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German "Stellarator" goes online - first plasma produced

Discussion in 'Science' started by chainbolt, Dec 11, 2015.

  1. chainbolt

    chainbolt Member

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    After about nine years of construction, one year of preparatory tests, and spending 1 billion Euro, the fusion facility “Wendelstein 7-X” was officially put into operation in Germany today and produced helium plasma at 10 million degree for the first time. They will start experimenting with hydrogen in January 2016. The target is hydrogen plasma, which needs 100 million degree.

    Wendelstein 7-X

    [​IMG]

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    Interesting competition with the much more (15 times) expensive ITER project based on the Tokamak design.
     
    Last edited: Dec 11, 2015
  2. RobRoySyd

    RobRoySyd Member

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    A better discourse on this stellarator here: http://news.sciencemag.org/physics/2015/10/feature-bizarre-reactor-might-save-nuclear-fusion

    The Tokomak and Stellarator are based on the same design concept. The Stellarator attempts to solve one of the challenges the Tokomak design faces but introduces much greater manufacturing and engineering challenges.

    It's still too early to be popping the champagne.

     
  3. OP
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    chainbolt

    chainbolt Member

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    I think the objective is the same, but the Tokomak and Stellarator design concept are much different. And that's the reason why both designs have different names in the first place, and it also explains why the required investment is much lower for a stellarator. The basic idea of the stellarator is to use areas of differing magnetic fields to cancel out the forces on a particle as it travels around the confinement area. The tokamak provides the required twist to the magnetic field lines not by manipulating the field with external currents, but by driving a current through the plasma itself.

    The design difference is very apparent if you see the inside of the devices. Because stellarator uses areas of differing magnetic fields the inside looks like a twisted tube or intertwined coils.

    Here is a schematics display of the stellarator design. You can easily see the twisted tube that confines the plasma.

    [​IMG]

    [​IMG]

    German 7X Wendelsetin Stellarator

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    Japanese Helical Stellarator

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    Because a Tokamak device is driving a current through the plasma itself, it looks just like a round tube. The concept does not require a "twisted" geometry.

    Here is how a tokama device looks like. Example: ITER.

    [​IMG]

    As you can see, the design of a stellarator and tokama device is much different, simply for the reason that they are based on different technical concepts. It seems the stellarator design is cheaper and provides for more stable results, while the more challenging tokamak design could provide for better results.
     
    Last edited: Dec 14, 2015
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  4. RobRoySyd

    RobRoySyd Member

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    The objective of all fusion reactor designs is the same, produce usable energy from nuclear fusion.
    Beyond that there's several different classes of approach, one will produce pulses of energy and others are continuous.

    On the pulsed front there's ideas such as Dense Plasma Focus being explored. If that can be made to work and is commercially viable....Well both the Tokomak and Stellarator will be white elephants.


    Both the Tokomak and Stellarator are continuous and the underlying concept is the same. Hold a plasma using magnetic confinement that's hot and dense enough to produce more energy from nuclear fusion than is used heating and confining the plasma. Both these designs are trying to avoid what Dense Plasma Focus embraces, pinching of the plasma.

    Maybe the Stellarator is a better way to achieve plasma confinement than the Tokomak. Whichever one proves to be the best will be the one the next generation goes with. Regardless both still face the same issues.

    Once we have a way of confining the plasma undergoing fusion a way still has to be found to get usable heat out of the plasma. A way to remove the fusion products and a way to inject fuel into the plasma has to be found. A lot of the money being spent on ITER is going into addressing these challenges. Whatever solutions to the challenges ITER finds are applicable to both the Tokomak and Stellarator designs.
     
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  5. Billzilla

    Billzilla Member

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    In my very inexpert opinion, that's the one that needs buckets of money thrown at it.
     
  6. RobRoySyd

    RobRoySyd Member

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    I don't think the Focus Fusion people need much more funding at this stage. Their current issue seems to be corrosion of the tungsten electrodes caused by the presence of oxygen in the chamber.
     
  7. OP
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    chainbolt

    chainbolt Member

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    LOL :leet:

    The OBJECTIVE of fusion reactors is the same. The DESIGN is different. Stellarator and Tokomak follow different designs, that's the reason why they have different names in the first place.

    Right, therefor it's seems to be meaningful to try both concepts.
     
    Last edited: Dec 15, 2015
  8. RobRoySyd

    RobRoySyd Member

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    Noooo :)

    Both the Tokomak and the Stellarator are intended to produce self sustaining fusion from a (very) high temperature low density plasma using magnetic confinement. Magnetic confinement has issues and the Tokomak and Stellarator take different approaches to solving that specific issue within the one class of fusion reactors.

