Fast ignition (FI) and shock ignition (SI) are alternative two-step ignition schemes of inertial confinement fusion (ICF), which have the potential to provide significantly higher gains than conventional hot-spot ignition. In FI and SI, compression of the fuel to high density and heating are achieved in separate processes. Similar to conventional ICF, a number of long pulse lasers can be used to compress the fuel to high densities. Subsequently, FI utilizes a short pulse (~ 10 ps), high intensity (>1019 W/cm2) laser to create relativistic electrons (1-3 MeV) to heat and ignite the compressed fuel plasma; while SI uses an intensity spike (~1016 W/cm2) at the end of a highly shaped pulse to launch strong shocks of the order of ³ 300 Mbar that spherically converge and collide with the rebounded shocks to trigger ignition. Copious hot electrons are also expected in SI as the result of parametric laser plasma. Fast electrons with moderate energies (50 – 100 keV) can be stopped in the compressed ablator facilitating strong shock generation. Both schemes involve complex physics of nonlinear laser plasma interaction, energetic particle generation and transport in varying temperature and density plasmas. In this talk, I will describe recent experiments with multiple kilojoule lasers and modeling to address critical issues related to fast electron source generation, transport and energy deposition in compressed high density plasmas for the development of the FI and SI laser fusion schemes.
Mingsheng Wei received her Ph.D. degree in laser plasma physics from Imperial College, London in 2005. From 2005 to 2010, she was a Project Scientist at the Center for Energy Research, UC San Diego. In 2010, Dr. Wei joined the Inertial Fusion Technology (IFT) Division of General Atomics, San Diego, where she currently serves as Senior Scientist and Principal Investigator leading research in the area of High Energy Density Physics and ICF. She also interfaces with national labs and academics on GA’s target fabrication. Dr. Wei has about 100 journal publications including Nature Physics and Physical Review Letters among others. Her work has received more than 3800 citations with H-index of 32.