Interaction Physics of the Fast Ignitor Concept

The interaction of relativistic electrons produced by ultrafast lasers focusing them on strongly precompressed thermonuclear fuel is analytically modeled. Energy loss to target electrons is treated through binary collisions and Langmuir wave excitation. The overall penetration depth is determined by quasielastic and multiple scattering on target ions. It thus appears possible to ignite efficient hot spots in a target with density larger than 300 g/c${\mathrm{m}}^{3}$.