A New Numerical Treatment of Hohlraum Boundaries for ALE RAD/Hydro Codes

Numerical treatment of the Laser Entrance Hole (LEH) region in hohlraums and halfraums with Arbitrary Lagrangian Eulerian (ALE) or pure Lagrangian codes is difficult near the Lagrangian boundary interface. For example, recent studies have focused on ALE methods for boundaries with rezoning to simulate the LEH window motion and the sliding contact between the window and the LEH edge. We propose a technique for handling such boundary complications based on the inclusion of a wrap around very-low density mesh structure. Additional ALE rezoning features such as material zone weighting are included to preserve numerical accuracy. We demonstrate the ability of ALE simulations using our technique to run to late time with very little user intervention. We benchmark our simulation results with experimental data from both two and three-dimensional halfraum experiments shots on the Helen and Omega Lasers