• Macgowan, B.
• Munro, D.
• Eder, D.
• Bailey, D.
• Mann, K.
• Tobin, M.
• Andrews, J.
• Koniges, Alice
• Alley, E.

Abstract

Shrapnel fragments from target/diagnostic components can adversely affect the lifetime of the debris shields on the 192-beam National Ignition Facility (NIF) laser. An important class of these components is thin metal plates used for shields, pinhole arrays, etc. These plates are loaded by laser light or by x-rays from the target. As a result of this impulse loading, a shock is sent into the metal and after reflection from the rear surface fragmentation can occur. The spatial, size, and velocity distributions of fragments have been measured using aerogel capture on the Helen laser at AWE. We model these experiments using the 2D LASNEX code. The calculated strain rates are used to estimate the average size of the fragments, which are combined with calculated density and velocity to give spatial, size, and velocity distributions of the fragments. We discuss the impact of these calculations on proposed NIF target/diagnostic configurations and the sensitivity of the shrapnel and debris generation to target design. <P />...

Topics

• density
• impedance spectroscopy
• surface
• experiment