Magnetic configuration effects on the Wendelstein 7-X stellarator

Tutkimustuotos: Lehtiartikkeli

Tutkijat

Organisaatiot

  • Max-Planck-Institut für Plasmaphysik
  • University of Greifswald
  • Technical University of Berlin
  • Australian National University
  • Forschungszentrum Jülich
  • Princeton Plasma Physics Laboratory
  • National Institutes of Natural Sciences - National Institute for Fusion Science

Kuvaus

The two leading concepts for confining high-temperature fusion plasmas are the tokamak and the stellarator. Tokamaks are rotationally symmetric and use a large plasma current to achieve confinement, whereas stellarators are non-axisymmetric and employ three-dimensionally shaped magnetic field coils to twist the field and confine the plasma. As a result, the magnetic field of a stellarator needs to be carefully designed to minimize the collisional transport arising from poorly confined particle orbits, which would otherwise cause excessive power losses at high plasma temperatures. In addition, this type of transport leads to the appearance of a net toroidal plasma current, the so-called bootstrap current. Here, we analyse results from the first experimental campaign of the Wendelstein 7-X stellarator, showing that its magnetic-field design allows good control of bootstrap currents and collisional transport. The energy confinement time is among the best ever achieved in stellarators, both in absolute figures (τE > 100 ms) and relative to the stellarator confinement scaling. The bootstrap current responds as predicted to changes in the magnetic mirror ratio. These initial experiments confirm several theoretically predicted properties of Wendelstein 7-X plasmas, and already indicate consistency with optimization measures.

Yksityiskohdat

AlkuperäiskieliEnglanti
Sivut855-860
Sivumäärä6
JulkaisuNature Physics
Vuosikerta14
Numero8
TilaJulkaistu - 1 elokuuta 2018
OKM-julkaisutyyppiA1 Julkaistu artikkeli, soviteltu

ID: 38841735