Quasilinear transport modelling at low magnetic shear
- FOM Institute DIFFER-Dutch Institute for Fundamental Energy Research, Association EURATOM-FOM, Nieuwegein (Netherlands)
- CEA, IRFM, F-13108 Saint Paul Lez Durance (France)
- UMR 6633 CNRS-Universite de Provence, Marseille (France)
- Laboratoire de Physique des Plasmas, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex (France)
- Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, D-85748 Garching (Germany)
Accurate and computationally inexpensive transport models are vital for routine and robust predictions of tokamak turbulent transport. To this end, the QuaLiKiz [Bourdelle et al., Phys. Plasmas 14, 112501 (2007)] quasilinear gyrokinetic transport model has been recently developed. QuaLiKiz flux predictions have been validated by non-linear simulations over a wide range in parameter space. However, a discrepancy is found at low magnetic shear, where the quasilinear fluxes are significantly larger than the non-linear predictions. This discrepancy is found to stem from two distinct sources: the turbulence correlation length in the mixing length rule and an increase in the ratio between the quasilinear and non-linear transport weights, correlated with increased non-linear frequency broadening. Significantly closer agreement between the quasilinear and non-linear predictions is achieved through the development of an improved mixing length rule, whose assumptions are validated by non-linear simulations.
- OSTI ID:
- 22072455
- Journal Information:
- Physics of Plasmas, Vol. 19, Issue 6; Other Information: (c) 2012 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 1070-664X
- Country of Publication:
- United States
- Language:
- English
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