% IMPORTANT: The following is UTF-8 encoded.  This means that in the presence
% of non-ASCII characters, it will not work with BibTeX 0.99 or older.
% Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or
% “biber”.

@ARTICLE{Iglesias:872838,
      author       = {Iglesias, D. and Bunting, P. and Coenen, J. W. and
                      Matthews, G. F. and Pitts, R. A. and Silburn, S. and Balboa,
                      I. and Coffey, I. and Corre, Y. and Dejarnac, R. and Gaspar,
                      J. and Gauthier, E. and Jachmich, S. and Krieger, K. and
                      Pamela, S. and Riccardo, V. and Stamp, M.},
      title        = {{A}n improved model for the accurate calculation of
                      parallel heat fluxes at the {JET} bulk tungsten outer
                      divertor},
      journal      = {Nuclear fusion},
      volume       = {58},
      number       = {10},
      issn         = {1741-4326},
      address      = {Vienna},
      publisher    = {IAEA},
      reportid     = {FZJ-2020-00308},
      pages        = {106034 -},
      year         = {2018},
      abstract     = {Parallel heat flux calculations at the JET divertor have
                      been based on the assumption that all incoming heat is due
                      to the projection of the heat flux parallel to the magnetic
                      line, , plus a constant background. This simplification led
                      to inconsistencies during the analysis of a series of
                      dedicated tungsten melting experiments performed in 2013,
                      for which infrared (IR) thermography surface measurements
                      could not be recreated through simulations unless the
                      parallel heat flux was reduced by $80\%$ for L-mode and
                      $60\%$ for H-mode. We give an explanation for these
                      differences using a new IR inverse analysis code, a set of
                      geometrical corrections, and most importantly an additional
                      term for the divertor heat flux accounting for non-parallel
                      effects such as cross-field transport, recycled neutrals or
                      charge exchange. This component has been evaluated comparing
                      four different geometries with impinging angles varying from
                      2 to 90°. Its magnitude corresponds to $1.2\%–1.9\%$ of ,
                      but because it is not affected by the magnetic projection,
                      it accounts for up to $20\%–30\%$ of the tile surface heat
                      flux. The geometrical corrections imply a further reduction
                      of $24\%$ of the measured heat flux. In addition, the
                      application of the new inverse code increases the accuracy
                      of the tile heat flux calculation, eliminating any previous
                      discrepancy. The parallel heat flux computed with this new
                      model is actually much lower than previously deduced by
                      inverse analysis of IR $temperatures—40\%$ for L-mode and
                      $50\%$ for H-mode—while being independent of the geometry
                      on which it is measured. This main result confirms the
                      validity of the optical projection as long as a non-constant
                      and non-parallel component is considered. For a given total
                      heating power, the model predicts over $10\%$ reduction of
                      the maximum tile surface heat flux compared to strict
                      optical modelling, as well as a $30\%$ reduced sensitivity
                      to manufacturing and assembling tolerances. These
                      conclusions, along with the improvement in the
                      predictability of the divertor thermal behaviour, are
                      critical for JET future DT operations, and are also directly
                      applicable to the design of the ITER divertor monoblocks.},
      cin          = {IEK-4},
      ddc          = {620},
      cid          = {I:(DE-Juel1)IEK-4-20101013},
      pnm          = {174 - Plasma-Wall-Interaction (POF3-174)},
      pid          = {G:(DE-HGF)POF3-174},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000443247800003},
      doi          = {10.1088/1741-4326/aad83e},
      url          = {https://juser.fz-juelich.de/record/872838},
}