| Autor: |
Park JK; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Yang SM; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Logan NC; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Hu Q; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Zhu C; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Zarnstorff MC; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Nazikian R; Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543, USA., Paz-Soldan C; General Atomics, San Diego, California 92121, USA., Jeon YM; National Fusion Research Institute, Daejeon 305-333, Republic of Korea., Ko WH; National Fusion Research Institute, Daejeon 305-333, Republic of Korea. |
| Abstrakt: |
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. |
