Plasma Instabilities: Resonant Three Wave Interaction

This lecture delves into the mechanism of resonant three wave coupling, focusing on Stimulated Raman Scattering (SRS) in a non-magnetized plasma. The instructor derives model equations for light waves and Electron Plasma Waves (EPWs), emphasizing the importance of matching conditions for effective coupling. Conditions for parametric instability and the number of solutions are discussed, along with the development of energy transfer among the waves. The lecture also covers the basic mechanism of parametric instabilities affecting laser light in plasma, such as SRS and Stimulated Brillouin Scattering (SBS), and their implications in inertial fusion. The presentation includes the system of three coupled oscillators and the derivation of slow time-scale equations for wave amplitudes. The lecture concludes with illustrations from simulations and further reading recommendations.