SPECTRA OF DEVELOPED LANGMUIR TURBULENCE IN A NONISOTHERMAL MAGNETIZED PLASMA

Strong Langmuir turbulence driven by a relativistic electron beam has been investigated by the laser scattering technique. The special features of the experiments are as follows: (i) in the regime under study, Langmuir turbulence is well developed, and the temporal and spatial scales of the turbulent region far exceed those of a single caviton; (ii) the dispersion of the electron plasma waves is governed by the magnetic field, although ω pe≫ωBe; and (iii) the temperature of plasma electrons is much higher than that of ions, i.e., the damping of ion-acoustic waves is small. k-Spectra of electron plasma waves are measured in a broad spectral region by means of CO2-laser scattering. Criterion of modulational instability of observed spectra is estimated. The role of conversion and scattering of Langmuir waves by ion-acoustic waves in nonlinear energy transfer is discussed. © 1995 American Institute of Physics.