Modeling of nonlocal electron transport in laser-driven double-ablation fronts

At laser intensities relevant to ICF, steep temperature gradients lead to nonlocal electron thermal transport. This is important for laser-plasmas because energy is transported into the denser plasma via electron and radiation thermal transport. For low- to mid-Z materials, these transport mechanisms are dominant at different locations, producing two distinct fronts in the temperature and density profiles known as double-ablation fronts (DAF)¹. This work studies the effect of nonlocal electron transport on the development of DAF features in planar foils.

Radiation-hydrodynamic HYDRA simulations are with the Schurtz-Nicolai-Busquet (SNB) nonlocal transport model^2,3. Vlasov-Fokker-Planck modeling confirms SNB heat flux predictions, which indicate the presence of localized preheating between the electron and radiation transport fronts, with increasing significance at higher laser intensities. Notably, this short-range preheat enhances the radiation transport in the irradiated foil and modifies the resulting DAF structure.

¹Sanz et al., Phys. Plas. 16, 082704 (2009)

²Schurtz et al., Phys. Plas. 7, 4238 (2000)

³Brodrick et al., Phys. Plas. 24, 092309 (2017)