DrChristopherWalsh

My research focuses on 3-D Magneto-hydrodynamic modelling of inertial confinement fusion (ICF) capsules on both the OMEGA Laser Facility and the National Ignition Facility. Magnetic fields are generated within ICF capsules but can also be applied in order to improve capsule performance.

Magnetic fields are spontaneously generated at the edge of perturbed ICF hot-spots during stagnation, but are not considered when designing targets. Our research suggests field strengths greater than 10,000T are reached in implosions on the National Ignition Facility, significantly altering the thermal conduction. Although intuition would suggest that these magnetic fields thermally insulate the hot-spot, we find that the Righi-Leduc heat flow (heat flow deflected by the magnetic field) allows cold spikes to penetrate further into the hot core and that the overall energy containment is worsened by the self-generated fields. 

Magnetic fields can be applied to ICF capsules to reduce thermal and fusion-produced α-particle losses from the hot-spot. On the OMEGA Laser Facility this has been shown to increase the hot-spot temperature and neutron yield by 15% and 30% respectively. Our simulations match these experiments well and are then used to estimate the effect of applying magnetic fields on the National Ignition Facility. While bringing the hot-spots closer to ignition, we also study inherently 3-D effects, such as hot-spot elongation and how the Righi-Leduc heat flow cools the capsule.