|Title||Quasilinear transport modelling at low magnetic shear|
|Publication Type||Journal Article|
|Year of Publication||2012|
|Authors||J. Citrin, C. Bourdelle, P. Cottier, D.F Escande, O.D Gurcan, D.R Hatch, G.MD Hogeweij, F. Jenko, M.J Pueschel|
|Journal||Physics of Plasmas|
|Type of Article||Article|
|Keywords||GRADIENT-DRIVEN MODE, PARTICLE, STABILITY, TOKAMAKS, TORE-SUPRA, TURBULENCE|
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. (C) 2012 American Institute of Physics.
|Alternate Title||Phys. Plasmas|
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