Study of ion coupling in dense matter using nuclear reactions for applications to ion fast ignition

Since the record-breaking result on December 5^th, 2022, at the National Ignition Facility (NIF) that demonstrated fusion gain > 1 in the laboratory for the first time, interest in inertial fusion energy (IFE) schemes for commercial power generation has grown significantly. However, understanding ion stopping in compressed matter is a crucial open physics question, particularly for fast ignition concepts, and additionally for heavy ion fusion. Ion fast ignition (IFI) is one scheme that may provide a feasible pathway to IFE through using short-pulse lasers to generate ions that can heat a pre-compressed fuel assembly thereby potentially reducing the driver energy and symmetry requirements that make conventional inertial confinement fusion (ICF) schemes challenging for commercial power generation. While promising, one major physics question in this concept is how to efficiently couple the ions into the compressed core to achieve the necessary heating. To address this fundamental question, we conducted an integrated IFI experiment at the OMEGA/EP facility using a novel nuclear reaction-based methodology. Our approach aims to directly measure the coupling of laser-driven deuterons into a pre-compressed Helium-3 fuel assembly by detecting protons generated from D-³He fusion reactions using OMEGA's charged particle diagnostic suite. The advantage and novelty of this scheme is that the deuterons and ³He are initially separate, and thus the only way to create D³He reactions is with ions accelerated into the gas. We present preliminary results from these experiments, providing crucial data for understanding and measuring ion coupling in fast ignition concepts.