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Title: Exploring drift effects in TCV single-null plasmas with the UEDGE code

This study explores the effects of particle drifts across the magnetic field in TCV single-null plasmas using the two-dimensional edge plasma transport code UEDGE. In particular, it aims to reproduce a double-peaked density target profile, a feature which has been observed both at JET and in a TCV forward-field ($${\rm{\nabla }}B$$ drift of core ions towards the X-point) discharge. Initial simulations are performed with drift effects turned off. This allows identification of the input parameters that strongly influence the computed steady-state but are not well known from the experiment. Including cross-field drifts self-consistently in the simulations brings computed profiles at the inner target closer to the experiment, with the double peak being reproduced for the density. In agreement with the experiment, simulations of a similar reversed-field shot yield lower n e and higher T e at the inner target, as well as unchanged temperatures at the outer plate. However, several discrepancies remain. In the forward field case, the inner target density peak near the separatrix is much sharper than seen experimentally. Furthermore, simulations show a strong dependence of the outer plate density and of the outer/inner power sharing on toroidal field direction. Experimentally, no such dependencies are observed. In the simulations, the changes of target profiles with field direction are mainly due to E × B drifts in the divertor region. Finally, while these simulations highlight the importance of E × B drifts in these TCV plasmas, the remaining differences with the experiment indicate that their role is overestimated in the simulations.
Authors:
 [1] ; ORCiD logo [2] ;  [3] ;  [3] ;  [2] ;  [2] ;  [2]
  1. École Polytechnique Fédérale de Lausanne (EPFL) (Switzlerland). Swiss Plasma Center (SPC); Univ. of Oxford (United Kingdom). Rudolf Peierls Centre for Theoretical Physics
  2. École Polytechnique Fédérale de Lausanne (EPFL) (Switzlerland). Swiss Plasma Center (SPC)
  3. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Report Number(s):
LLNL-JRNL-746959
Journal ID: ISSN 0741-3335; 931709
Grant/Contract Number:
AC52-07NA27344
Type:
Accepted Manuscript
Journal Name:
Plasma Physics and Controlled Fusion
Additional Journal Information:
Journal Volume: 59; Journal Issue: 10; Journal ID: ISSN 0741-3335
Publisher:
IOP Science
Research Org:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); École Polytechnique Fédérale de Lausanne (EPFL) (Switzlerland)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; TCV; UEDGE; drifts; single-null
OSTI Identifier:
1465288