    Efforts such as the one being run at the National Ignition Facility are in a different class. It uses a high density plasma contained by inertia.

    The name "Stellarator" is a bit misleading as it implies some similarity to stellar objects. Stellar objects such as our sun have high density low temperature plasma that enables sustained fusion. Confinement happens thanks to gravity. The NIF facility produces conditions much closer to that in the Sun then either the Tokomak or Stellarator.


    It goes beyond that really. The ITER people are as confident as can be that their machine will produce self sustained fusion for long enough for materials to be tested and diagnostics run. Many Tokomaks have been built over the past 50 years, there's even ones other than the one at ITER under construction. Tokomaks are well understood entity. The Stellarator is only now a feasible solution to the magnetic confinement problem.

    When / if ITER does achieve sustained fusion for a reasonable period of time (minutes) it will then spend years running diagnostics and investigating the materials science problems. That means robotic devices have to able to get inside the machine to change out components. It'll be too radioactive inside the containment vessel for humans to enter for a period of time. The regular shape of the Tokomak makes this much easier. A robotic arm that could reach every point in the Stellarator would require many degrees of freedom. There's a much higher risk of something going wrong requiring testing to stop until it was safe for a human to enter.

    Here's a pretty easy read of the whole Tokomak - Stellarator competition: https://en.wikipedia.org/wiki/Stellarator#Comparison_to_tokamaks

     
  9. Bulk Nutrients

    Bulk Nutrients Member

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    Is that duct tape? :leet:

    [​IMG]
     
  10. OP
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    chainbolt

    chainbolt Member

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    Maybe to prevent leakage? The plasma seems to be quite "fluid". :leet:
     
  11. becubed

    becubed Member

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    [​IMG]

    H R Geiger should sue.
     
  12. RobRoySyd

    RobRoySyd Member

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    Of some actual relevance to this discussion:

    https://www.ipp.mpg.de/16931/einfuehrung

    The Stellarator we're discussing will not even attempt to produce energy yielding fusion.
     
  13. xoameister

    xoameister (Banned or Deleted)

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    German science nerds turn on new fusion reactor

    The global nerd community is getting excited about the new German experimental fusion reactor, which is a departure from the usual Tokamak design.

    So far, Germany has wasted more than a billion dollars on this giant test tube - money which would have been better spent on stimulating Germany's pathetically flat property market.

    The German president hopes that fusion energy may provide the nation's formidable industrial sector with a source of cheap yet clean energy. Germany's president earned a Doctorate in Physics and worked as a professional scientist.
     
  14. Gonadman2

    Gonadman2 Member

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    Insightful post, I enjoyed it while lamenting the country I live in at the same time...
     
  15. dr_deathy

    dr_deathy Member

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    Real achievement is worth more then BS money ever will be. So no they havnt wasted any money at all.

    Good on them for not letting big banks run the country i suppose, this is as big as the moon landing for who ever gets it going and could be the fix for climate change.

    also its only half a billion, if it works its worth trillions.
     
  16. OP
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    chainbolt

    chainbolt Member

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    I think these 2 (Tokamak and Stellerator) fusion energy technologies are developed in parallel. Germany is also a major contributing member to the bigger (Tokamak) ITER project.

    The impact of the billions spent into fusion research will be known in maybe 20 or 30 years.

    As far as the linked article about the German housing market is concerned, it's a bit strange, what they claim. It is true that Germany has avoided a "housing bubble" so far, but housing prices have been constantly rising since the GFC.

    This is all true.
     
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  17. RnR

    RnR Member

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    Incidently, the heat loss problem in fusion may have given a glimpse into a potential solution...

    http://news.mit.edu/2016/heat-loss-fusion-reactors-0121

    Research should be applicable for all types of fusion tech :thumbup:
     
  18. Lasmi

    Lasmi Member

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    You almost got us with your trolling but no, you had to take it a step too far into insanely ridiculous territory by saying the money would be better spent artificially inflating real estate....in a country where the real estate market will start to pick up naturally because of the extra million people they brought in last year.

    I'll be amazed if that research benefits only fusion technology.

    That's what is so great about big physics. For the most part we have no idea of the many benefits to other fields fusion research will bring. Medicine has been a huge beneficiary of physics research in the past and it probably will again.
     
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  19. Perko

    Perko Member

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    You need to read Xoa's posts to get the context/long running critique of government attitudes towards science vs. real estate, law, mining etc.

    I laughed.

    More melanoma funding?
     
  20. OP
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    chainbolt

    chainbolt Member

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    Or a replacement for teflon? (kidding).
     

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