He reactions at varying center-of-mass energies relevant to nuclear astrophysics at the NIF and OMEGA*

Nuclear reactions relevant to astrophysics have been studied using the inertial confinement fusion platform as an alternative approach to accelerator-based efforts. Initial work has been done to study T-³He and ³He-³He reactions, which play an important role in big-bang nucleosynthesis and stellar nucleosynthesis, respectively. Direct-drive exploding pusher implosions at the National Ignition Facility (NIF) and OMEGA laser facilities employed thin-glass-shell capsules to maximize yield at low areal densities. Different methods were used to vary ion temperature for both reactions to explore changes in the proton energy spectrum generated from the T-³He and ³He-³He reactions at different center-of-mass energies. Also, the branching ratio for the T(³He,D) ⁴He and T(³He,np) ⁴He reactions at different center-of-mass energies was determined. Charged particle energy spectra were measured with different diagnostics including wedge range filters, step range filters, and magnetic recoil spectrometers at the NIF and OMEGA. Compact magnetic spectrometers (MagSpec) were used for recent shots at the NIF, and charged particle spectrometers were used on OMEGA. Future experiment plans based on these results are also presented.