*3.4. Axisymmetric LIW Simulation*

Due to axisymmetric loading conditions of the laser pulse pressure, an axisymmetric numerical analysis was deemed reasonable for simulation of the LIW process (performed using Abaqus/Explicit software version 16.4-4). The LIW simulation was divided into two steps; during the first step, a pressure load was applied to the flyer as inherited from the measured spatial and temporal profiles of the laser beam pulse. The measured spatial profile was inputted as an analytical field to define the spatial distribution of the pressure load. The measured temporal profile was inputted as the amplitude of the pressure load. This pressure load was applied to the top surface of the flyer and launched it towards the target plate until contact was initiated. In the second step, the flyer collided with the target at a very high-speed profile in the center of the laser impact area, resulting in large deformations. Since large deformations in purely Lagrangian finite elements result in excessive distortion, an ALE domain was utilized in the second step. A meshing frequency of 1 increment, with 50 remeshing sweeps per increment and 50 initial remeshing sweeps were used. About 80,000 4-node axisymmetric, quadrilateral elements of 2.5-micron edge length with bilinear displacement, reduced integration, and hourglass control (CAX4R) were used. The target foil was placed on a fixed analytical rigid body representing the fixed specimen in the LIW setup. In addition, another fixed analytical rigid body was included on top of the flyer foil to act as the fixed transparent overlay. The kinematic contact method was implemented between the foils while the penalty contact method was applied between each foil-rigid body pair (flyer-transparent overlay and target-fixed specimen). The contact interaction property in both the kinematic and the penalty methods was "hard" contact allowing separation after contact. A schematic of the LIW setup in the axisymmetric simulation is shown in Figure 9a. The velocities in different regions of the foils as well as the deformed foil shapes after collision were simulated. Details on the axisymmetric simulation results are provided in Section 4.

**Figure 9.** Schematic of the LIW simulations: (**a**) Axisymmetric; (**b**) Eulerian.
