Dr. Andrew Spann was part of a team of authors of an article titled "Lasergate: a windowless gas target for enhanced laser preheat in magnetized liner inertial fusion." Veryst conducted the simulations for this work using COMSOL Multiphysics. The article was published online in Physics of Plasmas (Vol.28, Issue 11), on Nov. 5, 2021. In addition to a detailed explanation of the research process, the article discusses possible future applications of this work. Veryst’s COMSOL simulations can be found in Supplemental material “Lasergate Analytics and Simulations.”
Read the abstract, below, or read the full article at https://doi.org/10.1063/5.0059334
At the Z Facility at Sandia National Laboratories, the magnetized liner inertial fusion (MagLIF) program aims to study the inertial confinement fusion in deuterium-filled gas cells by implementing a three-step process on the fuel: premagnetization, laser preheat, and Z-pinch compression. In the laser preheat stage, the Z-Beamlet laser focuses through a thin polyimide window to enter the gas cell and heat the fusion fuel. However, it is known that the presence of the few μm thick window reduces the amount of laser energy that enters the gas and causes window material to mix into the fuel. These effects are detrimental to achieving fusion; therefore, a windowless target is desired.
The Lasergate concept is designed to accomplish this by “cutting” the window and allowing the interior gas pressure to push the window material out of the beam path just before the heating laser arrives. In this work, we present the proof-of-principle experiments to evaluate a laser-cutting approach to Lasergate and explore the subsequent window and gas dynamics. Further, an experimental comparison of gas preheat with and without Lasergate gives clear indications of an energy deposition advantage using the Lasergate concept, as well as other observed and hypothesized benefits. While Lasergate was conceived with MagLIF in mind, the method is applicable to any laser or diagnostic application requiring direct line of sight to the interior of gas cell targets.