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[martinuzz]

Another step forward for fusion reactor tech in my home town of Eindhoven. With the completion of Differ's Magnum PSI, we now have the world's largest test setup to expose fusion reactor exhaust wall materials to temperatures as hot as the sun, for a long duration.

With their first test they set a new record, when an intense beam of deuterium plasma at temperatures of 50000C (90032F) was aimed at tungsten matrix blocks for 18 hours.
This is equivalent to the amount of energy that the walls of the Iter test reactor would be subject to over the period of an entire year.

Project member Hans van Eck's first assessment is that the material withstood the extreme temperatures without any visible damage, but extensive analysis is still underway.

Up until now, the only way to predict how a material would respond to these temperatures, was by using computer simulation. The Dutch reactor is the only one in the world that can realistically reproduce the long term heat exposure within a fusion reactor.

Dutch fusion expert Marc Beurskens, who works at a German fusion reactor project in Greifswald, says '"This is an important moment. We could never reproduce the particle- and energy flux that we are going to have in the Iter and later, the Demo reactors. To make any meaningful estimates of reactor wall and exhaust wear, we really need linear installations like the Magnum-PSI in Eindhoven. It's really cool that they managed to get it to work".

Pretty awesome. We already had an underground particle accelerator ring (okok, a small one, but still), and now we are creating localized zones with stellar temperatures.
I just need to remember to run if ever a Gordon Freeman is employed at our High Tech Campus. And maybe I should start using a Geiger counter on my garden vegetables.

https://www.volkskrant.nl/wetenschap/dit-lab-in-eindhoven-kan-temperaturen-zo-hoog-als-de-zon-aan-dat-is-een-belangrijke-stap-vooruit-voor-kernfusie~a4584768/

https://www.differ.nl/news/magnum-psi-plasma-exposure-record

[smjjames]

Next would be much longer term tests I'd imagine. If it worked for an eqivalent of a year without visible damage, then it could last many years, possibly decades.

Could also see it as an application for re-entry heat shields?

[wierd]

Nuke plasma is a different beast than re-entry abrasion.

Also, shield material has different requirements. Re-entry ablative heat shields need to withstand some pretty extreme acoustic stresses.
Nuke reactor needs to withstand aggressive neutron exposure which causes embrittlement.

[smjjames]

Oh yeah, good point.

Also, I don't think the plasma in fusion reactors has free neutrons, all they were doing here is simulating being blasted with stellar plasma.

[Starver]

'Easiest' fusion, Deuterium-Tritium, produces neutrons:
²H + ³H -> ⁴He + ¹n

Another version, Deuterium-Hydrogen, produces some neutrons:
²H + ²H -> either ³H + ¹H or ³He + ¹n
(Tritium decays to He-3 by beta decay, so may 'poison' the plasma of positive ions you pumped in there. Consult your local Fusion Physicist to find out if I'm on or way off the mark with this supposition. They are likely fast electrons, so may just escape to the side-walls of your reactor.)

You probably need to use Helium-3 (and not produced as above, hence the Iron Skies conflict for 'minable' lunar He-3 reserves) to get 'neutronless' fusion, undrer ideal conditions:
²H + ³He -> ¹H + ⁴He

Or go for something where fusing a Hydrogen with a heavier atom provokes overwhelmingly alpha (He-4) breakdown of the (now even) heavier element, with just a smudge of neutron release from secondary decay paths.


There's going to be a neutron flux of some kind, pretty much, though some don't depend upon them for their energy-harvesting, while for others it's the main (and magnetically-untrappable) baryonic product that the reactor walls will directly encounter, as well as all the rest of the radiation. We've yet to work out which methods of fusion can be best tapped for energy, and in what manner, so it's rather up in the air wheher we can make it as contained as a Mr Fusion or would have to take it for granted that it's going to pepper its shielding with free neutrons and call that more acceptable (given the scale advantages over the various modes of fission-wastes) and worth the differnt hassle.

[Trekkin]

Any fusion reaction with deuterium in the plasma is going to produce neutrons by D-D side reactions, whatever the products of the intended reaction, and those reactions also have the lowest requisite plasma temperatures (and so are the most feasible to produce from a technical perspective.)

Aneutronic fusion is theoretically possible, but designing a reactor to withstand bombardment by and recover energy from fast neutrons is a better-understood problem than efficiently sustaining a plasma temperature to permit aneutronic reactions.

[inteuniso]

Something I did not expect to see for a long time, let alone today.

Stumbled upon this Atlantic article about how we miiiiiight not be the first industrial, or even spacefaring, civilization on this planet. Talk about a mainstream paradigm shift, right? Certainly could help explain why Sumerians say sky people gave them all their knowledge and technology and the Egyptians have a recorded lineage extending back 30,000 years.

