Radiative type-III ELMy H-mode in all-tungsten ASDEX Upgrade

TitleRadiative type-III ELMy H-mode in all-tungsten ASDEX Upgrade
Publication TypeJournal Article
Year of Publication2012
AuthorsJ. Rapp, A. Kallenbach, R. Neu, T. Eich, R. Fischer, A. Herrmann, S. Potzel, G.J van Rooij, J.J Zielinski, ASDEX-Upgrade Team
JournalNuclear Fusion
Volume52
Number12
Pagination122002
Abstract

The type-III ELMy H-mode might be the solution for an integrated ITER operation scenario fulfilling the fusion power amplification factor (output fusion power to input heating power) of Q = 10 with simultaneous acceptable steady-state and transient power loads to the plasma-facing components. This highly radiative type-III ELMy H-mode is achieved by nitrogen seeding. Experiments on the tokamak ASDEX Upgrade, in which all plasma-facing components are coated with tungsten, showed favourable confinement conditions ( H 98( y ,2) = 1) at high plasma pressure ( β N = 2.4). The power load to the plasma-facing components is as low as ≈3 MW m −2 during the peak heat loads due to edge localized modes (ELMs) at high radiative power fractions of f rad ≈ 0.75. In those high-density discharges the central impurity concentration is very low as a result of hollow nitrogen density profiles and minimal erosion of tungsten. The tungsten erosion is not only suppressed in between ELMs, when the divertor is detached, but also during the type-III ELM activity. Such low impurity concentrations in the plasma core might lead to even higher fusion amplification factors in ITER than 10. This is a demonstration of the compatibility of the radiating type-III ELMy H-mode with a tungsten divertor and main chamber wall, with sufficient confinement and favourable power exhaust characteristics. Together with previous results in all-carbon devices this demonstration strengthens the case for a potential application of a Q = 10 scenario on ITER.

URLhttp://stacks.iop.org/0029-5515/52/i=12/a=122002
DOI10.1088/0029-5515/52/12/122002
Division

PSI

Department

PSI-E

PID

5e92bc68ccf9246677cfe86142687522

Alternate TitleNucl. Fusion
LabelOA

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