Validating the linear model in TGLF with linear CGYRO simulations using experimental DIII-D cases

In order to study present fusion experiments, and plan future fusion reactors, it is important to accurately model the heat and particle losses due to turbulence in magnetically confined plasmas. The trapped gyro-Landau fluid code (TGLF) is a quasi-linear model of gyrokinetic turbulence that relies on high-fidelity simulations with the CGYRO code for calibration. To validate the accuracy of the linear model in TGLF, the CGYRO code is run in its linearized setting for a range of experimental cases from the DIII-D tokamak. In general, the linear growth rates and quasi-linear weights of TGLF and CGYRO agree well, with better agreement found at the ion scales than the electron scales. There are also cases where an overprediction in the linear growth rates of kinetic ballooning modes by TGLF causes an overprediction of heat flux. By focusing on cases with deviations between TGLF and experiment, these linear CGYRO simulations identify any contribution to this deviation from the linear model in TGLF. These results from ongoing work will help validate the linear component of the TGLF model and will inform future model development and calibration efforts.