Magnetic island effects, interactions in tokamaks
This paper explores a number of aspects of isolated and interacting magnetic islands, and their effects, in tokamak plasmas. The temperature fluctuations induced by an isolated magnetic island in a rotating tokamak plasma are shown to be surprisingly small -- T{sub rms} {approx_lt} 0.1w{vert_bar}dT{sub 0}/dr{vert_bar} in which w is the island width. Pressure-gradient-driven neoclassical MHD magnetic islands are posited as the cause of the isolated low m/n islands sometimes observed in high performance tokamak plasmas. They also form the basis for a recently advanced interacting-island model for the tokamak magnetic ``equilibrium`` in which mostly non-overlapping islands, across which transport is rapid, are separated by ``good`` flux surface regions. In combination these bad, good transport regions produce ``stair-step`` temperature and pressure profiles. Finally, an interacting-island transport model is developed and shown to exhibit many of the transient transport properties observed in tokamak plasmas -- nonlinear response of temperature gradient to increased heating, pulse propagation faster than equilibrium, and fairly strong ``profile resiliency.``
- Research Organization:
- Wisconsin Univ., Madison, WI (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-86ER53218; FG02-92ER54139
- OSTI ID:
- 10137721
- Report Number(s):
- UW-CPTC-93-8; CONF-9308183-4; ON: DE94009209; BR: AT0500000/AT0520210; AT101014Z/AT101017H; TRN: 94:007494
- Resource Relation:
- Conference: Workshop on local transport studies in fusion plasmas,Varenna (Italy),30 Aug - 3 Sep 1993; Other Information: PBD: Oct 1993
- Country of Publication:
- United States
- Language:
- English
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