Radiofrequency sheath rectification on WEST: application of the sheath-equivalent dielectric layer technique in tokamak geometry*

Tierens, Wouter; Kumar, Atul; Klepper, Christopher; Lore, Jeremy; Myra, James R.; Hillairet, Julien; Urbanczyk, Guillaume; Helou, W.; Colas, Laurent; Grosjean, A.; Gunn, J.

doi:10.1088/1741-4326/ad80a9

Radiofrequency sheath rectification on WEST: application of the sheath-equivalent dielectric layer technique in tokamak geometry^*

Journal Article · Mon Oct 14 00:00:00 EDT 2024 · Nuclear Fusion

DOI:https://doi.org/10.1088/1741-4326/ad80a9· OSTI ID:2467562

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Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Lodestar Research Corp., Boulder, CO (United States)
CEA, IRFM, Saint Paul Lez Durance (France)
L’Institut Jean Lamour (IJL), Vandœuvre-lès-Nancy (France); Centre National de la Recherche Scientifique (CNRS) (France); Universite de Lorraine, Champenoux (France)
ITER Organization, St. Paul Lez Durance (France)
Univ. of Tennessee, Knoxville, TN (United States)

Radiofrequency sheath rectification is a phenomenon relevant to the operation of Ion Cyclotron Range of Frequencies (ICRFs) actuators in tokamaks. Techniques to model the sheath rectification on 3D ICRF antenna geometries have only recently become available (Shiraiw et al 2023 Nucl. Fusion 63 026024; Beers et al 2021 Phys. Plasmas 28 093503). In this work, we apply the 'sheath-equivalent dielectric layer' technique, used previously only on linear devices (Beers et al 2021 Phys. Plasmas 28 103508), in tokamak geometry, computing rectified sheath potentials on the WEST ICRF antenna. Advancing the state of the art in sheath rectification modeling, we compute the sheath potentials not just on the limiters, but also on the Faraday Screen bars. The calculations show a peak rectified DC potential of 300 V on the limiters and 500 V on the Faraday screen. Assuming a typical sputtering yield curve, the RF sheath rectification increases the sputtering yield from the limiters by a factor of 2.6 w.r.t. the sputtering due to the non-rectified thermal sheath.

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Research Organization:: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)

Sponsoring Organization:: USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR). Scientific Discovery through Advanced Computing (SciDAC); USDOE Office of Science (SC), Basic Energy Sciences (BES); USDOE Office of Science (SC), Fusion Energy Sciences (FES)

Grant/Contract Number:: AC05-00OR22725

OSTI ID:: 2467562

Alternate ID(s):: OSTI ID: 2474762

Journal Information:: Nuclear Fusion, Journal Name: Nuclear Fusion Journal Issue: 12 Vol. 64; ISSN 0029-5515

Publisher:: IOP ScienceCopyright Statement

Country of Publication:: United States

Language:: English

References (25)

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