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@INPROCEEDINGS{Boeyaert:891500,
      author       = {Boeyaert, D. and Wiesen, S. and Wischmeier, M. and
                      Dekeyser, W. and Carli, S. and Wang, L. and Ding, F. and Li,
                      K. and Liang, Y. and Baelmans, M.},
      title        = {{A}ssessment of plasma edge transport in {N}eon seeded
                      plasmas in disconnected double null configuration in {EAST}
                      with {SOLPS}-{ITER}},
      reportid     = {FZJ-2021-01566},
      year         = {2021},
      abstract     = {Assessment of plasma edge transport in Neon seeded plasmas
                      in disconnected double null configuration in EAST with
                      SOLPS-ITERD. Boeyaert1,3, S. Wiesen1, M. Wischmeier2, W.
                      Dekeyser3, S. Carli3, L. Wang4, F. Ding4, K. Li4, Y.
                      Liang1,4, M. Baelmans3, and the EAST-teama1Forschungszentrum
                      Jülich GmbH, Institut für Energie- und Klimaforschung –
                      Plasmaphysik, D-52425 Jülich, Germany2Max-Planck-Institut
                      für Plasmaphysik, Boltzmannstraße 2, 85748 Garching,
                      Germany3KU Leuven, Department of Mechanical Engineering,
                      Celestijnenlaan 300, 3001 Leuven, Belgium4Institute of
                      Plasma Physics, Chinese Academy of Sciences, Hefei 230031,
                      People’s Republic of China aSee appendix of Wan B.N. et al
                      2019 Nucl. Fusion 59 112003 d.boeyaert@fz-juelich.dePower
                      and particle exhaust is essential for future nuclear fusion
                      reactors [1]. This exhaust is determined by the
                      perpendicular/radial transport inside the Scrape-Off Layer
                      (SOL) which include drifts and currents, neutral kinetics,
                      radiation and (radial) anomalous transport. Under high power
                      conditions in future all-metal fusion devices like ITER or
                      DEMO, extrinsic impurity seeding is required to induce
                      divertor detachment through impurity radiation. Due to the
                      lack of surface chemistry, noble gases like neon (Ne) are
                      key candidates as main radiator. Besides JET [2], EAST is
                      the only tokamak that currently handles stable H-modes with
                      Neseeding in a metallic environment as the main (upper)
                      divertor is made out of tungsten. This device has the
                      flexibility to do both upper single null (USN) and double
                      null (DN) configurations with the latter showing good
                      prospects to handle exhaust with good core confinement [3].
                      USN discharges in EAST are setup as disconnected DN (DDN)
                      with a large separation between separatrices upstream
                      (drsep) of about ~ 2cm. This causes a remaining influx of
                      eroded C impurities from the lower (non-active) divertor.
                      This contribution analyzes Ne seeded and unseeded DDN
                      deuterium discharges at EAST with decreasing drsep, both
                      with experimental data from EAST and SOLPS-ITER simulations
                      [4] . Ne seeded discharges in H-mode from the 2019 EAST
                      campaign are studied (heating power Pheat = 2.5 MW, plasma
                      current Ip = 0.4 MA and toroidal field Bt = 2.4 T). For the
                      first time, a DDN configuration with divertor Te-feedback
                      for the Ne puff strength was attempted to achieve steady
                      divertor conditions. A radiative fraction Prad/Pheat of up
                      to $30\%$ was achieved with Ne seeding while $10\%$ is
                      achieved without. Ne in all cases was injected from the
                      upper (active) outer target and a significant target
                      temperature drop was identified from the Langmuir probes.
                      The effect of a DDN configuration however is limited as the
                      upstream power scrape-off width (~0.5cm [5]) is
                      significantly smaller compared to the achieved separation
                      between the separatrices (drsep ~ 1.5 cm). SOLPS-ITER
                      simulations are being carried out to interpret the
                      experimental results to understand the influence of the
                      different transport types in the SOL for a dissipative DDN
                      divertor geometry with and without Ne seeding and C erosion.
                      The model includes for the first time for EAST fluid drifts
                      and edge currents in the SOL. SOLPS-ITER will be used to
                      predict the performance of a Ne seeded EAST DN divertor
                      (with drsep = 0) being closest to one of theconsidered DEMO
                      divertor geometries. [1] M. Wischmeier, et al., J. Nucl.
                      Mater. 22-29 (2015) 463; [2] S. Glöggler, et al., Nucl.
                      Fusion. 126031 (2019) 59 ; [3] H. Meyer, et al., Nucl.
                      Fusion. 64-72 (2006) 46; [4] S. Wiesen et al., J. Nucl. Mat.
                      480-484 (2015) 463 ; [5] T. Eich, et al., Nucl. Fusion
                      093031 (2013) 53},
      month         = {Jan},
      date          = {2021-01-25},
      organization  = {24th International Conference on
                       Plasma Surface Interactions in
                       Controlled Fusion Devices (PSI 2020),
                       virtuell (virtuell), 25 Jan 2021 - 29
                       Jan 2021},
      cin          = {IEK-4 / ICG-4},
      cid          = {I:(DE-Juel1)IEK-4-20101013 / I:(DE-Juel1)VDB793},
      pnm          = {134 - Plasma-Wand-Wechselwirkung (POF4-134)},
      pid          = {G:(DE-HGF)POF4-134},
      typ          = {PUB:(DE-HGF)1},
      url          = {https://juser.fz-juelich.de/record/891500},
}