학술논문
Cylindrical Driven Shocks in Ceria
Document Type
Conference
Author
Freeman, M. S.; Rousculp, C. L.; Fredenburg, D. A.; Bradley, J. T.; Donovan, P. M.; Dunwoody, J. T.; Fierro, F.; Griego, J. R.; Lamar, J. C.; Mariam, F. G.; Neukirch, L. P.; Oro, D. M.; Patten, A. R.; Randolph, R. B.; Reass, W. A.; Reinovsky, R. E.; Saunders, A.; Sjue, S. K.; Tang, Z.; Turchi, P. J.; Voorhees, T. J.
Source
2018 16th International Conference on Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS) Megagauss Magnetic Field Generation and Related Topics (MEGAGAUSS), 2018 16th International Conference on. :1-5 Sep, 2018
Subject
Language
Abstract
Shock compression of granular ceria (CeO 2 ) was studied in converging cylindrical geometry using LANL proton radiography, and driven by the Precision High Energy-Density Liner Implosion Experiment (PHELIX) magnetic implosion system. PHELIX delivered nearly 4 MA to a 1.25-mm thick liner-impactor to magnetically accelerate it to ~0.8-1.0 mm μs −1 . The impactor launched a shock in the cylindrical Al outer wall of the target assembly containing equiaxed, 0.63-μm-mean diameter ceria powder initially compacted to a static density of 3.95 or 4.03 g cm −3 . The cylindrically converging shock in the target was observed with a series of 21 proton-radiographic frames down the axis of the cylinder. Proton radiography was performed using a ×3 magnetic lens magnifier and a 7.5-mrad collimator. The proton radiographic views were transformed from transmission images to areal density images, for comparison to a model. Results indicate that significant energy was expended in compacting the porous CeO 2 , as the wave velocity markedly decreases during convergence, and a clear shock reflected from the axis was not observed. These observations are inconsistent with pre-shot modeling, and highlight the need for an improved understanding of the physics of compaction under non-ideal loading configurations.