Coupling of electromagnetic filamentation instability and electrostatic Langmuir parametric instabilities in laser—plasma interactions

The interaction of electromagnetic filamentation instability and electrostatic Langmuir parametric instabilities (parametric decay instability and oscillating two-stream instability) driven by an intense laser in a plasma is examined. Near the critical layer of an underdense plasma, where the incident laser frequency is close to the local plasma frequency, coupling of unstable electromagnetic and electrostatic modes may occur. The transition from purely electromagnetic and purely electrostatic instabilities to hybrid instabilities is analysed using the generalized Zakharov equations.