Successfull stellarator fusion reactor magnetic cage test

It seems the Germans have got something working, achieved closed flux surfaces required for stable plasma confinement in their Wendelstein 7-X stellarator.
www.ipp.mpg.de...

The stellarator is a ring type fusion device. In difference to a tokamak it relies on a complex magnetic field, twisting the plasma ring, to achieve stable confinement. The tokamak requires an additional current which affects stability, practically limiting it to a pulsed operation mode.

Wendelstein 7-X is supposed to hold the plasma up to 30 minutes. First plasma tests are scheduled for this year. So I expect to hear more about it in the future.

Wikipedia: en.wikipedia.org...

I understand this is related to the development of fusion power, but I'm not well versed enough in physics to understand if this is a minor or major breakthrough.

I'm assuming that since you posted this you have a greater understanding than I do. Can you share your thoughts for those who are interested but don't quite grasp the specifics?

Thanks!

a reply to: Midnight4444
Not sure if one can use the word "major breaktrough" in conjunction with fusion reactors. They've been messing with them for over 50 years now. It is more of an important step towards getting something that works.

Personally I feel stellarators will be more successful/effective than tokamaks, as confinement times seem to be the most limiting factor to get fusion going.

Wow! Nice flux rings there!

Does anybody know what happened to the National Ignition Facility? Wiki'ed that, but I don't know how far this system will bring us.

a reply to: moebius

Getting fusion going is not the problem at all; containing the reaction is the problem.

a reply to: notmyrealname

Yes, sloppy language.

Containing the reaction is not a problem either.

I guess the terms maintaining/retaining would be a better fit.

originally posted by: notmyrealname
a reply to: moebius

Getting fusion going is not the problem at all; containing the reaction is the problem.

Thank you, I am always surprised by the glossing over of the most important undiscovered fusion containment technique.

The amount of radiation produced by hydrogen fusion is truly immense, just look at the sun.

It isn't simply dangerous but, the containment vessels we have would become brittle and shatter very quickly under any sustained reaction, levitated dipole or not. H3 is much more viable.

originally posted by: greencmp

originally posted by: notmyrealname
a reply to: moebius

Getting fusion going is not the problem at all; containing the reaction is the problem.

Thank you, I am always surprised by the glossing over of the most important undiscovered fusion containment technique.

The amount of radiation produced by hydrogen fusion is truly immense, just look at the sun.

It isn't simply dangerous but, the containment vessels we have would become brittle and shatter very quickly under any sustained reaction, levitated dipole or not. H3 is much more viable.

Neutron radiation is the result of the fusion plasma reaction, and a layer of water [not certain what depth is necessary]. will block the neutron radiation from penetrating a vessel; whether a containment one --- or a starship for that matter.

a reply to: Erno86

That is the big advantage in my mind with helium 3 fusion, it is aneutronic.

The charged protons it produces can be magnetically contained so it could really be useful at smaller scales with direct conversion.

a reply to: greencmp

These are all aneutronic fusion reactions.

Deuterium–helium-3 fusion 2D + 3He → 4He + 1p + 18.3 MeV
Deuterium–lithium-6 fusion 2D + 6Li → 2 4He + 22.4 MeV
Proton–lithium-6 fusion 1p + 6Li → 4He + 3He + 4.0 MeV
Helium-3–lithium fusion 3He + 6Li → 2 4He + 1p + 16.9 MeV
Helium-3-helium-3 fusion 3He + 3He → 4He + 2 1p + 12.86 MeV
Proton–lithium-7 fusion 1p + 7Li → 2 4He + 17.2 MeV
Proton–boron fusion 1p + 11B → 3 4He + 8.7 MeV
Proton–nitrogen fusion 1p + 15N → 12C + 4He + 5.0 MeV[2]

a reply to: machineintelligence

You could have linked wiki rather than straight up copy.....

originally posted by: machineintelligence
a reply to: greencmp

These are all aneutronic fusion reactions.

