| Home > Publications database > Characterisation of small ELM experiments in highly shaphed single null and quasi-double null plasmas in JET |
| Journal Article | PreJuSER-48333 |
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2005
IAEA
Vienna
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Please use a persistent id in citations: http://hdl.handle.net/2128/1895 doi:10.1088/0029-5515/45/5/001
Abstract: This paper describes experiments with highly shaped JET H-mode plasmas, which were directed to developing regimes where Type I ELMs are replaced by other edge relaxations, while maintaining the pedestal pressure of Type I ELMy H-modes. It was found that Type II ELMs coexisted with Type I, up to densities of the order of the Greenwald limit, where Type III ELMs appear, and the good confinement was lost. Only at the highest edge collisionality was it observed that Type II ELMs completely replace Type I. At high beta(p) and q(95), 'grassy' ELMs replace Type I completely. The MHD spectra characteristics for grassy ELMs are significantly different from those of Type II ELMs. This paper details the experiments, briefly compares the results to those obtained elsewhere and suggests open lines of investigations for the assessment of the potential of grassy ELM regimes as an ELM mitigation technique.
Keyword(s): J
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