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Report No.

Balance of the stored energies sustained by the internal and edge transport barriers and effects of ELMs and L-H transitions in JT-60U

Kamada, Yutaka; Yoshida, Maiko; Sakamoto, Yoshiteru; Koide, Yoshihiko; Oyama, Naoyuki; Urano, Hajime; Kamiya, Kensaku; Suzuki, Takahiro; Isayama, Akihiko; JT-60 Team

For understanding of the physics processes determining the radial profiles of the kinetic plasma parameters in the advanced tokamak plasmas, correlation between the edge and the internal transport barriers (ETB and ITB) has been studied. We fond that the edge pedestal beta, $$beta$$$$_{p-ped}$$, increases almost linearly with the total $$beta$$$$_{p}$$, over a wide range of the plasma current for the type I ELMing H-mode, and the dependence becomes stronger with increasing triangularity. This dependence is not due to the profile stiffness. However, with increasing the stored energy inside the ITB radius (W$$_{ITB}$$), the total thermal stored energy (W$$_{th}$$) increases and then the pedestal stored energy (W$$_{p-ped}$$) increases. With increasing W$$_{p-ped}$$, the ELM penetration depth expands more inward and finally reaches the ITB-foot radius. At this situation, the ITB radius cannot move outward and the ITB strength becomes weak. Then the fractions of W$$_{ITB}$$ and W$$_{p-ped}$$ to W$$_{th}$$ become almost constant. We also found that the type I ELM expels/decreases edge toroidal momentum larger than ion thermal energy. The ELM penetration radius for toroidal rotation tends to be deeper than that for ion temperature, and can exceeds the ITB radius. The ELM affected area is deeper for CO rotating plasmas than CTR rotating ones. The ELM affected area is deeper in the order of the toroidal rotation (V$$_{t}$$), the ion temperature (T$$_{i}$$) and then the electron temperature (Te). The L-H transition also changes the V$$_{t}$$-profile more significantly than the Ti-profile. After the L-H transition, in the ELM-free phase, the pedestal V$$_{t}$$ sifts into the CTR direction deeply and suddenly, and after that the pedestal V$$_{t}$$ and T$$_{i}$$ evolves in the similar timescale. The change in V$$_{t}$$ by ELM and L-H transition may affect degradation / evolution of ITBs.



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Category:Physics, Fluids & Plasmas



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