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@INPROCEEDINGS{Ding:891687,
      author       = {Ding, F. and Chen, X. H. and Wang, L. and Ding, Rui and
                      Brezinsek, Sebastijan and Zhang, L. and Hu, Z. H. and Zhang,
                      Q. and Ma, Q. and Ye, D. W. and Luo, Y. and Zhang, Z. T. and
                      Sun, Y. W. and Luo, G.-N. and team, the EAST},
      title        = {{I}nvestigation of divertor {W} source and its control in
                      {EAST} {H} mode plasmas},
      reportid     = {FZJ-2021-01670},
      year         = {2021},
      abstract     = {Investigation of divertor W source and its control in EAST
                      H mode plasmas F. Ding1*, X. H. Chen1, L. Wang1, R. Ding1,
                      S. Brezinsek2, L. Zhang1, Z. H. Hu1, Q. Zhang1, Q. Ma1, D.W.
                      Ye1, Y. Luo1, Z.T. Zhang1, Y. W. Sun1, G.-N. Luo1 and the
                      EAST team1 Institute of Plasma Physics, Chinese Academy of
                      Sciences, Hefei 230031, People’s Republic of China 2
                      Forschungszentrum Jülich GmbH, Institut für Energie- und
                      Klimaforschung—Plasmaphysik,Partner of the Trilateral
                      Euregio Cluster (TEC), 52425 Jülich, Germany*E-mail:
                      fding@ipp.ac.cnAn effective control of W erosion at the wall
                      is not only a concern for the lifetime of Plasma-facing
                      Material (PFM), but also a prerequisite for maintaining a
                      low W concentration in the plasma core. In high confinement
                      plasma discharges, a large amount of energetic particles in
                      pedestal are ejected onto divertor targets in a timescale
                      less than 1 ms during the burst of edge localized mode
                      (ELM), even penetrating the detached divertor edge and
                      inducing significant W erosion at the divertor targets [1],
                      which contributes most of the W source in H-mode plasma and
                      needs to be well understood and controlled. In EAST,
                      intra-ELM W sources are resolved and studied via photo
                      multiplier tube (PMT) measurements with optical filters. The
                      non-W spectral emissions passing through the narrowband
                      filter were deducted via a cross-calibration with
                      spectrometer system with high spectral resolution. It is
                      observed that the intra-ELM W erosion has a linear
                      dependence on the plasma energy loss during each ELM burst
                      when the carbon content in plasma is maintained at a
                      relatively low level. However, high carbon content in plasma
                      can alter this dependence by inducing stronger W sputtering
                      even with a low ELM energy loss. In helium plasma
                      discharges, the ELM-induced W sputtering behaves more like
                      those in deuterium (D) plasmas with high C content,
                      indicating the effect of main ion mass. ELM frequency
                      effects on divertor W source are addressed in two different
                      regimes, the natural ELMs and the resonant magnetic
                      perturbation (RMP) mitigated ELMs. It is found that
                      intra-ELM W erosion rate with natural ELMs can roll over
                      after a certain ELM frequency, that is, firstly rise and
                      then drop with the increase of ELM frequency, while a
                      continuous growth of intra-ELM W erosion rate is observed
                      with RMP-mitigated ELMs from around 40 Hz to 300 Hz. These
                      should be the major reason for the indistinctive mitigation
                      of total W source, including intra- and inter-ELM W sources,
                      with the increase of ELM frequency Moreover, the asymmetric
                      distribution of W source in the divertor during H mode
                      discharges are investigated both poloidally and toroidally.
                      The ELM burst can induce an obviously stronger W erosion at
                      outer divertor than at inner divertor, which can be
                      influenced by the toroidal magnetic field direction, plasma
                      density as well as the ELM-induced plasma energy loss. The
                      toroidal non-axisymmetric distribution at the outer divertor
                      can be observed by rotating RMP field toroidally,
                      characterized by local W erosion peaks in toroidal
                      direction. The two poloidally separated W sources at the
                      divertor targets exhibit different responses to the neon
                      seeding, mitigated around the strike point, while enhanced
                      in the outer one, which could enhance the leakage of W
                      impurity into main plasma.[1] S. Brezinsek et al., Nucl.
                      Fusion 59, 096035 (2019).},
      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 / IEK-1 / IBG-3},
      cid          = {I:(DE-Juel1)IEK-4-20101013 / I:(DE-Juel1)IEK-1-20101013 /
                      I:(DE-Juel1)IBG-3-20101118},
      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/891687},
}