PERSPECTIVE FOR HIGH ENERGY DENSITY STUDIES USING X-RAY FREE ELECTRON LASERS
Institute of Electrical and Electronics Engineers (IEEE) 1 (2009) 1-1
Predicting EXAFS signals from shock compressed iron by use of molecular dynamics simulations
High Energy Density Physics 5:1-2 (2009) 44-50
Abstract:
Simulated EXAFS signals from ab initio models and configurational averaging of molecular dynamics (MD) data are compared for α-Fe, and configurationally averaged MD EXAFS signals are compared with experimental data for iron shock compressed to pressures above the α-ε{lunate} transition pressure. It is shown that molecular dynamics potentials and ab initio models capable of recreating similar vibrational density of states lead to EXAFS signals in good mutual agreement. The effects of the classical nature of the phonon distribution in the MD and the anharmonicity of the potential give rise to noticeable differences between ab initio models and configurational averaging of MD data. However, the greatest influence on the spectra is the form of the potential itself. We discuss the importance of these effects in simulating EXAFS spectra for shock compressed polycrystalline iron. It is shown that EXAFS is an insensitive probe for determining the nature of the close packed product phase in this system. © 2009 Elsevier B.V.Third harmonic order imaging as a focal spot diagnostic for high intensity laser-solid interactions
Laser and Particle Beams 27:2 (2009) 243-248
Abstract:
As the state of the art for high power laser systems increases from terawatt to petawatt level and beyond, a crucial parameter for routinely monitoring high intensity performance is laser spot size on a solid target during an intense interaction in the tight focus regime (<10m). Here we present a novel, simple technique for characterizing the spatial profile of such a laser focal spot by imaging the interaction region in third harmonic order (3laser). Nearly linear intensity dependence of 3laser generation for interactions >1019Wcm2 is demonstrated experimentally and shown to provide the basis for an effective focus diagnostic. Importantly, this technique is also shown to allow in-situ diagnosis of focal spot quality achieved after reflection from a double plasma mirror setup for very intense high contrast interactions (>1020Wcm2) an important application for the field of high laser contrast interaction science. © Cambridge University Press 2009.Measurements of radiative shock properties using X-ray thomson scattering
2009 IEEE International Conference on Plasma Science - Abstracts IEEE (2009) 1-1
The effect of a radiation field on excitation and ionisation in non-LTE high energy density plasmas
High Energy Density Physics Elsevier 5:1-2 (2009) 23-26