Martin Wood Complex, Department of Physics, University of Oxford, Parks Road, Oxford, OX1 3PU
Professor Peter Norreys, University of Oxford
Abstract
The recent progress at the National Ignition Facility (NIF) has sparked fresh excitement around the topic of inertial fusion energy (IFE) [1–5]. However, significant advances are still required before the goal of practical fusion energy can be realised. In particular, while the recently achieved gain of 4 represents an unprecedented milestone [5], it is still short of the minimum value of > 50 likely to be required for a viable fusion reactor [6]. In addition, current target designs are expensive and time-consuming to produce [7], while cost estimates for future inertial fusion reactors require low cost and high repetition rates [8, 9]. Wetted-foam capsules are seen as promising solutions for future IFE reactor targets, with the potential to enable high gain performance at low cost. The CH foams, used to contain the DT liquid fuel, can potentially be 3D printed, which could significantly improve the production rates and costs compared to conventional DT-ice targets. A variety of designs based on this technology have been proposed, ranging from more conventional designs (where the wetted-foam layer replaces a DT ice layer [10, 11,12]) to novel dynamic-shell approaches [7, 13]. Despite their potential, the shock response of low-density foams remains poorly characterised, limiting the accuracy of hydrodynamic simulations. Here, I will review experimental measurements of the equation of state (EOS) for silica (SiO2) aerogel and plastic (TMPTA) foams under laser-driven shock compression, conducted recently by my team over the past few years at the Vulcan, GEKKO XII and LULI2000 laser facilities [14-15] with colleagues from the UK, France, the EU, the USA and Japan. Shock pressures between 50 and 160 GPa were achieved, and the corresponding states were determined using established impedance matching techniques with a quartz reference material. Towards the end, I will also touch upon promising AI simulation approaches to target and laser beam optimisation of wetted foam implosions, novel approaches to parametric instability suppression using broad-bandwidth laser pulses [16], heat flows in burning plasmas [17] and (very briefly) ultra-bright X-ray source generation [18].
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[2] A. L. Kritcher et al., Physical Review E 106, 025201 (2022).
[3] A. B. Zylstra et al., Physical Review E 106, 025202 (2022).
[4] A. B. Zylstra et al., Nature 601, 542–548 (2022).
[6] E. M. Campbell et al., “Laser-direct-drive program: Promise, challenge, and path forward”, Matter and Radiation at Extremes 2, 37–54 (2017).
[7] V. N. Goncharov et al., Physical Review Letters 125, 065001 (2020).
[8] G. R. Tynan et al., Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 378, 20200009 (2020).
[9] K. Gi et al., Energy Strategy Reviews 27, 100432 (2020).
[10] R. E. Olson et al., Physics of Plasmas 28, 122704 (2021).
[11] R. E. Olson et al., Physical Review Letters 117, 245001 (2016).
[12] R. E. Olson et al., Nuclear Fusion 66 026002 (2026).
[13] I. V. Igumenshchev et al., Physical Review Letters 131, 015102 (2023).
[14] R. Paddock et al., Physical Review E 107, 025206 (2023).
[15] J.J. Lee et al., Physical Review E (under review 2026).
[16] R. Ruskov et al. Journal of Plasma Physics 90(6), 905900621 (2024).
[17] H. Martin et al. Bulletin of the American Physical Society DPP (2025).
[18] R. Timmis et al., https://www.researchsquare.com/article/rs-7284658/v1 .
Peter Norreys*, Jordan Lee, Eduard Atonga, Elliott Denis, Abigail James, Heath Martin, Julian Mathe*, Robert Paddock**, Joshua Redfern, Rusko Ruskov, Robin Timmis, Linghao Yang*, Zixin Zhang and Ramy Aboushelbaya
Department of Physics, Atomic and Laser Physics sub-Department, University of Oxford, Clarendon Laboratory, Parks Road, Oxford, OX1 3PU, UK
* Also at University College Oxford, High Street, Oxford OX1 4RH
** Now at: Central Laser Facility, UKRI-STFC, Rutherford Appleton Laboratory, Harwell Campus, Didcot, Oxon, OX11 0QX, UK