Fusion energy research rewards science

Still with us, Imperial College's Brian Appelbe...

Chris - As I listened to what Hannah said, Brian, and what you told us at the top of the programme, I'm increasingly coming to the view that this is less a physics problem now and more a material science and an engineering challenge. Is that fair or are there still quite a lot of scientific issues to solve?

Brian - What I would say is because we've had successes on the scientific side over the last few years, such as what happened at the National Ignition Facility in America, we are beginning to think more about the engineering challenges. So we still have lots of physics that we need to do to make sure we fully understand how these plasmas behave. But there is a confidence building that we need to start thinking about the next set of problems about how we recover the energy, how we drive these reactions. I think we can straddle both of these challenges.

Chris - Have we created those sorts of conditions on Earth before or are we into uncharted territory trying to make things at 200 million degrees?

Brian - So I think for me personally and for a lot of my colleagues that's the really exciting thing. That when we step back, at the end of the day, what we're doing is we're creating these unique plasmas on earth. It's the hottest substance that we can create and therefore we're able to study it in the laboratory. And what that can do is it can tell us a lot of things about, say, how the universe behaves, how things like supernovae evolve, and how elements are formed in the universe. So whilst trying to achieve the commercial goals of fusion energy, we are still doing fundamental science.

Chris - How will scientists be trying to tackle this? Is this all about computer modelling? Is this just building really powerful computer systems that can work out, when we put things under this enormous strain and pressure and we scale it up to the sorts of sizes that they're talking about, then trying to work out where the particles are trying to go and how fast, and therefore how much energy they're dissipating. Is it basically a computer modelling problem?

Brian - Computers are very, very helpful and we use the world's most powerful computers for doing simulations of these plasmas. But the fundamental issue really is that when you are trying to do fusion, you always are trying to balance a pencil on its point. We have all these instabilities that we have to fight to keep our hot plasma confined. And so the computer simulations help us to understand how we can keep the pencil balancing on its point. But at the end of the day, computer simulations are not infallible. We have to make sure that they're correctly predicting the outcomes of the existing experiments that we can do.

Chris - Do you think George Freeman's going to get his dream in 2040? There'll be a plant running, it will be a net producer of energy?

Brian - If he is willing to support his dream with whatever cash is required, then yes. I always think of the moon landings in 1960. JFK said at the start of the 1960s, America will put a man on the moon by the end of the decade. And he didn't talk about the commercial aspects of it. That was the goal. Get a man on the moon. And I think that's what we should be doing with fusion.

Chris - He also said, "we don't do it because it's easy, we do it because it's hard." And this is a sort of similar problem, isn't it?

Brian - I think so. Yes. I feel we need that attitude.

Chris - And presumably in the course of solving this very hard to solve problem, a bit like the Reimann hypothesis has made mathematicians develop all kinds of exciting new maths to find prime numbers, and they still haven't won the prize. They nevertheless have done some exciting maths doing it. Are we discovering some exciting physics along the way?

Brian - We certainly are. We're discovering lots about astrophysics, also technology developments, things like laser developments, high temperature superconducting magnets. There's lots of technologies that are required for fusion whereby it's the investment from fusion that's driving the progress.