Modelling isentropic compression and shock propogation in magnetically driven foil and liner experiments
Supervisor: Dr Jerry Chittenden (Plasma Physics Group)
Developing techniques to simulate the ramped or shocked compression of solid materials is becoming increasingly important within computational high energy density science. Applications of these models include the simulation of experiments designed to measure material properties using methods such as isentropic compression experiments (ICE) as well as high energy density applications such as inertial confinement fusion (ICF).
A new 2MA pulsed power driver (MACH) under construction is expected to provide data on off-Hugoniot equation of state properties from solid materials compressed by magnetic pressures of several hundred kbar. The quality of the data obtained will rely on our ability to design a target cell with pressure uniformity across the surface and to model the propagation of magnetic diffusion and compression waves through the material. This work will involve the incorporation of modified equation of state, resistivity and material strength models into Imperial's well established 3D magneto-hydrodynamics 'Gorgon' as well as other 1D Lagrangian models. This work will be done in collaboration with Dr Andrew Barlow, Dr Steve Rothman and others at AWE. Once developed and tested against data from MACH, the same models can be used to simulate isentropic compression experiments at Sandia National Laboratory.
The development of such models will also allow different aspects of inertial confinement fusion target design to be studied, such as behaviour of shock propagation through ablator materials. A fusion application of particular interest for these models will be the magnetic liner fusion concept (MagLIF) currently being developed by Sandia National Laboratory. Here the propagation of shockwaves driven into the cylindrical metal liner can be controlled by changing the magnetic pressure through current pulse shaping and can be used to control the adiabat of the fuel inside the liner during compression.
The studentship will involve working on the boundary between plasma physics and materials science. The student will be responsible for making modifications of existing MHD codes to incorporate new material science and resistivity models and testing results against data from the new MACH generator. The student will also evaluate how the details of equation of state, material strength and resistivity can be used to improve our understanding of ICF experiments and facilitate the advanced design concepts.