Turbulent field fluctuations in gyrokinetic and fluid plasmas
This work addresses uncertainty in fusion reactor design by validating reduced turbulent transport models, which is incremental but crucial for improving predictive accuracy.
The researchers tackled the problem of predicting edge plasma turbulence in magnetic confinement fusion reactors by directly comparing turbulent field fluctuations between electrostatic two-fluid theory and electromagnetic gyrokinetic modeling, finding good overall agreement in magnetized helical plasmas at low normalized pressure.
A key uncertainty in the design and development of magnetic confinement fusion energy reactors is predicting edge plasma turbulence. An essential step in overcoming this uncertainty is the validation in accuracy of reduced turbulent transport models. Drift-reduced Braginskii two-fluid theory is one such set of reduced equations that has for decades simulated boundary plasmas in experiment, but significant questions exist regarding its predictive ability. To this end, using a novel physics-informed deep learning framework, we demonstrate the first ever direct quantitative comparisons of turbulent field fluctuations between electrostatic two-fluid theory and electromagnetic gyrokinetic modelling with good overall agreement found in magnetized helical plasmas at low normalized pressure. This framework is readily adaptable to experimental and astrophysical environments, and presents a new technique for the numerical validation and discovery of reduced global plasma turbulence models.