(TH/P9-14) Integrated simulation of ELM Energy Loss and Cycle in Improved H-mode Plasmas

N. Hayashi1), T. Takizuka1), N. Aiba1), N. Oyama1), T. Ozeki1), S. Wiesen2), V. Parail3)
 
1) Fusion Research and Development Directorate, Japan Atomic Energy Agency, Ibaraki, Japan
2) Euratom FZJ Association, Institute of Energy Research, Julich, Germany
3) Euratom UKAEA Fusion Association, Culham Science Centre, Abingdon, UK

Abstract.  Integrated transport code with a stability code for peeling-ballooning modes and a transport model of scrape-off-layer (SOL) and divertor plasmas has been improved to take account of the density dynamics, which realizes for the first time the comprehensive study from energy and particle losses due to an edge localized mode (ELM) crash to its cycle. The integrated code reproduces a series of ELMs with experimental characteristics of type-I ELMs, which include the ELM frequency increasing linearly with the input power and the collisionality dependence of the ELM energy loss, and clarifies the following mechanisms. The steep pressure gradient inside the pedestal top as well as the low collisionality, required for improved H-mode plasmas with the HH98y2 factor above unity, is found to enhance the ELM energy loss and reduce the ELM frequency so that the power loss due to ELMs keeps almost constant. The steep pressure gradient inside the pedestal top broadens the region of the ELM enhanced transport. It is found that the collisionality dependence of the ELM energy loss is caused not only by the bootstrap current and the SOL transport but also by the equipartition effect, which enhances ion convective and charge-exchange losses in the low collisionality.

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