ORNL has a long history of developing custom applications for simulating a range of plasma physics phenomena supporting the DOE-Fusion Energy Science Program. Example application areas of custom tools are developed with an eye towards taking advantage of the most advanced computational capabilities. These areas include:
- Magnetohydrodynamic (MHD) equilibrium
- Plasma heating and current drive
- Tokamak disruptions and runaway electron dynamics
- Interactions between energetic particles and plasma waves
- Integrated multiphysics simulations for predicting reactor performance
Recent tools developed include the Parallel Variational Moment Equilibrium Code (PARVMEC), which has extended the world-leading 3D MHD equilibrium model VMEC to take advantage of modern computing capabilities. This is the community standard model for 3D equilibria in experiments such as stellarators and is currently being extended to allow for islands and stochastic fields in the SIESTA code. ORNL also leads development of models for heating and current drive using radiofrequency waves, with the AORSA code being the only full-wave simulation capable of treating perpendicular wavelengths on the scale of the ion Lamor radius or smaller. ORNL is also developing community-leading simulation of energetic particles in fusion plasmas, including one example through the full-orbit KORC code which was developed to provide high-fidelity modeling of runaway electron dynamics following tokamak disruptions. Models of the interaction of energetic particles with waves in plasma, including both Alfvenic instabilities and externally driven modes, are being developed using the gyrofluid approximation in 2D (TAEFL) and 3D (FAR3D). ORNL has also developed expertise in coupled plasma simulations using the Integrated Plasma Simulation (IPS) framework. This framework is used to build integrated simulations for a variety of needs. As an example, the FASTRAN modeling tool combines a large set of simulation components, including models for plasma equilibrium, stability, and transport, providing the predictive capability needed to develop advanced tokamak scenarios and other simulations. This approach is currently being extended into CESOL, which includes models for the plasma boundary layer. Various other integrated simulation capabilities are being developed, such as coupling plasma models with materials simulations to model plasma-surface interactions.