Details

Autor(en) / Beteiligte

• Park, J-K
• Yang, S M
• Logan, N C
• Hu, Q
• Zhu, C
• Zarnstorff, M C
• Nazikian, R
• Paz-Soldan, C
• Jeon, Y M
• Ko, W H

Titel

Quasisymmetric Optimization of Nonaxisymmetry in Tokamaks

Ist Teil von

• Physical review letters, 2021-03, Vol.126 (12), p.125001-125001, Article 125001

Ort / Verlag

United States: American Physical Society

Erscheinungsjahr

2021

Quelle

American Physical Society

Beschreibungen/Notizen

• Predictive 3D optimization reveals a novel approach to modify a nonaxisymmetric magnetic perturbation to be entirely harmless for tokamaks, by essentially restoring quasisymmetry in perturbed particle orbits as much as possible. Such a quasisymmetric magnetic perturbation (QSMP) has been designed and successfully tested in the KSTAR and DIII-D tokamaks, demonstrating no performance degradation despite the large overall amplitudes of nonaxisymmetric fields and strong response otherwise expected in the tested plasmas. The results indicate that a quasisymmetric optimization is a robust path of error field correction across the resonant and nonresonant field spectrum in a tokamak, leveraging the prevailing concept of quasisymmetry for general 3D plasma confinement systems such as stellarators. The optimization becomes, in fact, a simple eigenvalue problem to the so-called torque response matrices if a perturbed equilibrium is calculated consistent with nonaxisymmetric neoclassical transport.