Deuterium–helium-3 fusion 2D + 3He → 4He + 1p + 18.3 MeV
Deuterium–lithium-6 fusion 2D + 6Li → 2 4He + 22.4 MeV
Proton–lithium-6 fusion 1p + 6Li → 4He + 3He + 4.0 MeV
Helium-3–lithium fusion 3He + 6Li → 2 4He + 1p + 16.9 MeV
Helium-3-helium-3 fusion 3He + 3He → 4He + 2 1p + 12.86 MeV
Proton–lithium-7 fusion 1p + 7Li → 2 4He + 17.2 MeV
Proton–boron fusion 1p + 11B → 3 4He + 8.7 MeV
Proton–nitrogen fusion 1p + 15N → 12C + 4He + 5.0 MeV[2]

Yes and that is the key characteristic for scalable power solutions in my opinion (aneutronic fusion), many of these are preferable to 3HE considering the variety of circumstances they may be deployed in though, I still generally advocate for helium 3 as the most likely solution to foster safe and plentiful energy for humanity into the next millennium.

a reply to: greencmp

The ones with deuterium in are not going to be aneutronic in practice, though, because you're going to have a lot more D-D fusion than the aneutronic reaction.

a reply to: Bedlam

True to an extent but, if the physics generally allocate the energy into protonic matter rather than neutronic emissions, I tend to prefer that process.

What you are saying is that some hydrogen-hydrogen fusions will statistically occur in a tokamak-type reactor but, this isn't the only or best way to conduct material fusion in my opinion, especially with direct conversion which I hope is the great liberator and enabler of all galactically significant human endeavor.

originally posted by: greencmp
What you are saying is that some hydrogen-hydrogen fusions will statistically occur in a tokamak-type reactor ...

Given the different Coulomb barrier heights, the D-D reaction is going to be preferred, sadly enough.

...but, this isn't the only or best way to conduct material fusion in my opinion, especially with direct conversion which I hope is the great liberator of human endeavor.

p-B11 is your boy, then. It's about the easiest to do, and the reactants are easy to come by, but even then it's awfully difficult to do.

Although you never know. Maybe a couple of places are having at least some success with it. If I had my druthers, that's the one I'd like to see.

a reply to: Bedlam

Spot on.

a reply to: Bedlam

In our testing at the facility I work with we have found the lowest energy inputs are achieved with the Proton–boron fusion 1p + 11B → 3 4He + 8.7 MeV. These are very energetic reactions with few detectable neutrons being emitted. These are accomplished within a stable hydrogen plasma vortex filament striking a boron hydride coated cathode.

Looks like the machine is ready, will hopefully get government clearance today.

Can't wait to see if they'll manage to get stable high-temperature operation.

a reply to: moebius

They did. For 1/10 second, but they did. (Does plasma count?)
He-reaction only, H will follow next year.

Researchers from the Max Planck Institute for Plasma Physics (IPP) produced the first helium plasma in the Wendelstein 7-X stellarator last December [2015]. Since then, they have cleaned the plasma vessel with many more helium discharges. On 3 February [2016] they produced a hydrogen plasma in the world's biggest and most advanced stellarator-type nuclear fusion device for the first time.
...
So that explains the strangely twisted form of the coils in the Wendelstein 7-X. How did you come up with this?

The geometric characteristics of the plasma in a conventional stellarator make it very difficult to achieve good plasma confinement. It's like having a limp: you can do as much training as you like, but you're never going to be a 100-metre sprinter. However, our former Director, Jürgen Nührenberg, discovered a hidden symmetry characteristic of plasmas in the 1980s which makes it possible to also confine a plasma without plasma current. The shape of the plasma and the magnetic field resulted from this. Using what were very powerful computers at the time, Jürgen Nührenberg calculated how the magnetic coils had to be shaped to generate this field.

Source: Phys.org, Feb. 5, 2016 - Plasma physicist discusses the Wendelstein 7-X stellarator

The twists in the magnets come from how plasma twists in a one-twist stellarator. The actual term is "fully optimized" stellarator. As stated, it took until the 1980's before computing power was strong enough to do the calculations.

Of February 3, 2016, the first hydrogen plasma was created. They ran over 20 "shots" to check instrumentation. They started running at one power level (2 MJ of power) and everything checked out so they upped the power (4 MJ). The plasma lasted 1 second. Then they did more shots, 940 shots in total, where they reached temperatures of ~100 million °C in the electron plasma and ~10 million °C for the ions. The plasma lasted 6 seconds.

Source: Max Plank Institute for Plasma Physics, newsleter, 07 April, 2016, download PDF here (ipp.mpg.de)

[ETA: On March 10, 2016, the device was shutdown for upgrades. Start up is "first half 2017" - newleter]