Optimizing experimental yields for magnetized inertial fusion

Magnetized Liner Inertial Fusion (MagLIF) is a promising alternative to conventional inertial confinement fusion. It employs a laser to preheat a magnetized fuel target, reducing heat loss and increasing neutron yields. Because of the addition of extra variables, however, identifying the most effective parameters can be a challenge.

Peebles et al. detailed experiments at the OMEGA Laser Facility to study the impact of preheating and magnetization on fusion yields. The data from this scaled-down MagLIF experiment can help guide implementations at the full-scale Z Machine facility at Sandia National Laboratories.

“Thanks to the increased shot rate and better diagnostic access at OMEGA, more data could be collected on the basic premise of MagLIF,” said author Jonathan Peebles.

In their experiments, the team found that employing either magnetization or preheating individually led to a 60% increase in neutron yield, while implementing both resulted in an increase of nearly 500%. However, increasing the preheat energy beyond a threshold caused the yield to drop again, due to mix from thermal conduction of the preheated gas into the cylinder walls.

“The not only suggests that mix is the primary performance dampener for these experiments, but also that mix comes from multiple sources in full-scale experiments,” said Peebles. “Our experiments indicate that mix is heavily tied to the preheat component in the scaled experiment and that the best performance was achieved with marginally preheated fuel.”

While the OMEGA team has concluded their planned MagLIF experiments, they are excited about employing recent upgrades to the facility, such as more powerful magnetic fields and shaped beam pulses, to further explore MagLIF dynamics.

Source: “Demonstration of neutron-yield enhancement by laser preheating and magnetization of laser-driven cylindrical implosions,” by Jonathan Peebles, Jonathan R. Davies, Daniel H. Barnak, Vladimir Yu. Glebov, Edward C. Hansen, Peter Ver Bryck Heuer, Luis Stephan Leal, Mark Bonino, David Harding, Adam Sefkow, Kyle J. Peterson, Daniel B. Sinars, E. Michael Campbell, and Riccardo Betti, Physics of Plasmas (2023). The article can be accessed at https://doi.org/10.1063/5.0159653 .