Intense laser plasma interactions: From Janus to Nova

An overview of intense laser plasma interactions is given. The relevant physical processes range from collisional absorption to the excitation of instabilities, such as stimulated Raman and Brillouin scattering. These processes and important consequences that include suprathermal particle generation and enhanced absorption or scattering have been examined in theory, computer simulation, and experiments. The interaction physics has been studied in experiments using electromagnetic waves with wavelengths ranging from a fraction of a micron to tens of meters. Virtually every major interaction process has now been identified in laser plasma experiments, which have grown remarkably in sophistication over the years. Various control techniques have been demonstrated, and some intensity-wavelength regimes for efficient laser plasma coupling have been successfully identified. Indeed, current implosion experiments show excellent coupling of laser energy into thermal plasma. Future challenges include a better understanding of nonlinear levels, the competition of instabilities in large plasmas, and the beneficial effects of laser beam smoothing.