Adaptive Workflow for Simulation of Cold Plasma in RF Heaters

This poster will describe a workflow for the execution of adaptive high-performance simulations of RF fusion systems. In this workflow, the simulation input consists of a CAD model attributed with the needed analysis attributes. The analysis mesh is automatically generated and the analysis steps are executed using the time-harmonic Maxwell's equations using MFEM libraries. A patch recovery-based error estimator is used to drive a conforming mesh adaptation procedure using PUMI mesh adapt libraries.

To demonstrates the application of the developed adaptive procedure to problems of interest, we will solve the time-harmonic Maxwell's equations in the cold plasma approximation regime, to capture the lower hybrid resonance using mesh adaptation. In the cold plasma regime, the spatial variations of the permittivity of the plasma will dictate the wavelength of the propagated wave modes, and this wavelength is expected to become extremely short when some of the components of the permittivity tensor tend to zero, a phenomenon known as the lower hybrid resonance. When this happens, one will need to use a very fine mesh to obtain accurate finite element solutions. Using the adaptive workflow, our results show that we are able to effectively identify such regions in the domain as needed and use mesh modification operations to modify the mesh locally to achieve high levels of accuracy.