Integrated simulations of proton fast ignition of inertial fusion targets

Ion fast ignition (IFI) is an alternative scheme with lower energy and symmetry drive requirements [Roth et al., PRL 86, 436 (2001)]. Many ion beam requirements estimated so far for IFI are based on strong assumptions about beam focusing and beam-plasma interaction. Some effects have been ignored, such as: i) divergence of laser-driven protons generated in hollow cones [Morace et al., Sci. Rep. 12, 6876 (2022)], ii) anomalous energy deposition of intense ion beams in resistive plasmas [Kim et al., PRL 115, 054801 (2015)], and iii) improved modelling of stopping power. Dedicated experiments have shown the BPS stopping model [Brown et al., Phys. Rep. 410, 237 (2005)] fits the measurements of ion stopping, while the standard models show substantial differences.

We intend to evaluate the laser energy requirements of the IFI scheme for realistic fuel configurations. We have conducted integrated simulations of IFI, from ion generation to fuel ignition, combining PIC, hybrid, and radiation-hydrodynamic simulations with the codes EPOCH [Arber et al., PPCF 57, 113001 (2015)], PETRA [Honrubia et al., PoP 16, 102701 (2009)], and FLASH [Fryxell et al., ApJS 131, 273 (2000)]. We will analyze the relevance of the effects mentioned above. Our results will allow us to assess IFI as an alternative ignition scheme.