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Center for Nonlinear Studies |
Many electromagnetic particle-in-cell (EM-PIC) simulations are based upon a structured Cartesian mesh due to its simple underlying theory and code structure. In these simulations, the curved or slanted geometric features of real world systems are often approximated via staircasing, which introduces several sources of numerical error. Cut-cells may be inserted near irregular metallic boundaries to avoid such errors, but they often under resolve small features. An unstructured mesh can successfully resolve both irregular boundaries and small geometric features, but can also significantly increase the simulation run time. In order to achieve good geometric representation while minimizing simulation run time, we have developed a hybrid mesh EM-PIC simulation. The primary contribution of this simulation is its ability to handle a Cartesian mesh, a Cartesian mesh with bordering cut-cells, or an unstructured mesh, as well as any combination thereof. Although the exact mesh structure is left for the user to decide, cut-cells are recommended for resolving large metallic features, while an unstructured mesh should surround small features. The various numerical methods utilized in this simulation will be presented, as well as the overall code structure. Several comparisons between this work and both Cartesian and unstructured EM-PIC codes in terms of accuracy and computational efficiency will also be presented.
Host: Gian Luca Delzanno