Particle-in-Cell Simulations of Laser-plasma Instabilities Relevant to Shock Ignition*

In the shock-ignition (SI) approach to direct-drive inertial confinement fusion (ICF) a high-intensity laser pulse is used to drive a converging shock through a pre-compressed direct-drive target to achieve ignition. Studies over the last decade have indicated that laser-plasma instabilities (LPIs) play a key role in determining the effectiveness of this ignitor shock. In particular, the hot electron distribution produced by LPIs is vital; electrons with energy over ~100keV may preheat the target ahead of the shock, while those of lower energy deposit their energy in the dense shell behind it and enhance its strength.

Modelling these instabilities is challenging due to the disparity in length and time-scales over which experiments take place and those on which LPIs develop. Furthermore,  the behaviour of LPIs depends on detailed kinetic physics, necessitating the use of computationally expensive simulation methods. Here we present 2D particle-in-cell simulations of large-scale coronal plasmas relevant to SI. We discuss the dynamics of the instabilities produced and the resulting hot-electron distributions.