
The first plasma: the Wendelstein 7-X fusion device is now in operation - aurhum
http://www.ipp.mpg.de/3984226/12_15
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sawwit
Here is a time lapse video of the 9 year construction, quite fascinating to
watch:
[http://www.ipp.mpg.de/115632/zeitraffer_w7x](http://www.ipp.mpg.de/115632/zeitraffer_w7x)

YouTube mirror:
[https://www.youtube.com/watch?v=u-fbBRAxJNk](https://www.youtube.com/watch?v=u-fbBRAxJNk)

A more technical video explaining how it works:
[https://www.youtube.com/watch?v=lyqt6u5_sHA](https://www.youtube.com/watch?v=lyqt6u5_sHA)

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smackfu
Video title: "Fusion reactor designed in hell makes its debut"

~~~
Someone1234
That's related to a quote from this article about how hard the thing was to
build: [http://news.sciencemag.org/physics/2015/10/feature-
bizarre-r...](http://news.sciencemag.org/physics/2015/10/feature-bizarre-
reactor-might-save-nuclear-fusion)

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ChuckMcM
Pretty cool. One of the more interesting things about fusion research is how
the expansion of the ability to do complex fluid dynamics has helped design
plasma flows. Such designs were computationally infeasible before. The inter-
related requirement of computation and understanding on the delivery of viable
fusion solutions has been, in my opinion, the unseen anchor of fusion.

~~~
noobermin
I think people know this, they just don't want to admit it. As someone who
works with people who used to work with ICF, I've been told the reason that
NIF flunked is that it was designed with 1D simulation codes because back
then, that's all they could manage. One of the issues they inevitably ran into
were plasma instabilities similar to Rayleigh-Taylor instabilities[0] that one
only sees in two (or more) dimensional systems, but not 1D. These
instabilities reduce the efficacy of heating and compression needed to achieve
ignition, and were an unpleasant surprise when they actually performed the
experiments. Even to this day, 2D simulations are fairly common and littered
throughout the literature, and their justification (arguments of approximate
symmetry) are suspect, at least to me. 3D sims are coming on the scene, but
they often have to sacrifice things like spatial resolution that hurt's the
simulation's physics in other way.

Computational feasibility is one of the things physicists in that field need
to admit is holding them back, and may be a little humility in seeking out
advice from computer scientists is warranted in my opinion[1].

[0]
[https://en.wikipedia.org/wiki/Rayleigh%E2%80%93Taylor_instab...](https://en.wikipedia.org/wiki/Rayleigh%E2%80%93Taylor_instability)

[1] this statement won't give me much criticism here, but it wouldn't go down
well in a room of my peers.

~~~
jessriedel
Honest question: do you really think talking much with computer scientists
would help? My impression is that most of the improvements (besides Moore's
law) in the power of simulation of physical systems has come from either new
physical insights, or computational insights developed by physicists who were
mostly self-taught numerical techniques. It seems very plausible to me that
there are honest-to-goodness CS insights that remain unexploited, such as
better parallelizing physical simulations, but the track record hasn't been
good. Why aren't CS people coming in and showing everyone how it should be
done?

(For what it's worth, I'm a physicist, but not one who does anything
numerical, and I'm happy to admit arrogance by physicists could be a problem
here.)

~~~
mrottenkolber
If you ask me they mostly need software engineers, not “CS people” especially.
Whenever I talk to a scientist about their software, I see great opportunities
and interesting problems that are solved in suboptimal ways. To be blunt,
scientists can't code (and neither can most “CS people” for that matter).
Every scientist (be it physics or CS) could use a professional software
people, who have experience with developing and maintaining complex code
bases. The problem is, there is no funding. Let's say a researcher gets a
budget for some hardware and 10 PhD students, then there is nothing left to
pay the engineer with. We're too expensive.

~~~
gaze
What's really funny is I started in software (have code committed to some open
source projects... BIND, Valgrind), and then moved to Physics. The code is
garbage because the constraints are totally different. Experiments and code
can be brittle and still work. There's no time to consider user experience for
fellow grad student when there's so much else to do... though I do know of
SOME students who make time to write good code. Hats off to them.

~~~
Hockenbrizzle
I'm a mechanical engineer in physics and I've had no formal training in
writing code or computer science, yet, I am now doing simulations for atomic
physics in Python. I am designing some software library package which will
serve as a sort of diagnostic/design tool for future experiments with a
machine being built.

