Error field predictability and consequences for ITER

Journal Article · 06 October 2024 · Nuclear Fusion

DOI: https://doi.org/10.1088/1741-4326/ad7ed6 · OSTI ID:2459355

Pharr, M. ; Logan, N. C. ; Paz-Soldan, C. ; Park, J. K.; Hansen, C.

Abstract ITER coil tolerances are re-evaluated using the modern understanding of coupling to least-stable plasma modes and an updated center-line-traced model of ITER’s coil windings. This reassessment finds the tolerances to be conservative through a statistical, linear study of n  = 1 error fields (EFs) due to tilted, shifted misplacements and nominal windings of central solenoid and poloidal field coils within tolerance. We also show that a model-based correction scheme remains effective even when metrology quality is sub-optimal, and compare this to projected empirical correction schemes. We begin with an analysis of the necessity of error field correction (EFC) for daily operation in ITER using scalign laws for the EF penetration threshold. We then consider the predictability of EF dominant mode overlap across early planned ITER scenarios and, as measuring EFs in high power scenarios can pose risks to the device, the potential for extrapolation to the ITER Baseline Scenario (IBS). We find that carefully designing a scenario matching currents proportionally to those of the IBS is far more important than plasma shape or profiles in accurately measuring an optimal correction current set.

• Research Organization: Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
• Sponsoring Organization: National Research Foundation of Korea (NRF); USDOE; USDOE Office of Science (SC), Fusion Energy Sciences (FES)
• Grant/Contract Number: SC0022272
• OSTI ID: 2459355
• Journal Information: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 12 Vol. 64; ISSN 0029-5515
• Publisher: IOP PublishingCopyright Statement
• Country of Publication: IAEA
• Language: English