Speaker: Steve Ivancic, Laboratory for Laser Energetics, University of Rochester
Title: Observing Stars in the Laboratory: Ultrafast X-ray Imaging of Imploded Inertial Confinement Fusion Capsules
Abstract: The OMEGA laser system at the University of Rochester is used to implode fusion fuel containing capsules to the high temperatures necessary to generate nuclear fusion in the laboratory. The time dependent morphology of imploded capsules at and around stagnation provides a key observable in the assessment of implosion performance. The size, shape and offset of the stagnated fuel is the product of multidimensional effects arising from laser beam imbalance, capsule non-uniformity and initial target offset. Cryogenic deuterium-tritum layered implosions on the 60-beam, 30-kJ, 351-nm OMEGA laser system are observed along two semi-orthogonal lines of sight at peak thermonuclear output with time-gated x-ray imagers capable of 30-ps temporal resolution and < 10-um spatial resolution to capture the three-dimensional nature of the core. One such imager combines an electron-dilation imager and a hybrid complementary metal-oxide semiconductor (hCMOS) sensor to capture multiple gated frames along a single line of sight. Core size and shape inferred from 4-9 keV thermal x-rays measured along the mutually perpendicular axis from the two co-timed detectors yields remarkable (<2%) agreement. Developments in x-ray optics have enabled sub 1-mm imaging allowing the observation of features such as jets, RT-instabilities and burn waves into the imploded fuel. These unique views provide a measure of the three-dimensional low-mode shape and temporal evolution of the imploded hot spot. Such measurements can provide a more complete picture of target performance and provide a path to realizing high-gain thermonuclear fusion capsule designs.
Bio: Steven Ivancic is the group leader for Diagnostic Development and Integration at the Laboratory for Laser Energetics. His research focuses in the development of instrumentation in support of experimental high-energy-density physics. The specific applications of which are in x-ray imaging, detector development, and time-dependent spectroscopy, with application to the assessment of implosion performance of cryogenic deuterium–tritium fuel in directly driven thermonuclear fusion experiments at the Omega Laser Facility. As the leader of the Diagnostic Development and Integration Group, he oversees the implementation of new diagnostic capabilities at the Omega Laser Facility, and works closely with scientific, engineering, and operations teams to ensure safe and scientifically reliable results from the facility for all users. He is the recipient of the National Nuclear Stockpile Administration Defense Program’s Award of Excellence and sits on the leadership committee for the National Diagnostic Working Group.
This talk will be offered in a hybrid format. If you wish to participate remotely, please send an email to [email protected].