Electron parametric instabilities driven by relativistically intense laserlight in plasma

A unified treatment of electron parametric instabilities driven by ultraint ense laser light in plasma is described. It is valid for any intensity, pol arization, plasma density, and scattering geometry. The method is applied t o linearly polarized light in both underdense plasma and overdense plasma a ccessible by self-induced transparency. New options arise which are hybrids of stimulated Raman scattering, the two plasmon decay, the relativistic mo dulational and filamentation instabilities, and stimulated harmonic generat ion. There is vigorous growth over a wide range of wave numbers and harmoni cs.