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(OV/2-1) Overview of ASDEX Upgrade Results

H. Zohm^1)
 
1) Max-Planck-Institut für Plasmaphysik, Garching, Germany

Abstract.  Recent work on ASDEX Upgrade focused on transport, stability and exhaust as well as scenario integration. Regarding transport, temperature profiles are usually `stiff', i.e. limited by a critical T/gradT up to r/a = 0.9. Locally, this can be exceeded in ITBs leading to central values in excess of 20 keV. Particle transport is well described by the neoclassical pinch plus a diffusion coefficient D proportional $\chi$ explaining the flat density profiles under strong central heating. Stability in conventional and flat shear advanced scenarios is limited by NTMs. A regime with `acceptable' NTMs has been found. Regarding NTM stabilisation by ECCD, stationary operation at $\beta_{N}^{}$-values above the onset value was demonstrated. In ELM physics, the type II ELM operational space has been extended to q₉₅ = 3.5. Regarding exhaust, the new divertor is adapted to all triangularities. With increased inner wall W-coverage, usually no problems are encountered. With low central heating, W-accumulation may occur, but is effectively reduced by increased central heating. Combining these elements led to the `high $\beta_{N}^{}$' regime combining HH = 1.1, $\beta_{N}^{}$ = 3.5 and n/n_GW = 0.9 in steady state with type II ELMs.

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