An elegant weapon for a more civilised age?
Or so says Obi-Wan as Luke opens a lightsaber for the first time and wields it with somewhat haphazard skill. You know the scene. You’re kind of relieved that Luke’s holding the sabre the right way up as he schvrmmmmmms the blade through the darkness of Obi Wan’s hut on Tattoine. You imagine yourself holding the sabre, feeling its weight in your hand, lunging forward with grace, poise and that sound. Not as clumsy or as random as a blaster, Obi Wan observes, and that’s the beautiful thing.
Disappointingly, however, the laws of physics mean you can’t actually use light this way – light simply travels on until it hits an object, so a controlled blade of this kind can’t exist unless you could confine plasma as a hot gas by means of a complicated magnetic field. Even if you could, says Professor Carsten Welsch, Head of Physics at the University of Liverpool and Head of Communication for the Cockcroft Institute, you also wouldn’t be able to see the blade of the sabre unless you looked directly into it -– ‘in which case it would probably be the last thing you’ll ever see.’
Professor Carsten Welsch
But even as The Last Jedi prepares to hit cinemas, there are advances in laser technology that already allow us to do some incredible things, in clinical surgery for example, where high precision lasers controlled by robot arms can now replace knives.
And if lightsabers themselves still belong in a galaxy far, far away, in the not too distant future of the real world, scientists from a consortium of labs and universities spanning five EU member states aim to build the world’s first high-energy plasma-based accelerator. The EuPRAXIA project, would see a high intensity laser pulse propelling electrons to the speed of light to make advances with applications in science, industry, medicine and the energy frontier.
No-one’s going to be brandishing a blade of light capable of defeating imperial forces any time soon, but plasma acceleration research is at the, well, cutting edge of laser science, and brings us about as close as the laws of physics will let us get.
Lightsabers themselves might be the stuff of fiction, but EuPRAXIA’s 5GeV plasma accelerator would still embody something of their ‘elegance’ and enabling applications such as 3-D printing for metals, non-destructive testing for aircraft, or the production of Free Electron Lasers (FELs) that can be used in the exploration of nanoparticles. Most importantly, EuPRAXIA will work to make accelerators smaller, more portable and cost-effective, opening up even more possibilities for their use. “Assuming results from the final accelerated beam would be even better than that currently achieved, for example ultra-short high energy electron pulses generating highest quality light pulses, then many additional applications across material and life sciences, chemistry and surface studies come into reach,” says Professor Welsch.
Welsch explains that the project is still in the proof-of-principle phase, but EuPRAXIA is establishing dynamic new areas of research and supporting early career researchers with international training programmes. “An important aspect of EuPRAXIA is to identify the exact user, experiment and application needs and determine where a plasma accelerator provides major benefits,” he notes. Cockcroft Institute experts have also held outreach events in UK secondary schools to encourage more pupils to study Physics and cultivate a new generation of researchers. Given there’s a global shortage of accelerator scientists and engineers, (though possibly not wannabe Jedi) there couldn’t be a better time to get involved.
One thing’s for sure, Obi-Wan’s civilised age is getting a little less far away.
• The Cockcroft Institute is an international centre of excellence for accelerator science and technology in the UK. Read more at www.cockcroft.ac.uk
• More information about EuPRAXIA can be found at www.eupraxia-project.eu
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