Duran, I., Jesko, K., Fuchs, V., Groth, M., Guillemaut, C., Gunn, J. P., Horacek, J., Pitts, R. A., & Tskhakaya, D. (2015). Assessment of the effect of parallel temperature gradients in the JET SOL on Tₑ measured by divertor target Langmuir probes. Journal of Nuclear Materials, 463, 432–435. https://doi.org/10.1016/j.jnucmat.2015.01.051
E134-03 - Forschungsbereich Atomic and Plasma Physics
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Zeitschrift:
Journal of Nuclear Materials
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ISSN:
0022-3115
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Datum (veröffentlicht):
Aug-2015
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Umfang:
4
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Verlag:
ELSEVIER
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Peer Reviewed:
Ja
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Keywords:
General Materials Science; Nuclear and High Energy Physics; Nuclear Energy and Engineering
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Abstract:
Higher than expected electron temperatures (Te) are often measured by divertor Langmuir probes (LP) in
high recycling and detached regimes in JET and other tokamaks. As a possible mechanism to explain this
discrepancy, we investigate the effect of penetration of fast, almost collisionless electrons connecting the
hot upstream scrape-off layer (SOL) region to the divertor targets in JET. We simulate the electron velocity
distribution function (EVDF) near the divertor targets using a simple 1D kinetic model using parallel
SOL profiles from EDGE2D-EIRENE simulations. The resulting EVDF is used to construct synthetic LP current-
voltage (IV) characteristics and evaluation of Te is performed in the same way as for experimental
data. Results indicate that the process does not explain the anomalously high Te values estimated from
the target probe measurements if the EDGE2D-EIRENE simulated parallel profiles are a good representation
of reality.
