Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

ipp.mpg.de

Post reply on HN
Print view View original

201–210 of 322 posts

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#201

Post by dylan604 »

hinkley wrote: post #197
dylan604 wrote: post #179

Earlier quoted context omitted.

I didn't either, since I spelled it Warf! I never watched Star Trek (probably get my HN privileges revoked for that), but I did know that much. And then the Reading Rainbow guy's "whatever happened will happen again". I know the character's name is Geordie or whatever, but he didn't have the right accent for him to be a Geordie, so he will forever be Reading Rainbow guy instead.

He could have been the Jeopardy guy too.

But I didn't grow up watching him on Jeopardy, so no, he would never be that guy either.

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#202

Post by RRWagner »

jkestner wrote: post #195
eternityforest wrote: post #76

Earlier quoted context omitted.

Doing CAD design is really interesting. A lot of stuff is just 2.5D, extrusions of 2D sketches sitting on other 2D sketches. Then you accidentally make something truly 3D by intersecting things and realize you have no idea what you're looking at, couldn't imagine it if you closed your eyes, couldn't replicate it if you had a picture of the result and didn't know the 2D inputs that made it... and then you realize ther…

CAD is hard! I think about this a lot as I'm doing a makerspace at an elementary school and adults think it needs a 3D printer, but what are kids going to print on it? I think for me, the prerequisites for mastering CAD were 1) the practice I got visualizing 3D shapes so I could translate them into unambiguous mechanical drawings on paper (I swear, I'm not that old but my college was behind and we were the last class…

Try Blockscad3d.com

It's a block language where you program the object rather than manipulate shapes. It works well for my brain. Ymmv

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#203

Post by MBCook »

cyberax wrote: post #189
Simon_O_Rourke wrote: post #72

Earlier quoted context omitted.

Just curious as to why a Mobius strip type arrangement is better than a toroid? Is it anything to do with the turbulence in the plasma flow being easier to control?

It's actually really easy to explain. Draw a torus and then draw rectangular "bands" across it, they will represent the containment magnets. Due to pure geometry, the area closer to the center will have a smaller distance between bars. This means that the magnetic field will be stronger near the center. This in turn means that particles will separate (depending on charge) and drift to the sides. It seriously interfer…

How do Tokamaks solve the issue since they’re still torus shaped?

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#204

Post by dylan604 »

fastball wrote: post #199
mastersummoner wrote: post #177

Earlier quoted context omitted.

I've listened to that song hundreds of times yet somehow never realized it was Worf.

Genuine question: why? That isn't even a song, it's just a vinyl record skipping for a minute and a half.

I think you're not considering the first album with an actual track called Mobius. You're thinking of the opening cut on Orbital II (the brown album). That one is the one where the "where time becomes a loop" becomes fun. The Mobius track is the one where "whatever happens, will happen again" is also included. Sorry, but I will have to deduct Orbital fanboi points, and you will lose your next turn

https://www.youtube.com/watch?v=4PG5PCd284o

Edit: But as to the why, it's fun. Just like the "input/output translation" trickery.

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#205

Post by greesil »

cyberax wrote: post #196
greesil wrote: post #180

Earlier quoted context omitted.

Zap Energy. They're at least thinking about co-opting existing infrastructure. https://www.neimagazine.com/news/newszap-energy-considers-re... Also their concept is just so weird, I love it. Worst case it works in space as a nuclear fusion drive :) My guess is that they're all going to tank without government money, unless by some miracle they have truly found some special low-cost of operation on the first try that…

Sorry, but this is bullshit. A steam turbine and a generator will be a _minor_ detail in the overall list of expenses building a fusion generator. It's like saying: "We should build an airport here in the desert, because we'll be able to save on cutting the grass!"

How would you know?

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#206

Post by hobs »

themagician wrote: post #63
KyleBerezin wrote: post #3

Ahh, Wendelstein is that stellerator reactor. The stellerator is really cool, and an alternative to a tokamak reactor. Tokamak is the doughnut shaped reactor, and it has a problem where the plasma near the outer circumference has less magnetic confinement. The stellerator is similar, but confines the plasma to a ribbon and folds it over on itself in a mobius-like arrangement. I used to be really interested in this, b…

I find the geometry of things like this fascinating. We typically think in such simple shapes. I feel like my brain can do triangle, rectangle and maybe hexagons and that's about it. I remember when I finally understood radians enough to really understand circles and waveforms—I felt so enlightened. Like I actually remember the moment when it clicked. For years I was just "doing the work" without actually understandi…

Just play Asteroids, congrats, add a twist between certain edges (which would manifest as a flip) and you now are in the mobius.

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#207

Post by kortex »

dale_glass wrote: post #64
tboughen wrote: post #50

Earlier quoted context omitted.

My favourite fact about it comes from https://phys.org/news/2016-02-plasma-physicist-discusses-wen... “…the supporting structure can only withstand the forces if the interfaces between the ten individual segments of the central rings, which weighs several tonnes, are built with a level of precision of less than 100 millionths of a metre…” - and they found a small family business in the north of Italy capable of doing…

Odd units. 1 meter = 100 cm = 1000mm. So 1 millionth of a meter = 1/1000th of 1mm. thus, 100 millionths of a meter = 0.1mm, or ~4 thou in American units. Easily achievable by hobbyists, let alone by serious, professional equipment. Sure, that is a pretty exacting specification for what I suppose is a big machine, but I'm pretty sure very normal things like say, car engines get made to far tighter tolerances.

What usually matters more than absolute tolerances is relative tolerance, aka ppm. 100 micron / 4 thou tolerance can be achieved with hand tools and a bit of patience on the benchtop scale, say a 4" part. That's about 1000 ppm, or 0.1%. If I gave you a meter stick, you could probably eyeball marking something +/- 1mm.

Getting the same finish on a 120"/3m coil is 33 ppm. 100 ppm / 0.01% for any operation or process tends to be where things start to get really challenging. Deflection goes up by the length cubed, so increasing the size of all the tooling relative to the tolerance gets really challenging really fast.

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#208

Post by howenterprisey »

TaylorAlexander wrote: post #139
cmplxconjugate wrote: post #39

Earlier quoted context omitted.

My best friend works for them in diagnostic sub-systems development. The product is still a long way off delivery with many systems being actively designed and refined. Basically it’s busy but will still be quite a while (3-5+ years at least).

Makes sense. I would love to see a blog post with some progress pics, but I understand that building a fusion reactor is simply a slow process!

Their progress pics are on Instagram and TikTok (unfortunately): https://www.instagram.com/cfs.energy/

Re: Wendelstein 7-X: Gigajoule energy turnover generated for eight minutes

#209

Post by andrewflnr »

sdwr wrote: post #74
Eji1700 wrote: post #47

Earlier quoted context omitted.

I'm honestly not sure if you're joking but in case you're not, the "minimum viable size" is hardly the largest issue with what you're proposing and it sounds like you're not getting what the key issues are. You're talking about taking a technology that's so finicky we've barely gotten it to work after almost 100 years and rocketing it into space? We're no where near good enough at this to get a test that would work a…

That was not a real question, it was a subconscious plea for elon musk to take over and make it work. "Shooting it into space" is a reference to how SpaceX disrupted the rocket industry through a "fail fast" mentality, aggressive goals, and sheer force of will.

It's true that working on fusion is high on the list of better uses for $44B than buying an overpriced social media platform.
Post reply on HN