Hacker News Reader

Comment by ilaksh | Hacker News Reader

Thanks..right I know about plasma in general, I just assumed in this case it was caused by the fusion. Maybe not. But they have fusion right? Just not recovering any/enough energy to make up for power requirements.

View on HN

The article is light on details. It doesn't mention an operating temperature or Q factor.

I would hazard to guess that no - they did not achieve fusion. They achieved plasma which is a precursor to fusion. Controlled plasma, at a high enough temperature, is an environment in which fusion can occur. All this article says is they created controlled plasma. Crucially, they did so with high temperature magnets which is fairly novel.

https://en.wikipedia.org/wiki/Fusion_energy_gain_factor You might also be interested in reading this. Q factor is what's used to discuss whether a fusion device is generating net positive energy.

No tokamak, even one intended to achieve fusion, would first be operated on D or DT. They'd first extensively test it with ordinary hydrogen.

I doubt they have achieved any fusion reactions. They don't state any numbers on density or temperature so it's impossible to know. But in general plasma is never "caused by" fusion. Creating a plasma is quite easy compared to getting it hot and dense enough to fuse.

They likely can have some fusion reactions (if they use fusible fuel, like D-D). Fusion is not that hard to achieve, you can do that on a table-top scale (Farnsworth Fusion).

I'm musing about the phrase:

> plasma is never "caused by" fusion

Which do you suppose comes first in a gravitational confinement scenario, plasma or fusion? It sorta seems like a chicken/egg scenario. I mean you gotta get those electrons out of the way, but where does he heat come from to do that, if not fusion?

Definitely plasma. Look at star formation in nebulae. Most of the hydrogen in them are in glow mode plasma. It takes a very small amount of energy to ionize plasma and a a huge amount to fuse it. So when stars are forming they might start as cold hydrogen, but they get progressively warmer and more dense until they ionize, then get even warmer and more dense, until they're burning.

https://en.wikipedia.org/wiki/Star_formation

Reply on news.ycombinator.com