Split radiographic tracer technique to measure the full width of a high energy density mixing layer

Simulation and flow physics of a shocked and reshocked high-energy-density mixing layer

“…They included treatments of distinct ion and free-electron internal energies, non-ideal EOSs, radiation transport and plasma-state models of the transport processes of mass diffusion, viscous dissipation and thermal conduction. Two critical aspects of the simulations were tuned to available data from the NIF experiments: radiation temperature boundary conditions were determined from measurements of the shock positions, and the interface initial perturbation was scaled based on measurements (Huntington et al 2020) of the mixing-layer width. The simulated perturbation was carefully designed such that it captured key features of the experimental perturbations and it converged to an analytic form under mesh refinement.…”

“…There are important similarities and differences between the computational model and the experimental geometry of a Reshock Campaign NIF target. That geometry is described fully by Nagel et al (2017), Wang et al (2018) and Huntington et al (2020). In the experiments, the main ablator region consisted of several plastic components of different compositions but approximately the same density -a design created to optimize quality of X-ray radiographs of the mixing layer (Huntington et al 2020).…”

“…The first of these involved a standard Reshock Campaign target, with two halfraums, as described in § 2. Using the techniques of Nagel et al (2017) and Huntington et al (2020), an X-ray radiograph was taken at a time when both the main shock and reshock were clearly visible in the foam region. Hence, this shot gave measurements of the two shock positions at a known time.…”

“…While these irregularities have not been exhaustively studied, their characteristic modes are expected to be of higher frequency and lower amplitude than those in the nominal multimode profile. For example, characteristic pore sizes in the foam have been observed to be sub-μm (Huntington et al 2020). In the present study, we choose to construct δ *…”

“…The edges appear where X-ray transmission through the plasma changes, e.g. due to density and species variations (Nagel et al 2017;Huntington et al 2020). However, W can be sensitive to the structure of individual jets and other flow features at the edges of the mixing layer (Zhou & Cabot 2019).…”