Three-Dimensional Electric-Field Reconstruction at Fluid Scales: Application to Inline Modeling of Cross-Beam Energy Transfer in the Presence of Caustics*

The description of laser propagation inline to large-scale hydrodynamic–radiative codes has traditionally relied on ray-optics methods, which have been limited to effects such as refraction and inverse bremsstrahlung heating. Nonlinear laser–plasma interaction models have emerged, relying on various methods for the computation of the laser-intensity distribution in plasma. However, self-consistent computation of these effects requires more advanced propagation models that can provide the local electromagnetic field. Furthermore, many laser configurations produce caustics, where conventional ray optics models break down. We present a novel method based on inverse ray tracing in the complex plane coupled to an adaptively refined propagation mesh and etalon integrals, which allows CPU-efficient reconstruction of the electromagnetic field at large fluid scales and at caustics. Notably, this decouples the hydrodynamic mesh from the propagation mesh. The model is interfaced with the ASTER 3-D hydrodynamic–radiative code. Applications to inline 3-D cross-beam energy transfer calculations are presented.