A dream of powering Earth with the same energy that powers stars will become reality within the next 100 years.

The JET and MAST tokamaks at Culham Laboratory in Oxfordshire are the most successful fusion machines on the planet.

Professor Steven Cowley, Director of the Culham Centre for Fusion Energy, is the winner of the 2012 Glazebrook Medal awarded by the Institute of Physics for his leadership of the UK’s fusion energy programme and his major contributions to plasma and fusion science.

“When fusion energy powers your home, we’ll be there at the finishing line,” he says.


Fusion is what makes stars hot.

What’s going on in the centres of all stars is small nuclei of atoms are being joined together to make bigger ones. It’s a process we would like to harness to power the Earth.

Fusion’s been a long time coming. It has taken a long time to get where we are but we can actually do fusion. And we’ve just always been at the innovative frontier of fusion. So the fusion reaction that we’d really like to do, or we do in fact in JET, is a reaction between two isotopes of hydrogen: deuterium and tritium. Deuterium is heavy hydrogen, tritium is sort of super heavy hydrogen and we want to join them together to make helium and with it lots of energy.

JET is a very large device. I mean, if you stand next to it, you’re dwarfed by its scale. JET is a device that has a radius of 3 metres but in order to get to the stage where we can actually burn a plasma, fully self-sustained fusion, we have to go to the next stage which is ITER.

ITER is twice the size of jet – really an enormous device. The bigger we make the device, the more perfect the confinement of the plasma. And therefore, as we get to bigger devices, the fusion performance goes up and up.

It’s very important in motivating people in a lab like Culham to constantly be showing progress to be moving towards the final goal

One of the challenges of fusion research is that it is not one thing. It is engineering, it is theoretical physics, it is experimental physics, it is material science and you’ve got to put all these things together to make the eventual product. And it is a challenge for someone like me who has spent their whole career doing calculations to really integrate with engineers, fitters, people just working on the machine.

I’ve worked my life trying to understand what the hell is going on inside hot plasmas. Hot plasmas in the cosmos, hot plasmas in fusion experiments. And they wriggle, they shake, they move around. And describing what that is and how that works has been my life’s work.

JET produces a magnetic cage that holds the hot plasma. The shape of that magnetic cage turns out to be very important and JET chose exactly right. And it is that shaping of the cage and the flexibility of the design that has meant that JET has continued to innovate from 1983. And we’re heading on one more year to 30 years of operation of JET, every year getting better.

The flagship of the UK programme is an innovative device called MAST. We evolved the design to what we call a spherical tokamak. It really has remarkable properties. Some of the innovations that we are introducing in the MAST programme will allow us to bring down the cost and the scale of the fusion to a more manageable size making the development of the first commercial reactor easier and something that will be within our grasp.

I don’t like to do research alone. I love doing it for young people because they’re enthusiastic about it, they’re learning about it, they’re working hard, and together, I feel like I am passing on something, but I also feel like I am getting a tremendous amount out of it.

The most enjoyable things that I have ever done, it’s the moments of discovery. The moments when you’re doing a calculation and you say ‘yeah, yeah, that must be right. That just looks right, it feels right ,it seems exactly what the experiment is doing.’

It’s great to just be amongst it. Just to be there. To see the results happen. To have the experiments perform. It is not just your ideas it is everybody else’s ideas it is the collective effort.

This award of the Glazebrook Medal is an award for Culham. Here in South Oxfordshire is a world leading scientific institution and I am very proud about that. I am lucky to lead the organisation.

I’m very lucky to have an extraordinarily strong, clever, motivated, skillful set of people working at Culham. And we’ll be there at the finishing line. We’ll be there when fusion is actually a power source that people will actually get some of their electricity from.

About the film

Filmed on location at:

Director: Martyn Bull
Producer: Thomas Delfs
Camera: Mark Whatmore
Editors: Liam Angell, Mike Willbourne
Cast: Professor Steve Cowley

Production company: insitu
Client: Institute of Physics

Camera: RED Epic, Canon 550D

Solar visualisation: NASA/ESA Helioviewer project
NGC3314 overlapping galaxies: NASA, ESA, the hubble heritage team (STScI/AURA) – ESA/Hubble collaboration, and W. Keel (University of Alabama)
Superbubble in the large magellanic cloud: NASA/CXC/U.Mich/S.Oey, IR: NASA/JPL, Optical: ESO/WFI/2.2-m
ITER images and video: The ITER Organisation

Further reading

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