General computational spectroscopic framework applied to Z-pinch dynamic hohlraum K-shell argon spectra

Abstract

We describe a general computational spectroscopic framework for interpreting observed spectra. The framework compares synthetic spectra with measured spectra, then optimizes the agreement using the Dakota toolkit to minimize a merit function that incorporates established spectroscopic techniques. We generate synthetic spectra using the self-consistent nonlocal thermodynamic equilibrium atomic kinetics and radiative transfer code Cretin, relativistic atomic structure and cross section data from Hullac, and detailed spectral line shapes from Totalb. We test the capabilities of both our synthetic spectra model and general spectroscopic framework by analyzing a K-shell argon spectrum from a Z-pinch dynamic hohlraum inertial confinement fusion capsule implosion experiment. The framework obtains close agreement between an experimental spectrum measured by a time integrated focusing spectrometer and the optimal synthetic spectrum. The synthetic spectra show that considering the spatial extent of the capsule and including the effects of optically thick resonance lines significantly affects the interpretation of measured spectra.

Argon K-shell and bound-free emission from OMEGA direct-drive implosion cores

“…In particular, time-resolved K-shell spectroscopy of argon-doped deuterium-filled plastic shells has proved to be very useful for diagnosing implosion cores in both direct-and indirect-drive ICF experiments [1][2][3][4][5][6][7]. Most of these applications have relied on using the photon energy range associated with the moderately optically thick HeB (ls3p-ls 2 ) and Lyj3 (3p-ls) lines, and their associated Li-and He-like satellite transitions, specifically, the photon energy range from 3500 eV to 4000 eV.…”