Introduction to the physics of large amplitude plasma waves

Understanding the behavior of large amplitude plasma waves is important for many practical applications ranging from particle acceleration to plasma heating. A rich variety of nonlinear effects can limit the amplitude of a driven electron plasma wave, including nonlinear frequency shifts, wave-particle interactions, and coupling to other waves. A useful upper limit is provided by wavebreaking, which leads to a strong distortion of the electron velocity distribution. In general, energy coupling into other waves by ion density fluctuations is very important. A feedback mechanism allows this coupling to be very efficient, even starting from thermal level ion waves. The result is a collapse into shorter wavelength electron plasma waves which transfer their energy into a suprathermal electron tail.