Marty serves as a computational physicist for the Lawrence Livermore National Lab in the National Ignition Facility group. He received his Bachelor’s Degree in Nuclear Engineering from U.C. Berkeley. After graduating, Marty was awarded a Berkeley Fellowship for Graduate Study and proceeded to earn a Ph.D. in Nuclear Engineering from the University of California at Berkeley in 1993.
This graphic shows a high-resolution 3D HYDRA capsule simulation of a June 2017 NIF shot. The spherical contour surface shows the ablation front colored by ion temperature. The cutaway view shows density on the right where the capsule shell contains the hot spot. The jet from the fill tube is visible near the equator. Ion temperature is shown on the left. Credit: Marty Marinak.
Dr. Marinak is the lead developer for HYDRA, the principal Inertial Confinement Fusion (ICF) simulation code used today. It is because of that simulation capability—combined with exponential growth in high performance computing (HPC) at LLNL, which allowed for the first high-resolution fully spherical 3D simulations of ICF implosions, as well a breakthroughs in ignition at NIF. The code continues to be fundamental for target designers to “try things out” and provides insights into which designs could be successful, given that there are limited numbers of "shots" from the NIF each year.
In April 2023, the National Ignition Facility published an article "Computing Codes, Simulations Helped Make Ignition Possible," with a few quotes from Marty regarding the work he was doing designing codes and computer simulations that have enabled NIF's quest for ignition. Codes are what provide valuaable information that can be used to analyze data and extrapolate predicted results from implosion symmetry, stability and timing, to better tailor new trials for success.
Now that NIF has achieved ignition, this has validated the success of the HYDRA codes developed which enabled the scientists working with the target fabrication team and the laser teams to view full-sphere simulations, giving them a much clearer understanding of what problems needed to be fixed to make ignition happen. In doing so, HYDRA guided the ICF process to move closer to the target reality and achieve success.
“When we started generating diagnostics from full-sphere 3D simulations, a lot of the mysteries went away,” Marinak said. “The simulations told us if you fixed just one of those issues, you probably wouldn't be able to measure an improvement. Even if you fixed all of them to within target fabrication’s abilities, you still wouldn't get the capsule to ignite. That was the turning point. We couldn’t just fix the sources of asymmetry. We needed a more robust target. . . .
Based on the knowledge gained from HYDRA and other codes, Marinak was confident target design was “moving in the right direction” and would eventually result in higher yields.
“I always thought we would make it, but ignition is difficult and was harder to accomplish than we had thought, and that's probably why there’s no one else in the world that has done it,” Marinak said. “Now we have a much clearer understanding of the behavior of these implosions and the challenges that must be overcome.
“We promised that we could do this thing that no one else has done before for stockpile stewardship and for other purposes, and it was greatly rewarding to finally see that we helped to make that happen.”
Dr. Marinak is the principal author on a number of articles in peer-reviewed scientific journals, and co-author on many more.
