Turbulent Mixing in a Spherical Implosion

Society faces a critical need for a long term energy source. In the long term, Inertial Confinement Fusion (ICF) provides a potential pathway towards utilisation of fusion power as an energy source. In ICF, powerful lasers are employed to rapidly compress a small sphere of deuterium/tritium to the required temperature and pressure to produce fusion. In the long term, such small spheres could be imploded multiple times per second, with each pulse providing a small release of energy. With even a modest conversion rate, a system could provide enough energy to sustain mankind for many centuries. However, fluid instabilities develop and these can prevent fusion being achieved.

Research within our University of Sydney group aims to understand how the instabilities develop and transition to turbulence, and thus inform the future design of the fuel capsules, utilising very high resolution computations undertaken on several thousand computational cores. This computation was undertaken by Sydney PhD student Moutassem El Rafei, who has developed a novel semi-Lagrangian, very high order accurate algorithm for the Euler equations in spherical coordinates. It highlights the development of perturbations from linear, through to nonlinear, and turbulent mixing.

For more information, please see:
M El Rafei, B Thornber "Numerical study and buoyancy–drag modeling of bubble and spike distances in three-dimensional spherical implosions" Physics of Fluids 32 (12), 124107, 2020

M El Rafei, M Flaig, DL Youngs, B Thornber "Three-dimensional simulations of turbulent mixing in spherical implosions", Physics of fluids 31 (11), 114101, 2019

M El Rafei, B Thornber "Numerical Study of Compressible Turbulent Mixing in Spherical Implosions Comparing Different Initial Perturbations", Proceedings of the 21st Australasian Fluid Mechanics Conference, 2020

M El Rafei, L Heidt, B Thornber "A comparison of a modified curvilinear approach for compressible problems in spherical geometry and a truly spherical high-order method", Proceedings of the 21st Australasian Fluid Mechanics Conference, 2018