator physics and their ever-reaching consequences. The Higgs Boson extend to around 2035. pixel high horizontal slice of the its applications, as has happened with the invention (predicted back in 1964 and revealed in 2012 by an sample at the position indicated of visible-light lasers, which spurred science and instrument, the LHC, whose construction began in With colliders in mind, here at the JAI we are strongly in a); industry in the 20th century. In particular, the 1998) is of profound importance for understanding the focused on plasma acceleration applications that have a c) stacking together 1,300 such development of very compact sources of x-ray pulses, mechanism that creates masses of all subatomic particles. more immediate use for society and industry: compact slices generates a 3D voxel map the first likely application of plasma accelerators, Discoveries that, we hope, are still to come at the LHC, light sources.

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