AWhat changed
The Wendelstein 7-X team used pellet-fuelled 2018 stellarator discharges to test whether magnetic-field optimization reduced neoclassical energy transport. A team report describes one high-performance discharge with 4.5 MW heating and about 0.23 s energy confinement. From measured density and temperature profiles and modeled transport, the authors infer that similarly scaled less-optimized configurations would have required more heating to sustain the profiles. In a separate longer discharge, stable detached divertor operation with particle exhaust was maintained for over 26 seconds at 5 MW.
Scientific scope
The Wendelstein 7-X team used pellet-fuelled 2018 stellarator discharges to test whether magnetic-field optimization reduced neoclassical energy transport. A team report describes one high-performance discharge with 4.5 MW heating and about 0.23 s energy confinement. From measured density and temperature profiles and modeled transport, the authors infer that similarly scaled less-optimized configurations would have required more heating to sustain the profiles. In a separate longer discharge, stable detached divertor operation with particle exhaust was maintained for over 26 seconds at 5 MW. The comparison of neoclassical losses uses measured profiles and modeled reference magnetic configurations, not direct simultaneous measurements in the other machines. The high-performance pellet-fuelled phase lasted less than a second; it is not the same demonstration as the longer detached discharge. Turbulent transport and impurity buildup remain concerns. This does not establish a sustained high-performance reactor or net electricity. The source is a 2021 team overview. The original journal analysis, its correction and the diagnostic data may add qualifications to the overview.
Evidence
The linked original works support the scoped statement and contribution attribution. WRS has not independently replayed experiments or reconstructed a full mathematical proof. The comparison of neoclassical losses uses measured profiles and modeled reference magnetic configurations, not direct simultaneous measurements in the other machines. The high-performance pellet-fuelled phase lasted less than a second; it is not the same demonstration as the longer detached discharge. Turbulent transport and impurity buildup remain concerns. This does not establish a sustained high-performance reactor or net electricity. The source is a 2021 team overview. The original journal analysis, its correction and the diagnostic data may add qualifications to the overview.
Contributors
- The named authors in the research record · SCIENCE: Credit belongs to the cited collaborations. The individual author list is incomplete; no sole discoverer or individual effort share is inferred.
Provisional WRS assessment, edition 2026-10-28.1. Independent expert calibration is pending. This grade does not certify correctness or assign ownership.
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