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MSEE Seminar: Kim Knight, LLNL

Understanding the Influence of Environment on Nuclear Explosion Physics and Chemistry

With the explosion of the world’s first nuclear test, Trinity, in 1945, the formation of post-detonation debris (‘fallout’) became a topic of study and research. Initial interest in the glassy materials produced from near-surface nuclear events centered around study of formation mechanisms, as well as a drive to understand dispersion of debris and its contribution as a radiological hazard. As above ground nuclear testing dwindled in the late 1960’s, however, this area of research all but disappeared. Changing perceptions of nuclear threats and concerns over nuclear effects have brought about a resurgence of interest to improve our understanding of how fireballs evolve, the conditions under which fallout forms, and how physical and chemical processes can be perturbed by local explosion conditions. I will review recent contributions aimed at furthering our modern understanding of the interaction of the local environment with a nuclear explosion including the formation of fallout and work to understand when and how the local explosion environment may influence the evolution of a nuclear explosion.

As staff at Lawrence Livermore National Laboratory for over a decade, Kim Knight’s primary role has been coordination and execution of the forensic analysis of radioactive and nuclear materials in support of national security and related research. Prior to joining LLNL, she completed a PhD at the University of California, Berkeley as a geochemist specializing in application of radioactive decay systems to understand earth systems processes. Later she transitioned to The University of Chicago, developing methods for measuring nucleosynthetic signatures in trace amounts of stellar dust and early solar system materials. Her past and present work provide unique insight into the identification, handling, and coordinated characterization of material samples by diverse technical methods to interpret material signatures and she is a recognized resource for challenging samples and complex scenarios. In addition to programmatic work, her research and vision have been instrumental to the modern renaissance in study of post-detonation debris to advance environmental considerations, weapons science, post-detonation forensics, and related applications.