New structures for areal density symmetry control in indirectly driven ICF target designs*

Asymmetry of the compressed fusion fuel configuration, as characterized by a variation in areal density, in ICF implosions is a known performance limitation [1]. While ignition has been achieved on the NIF, implosion symmetry wasn’t perfect [2] and subsequent experiments that have extended fusion performance still struggle with symmetry control [3] and would, in principle, perform much better if the areal density uniformity of the fuel was improved by eliminating thin regions in the DT fuel.



In indirect-drive (IDD), altering the time-dependent laser cone-fraction and cross-beam energy transfer are the usual tactics for controlling implosion asymmetry in IDD target designs [4], but it may be that those tools have been pushed to their limits. In this talk, we present a new tactic for controlling the implosion.



In simulations, the new tactic appears to be quite effective at reducing the swing of x-ray drive from waist-hot to pole-hot, thus achieving a more one-dimensional fuel configuration at peak compression. Simulations show that a factor of ~2 in yield performance can be obtained via this technique, when applied to past record implosions on the NIF.



Review and release number :LLNL-ABS-2007032.



Sorting Category: 7.00



[1] O. Hurricane, et al., Phys. Plasmas, 29, 012703 (2022)

[2] H. Abu-Shawareb, et al. (Indirect Drive ICF Collaboration), PRL, 129, 075001 (2022)

[3] H. Abu-Shawareb, et al. (Indirect Drive ICF Collaboration), PRL, 132, 065102 (2024)

[4] A. Kritcher, et al., PRE, 109, 025204 (2024)