Exploring 3D radiation asymmetries in inertial confinement fusion hohlraums with a dynamic view factor model*

Inertial confinement fusion (ICF) experiments at the National Ignition Facility (NIF) seek to drive a spherical deuterium-tritium target to high temperatures and pressures. Fusion performance is significantly affected by the symmetry of the radiation environment produced inside the cylindrical hohlraum enclosure driven by 192 laser beams. Presently, full 3D ICF radiation-hydrodynamic calculations with sufficient resolution are very computationally expensive, limiting their utility. We combine a view factor model [1] with dynamic data from 1D and 2D radiation-hydrodynamic simulations [2] to rapidly assess the impact of drive asymmetry arising from a variety of sources across a range of NIF experiments. Special attention is given to measured laser power imbalance and the ablated hohlraum wall plasma (“gold bubble”) that interferes with inner laser beam propagation and symmetry control in the latter half of ICF experiments.

 

[1] J. J. MacFarlane, J. Quant. Spectr. Rad. Transfer 81, 287 (2003)

[2] M. M. Marinak, et al., Phys. Plasmas 8, 2275 (2001)