Reduction of heat load localized onto the divertor plates is a critical issue in magnetic confined fusion devices. Enhancement of radiation loss in the scrape-off layer (SOL) and divertor plasmas by injecting impurity is most effective for expansion of the heat-loaded area. While, the impurity penetration into the core plasma should be suppressed to keep the high temperature by avoiding fuel dilution and high core radiation loss. In JT-60U, the total radiation loss reached up to 90% of the heating power by injecting argon into high density advanced tokamak plasmas with the reduced transport region [1]. In order to extrapolate this result to ITER and DEMO reactor, the impurity transport is modeled using a 1-D transport code in the core plasma and the 2-D fluid code UEDGE [2] in the SOL and divertor plasmas. The argon density profile, evaluated by fitting the calculated soft x-ray profile to measured one in the 1-D transport code, was more peaked by a factor of about 2 than the electron density profile. The argon density reached about 1% in the central region. On the other hand, the intrinsic impurity carbon density had relatively flat profile. In the UEDGE calculation, the calculated carbon density at the plasma edge was consistent with the measurement. However, the argon density was smaller by a factor of 3-4 than that evaluated above. The radiation loss power calculated based on the evaluated argon and carbon densities was smaller than the measurement. Effects of the input parameters on the UEDGE calculation will be discussed.

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