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

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

#231

Post by tsimionescu »

nerdponx wrote: post #105
tsimionescu wrote: post #59

Earlier quoted context omitted.

Most of the answers are missing the actual (proposed) mechanism. The energy of the reaction is mostly carried away as high-energy neutrons. So, the way to get energy back is to "capture" those neutrons. Since neutrons are not electrically charged, you can't use them to directly create electricity, so all you're left with is using them for heat. Unfortunately, since they are electrically neutral, they're also relative…

It's always fascinating to me that, no matter how many interesting new ways to release lots of energy we develop, we are still stuck with the same method for converting it to electricity: release the energy as heat, use heat to make steam, use steam to drive generator.

Well, we do have some other strategies. Hydro and wind just turn the turbine mechanically, they don't heat up water to make steam. And photovoltaics create electricity directly using an effect that won Einstein the Nobel prize and began the age of quantum mechanics, so that's about as advanced as they come.

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

#232

Post by adrianN »

KyleBerezin wrote: post #218
colordrops wrote: post #215

Earlier quoted context omitted.

Is the charge static or in motion? If in motion, isn't this basically a perpetual motion machine? Electrons have mass right?

In motion. Yes it is perpetual motion. The same thing can be observed in superfluids.

It is my understanding that electrons on a curved trajectory will lose energy to electromagnetic radiation. Is that not the with electrons in a superconductor?

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

#234

Post by t0mas88 »

jahnu wrote: post #31
t0mas88 wrote: post #28

Earlier quoted context omitted.

For less than 15 billion euro you could buy enough solar to power a country the size of the Netherlands. With 5 billion to spend on batteries you might even make it through night time usage. Or in other words: Fusion is too expensive at this point to be useful.

That seems amazingly cheap! Are we really down to that low level of cost?

1 euro per kW of capacity isn't that low, residential systems can get below that and it includes installation cost and an inverter which would both scale better for a bigger system.

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

#236

Post by danbruc »

rurban wrote: post #235

Major unit errors, I assume: > In individual areas, temperatures of up to 600 degrees Celsius are reached (red areas). The divertor tiles can withstand temperatures of up to 1200 degrees Celsius. How many 0's are missing there?

None.

The picture does NOT show the plasma itself, but the temperature distribution at the water-cooled divertor baffles.

It's about the temperature of parts of the vessel that get heated by leakage from the contained plasma.

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

#237

Post by eternityforest »

nomel wrote: post #194
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…

Coming from 3d sculpting to CAD was...eye opening. It really makes you realize how much of design constrained by the CAD tools, which are mostly constrained by manufacturability. If true 3d printing* ever gets cheap, it'll be interesting to see how much form will be able follow function, rather than manufacturing cost. * true 3d, as in overhang are allowed. Something like a cheap FDM is more 2.5d, since overhangs are…

Overhangs up to 45 degrees work fine, and usually steeper. Bridges also work, most of the time, although I am having trouble with them at the moment.

They're not quite unconstrained, and the layer adhesion strength makes some geometries not strong, but they're much more than 2.5D.

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

#238

Post by danbruc »

dumdumchan wrote: post #181

> The energy turnover of 1.3 gigajoule was achieved with an average heating power of 2.7 megawatts, whereby the discharge lasted 480 seconds. Can a physicist/thermal engineer explain what this means?

They heated the plasma with a power of 2.7 MW for 480 s which in total deposited 2.7 MW × 480 s = 1296 MJ, i.e. 1.3 GJ, of energy into the plasma heating it up. That is the energy of 310 kg of TNT (4.184 MJ/kg) or burning 38 l of gasoline (34.2 MJ/l). Keep in mind that this energy was deposited into the plasma which has a mass of only about 10 mg.

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

#239

Post by eternityforest »

waldothedog wrote: post #119
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…

Interesting. With a very strong reference for the experience of skateboarding, reading your sentence made me think about how hard it is to explain! I suppose when it’s going well, it feels like body/mind flow, when it’s going poorly it feels like physics :)

That kind of thing is super amazing! I've secretly suspected for a while that people who are able to skateboard or do similar things must live in 4 or 5 dimensions.

I can't figure out any kind of way someone could do that with anything resembling what I understand "thought" to be like, so I assume you must be able to process entire sequences and their alternate possibilities simultaneously?

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

#240

Post by dr_dshiv »

dylan604 wrote: post #220
egypturnash wrote: post #216

Earlier quoted context omitted.

It's two copies of "...where time becomes a loop." One on the left, one on the right. One of them is slightly shorter than the other, so that as they repeat again and again, they slide in and out of phase. The track ends after they come back into phase. If you listen to this with headphones, or speakers with decent separation, paying attention to this feels interesting. It's similar to the way listening to "binaural…

>remember, this album is from a time when people bought CDs and probably stuck them into a one-disc player You just describe the first time I every danced with Lucy. I went back and forth with this disc and The Orb's A Huge Ever Growing Pulsating Brain That Rules from the Centre of the Ultraworld.

Same!
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