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Author(s):
K. Ioth, S.-I. Itoh, A. Fukuyama, M. Yagi and M. Azumi
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Title:
Model of the L-Mode Confinement in Tokamaks
Date of publication:
Sep. 1992
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Key words:
L-mode, current diffusivity, transport-MHD, tokamaks ballooning mode, anomalous transport, profile resilience
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Abstract:
Model of the L-mode confinement in tokamaks is developed based on the microscopic ballooning mode instability. The anomalous transport coefficients determine the stability below the critical beta against the ideal MHD ballooning instability. The current-diffusivity has strong destabilizing effect, while the thermal transport chi and ion viscosity tend to stabilize the mode. The stability boundary for the least stable microscopic ballooning mode determines the anomalous transport coefficients. The obtained formula is compared with experimental observations on the L-mode confinement. The predictions on (1)the radial shape of chi, (2)the temperature-profile resilience, (3)the global confinement characteristics, such as the power degradation and the dependences on the plasma current, current profile and mass number, and (4)the ratio of the perturbative chi to the energy balance chi are consistent with experimental database.
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