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Error field measurements with rotating RMP fields for DIII-D H-mode

Journal Article · · Nuclear Fusion
 [1];  [1];  [2];  [3];  [2];  [1];  [4];  [3];  [5];  [6];  [1]
  1. General Atomics, San Diego, CA (United States)
  2. Princeton Plasma Physics Laboratory (PPPL), Princeton, NJ (United States)
  3. Columbia Univ., New York, NY (United States)
  4. Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
  5. Oak Ridge Associated Universities (ORAU), Oak Ridge, TN (United States)
  6. Univ. of California, San Diego, CA (United States)
+ Show Author Affiliations

3D magnetic sensors are employed to identify the amplitude and toroidal phase of error fields (EF) by analyzing the torque balance for magnetic islands entrained by rotating resonant magnetic perturbations (RMPs) in DIII-D H-mode plasmas. This technique of torque balance allows for efficient error field identification, offering a valuable tool for scenario-specific and optimized error field compensation (EFC) and requires only magnetic diagnostics. The torque balance used in this work includes the contribution from electromagnetic torque due to error fields, wall response, RMP fields, and viscous. Results show that viscous torque plays a crucial role, particularly during locked modes and H-mode plasmas, ensuring accurate data fits with lower residuals. The torque balance technique reveals that the L- and H-mode plasmas have distinct EF configurations, and consistent with a model-based EF analysis including MHD response in IPEC and the SURFMN EF simulation. This technique shows great robustness in measuring the intrinsic EF amplitude regardless of its amplitude or toroidal phase. Repeated discharges with EFC disparities exhibit consistent results of intrinsic error field within a reasonable range near the “standard” error field compensation. Additionally, the use of a rotating n = 1 resonant magnetic perturbation offers the advantage of reducing disruption risks by entraining saturated magnetic islands. These findings are instrumental for optimizing EF correction in fusion devices, thereby enhancing tearing mode suppression and overall plasma stability.

Research Organization:
General Atomics, San Diego, CA (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Fusion Energy Sciences (FES)
Grant/Contract Number:
FC02-04ER54698; AC02-09CH11466; AC05-00OR22725; FG02-04ER54761; FG02-05ER54809; SC0010685; SC0022270
OSTI ID:
3005887
Journal Information:
Nuclear Fusion, Journal Name: Nuclear Fusion; ISSN 0029-5515; ISSN 1741-4326
Publisher:
IOP Science - IAEACopyright Statement
Country of Publication:
United States
Language:
English

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Related Subjects

3D magnetic sensors
error field
torque balance