Unstructured Mesh Technologies for Massively Parallel Simulation and Data Analysis of Magnetically Confined Plasmas

The simulation of magnetically confined plasmas requires considering multiple overlapping scales. Continuum models address reactor scale behaviors, while particle methods capture fine scale behavior. The complex combination of physics and reactor geometry results in simulations involving massive calculations and data sets, which can only be executed on parallel computers. Thus, there is a critical need for effective methods that can execute coupled simulations with fully parallel representations, and computations, at both the continuum and particle level with specific consideration of the ability to perform validation with experimentally measured data. The goal of this project is to develop structures and tools for multiscale plasma simulations that provide a parallel mesh and particle infrastructure, data analysis operations to support validation, geometry and meshing methods, methods for scalably coupled mesh and particle operations, and a user interface for specification of the fusion plasma simulation workflows. What was done in Phase I: A parallel mesh with particles infrastructure was defined and implemented including the procedures needed to support particle simulations. Preliminary support for particle simulations were added to a fusion plasma code using these methods. Data analysis methods have been initiated to support verification, validation and quantity of interest evaluation. The fusion device mesh generation procedure had been extended and a graphical user interface added. What was planned for Phase II Project? The parallel mesh with particle infrastructure will continue to be advanced with emphasis on using it to full advantage in two fusion plasma codes accounting for the needs of many core and accelerator supported nodes on massively parallel systems. This will include the full implementation of the new partitioning method defined in Phase I. The data analysis methods will be expanded to support the execution of uncertainty quantification operations. Mesh generation methods for stellarator devices will be developed. The graphical user interface will be extended to support the specification of uncertainty quantification operations. Commercial Applications and Other Benefits: The combined mesh plus particle methods to be developed will provide a set components that can support the new generations of multiscale/multi physics simulations needed in the modeling of fusion and fission reactors, and for application in nuclear medicine. The core methods to be developed will also of great use in the development of a number of engineering simulation areas such as modeling of additive manufacturing processes, the liquefaction of soils, etc. Key Words: Parallel simulation, simulation workflows, parallel geometry, mesh generation, mesh adaptivity