This title appears in the Scientific Report :
2015
Please use the identifier:
http://dx.doi.org/10.1088/0029-5515/54/12/123011 in citations.
Numerical evaluation of heat flux and surface temperature on a misaligned JET divertor W lamella during ELMs
Numerical evaluation of heat flux and surface temperature on a misaligned JET divertor W lamella during ELMs
A series of experiments has been performed on JET to investigate the dynamics of transient melting due to edge localized modes (ELMs). The experiment employs a deliberately misaligned lamella in one module of the JET bulk tungsten outer divertor, allowing the combination of stationary power flux and...
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Personal Name(s): | Dejarnac, R. (Corresponding author) |
---|---|
Podolnik, A. / Komm, M. / Arnoux, G. / Coenen, J. W. / Devaux, S. / Frassinetti, L. / Gunn, J. P. / Matthews, G. F. / Pitts, R. A. | |
Contributing Institute: |
Plasmaphysik; IEK-4 |
Published in: | Nuclear fusion, 54 (2014) 12, S. 123011 - |
Imprint: |
Vienna
IAEA
2014
|
DOI: |
10.1088/0029-5515/54/12/123011 |
Document Type: |
Journal Article |
Research Program: |
Plasma-Wall-Interaction |
Publikationsportal JuSER |
A series of experiments has been performed on JET to investigate the dynamics of transient melting due to edge localized modes (ELMs). The experiment employs a deliberately misaligned lamella in one module of the JET bulk tungsten outer divertor, allowing the combination of stationary power flux and ELMs to transiently melt the misaligned edge. During the design of the experiment a number of calculations were performed using 2D particle-in-cell simulations and a heat transfer code to investigate the influence on the deposited power flux of finite Larmor radius effects associated with the energetic ELM ions. This has been performed using parameter scans inside a range of pedestal temperatures and densities to scope different experimentally expected ELM energies. On the one hand, we observe optimistic results, with smoothing of the heat flux due to the Larmor gyration on the protruding side of the lamella which sees the direct parallel flux—the deposited power tends to be lower than the nominal value expected from geometric magnetic field line impact over a distance smaller than 2 Larmor radii, a finding which is always valid during ELMs for such a geometry. On the other hand, the fraction of the flux not reaching the directly wetted side is transferred and spread to the top surface of the lamella. The hottest point of the lamella (corner side/top) does not always benefit from the gain from the Larmor smoothing effect because of an enhanced power deposition from the second contribution. |