Tractable flux-driven temperature, density, and rotation profile evolution with the quasilinear gyrokinetic transport model QuaLiKiz

TL;DR

This paper presents an optimized quasilinear gyrokinetic transport model, QuaLiKiz, capable of rapidly predicting tokamak plasma profile evolution, including effects of rotation and impurities, with good agreement to experimental data.

Contribution

The paper introduces significant computational improvements in QuaLiKiz, enabling fast, flux-driven plasma profile simulations including rotation and impurity effects, suitable for integrated tokamak modeling.

Findings

Flux calculations are 10^6 to 10^7 times faster than nonlinear simulations.

Simulations successfully predict core plasma profiles within 5-25% accuracy.

Application to JET demonstrates practical, rapid profile evolution predictions.

Abstract

Quasilinear turbulent transport models are a successful tool for prediction of core tokamak plasma profiles in many regimes. Their success hinges on the reproduction of local nonlinear gyrokinetic fluxes. We focus on significant progress in the quasilinear gyrokinetic transport model QuaLiKiz [C. Bourdelle et al. 2016 Plasma Phys. Control. Fusion 58 014036], which employs an approximated solution of the mode structures to significantly speed up computation time compared to full linear gyrokinetic solvers. Optimization of the dispersion relation solution algorithm within integrated modelling applications leads to flux calculations $\times10^{6-7}$ faster than local nonlinear simulations. This allows tractable simulation of flux-driven dynamic profile evolution including all transport channels: ion and electron heat, main particles, impurities, and momentum. Furthermore, QuaLiKiz now includes the impact of rotation and temperature anisotropy induced poloidal asymmetry on heavy impurity transport, important for W-transport applications. Application within the JETTO integrated modelling code results in 1s of JET plasma simulation within 10 hours using 10 CPUs. Simultaneous predictions of core density, temperature, and toroidal rotation profiles for both JET hybrid and baseline experiments are presented, covering both ion and electron turbulence scales. The simulations are successfully compared to measured profiles, with agreement mostly in the 5-25% range according to standard figures of merit.