I've run into the problem of figuring out how to organize the whole dang thing
and sometimes have to go back and re-write a lot of code. Can you recommend
any good books that introduce computing concepts for applied physics and
engineering?

~~~
scrumper
My favorite general guidebook for writing good, readable, maintainable,
defensive code is "Code Complete": [http://www.amazon.com/Code-Complete-
Practical-Handbook-Const...](http://www.amazon.com/Code-Complete-Practical-
Handbook-Construction/dp/0735619670)

It isn't domain specific but there is so much good advice in there around
variable naming, code structure, general principles of bug-resistant coding
that you will get a tremendous amount from it.

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ericHosick
It seems like they've done all of this at a surprisingly low cost.

1 million assembly hours at 370 million project cost = 370 Euros/hour
(assembly + management overhead costs).

~~~
detaro
I think one important price factor is that this is "only" a plasma containment
experiment and will only run Helium and Hydrogen, not the Deuterium-Tritium-
mixture needed for energy-generating fusion.

This means it generates way less neutron radiation, which in turn means less
need for shielding and easier working conditions on and close to the
machinery, avoids material degradation, ...

Also, if I understand German sources correctly the 370 million doesn't include
wages of the people working there (maybe external construction contractors,
but not the effort by MPI personnel). (EDIT: found a quote of ~1 billion EUR
as cost for the entire project since 1995)

~~~
k4l3
Good call on the actual price. Still 1/13th the current cost of the not-yet-
operational ITER... Makes me wonder if the stellerator concept will be more
feasible in the long run.

~~~
fabian2k
I don't think you can draw any conclusions from comparing the price of
Wendelstein 7-X and ITER. ITER is much larger than Wendelstein, it looks like
the magnets in ITER are roughly 10 times as heavy, so ITER needs much more
material than Wendelstein.

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drmeister
This is absolutely awesome. So many people coming together to design and
construct such a complicated experiment. Excellent work and let's hope it
teaches us how to do fusion.

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PuffinBlue
Site was down for me so, mirror:

Fullpage screenshot:

[http://i.imgur.com/QIj2NWk.jpg](http://i.imgur.com/QIj2NWk.jpg)

Google Cache:

[http://webcache.googleusercontent.com/search?q=cache:5oATeaa...](http://webcache.googleusercontent.com/search?q=cache:5oATeaac608J:www.ipp.mpg.de/3985731/w7x_15_2+&cd=4&hl=en&ct=clnk&gl=uk)

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BuildTheRobots
Out of curiosity, how did you manage the full page screenshot?

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PuffinBlue
[https://www.reddit.com/r/LifeProTips/comments/281jav/lpt_pre...](https://www.reddit.com/r/LifeProTips/comments/281jav/lpt_press_shiftf2_and_type_screenshot_to_capture)

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mmanfrin
I feel that rarely does real life look more sci-fi than science fiction, but
the design of this device is _out there_.

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varjag
Even the name..

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lorenzhs
It's named after the eponymous mountain in Bavaria, referencing Princeton's
"Project Matterhorn" where early work on fusion was done

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sevensor
Wikipedia link for context:
[https://en.wikipedia.org/wiki/Wendelstein_7-X](https://en.wikipedia.org/wiki/Wendelstein_7-X)

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hughes
I understand that this is not meant to ever be a power-generating device. It
is meant merely to demonstrate that it's possible to sustain a hydrogen plasma
for 30+ minutes.

Is there any idea what scale of power generation we'd eventually be able to
make with a system of similar size in the future?

~~~
j_h_s
On a per mass, or per nucleon basis, fusion wins hands-down: one gram of
deuterium results in 10^12 J of energy, or 275 million kcal. Fission gives a
comparatively small 20 million kcal per gram of 235U. So fusion is over ten
times as potent. Keep in mind that chemical energy like that in fossil fuels
is capped around 10 kcal/g. - See more at: [http://physics.ucsd.edu/do-the-
math/2012/01/nuclear-fusion/#...](http://physics.ucsd.edu/do-the-
math/2012/01/nuclear-fusion/#sthash.2EOUiYSd.dpuf)

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zubspace
The video says, that the magnetic cage has been optimized by a super-computer.

Does someone know, why it looks like it looks? Why is it circular? Why are the
path and the surrounding magnets twisted like this? Please ELI5.

~~~
kitd
I'm no expert, but the stellerator design makes confinement of the plasma much
easier and energy-efficient. AIUI, the twists ensure that the particles making
up the plasma are evenly affected by the magnetic forces from the coils.

Hopefully someone who knows what they're talking about will be along soon ...

