Spectrally filtered fast imaging of internal magnetohydrodynamic activity in the DIII-D tokamak
- University of California-San Diego, 9500 Gilman Dr., La Jolla, California 92093 (United States)
- General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States)
The detailed poloidal structure of internal magnetohydrodynamic (MHD) modes is imaged using broadband visible bremsstrahlung emission from the core of the DIII-D tokamak. Spectral analysis of individual pixel time series recorded by a fast framing camera (up to 26 000 frames/s at 256x256 spatial resolution) is used to reconstruct two-dimensional images of mode amplitude. Application of this spectrally filtered fast imaging (SFFI) technique reveals spatially extended coherent structures that correspond to a (m,n)=(1,1) kink mode and a (2,1) neoclassical tearing mode rotating in the laboratory frame. The SFFI technique produces images with significantly less noise than images produced with the commonly used background subtraction method. Extension of SFFI to other core MHD events and coherent fluctuations in general is straightforward and could lead to further understanding of core MHD activity in fusion devices.
- OSTI ID:
- 21266670
- Journal Information:
- Review of Scientific Instruments, Vol. 79, Issue 10; Conference: HTPD08: 17. topical conference on high-temperature plasma diagnostics, Albuquerque, NM (United States), 11-15 May 2008; Other Information: DOI: 10.1063/1.2956983; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0034-6748
- Country of Publication:
- United States
- Language:
- English
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