PPPL celebrates role in first research plasma on W7-X stellarator in Germany

Eureka Alert 22-DEC-2015


A wide-angle shot of the Wendelstein 7-X (W7-X) taken in October when the device was still under construction. One of the gold-colored trim coils built and delivered by PPPL can be seen at the far right of the machine.

Scientists from the U.S. Department of Energy’s Princeton Plasma Physics Laboratory (PPPL) have reason to celebrate the first plasma of the Wendelstein 7-X (W7-X) stellarator at the Max Planck Institute in Greifswald, Germany earlier this month. The Laboratory has designed and contributed major components to the device and is collaborating on research. Three PPPL physicists attended the December 10 event.

PPPL leads the U.S. collaboration with W7-X, which is funded by $4 million from the Department of Energy’s Office of Science. Collaborators include researchers from Los Alamos National Laboratory and Oak Ridge National Laboratory, as well as researchers and students from Massachusetts Institute of Technology, the University of Wisconsin, and the University of Auburn.

The W7-X stellarator is the largest and most advanced fusion experiment of its kind in the world and could yield promising solutions to some of the most difficult challenges in developing fusion energy.

Stellarators are fusion devices that use twisting, potato chip-shaped magnetic coils to confine the plasma that fuels fusion reactions in a three-dimensional and steady-state magnetic field. The W7-X is planned to be the first optimized stellarator to confine a hot plasma in a steady state for up to 30 minutes. In doing so, it could demonstrate that an optimized stellarator could be a model for future fusion reactors.

PPPL’s contributions to the W7-X include:

  • Designing and delivering the five massive 2,400-pound trim coils that fine-tune the shape of the plasma in fusion experiments.
  • Leading magnetic field mapping experiments with the trim coils showing that their effects on the magnetic configuration were as predicted.
  • Designing and building a diagnostic device called an X-ray crystal spectrometer, one of several diagnostics created by U.S. researchers that will analyze experiments on W7-X.
  • Currently building two divertor scraper units in collaboration with Oak Ridge National Laboratory (ORNL) that will intercept heat coming from the plasma to protect the W7-X divertor targets from damage. (See https://www.pppl.gov/news/2015/12/collaboration-bears-fruit-w7-x-celebrates-first-research-plasma for more details).

PPPL physicists who have worked extensively on W7-X include:

  • Hutch Neilson, head of advanced projects at PPPL. He coordinates the U.S. collaboration on W7-X and was in Greifswald, Germany at the IPP/W7-X for several months last year.
  • David Gates, the stellarator physics leader at PPPL, was at the first plasma.
  • Sam Lazerson, a physicist, is currently in Greifswald working at the W7-X. (See https://www.pppl.gov/news/2015/12/pppl-researcher-maps-magnetic-fields-first-physics-experiment-w7-x)
  • Novimir Pablant, designed and built the diagnostic device on the machine with PPPL engineers, and installed it. He was also at the first plasma.