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funkyy
Can anyone explain tl;dr style how this will produce clean energy? I
understand the idea, but how fuel is being produced because it sounds they use
small quantities of helium which is easily accessible?

~~~
brian-armstrong
They're using helium to scale up and test that the various systems work. The
actual fusion will likely be done on deuterium and tritium, which are hydrogen
atoms with 1 and 2 neutrons respectively. Hydrogen is readily available via
electrolysis but you have to get the isotopes of it to serve as fuel.

Fusion reactions of this sort are quite clean. The actual reactor will be
bombarded by neutrons so parts of it will become radioactive but the effect
should be much less than a conventional fission reactor.

edit: as for how the actual energy production works, you get deuterium and
tritium up to very high temperatures and get the atoms to collide. The kinetic
energy in these reactions will be so high that electrostatic repulsion will
not be able to prevent the collision (normally, like repels like, but this
force can only stop so much energy). once the two collide, the strong nuclear
force takes over and forms helium and releases one of the neutrons plus a
whole bunch of energy

~~~
funkyy
Great, so to produce the fuel you can use energy from reactor, so it is self
serving, right? I cannot find any simplified information on how dirty this is,
what it takes to produce energy and what is the waste. It just says its clean
and revolutionary.

~~~
brian-armstrong
Deuterium is readily available- you can get it from sea water if you've got
the right equipment and enough patience. Tritium is more rare, but you can
actually use those released neutrons from the reactor to make some, if I
understand correctly. Either way, you only nees just a tiny amount of fuel-
fusion reactors leverage e=mc^2 pretty well

Unlike fission reactions, there are no leftover radioactive byproducts.
There's nothing to bury and there are no carbon emissions (like e.g. coal).
The reactor itself does become radioactive but this should be a much easier
problem to deal with.

Fusion is the transformation that powers the sun. Harnessing nuclear fusion is
one of the ultimate acts of power over nature that man can do.

~~~
funkyy
Great, explanation like that should be associated to majority of their
articles. Sounds like a great thing so good luck to them!

Thanks for explanation!

~~~
brian-armstrong
This is likely because they have a science bias, not a product bias. This
particular team and design will never produce more energy than it will
consume. It's specifically made to validate some ideas about reactor design.
Fusion reactors become more energy efficient as you scale them up, but also
more expensive. As a result, all such designs have to be vetted through a
series of cheaper but "nonfunctional" designs.

It would be hard for them to extoll all the virtues of this without knowing if
this design can work. One possible outcome from this test is that the reactor
design, the stellerator, is not presently feasible for power plant design.
That would be disappointing but at least they would have paid relatively less
to figure that out.

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huuu
Could this also be used to burn waste? There are already experiments witch
plasma gasification but those temperatures are much lower (13000°C).

Maybe some day we will all have a Mr. Fusion Home Energy Reactor in our
cars[1]

[1]
[http://backtothefuture.wikia.com/wiki/Mr._Fusion](http://backtothefuture.wikia.com/wiki/Mr._Fusion)

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borgchick
When I was growing up, this is the sort of stuff I dreamed we, humanity, would
be doing in this day and age. This is the stuff Star Trek is made of (probably
inspired by). Despite all the madness in the world today, I am glad some
others share my childhood dream.

~~~
ccozan
AFAIK, the Star Trek is using matter-antimatter reaction in the warp core [0].
We are however really far for this technology. Fusion on the other side is
reachable.

[0] [http://memory-alpha.wikia.com/wiki/Warp_core](http://memory-
alpha.wikia.com/wiki/Warp_core)

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bhz
Wow. So complex and tightly packed. I wonder if they have any information on
how serviceable the unit is, or what its operating life-cycle might be. In any
case, a fascinating achievement, this is a historic day certainly.

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datashovel
Does anyone here know the theoretical (usable) energy output they can expect
to get from this device?

~~~
gjm11
Zero. The Wendelstein stellerator is not intended to be energy-generating; I
don't think they even intend any fusion ever to happen in it.

~~~
tlmde
They certainly intend fusion to occur. Otherwise it's a scientific device; not
a power plant.

~~~
gjm11
It _is_ a scientific device. See
[http://www.ipp.mpg.de/16931/einfuehrung](http://www.ipp.mpg.de/16931/einfuehrung)
which, although it's ambiguous as to whether any fusion at all is intended to
happen, makes it clear that actually producing energy is not a goal.
[http://www.ipp.mpg.de/17064/strahlenschutz](http://www.ipp.mpg.de/17064/strahlenschutz)
does call it a "fusion device" and suggests that after a few years of
operation they'll be putting deuterium in and doing something that produces
neutrons, so I guess there must be a plan to do some actual fusion. But,
still, intended energy output: zero.

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humanfromearth
Great achievement. Let's hope we see first fusion reactions and then sustained
fusion soon.

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penetrarthur
Cheaper power will make bitcoin mining profitable again.

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geuis
Site got hugged to death. Needs a fusion powered server.

~~~
bemused
coldfusion!?

~~~
wiz21
or they could host it on steam

(now that's a bad joke)

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davesque
Very exciting.

