THz generation from relativistic plasmas driven by near- to far-infrared laser pulses
| Autor: | Déchard, J., Davoine, X., Bergé, L. |
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| Rok vydání: | 2019 |
| Předmět: | |
| Zdroj: | Phys. Rev. Lett. 123, 264801 (2019) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevLett.123.264801 |
| Popis: | Terahertz pulse generation by ultra-intense two-color laser fields ionizing gases with near- to far-infrared carrier wavelength is studied from particle-in-cell (PIC) simulations. For long wavelength ($10.6\ \mu$m) promoting a large ratio of electron density over critical, photoionization is shown to catastrophically enhance the plasma wakefield, causing a net downshift in the optical spectrum and exciting THz fields with tens of GV/m amplitude in the laser direction. This emission is accompanied by coherent transition radiation (CTR) of comparable amplitude due to wakefield-driven electron acceleration. We analytically evaluate the fraction of CTR energy up to 30 % of the total radiated emission including the particle self-field and numerically calibrate the efficiency of the matched blowout regime for electron densities varied over three orders of magnitude. Comment: 5 pages, 5 figures |
| Databáze: | arXiv |
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