To achieve a potential reactor in Inertial Fusion Energy (IFE) [1], targets must be engineered with precise microstructures that ensure hydrodynamic stability by minimizing instabilities, maximize energy coupling [2] while keeping the manufacturing cost low. A promising approach is the replacement of the traditional deuterium-tritium (DT) ice layers with wetted foams. Apart from the conventionally chemical foams, two-photon polymerization (TPP) 3D-printed lattices have emerged as a promising candidate.  However, the limited existing data on these architected structures necessitates further studies. New experiments are required to characterize their equation of state and understand how laser-driven shock dynamics and energy dissipation evolve within these complex geometries. In this talk, we present results from an experimental campaign at the SACLA facility where a 15 J laser pulse was used to drive shocks in foams with densities ranging from 70 to 314 mg/cm³. The materials investigated include TPP lattices, TMPTA foams, and silica nanosphere foams. Shock propagation was probed using the XFEL beam [3] and lithium fluoride (LiF)-based X-ray Phase Contrast Imaging (XPCI) [4]. By leveraging the high spatial resolution of LiF crystal detectors, we visualize the evolution of the propagation front and assess how target morphology influences shock uniformity. Our results reveal that while the stochastic structures of TMPTA and silica foams support smooth, bowed shock fronts, TPP foams exhibit a regime where shock formation is inhibited by diffusive plasma flow at low laser intensities. We show that the resulting propagation positions and velocities follow both a linear and power-law relation, indicating that multiplicative processes govern the internal dynamics. These findings offer a path toward fine-tuning foam architectures for more symmetric IFE compressions.

[1] O. A. Hurricane, “How ignition and target gain >1 were achieved in inertial fusion”, High energy Density Phys. 53, 101157 (2024)
[2] A.S. Moore, N.B. Meezan, J. Milovich, S. Johnson, R. Heredia, T.F. Baumann. M. Biener, S.D.
      Bhanarkar, H. Chen, L. Divol et al. “Foam-lined hohlraum, inertial confinement fusion experiments on the national ignition facility”, Physical Review E 102, 051201 (2020)
[3] Y. Inubushi, T. Yabuuchi, T. Togashi, K. Sueda, K. Miyanishi, Y. Tange, N. Ozaki, T. Matsuoka, R.
        Kodama, T. Osaka, S. Matsuyama, K. Yamauchi, H. Yumoto, T. Koyama, H. Ohashi, K. Tono, and
       M. Yabashi, “Development of an experimental platform for combinative use of an xfel and
       a high-power nanosecond laser”, Applied Sciences 10, 2224 (2020)
[4] Tatiana Pikuz, Anatoly Faenov, Takeshi Matsuoka, Satoshi Matsuyama, Kazuto Yamauchi, Norimasa Ozaki, Bruno Albertazzi, Yuich Inubushi, Makina Yabashi, Kensuke Tono, Yuya Sato, Hirokatsu Yumoto, Haruhiko Ohashi, Sergei Pikuz, Alexei N. Grum-Grzhimailo, Masaharu Nishikino, Tetsuya Kawachi, Tetsuya Ishikawa, and Ryosuke Kodama, “3d visualization of xfel beam focusing properties using lif crystal x-ray detector”, Scientific Reports 5, 17713 (2015)

 

Foam,Fusion