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  • Pedestal and scrape-off layer dynamics in ELMy H-mode plasmas in JET
    Beurskens, Marc ...
    Pedestal and scrape-off layer (SOL) dynamics due to edge localized modes (ELMs) have been studied on JET with improved diagnostic capability. The new high resolution Thomson scattering system enables ... detailed measurement of the space and time evolution of the T-e and ne pedestal profiles. The pedestal andSOL dynamics for type I ELMy H-mode plasmas have been studied for a wide range of plasma conditions. During a short period of <200 mu s after the ELM event radial profiles of filaments in the SOL electron density and temperaturehave been observed. After that period the SOL density is increased and remains high for several milliseconds. During the same period the electrontemperature shows no increase compared with the pre-ELM values. This SOL dynamics has been observed for a wide range of plasma parameters and is independent of plasma pedestal collisionality. For the first time on JET the convective and conductive ELM energy losses have been quantified using the newkinetic profile measurements. The findings provide detailed confirmation ofearlier observations based on different measurements and analysis. The pedestal region perturbed by the ELM is the same for both density and temperature and the ELM effect extends up to about 20% of minor radius. The convective energy losses do not vary significantly and are similar to 5% of the pedestal stored energy (W-ped) over a large range of pedestal collisionality nu(e)* from below nu(e)* = 0.1 to above nu(e)* = 0.5 whereas the conductive losses strongly decrease from similar to 20% of W-ped to 5% of W-ped with increasing nu(e)*. The experimental observations are compared with a simple model based on losses being driven by parallel transport.
    Source: Nuclear fusion. - ISSN 0029-5515 (Iss. 12, Vol. 49, 2009, 125006-1-125006-14)
    Type of material - article, component part
    Publish date - 2010
    Language - english
    COBISS.SI-ID - 24743719

source: Nuclear fusion. - ISSN 0029-5515 (Iss. 12, Vol. 49, 2009, 125006-1-125006-14)
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