Wendelstein 7-X...

Image Source: Science Mag

Topics: Nuclear Fusion, Nuclear Physics, Nuclear Power

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Researchers from the Max Planck Institute for Plasma Physics (IPP) produced the first helium plasma in the Wendelstein 7-X stellarator last December. Since then, they have cleaned the plasma vessel with many more helium discharges. On 3 February they produced a hydrogen plasma in the world's biggest and most advanced stellarator-type nuclear fusion device for the first time. Thomas Klinger, Director at the IPP, talks about the special features of the Wendelstein 7-X stellarator and its structure, and the prospects for the construction of a fusion power plant.

Professor Klinger, will Federal Chancellor Angela Merkel launch the world's first fusion power plant on Wednesday?

No, the Wendelstein 7-X will not supply any energy yet. What we are aiming to demonstrate is that a stellarator is just as suitable a device for a power plant as a tokamak, and that it can bring its two advantages into play here: first, its plasma is fundamentally more stable and, second, it can operate in continuous mode without further intervention. In contrast, a tokamak requires pulsed operation, which is a considerable disadvantage for a power plant.

If the stellarator has such advantages to offer, why is the ITER, the world's biggest fusion device, being built as a tokamak?

A crash course in plasma physics is needed to understand this: for the plasma in a fusion device to reach the temperature of 100 million degrees Celsius required for nuclear fusion, it must make as little contact as possible with the walls of the plasma vessel. For this reason, its charged particles are captured in a ring-shaped magnetic field. And this magnetic field must be twisted into a spiral.

Phys.org: Plasma physicist discusses the Wendelstein 7-X stellarator, Peter Hergersberg