Highly efficient conversion of laser energy to hard X-rays in high intensity laser-solid simulations

We present simulations which predict significantly higher laser to X-ray efficiencies than those previously found in high intensity (1e20-1e22 W/cm2) laser-solid simulations. The bremsstrahlung emission is shown to last for 10-100 ps, which is difficult to model with conventional particle-in-cell (P...

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Bibliographic Details
Published inarXiv.org
Main Authors Morris, Stuart, Robinson, Alex, Ridgers, Christopher
Format Paper Journal Article
LanguageEnglish
Published Ithaca Cornell University Library, arXiv.org 04.07.2021
Subjects
Angular distribution
Boundary conditions
Bremsstrahlung
High power lasers
Hybrid systems
Lasers
Mathematical models
Particle in cell technique
Physics - Plasma Physics
Refluxing
Simulation
Source code
X-rays
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Summary:We present simulations which predict significantly higher laser to X-ray efficiencies than those previously found in high intensity (1e20-1e22 W/cm2) laser-solid simulations. The bremsstrahlung emission is shown to last for 10-100 ps, which is difficult to model with conventional particle-in-cell (PIC) codes. The importance of collective effects is also demonstrated, showing the limitations of Monte Carlo modelling in these systems. A new, open-source hybrid-PIC code with bremsstrahlung routines has been developed to model this X-ray production in 3D. Special boundary conditions are used to emulate complex electron refluxing behaviour, which has been characterised in 2D full-PIC simulations. The peak X-ray efficiency was recorded in thick gold targets, with 7.4% conversion of laser energy into X-rays of energy 1 MeV or higher. The target size is shown to play a role in the conversion efficiency and angular distribution of emitted X-rays, and a simple analytic model is presented for estimating these efficiencies.
ISSN:2331-8422
DOI:10.48550/arxiv.2107.01723