Non-local electron transport: models and impact on direct-drive shock-ignition targets

Shock Ignition schemes require laser pulses with intensities exceeding 10^15 W/cm^2. At such intensities a few percent of electrons have a mean free path longer than the characteristic temperature gradient scale length. The classical Spitzer-Harm thermal conduction operator (even including flux-limitation) is no longer appropriate, non-local transport models need to be used to catch the underlying physics. We will first briefly compare two non-local electron transport models: Schurtz-Nicolai-Busquet [1] and the Colombant-Manheimer-Goncharov [2,3] model. We will highlight few key numerical aspects and discuss their use in inertial fusion hydrodynamic codes. We will then focus on the use such models in shock ignition target simulations. In the first place we will discuss the effect of non-local transport during the ablation phase where electron transport affects temperature and density evolution and generation of the ablation pressure. In the second place we will discuss how the models can also treat preheating of the target payload. References [1] G. Schurtz et al. Physics of Plasmas 7 10 (2000) pp. 4238-4249. [2] W. Manheimer et al. Physics of Plasmas 15 8 (2008) pp. 083103 [3] D. Colombant et al. Journal of Computational Physics 229 11 (2010) pp. 4369-4381