Diagnosing numerical Cherenkov instabilities in relativistic plasma simulations based on general meshes
| Autor: | Na, D. -Y., Nicolini, J. L., Lee, R., Borges, B. -H. V., Omelchenko, Y. A., Teixeira, F. L. |
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| Rok vydání: | 2018 |
| Předmět: | |
| Zdroj: | Journal of Computational Physics, vol. 402, 108880, 2020 |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1016/j.jcp.2018.108880 |
| Popis: | Numerical Cherenkov radiation (NCR) or instability is a detrimental effect frequently found in electromagnetic particle-in-cell (EM-PIC) simulations involving relativistic plasma beams. NCR is caused by spurious coupling between electromagnetic-field modes and multiple beam resonances. This coupling may result from the slow down of poorly-resolved waves due to numerical (grid) dispersion and from aliasing mechanisms. NCR has been studied in the past for finite-difference-based EM-PIC algorithms on regular (structured) meshes with rectangular elements. In this work, we extend the analysis of NCR to finite-element-based EM-PIC algorithms implemented on unstructured meshes. The influence of different mesh element shapes and mesh layouts on NCR is studied. Analytic predictions are compared against results from finite-element-based EM-PIC simulations of relativistic plasma beams on various mesh types. Comment: 31 pages, 20 figures |
| Databáze: | arXiv |
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