[ChairmanPoo]

Something I did not expect to see for a long time, let alone today.

Stumbled upon this Atlantic article about how we miiiiiight not be the first industrial, or even spacefaring, civilization on this planet. Talk about a mainstream paradigm shift, right? Certainly could help explain why Sumerians say sky people gave them all their knowledge and technology and the Egyptians have a recorded lineage extending back 30,000 years.

That´s not what the article says. At all.

It’s not often that you write a paper proposing a hypothesis that you don’t support. Gavin and I don’t believe the Earth once hosted a 50-million-year-old Paleocene civilization.
But by asking if we could “see” truly ancient industrial civilizations, we were forced to ask about the generic kinds of impacts any civilization might have on a planet

AKA: No there is no standing theory about ancient astronauts or whatnot. No, those scientists aren´t really saying saying that there were ancient astronauts on Earth or whatnot. They went from a thought experiment ("what kind of obscure evidence would a hypothetical past civilization leave?") to practical technological developments going from their hypothetical ("what kind of tools could we develop to search for obscure evidence?").  There is no paradigm shift, nor is this mainstream

[Frumple]

Something I did not expect to see for a long time, let alone today.

Stumbled upon this Atlantic article about how we miiiiiight not be the first industrial, or even spacefaring, civilization on this planet. Talk about a mainstream paradigm shift, right? Certainly could help explain why Sumerians say sky people gave them all their knowledge and technology and the Egyptians have a recorded lineage extending back 30,000 years.

Uh. It kinda' does the exact opposite of helping to explain either of those, though. It's talking geological time scales, stuff that happened well before current-ish humans existed. Doesn't explain much of anything regarding more human time scale stuff, except posit (from the nth perspective) that maybe just maybe we're on the road to envirofucking ourselves into extinction.

Can't say it's much of a paradigm shift, either. Vague acknowledgement of the possibility's been around at least as long as I have, near as I can recall, and what that article describes is vague acknowledgement of the possibility.

And ninja'd, more or less. Eh.

[inteuniso]

Uh. It kinda' does the exact opposite of helping to explain either of those, though. It's talking geological time scales, stuff that happened well before current-ish humans existed. Doesn't explain much of anything regarding more human time scale stuff, except posit (from the nth prospective) that maybe just maybe we're on the road to envirofucking ourselves into extinction.

Well, I've opened myself up to the idea that there can be civilizations that have come and gone on any planet in this solar system at any time before the last 200 years. Fuck, they could have habitats with millions of people in space and we would never know because we have no clue where to look.

You can't just deny the existence of something because you haven't see it. That's foolish.

That´s not what the article says. At all.

It’s not often that you write a paper proposing a hypothesis that you don’t support. Gavin and I don’t believe the Earth once hosted a 50-million-year-old Paleocene civilization.
But by asking if we could “see” truly ancient industrial civilizations, we were forced to ask about the generic kinds of impacts any civilization might have on a planet

Seeing that every hypothesis exists to be disproven or proven and they did neither, I believe you have thrown down the gauntlet, sir.

Besides, do you really think everybody who reads the headline of that is going to think "Oh that's poppycock there's surely no way!"

[Teneb]

You can't just deny the existence of something because you haven't see it. That's foolish.

What are your thoughts on invisible magical unicorns?

[ChairmanPoo]

Well, I've opened myself up to the idea that there can be civilizations that have come and gone on any planet in this solar system at any time before the last 200 years. Fuck, they could have habitats with millions of people in space and we would never know because we have no clue where to look.

You can't just deny the existence of something because you haven't see it. That's foolish.

[inteuniso]

Look, I don't know that's false. Is my field of view referring to this current universe, and the densely packed hitlers being everything else? Seeing that we can make Hitlers out of stardust and his DNA which I'm sure we can scrounge up/simulate from somewhere, this is a completely accurate photo.

[Frumple]

Besides, do you really think everybody who reads the headline of that is going to think "Oh that's poppycock there's surely no way!"

... of course they won't? There's an industry catering to (ripping off ) that sort of outlook, after all. Plenty of folks that'll bite the hook. Can't recall if it's the science or history channel that's famous for it, these days.

[ChairmanPoo]

Your Honors, Let it go on record that the plaintiff "interuniso"  has accepted the "densely packed Hitlers" theory  as fact

Besides, do you really think everybody who reads the headline of that is going to think "Oh that's poppycock there's surely no way!"

... of course they won't? There's an industry catering to (ripping off ) that sort of outlook, after all. Plenty of folks that'll bite the hook. Can't recall if it's the science or history channel that's famous for it, these days.

both, I think.  I once saw a science channel documentary on the psychic powers of ninjas.... actually lets leave that aside, because long before that a bigger problem became  apparent:  Their supposed "master ninja" wasnt even japanese