Exploration of the plasma dynamics and magnetization in laser-driven Ta₂O₅ and SiO₂ aerogel foam-lined hohlraums

In indirect-drive inertial confinement fusion (ICF) experiments, high-Z hohlraum wall blowoff impedes inner-cone beam propagation and results in an asymmetric implosion drive. Effective wall blowoff mitigation has included the use of non-cylindrical hohlruam geometries or a tamping gas-fill, but the drawbacks of these configurations motivate an alternative approach using inner-wall high-Z foam linings. To advance earlier foam-liner efforts by LLNL, a series of experiments studying hohlraums lined with Ta₂O₅ and SiO₂ aerogel foams were performed at OMEGA. To study the effects of foam-plasma magnetization, external MIFEDS-induced magnetic fields (~30 T) were applied to the hohlraum. Proton radiography, Thomson scattering, and x-ray framing cameras were used to probe the structure and dynamics of foam-plasma and wall blowoff, and the effects of self-generated electric and magnetic fields. The experiments were modelled with 3D HDYRA magnetohydrodynamic simulations, which reveal details about magnetized plasma flow and interface evolution. These results advanced our physics understanding of how the foam liners control the wall blowoff and improve hohlraum drive symmetry in indirect-drive ICF experiments. The work is supported in part by the U.S. DOE, NLUF, LLNL, and LRGF.