Lawrence Livermore National Laboratory

What is fusion, and where does research stand right now?

Well, fusion is the process of combining atoms, of overcoming those atoms' mutual electric repulsion so that they bind together. Quite a lot of energy is produced when this happens. And while people have already created fusion in experiments for decades, it's always been a process that takes in a lot more energy than it gives out. And it doesn't have to be. We're trying to bring experimental fusion to a point where the whole process starts to feed back on itselfwhere fusing atoms encourages more fusion to happen so that it becomes self-sustainingwhich we call ignition. And that's going to be necessary if fusion is ever going to be useful for power generation.

Everyone who's trying to create self-sustaining fusion is basically trying to achieve the same thing. That's being able to apply enough pressure to plasma for a sufficient amount of time that [the atoms] fuse together. Because that's just pressure and time, there are a number of methods you can use to get to that point.

Which method is the National Ignition Facility using?

Our laboratory was designed to develop and study what's called inertial confinement fusion. We're using lasers to place an extraordinarily high pressure on our plasma, around 300 billion atmospheres, but only for a very small amount of time: a fraction of a billionth of a second.

The other most common method being investigated is called magnetic confinement fusion. That's where you use magnetic fields to confine your plasma with relatively modest pressure, but you have to hold on to it for many seconds, which is not easy.

There is also a variety of other, lesser-known waysusing ion beams, for example. All these methods have pros and cons, and, honestly, I don't think we know enough yet to say which is the best method.

Last February your lab announced an exciting breakthrough called fusion bootstrapping. What happened?

What we really want is some of the energy that's created in a fusion reaction to be left behind, because that leftover energy can further drive up the temperature and make it more likely that other atoms will fuse. If that keeps happening over and over again, you basically end up with an exponential increase in the number of fusion reactions taking place. This is called a bootstrapping process.

And that's what we started to see in our experiment. Since last September, actually, the National Ignition Facility started to get a doubling in the number of fusion reactions because of that bootstrapping process, and that's the first time that's been seen in a laboratory. It's also the first indication that we're going to be on the right path to full ignition. We just need to push this process further, so we're quite excited about that.

Still, by most accounts we're a long way from ignition. What are the biggest challenges you face?

From a physics perspective, this is really a battle of control. When you try to stuff a lot of energy in a small volume, Mother Nature fights you in any way she can, and creates what we call instabilities. She's trying to wiggle that energy out of there in some way, and prevents you from trying to get it even denser and hotter. And every time we try to avoid instabilities, more crop upand it seems like there are an infinite number of them ready to be thrown at us. So, a lot of research is involved with just keeping everything as stable as possible.

At this point we know that to reach ignition, we just need to approximately double the pressure at the very center of our fusion reaction. The nice part is that now we're starting to see this bootstrapping process take place, which is helping us along the way. But it's not going to be an easy feat. It's still going require a lot more research.

Historically, why has fusion research been plagued by so much hype and unfulfilled promises?

I think that many decades ago scientists underestimated just how diabolical the instabilities that want to frustrate this process are. But, remember, scientists are also people. Generally we're trained to be realistic and dispassionate, but occasionally that breaks down and we can get overly excited or overly optimistic about what we're doing.

Alsoand this is just my opinionour federal funding system for science actually breeds some of this hype. If you go to the government and say, "Well, there's a small chance that this is going to work, and it's going to take many decades," in a way you're almost being too honest. They're not going to give you any money; they're going to put money into something that some other scientist said, truthfully or not, is guaranteed to work. Our system is sort of rigged for this. If you don't put a positive spin on things, you're much less likely to be funded.

This reverberates in the media too. You get more attention if you hype things. But there are some big costs, and this hype is damaging to the field. Funding fluctuates with promises. And the best thing for long-term research is to have steady, long-term funding.

Do you think we've now moved beyond the hype that flooded fusion research in the past?

I think so. We're doing that by being really brutally honest about what issues remain to be solved before we reach ignition. And I think that's healthy. You certainly can't solve an important scientific problem if you hide what the issues really are from yourself.

We're also highly sensitized and conscious of the danger of overhyping, because our lab has just been through a period where it had done that. We had the The National Ignition Campaign, which was meant to demonstrate ignition at the end of summer 2012. It just had an arbitrary end date [laughter]. The scientific staff warned against making any promise like that, and of course it didn't work out.

But with our bootstrapping breakthrough, we actually swung the pendulum the other way. When I originally published the paper on it, the paper's reviewers actually thought I was downplaying our findings too much. But I think it was the right thing to do, and even our critics said, wow, it looks like they've made some real progress and are also embracing a cultural change.

This is good, because, while there's always that snarky joke"Fusion is 20 years away and always will be"there actually has been steady, linear progress toward ignition over the decades. And I think if people are just patent, this will eventually work out.

With fusion research being such an expensive, uncertain, and monumental undertaking, what encourages you to keep working at it?

For one, the payoff really is enormous. Using fusion as an energy source would be huge for humanity, and would be game-changing scientifically and technologically. That's why it's definitely worth the large, long-term investment. And while fusion research is expensive and our facility here is expensive, you have to ask, [expensive] compared to what? Look at the money we'll spend on a Major League Baseball team or to develop, say, the F-35 fighter plane.

The only way to guarantee that fusion energy will never happen is by not pursuing this work. And if we do that, then who knows what possibilities we've given up?

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