Quasilinear transport modelling at low magnetic shear
Quasilinear transport modelling at low magnetic shear
复制标题
低磁剪切下的拟线性输运建模
DOI：
10.1063/1.4719697
复制
发表时间：
2012
影响因子：
2.2
通讯作者：
M. Pueschel
中科院分区：
文献类型：
--
作者：
J. Citrin;C. Bourdelle;P. Cottier;D. Escande;Ö. Gürcan;D. Hatch;G. Hogeweij;F. Jenko;M. Pueschel
准确且计算成本低廉的输运模型对于托卡马克湍流输运的常规和稳健预测至关重要。为此，QuaLiKiz [Bourdelle 等人，Phys. Plasmas 14, 112501 (2007)]最近开发了拟线性回旋输运模型。 QuaLiKiz 通量预测已通过参数空间大范围内的非线性模拟得到验证。然而，在低磁剪切下发现了差异，其中准线性通量明显大于非线性预测。发现这种差异源于两个不同的来源：混合长度规则中的湍流相关长度以及准线性和非线性传输权重之间比率的增加，与非线性频率展宽的增加相关。通过开发改进的混合长度规则，准线性和非线性预测之间的一致性显着提高，其假设通过非线性模拟得到验证。
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.