Speaker
Jonathan Citrin
Description
See the full Abstract at http://ocs.ciemat.es/EPS2018ABS/pdf/P5.1075.pdf
Fast isotope mixing in Ion Temperature Gradient driven turbulence
J. Citrin1 , C. Bourdelle2 , Y. Camenen3 , M. Marin1 , F.J. Casson4 , F. Koechl5 , M. Maslov4
and JET Contributors6
1 DIFFER - Dutch Institute for Fundamental Energy Research, Eindhoven, the Netherlands
2 CEA, IRFM, F-13108 Saint-Paul-lez-Durance, France
3 CNRS, Aix-Marseille Univ., PIIM UMR7345, Marseille, France
4 CCFE, Culham Science Centre, Abingdon, Oxon, OX14 3DB, UK
5 ÖAW/ATI, Atominstitut, TU Wien, 1020 Vienna, Austria
6 See the author list of X. Litaudon et al 2017 Nucl. Fusion 57 102001
Recent multiple-isotope experiments at JET have found evidence for ion particle transport co-
efficients larger than electron particle transport coefficients [1]. We apply GKW [2] nonlinear
and QuaLiKiz [3] quasilinear modelling to show the consistency with expectations of particle
transport in the Ion-Temperature-Gradient (ITG) driven regime. The effect is explained through
the dependency of particle transport coefficients on the wave-particle resonance condition [4].
In spite of the disparity in particle transport coefficient magnitude, ambipolarity is maintained
by large inward ion convective pinches being compensated by the large outward diffusion. In
multiple-ion experiments, the ambipolarity condition can be matched by the summation of mul-
tiple ion fluxes, providing for additional freedom where the large ion transport coefficients can
then provide fast ion mixing. We illustrate these ramifications for multiple-isotope transport
through JETTO [5, 6] integrated modelling with QuaLiKiz, through numerical experiments
based on a well modelled JET-ILW baseline discharge [7]. The large ion particle transport co-
efficients implies that the ion density profiles are uncorrelated to the corresponding ion source,
allowing peaked isotope density profiles even in the absence of core source. Furthermore, the
relaxation time of the individual ion profiles in a mixed system can be significantly faster than
the total density profile relaxation time which is constrained by the electrons. This leads to fast
isotope mixing and fast impurity transport in ITG regimes. In Trapped-Electron-Mode (TEM)
turbulence, the situation is the inverse: ion particle turbulent transport coefficients are smaller
than their electron counterpart.
References
[1] M. Maslov et al., to be submitted to Nucl. Fusion; M. Marin et al., this conference.
[2] A. Peeters et al., 2009 Computer Physics Communications 180 12.
[3] C Bourdelle et al. 2016 Plasma Phys. Control. Fusion 58 014036.
[4] C. Bourdelle, Y. Camenen, J. Citrin, M. Mirin et al., to be submitted to Nucl. Fusion.
[5] G. Cenacchi, A. Taroni, JETTO: A free-boundary plasma transport code, JET-IR (1988).
[6] M. Romanelli et al. 2014 Plasma and Fusion Research Volume 9, 3403023.
[7] J Citrin et al., 2017 Plasma Phys. Control. Fusion 59 12.
