Dynamics of multiple flux tubes in sawtoothing KSTAR plasmas heated by electron cyclotron waves: I. Experimental analysis of the tube structure
SCIE
SCOPUS
- Title
- Dynamics of multiple flux tubes in sawtoothing KSTAR plasmas heated by electron cyclotron waves: I. Experimental analysis of the tube structure
- Authors
- Choe, GH; Yun, GS; Nam, Y; Lee, W; Park, HK; Bierwage, A; Domier, CW; Luhmann, NC; Jeong, JH; Bae, YS
- Date Issued
- 2015-01
- Publisher
- IOP Publishing
- Abstract
- Multiple (two or more) flux tubes are commonly observed inside and/or near the q = 1 flux surface in KSTAR tokamak plasmas with localized electron cyclotron resonance heating and current drive (ECH/CD). Detailed 2D and quasi-3D images of the flux tubes obtained by an advanced imaging diagnostic system showed that the flux tubes are m/n = 1/1 field-aligned structures co-rotating around the magnetic axis. The flux tubes typically merge together and become like the internal kink mode of the usual sawtooth, which then collapses like a usual sawtooth crash. A systematic scan of ECH/CD beam position showed a strong correlation with the number of flux tubes. In the presence of multiple flux tubes close to the q = 1 surface, the radially outward heat transport was enhanced, which explains naturally temporal changes of electron temperature. We emphasize that the multiple flux tubes are a universal feature distinct from the internal kink instability and play a critical role in the control of sawteeth using ECH/CD.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/35912
- DOI
- 10.1088/0029-5515/55/1/013015
- ISSN
- 0029-5515
- Article Type
- Article
- Citation
- NUCLEAR FUSION, vol. 55, no. 1, page. 13015, 2015-01
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- There are no files associated with this item.
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