Design of a coil to correct magnetic field errors on the DIII-D tokamak
Small toroidally asymmetric errors on the ideally symmetric magnetic field of a tokamak are of concern for the design of next-generation devices and the performance of existing machines. Errors as small as one part in 10{sup 4} or less can be enough to cause detrimental effects on the stability and confinement of the plasma. Previously, we have used a simple perturbation coil mounted on top of the DIII-D tokamak (``n = 1 coil``) to enhance or partially reduce the error fields, resulting in significant effects on the stability of the plasma. Recently, careful measurements were made of the error fields created by the 18 field-shaping coils on DIII-D. Spectral analysis has yielded a better understanding of the source of the toroidal and poloidal field errors existing on the tokamak. With this new information, a much better error-field correction coil (``C-coil``) has been designed which should be able to nearly eliminate the m=2, n=1 component of the error field without introducing other toroidal modes. By dividing the C-coil into segments which can be connected in different configurations, we will be able to program the phase and amplitude of a variety of perturbation fields for experimentation. Alternatively, the coil can be configured and programmed to provide the maximum reduction of error fields for routine plasma operations, enabling a wider stable operating parameter space for the tokamak. Details of the C-coil design and its harmonic spectrum are presented.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER51114
- OSTI ID:
- 10114216
- Report Number(s):
- GA-A-20577; CONF-910968-58; ON: DE92005442
- Resource Relation:
- Conference: 14. IEEE symposium on fusion engineering,San Diego, CA (United States),30 Sep - 3 Oct 1991; Other Information: PBD: Nov 1991
- Country of Publication:
- United States
- Language:
- English
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