Wednesday, September 27

The key to nuclear fusion is inside stars. And we just took a key step to control it

“Clean, safe and virtually unlimited energy”: that is the best definition that can be made of the dream of nuclear fusion. and use dream despite the fact that I am convinced that we are getting closer because its achievement is proving to be an infernal puzzle. Every detail of the process, no matter how insignificant, takes years of work, money and ingenuity.

The good news is that we are making progress and the best example is the self-heating of plasma through nuclear fusion itself.

a bit of context. It is commonplace to say that nuclear fusion (that combination of atomic nuclei to release energy) is the physical process that powers the stars themselves. Still, it’s a very powerful metaphor for why we’ve had so much trouble recreating that process in the lab: It’s not easy to contain the heart of a stellar monster.

In the stars. It is so difficult, in fact, that to achieve it we need more energy than we can produce thanks to it. Or, put in other words, the critical point of our advances is to achieve a net generator of energy: to ensure that, as occurs in stars themselves, nuclear fusion itself is sufficient to keep the fuel in a plasmatic state and allow more reactions (and that the process is self-sustaining).

A step forward… As well, as they explain in Alex Zylstra and his team have managed to trigger self-heating fusion reactions using 192 laser beams to rapidly implode a capsule containing 200 µg of deuterium-tritium fuel. The details are explained in two articles (one in ‘Nature’ Y otro en ‘Nature Physics’) and represents a very important advance.

…a long way Until now it has been very difficult to reconcile the use of lasers and plasma control. In fact, often every time you tried to contain it, you had to stop using the lasers. Zylstra’s new capsule (and the large number of power sources) not only allows the plasma to be contained, but also allows more fuel to be used and more energy to be absorbed. In other words, it puts us on the path to stabilizing a fusion reactor once and for all.

Of course, the yield generated by these experiments is still low (170 kilojoules of energy), but it triples the yields obtained in previous experiments. We are talking about a technology that has been “20 years” away for decades: now, at last, we are closing that distance.