Order-of-magnitude increase in laser-target coupling at near-relativistic intensities using compound parabolic concentrators
Abstract
Achieving a high conversion efficiency into relativistic electrons is central to short-pulse laser application and fundamentally relies on creating interaction regions with intensities ≫1018W /cm2 . Small focal length optics are typically employed to achieve this goal; however, this solution is impractical for large kJ-class systems that are constrained by facility geometry, debris concerns, and component costs. We fielded target-mounted compound parabolic concentrators to overcome these limitations and achieved nearly an order-of-magnitude increase to the conversion efficiency and more than tripled electron temperature compared to flat targets. Particle-in-cell simulations demonstrate that plasma confinement within the cone and formation of turbulent laser fields that develop from cone wall reflections are responsible for the improved laser-to-target coupling. These passive target components can be used to improve the coupling efficiency for all high-intensity short-pulse laser applications, particularly at large facilities with long focal length optics.
- Publication:
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Physical Review E
- Pub Date:
- March 2021
- DOI:
- 10.1103/PhysRevE.103.L031201
- arXiv:
- arXiv:2012.11563
- Bibcode:
- 2021PhRvE.103c1201W
- Keywords:
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- Physics - Plasma Physics
- E-Print:
- 6 pages, 5 figures