@article{oai:repo.qst.go.jp:00048876,
 author = {神谷, 健作 and 伊藤, 公孝 and 伊藤, 早苗 and 神谷 健作},
 issue = {12},
 journal = {Nuclear Fusion},
 month = {May},
 note = {Non-uniformity effects of the edge radial electric field, Er, on the edge transport barriers (ETBs) formation have been identified with high-spatiotemporal resolution spectroscopic measurement. We found the decisive importance of Er-curvature (i.e. 2nd derivative of Er) on the ETBs formation at which the normalized ion temperature gradient, L_(T_i)^(-1)≡-(∇T_i)⁄T_i , has a local peak value in the pedestal region. On the other hand, the role of the Er-shear (i.e. 1st derivative of Er) was newly understood as for the expansion of pedestal width, compensating an unfavorable effect of the Er-curvature having its sign dependence on the transport reduction/enhancement, being expected by a theoretical model as L_(T_i)^(-1)∝(〖E_r^' E_r^'-E〗_r E_r^" )^0.5. A significant reduction of the inferred ion thermal transport coefficient in the pedestal region, χ_(i,ped.), due to the non-uniformity effects of Er was also confirmed quantitatively in the H-mode plasma at the initial ELM-free phase. When the inhomogeneity of radial electric field became strong enough, the inferred χ_(i,ped.) value was close to its neoclassical one at the later ELM-free H-phase until 1st type-I ELM onset. Even though, we observed the further reduction of electron density fluctuations (in the range up to 300 kHz) and D_α signals in association with the increment of electric field inhomogeneity. These suggest that the electron turbulent transport is suppressed further.},
 pages = {126003-1--126003-7},
 title = {Reduction of ion thermal transport due to non-uniformity effects of the radial electric field at the edge of the JT-60U tokamak},
 volume = {57},
 year = {2018}
}