84 / 2023-04-13 09:58:30

Role of hot electrons in mitigating ablative Rayleigh-Taylor instability

Hot electrons,ablative Rayleigh-Taylor instability,hydrodynamic instability

辐射和流体力学 > 流体力学不稳定性

In laser-driven inertial confinement fusion (ICF) specifically with high laser intensities, energetic (hot) electrons (HEs) can be generated via laser-plasma instabilities. HEs can significantly impact the target performance by modifying the implosion hydrodynamics. In this work, the effects of moderate-energy (about 20 to 40 keV) HEs on the evolution of ablative Rayleigh–Taylor instability (ARTI) are studied through numerical simulations with a multigroup diffusion model in which the HE population is treated as a high-energy group launched from the boundary. With HEs present, it is found that ARTI linear growth rates are reduced even though the acceleration of the implosion shell is enhanced by HEs. The reduction in the linear growth rate is owing to the increase in the ablation velocity and the density scale length, and this stabilization effect is greater in the shorter-wavelength modes and/or higher-energy HE cases. The ARTI linear growth does not get mitigated monotonically as the HE number density increases for a given fixed HE kinetic energy. The latest results showing that HEs can stabilize the highly nonlinear growth of multimode ARTI are also presented.