An Upper Bound for Stress Waves Induced by Volumetric Heating in IFE Chamber Walls

Abstract

Rapid heating by x-rays and ions in Inertial Fusion Energy (IFE) chambers will produce stress waves in dry chamber walls, in some cases leading to damage that will ultimately fail the structure. These waves can affect the surface or propagate to the substrate and produce delamination. Hence, it is important that these waves be understood. Models exist for thermally induced stress waves resulting from surface heating, but models with volumetric heating have not been presented for IFE conditions. In this paper we develop models for elastic stresses caused by rapid volumetric heating in a half-space. The stress wave models are obtained analytically for heating distributions which are both uniform over a finite region and exponentially decaying over the entire depth. These two cases cover the relevant heating for a typical IFE threat. Results are given for both x-ray and ion heating using threats from a direct drive target developed for the High Average Power Laser (HAPL) target.