Wendelstein 7-X stellarator getting ready for the next phase of operation [pdf]
Wendelstein 7-x is really not fusion research, but plasma physics research. At the energy&#x2F;temperature levels and magnetic field strength this machine is operating, plasma is showing all kinds of undesirable behavior, such as turbulence, radial forces... a little bit like the storms on Jupiter. This imposes many challenges, because as soon as the plasma escapes the magnetic field and touches the vessel, it rapidly cools - ending any potential fusion.<p>Wendelstein&#x27;s goal is to find out the viability of the stellarator concept, to see if it could be on par with the Tokamak concept, which so far have shown a better ratio of energy invested and energy won back, but come with their own bag of problems.<p>What the folks at Wendelstein are doing is a step by step verification of some of the hypothesis. There is this excellent 3h podcast with the scientific leader of Wendelstein [0], unfortunately it is in German. It is fascinating to hear their story on how they build this ultra complex piece of kit. The current change is the shielding of the vessel, which now permits higher energy levels and longer runs. Their long term goal is to operate at 100m K for 30 min.<p>Regarding the &quot;when we should stop trying&quot; and &quot;it is 30 years out&quot; adage: There has been great progress made in improving the ratio of energy invested and energy won back, the G-factor. Right now no fusion reactor is crossing the G &gt; 1 limit. But Iter would be design to yield about G = 5. Newer designs using high temperature superconductors could even yield G &gt; 10 with a smaller footprint. For more on the current state of fusion research, this video [1] from MIT is fantastic, albeit 1h long.<p>[0]: <a href="http:&#x2F;&#x2F;alternativlos.org&#x2F;36&#x2F;" rel="nofollow">http:&#x2F;&#x2F;alternativlos.org&#x2F;36&#x2F;</a><p>[1]: <a href="https:&#x2F;&#x2F;youtu.be&#x2F;L0KuAx1COEk?t=37m23s" rel="nofollow">https:&#x2F;&#x2F;youtu.be&#x2F;L0KuAx1COEk?t=37m23s</a>