EFDA-JET-CP(07)03/34

Measurements of Inboard-Outboard Asymmetry of Pedestal Temperature Collapse during Type I ELMs in JET

Despite the considerable theoretical and experimental effort, a complete physical model to describe the particle and energy losses during ELMs is far from being complete. On the experimental front, significant progress has been made in characterizing the dynamics and the spatial structure (poloidal asymmetry, radial distribution) of the ELM crash. A number of diagnostics have shown that the ELMs predominantly affect the pressure on the outboard midplane, which is consistent with the interpretation of ELM events as ballooning-type instabilities. Much of the effort of the fusioncommunity on this topic has been devoted to measuring the fast evolution of the plasma parameters during the ELM crash. However, there is an obvious need for more profile measurements covering the edge region on the inboard midplane to complement those at the outboard midplane. The objective of this paper is to report on a new set of recent measurements obtained at JET using high spatial and temporal resolution ECE data from both High-Field Side (HFS) and Low-Field-Side (LFS) midplane. Given the relative novelty of the technique, this paper focuses on the validation of the new HFS data and the identification of the limitations of the measurements and the data analysis. Further analysis is required but some preliminary results are presented here.
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