Thread by @arthurturrell

People think a *net energy gain* nuclear fusion experiment is a long way off (as far as the Sun, the nearest fusion reactor). Researching #TheStarBuilders, I discovered extraordinary progress... hold on to your seats for a 🧵on fusion #physics and advances in #fusionenergy! 1/n

What's net energy? It's putting 1 unit of energy into a fusion machine & getting *more* than 1 unit out. Breakeven in energy = same out as was put in. Scientists refer to percentages: 100% for breakeven, >100% for net energy gain. Gain is like a single match lighting a big fire🔥

Why is net energy gain important? It's the first step to developing fusion as a power source. Scientists have been trying since the 1940s, & it’s perhaps the greatest technical challenge humanity has ever taken on. And we *need* cleaner energy.
Now, let’s talk about the advances.

1st, the USA’s laser-based fusion machine (@LLnL) achieved a 60x increase in energy between 2011 & 2018, reaching 3% of breakeven. IMPORTANT: at that rate *they are not very many improvements away from breakeven in energy*. With a bit of finessing, they might just get there first

If finessing doesn’t work, they may only need to add a bit of extra juice to the laser. That raises energy in, yes, but it’s likely to raise energy out even more, because laser fusion is like using a match to light a fire; eventually it catches and lots of energy comes out.
Next:

ITER is a magnetic fusion experiment run by a large group of countries, coming 2025. It has the size, scale, & tech to wallop its fuel to 150million degrees! 'Proper' fusion fuel experiments won’t happen till 2035, but expect this behemoth to smash the 100% barrier when they do.

3rd, we’ve come so far and, extrapolating the trends, net energy gain is in sight. This gif shows the progress. Records are broken quite regularly; recently, China’s EAST magnetic fusion machine broke a world record by running with a temperature of 120 million degrees for 101s 🤯

Superconductors, advanced computing, & #machinelearning mean that even old approaches can be improved enormously. A paper in Nature just showed how favourable once-abandoned stellarator technology is: nature.com/articles/s4158…. Clever stats *tripled* energy in a laser experiment!

4th, there is the political will for more fusion, more quickly. In the US, a congressional bipartisan fusion energy caucus, led by @RepDonBeyer, has been set up. The US National Academies (@theNASEM) have argued for more effort on fusion: nationalacademies.org/our-work/a-str…

5th, a private fusion industry has appeared, with ~$2 billion invested according to recently formed @Fusion_Industry association. The entrepreneurs are taking risks on different approaches that might offer short cuts. @CFS_energy was just profiled in NYT: nytimes.com/2021/08/10/tec…

CFS are hardly the only ones. There's @FLFusion, @TokamakEnergy, @Helion_Energy, @GeneralFusion, @TAE, and more! The private sector is showing a real interest in nuclear fusion.

So there are *very* good reasons to be optimistic about #nuclear fusion, even if commercialisation is a huge technical challenge. There is enormous progress and a demonstration of net energy gain is closer than you think!

Read more in #TheStarBuilders, simonandschuster.com/books/The-Star…