Strongly driven laser-plasma coupling

An improved understanding of strongly driven laser-plasma coupling is impor tant for optimal use of the National Ignition Facility (NIF) for both inert ial fusion and for a variety of advanced applications. Such applications ra nge from high-energy x-ray sources and high-temperature hohlraums to fast i gnition and laser radiography. We discuss a novel model for the scaling of strongly driven stimulated Brillouin and Raman scattering. This model postu lates an intensity-dependent correlation length associated with spatial inc oherence due to filamentation and stimulated forward scattering. We first d escribe the model and then relate it to a variety of experiments. Particula r attention is paid to high-temperature hohlraum experiments, which exhibit low to modest stimulated Brillouin scattering even though this instability is strongly driven. We also briefly discuss the strongly nonlinear interac tion physics for efficient generation of high-energy electrons either by ir radiating a large plasma with near quarter-critical density or by irradiati ng overdense targets with ultra-intense laser light.