Measuring the oscillator strength of intercombination lines of helium-like V ions in a laser-produced-plasma
Journal of Quantitative Spectroscopy and Radiative Transfer, 2020, 256, 107326
Abstract:
We present results of measurements of the oscillator strength of intercombination lines of He-like Vanadium ions in high energy density (HED) laser-produced-plasmas and compare them with the simulations from commonly used codes and data from the NIST database. Whilst not yet sufficiently accurate to constrain different trusted atomic-physics models for the particular system studied, our results are in agreement with the available data within experimental error bars, yet differ from cruder approximations of the oscillator strength used in certain atomic-kinetics packages, suggesting that this general method could be further extended to be used as a measurement of the oscillator strength of additional atomic transitions under the extreme conditions that are achieved in HED experiments
Hydrodynamic conditions in laser irradiated buried layer experiments
Physics of Plasmas AIP Publishing 27:6 (2020) 063301-063301
Radiation transfer in cylindrical, toroidal and hemi-ellipsoidal plasmas
Journal of Quantitative Spectroscopy and Radiative Transfer Elsevier 235 (2019) 24-30
Abstract:
We present solutions of the radiative transfer equation for cylinders, hollow hemi-ellipsoidal shells and tori for a uniform plasma of fixed geometry. The radiative transfer equation is explicitly solved for two directions of emission, parallel and perpendicular to the axis of symmetry. The ratio between the fluxes in these two directions is also calculated and its use in measuring the frequency resolved opacity of the plasma is discussed. We find that the optimal geometry to use this ratio as an opacity measurement is a planar geometry.The use of geometric effects in diagnosing ion density in ICF-related dot spectroscopy experiments
High Energy Density Physics Elsevier 30 (2019) 45-51
Abstract:
We describe a method to calculate the ion density of High Energy Density (HED) cylindrical plasmas used in Dot Spectroscopy experiments. This method requires only spectroscopic measurements of the Heα region obtained from two views (Face-on and Side-on). We make use of the fact that the geometry of the plasma affects the observed flux of optically thick lines. The ion density can be derived from the aspect ratio (height-to-radius) of the cylinder and the optical depth of the Heα-y line (1s2p 3P1 → 1s 2 1S0). The aspect ratio and the optical depth of the y line are obtained from the spectra using ratios measured from the two directions of emission of the optically thick Heα-w line (1s2p 1P1 → 1s 2 1S0) and the ratio of the optically thick to thin lines. The method can be applied to mid-Z elements at ion densities of 1019 − 1020 cm−3 and temperatures of a the order of keV, which is a relevant regime for Inertial Confinement Fusion (ICF) experiments.ALICE: A non-LTE plasma atomic physics, kinetics and lineshape package
High Energy Density Physics Elsevier 26 (2018) 56-67