Theory of self-organized critical transport in tokamak plasmas
- Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan). Naka Fusion Research Establishment
A theoretical and computational study of the ion temperature gradient and {eta}{sub i} instabilities in tokamak plasmas has been carried out. In toroidal geometry the modes have a radially extended structure and their eigenfrequencies are constant over many rational surfaces that are coupled through toroidicity. These nonlocal properties of the ITG modes impose strong constraint on the drift mode fluctuations and the amciated transport, showing a self-organized characteristic. As any significant deviation away from marginal stability causes rapid temperature relaxation and intermittent bursts, the modes hover near marginality and exhibit strong kinetic characteristics. As a result, the temperature relaxation is self-semilar and nonlocal, leading to a radially increasing heat diffusivity. The nonlocal transport leads to the Bohm-like diffusion scaling. The heat input regulates the deviation of the temperature gradient away from marginality. The obtained transport scalings and properties are globally consistent with experimental observations of L-mode charges.
- Research Organization:
- Univ. of Texas, Austin, TX (United States). Institute for Fusion Studies
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG05-80ET53088
- OSTI ID:
- 100314
- Report Number(s):
- DOE/ET/53088-711; ON: DE95015449; TRN: 95:020414
- Resource Relation:
- Other Information: PBD: Jul 1995
- Country of Publication:
- United States
- Language:
- English
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