2-DIMENSIONAL DIVERTOR SIMULATION ON JT-60U

Divertor and scrape-off layer (SOL) plasmas were simulated in the JT-6 0U geometry with the UEDA code. Experimentally measured T-e profiles w ith 15-ch Langmuir probes and heat flux profiles with an IRTV camera a t the divertor prates were globally fit well with chi(perpendicular to ) = 2-4 m(2)/s for ohmic and L-mode discharges. The electron density a nd the particle amplification factor are maximized when T-e(div) appro ximate to 20 eV in an open divertor configuration. A further increase in particle flux leads to penetration of neutrals to the X-point. Alth ough baffle plates can reduce the neutral density around the main plas ma, particle recycling and heat load on the baffle plates becomes sign ificant when the aperture is narrower than 40 cm in JT-60U. Closing th e private region is effective to drop the neutral particle density nea r the X-point. A slot-like divertor shape with divertor gas puffing wa s found to be required to achieve cold divertor plasmas with particle fluxes at an H-mode level.