Measurement of the frequency and spectral width of the Langmuir wave spectrum driven by stimulated Raman scattering

Abstract
Thomson scattering was used to measure the spectrum of Langmuir waves, in both frequency and wave number, driven below quarter-critical density by a laser beam. These measurements were capable of detecting and identifying waves driven by stimulated Raman scattering(SRS) and also of detecting waves driven by other effects such as the bump-on-tail instability postulated by the enhanced Thomson scattering model of Raman emission. The observed Langmuir waves were consistent with SRS and not with other possible sources. The width in k-space of the measured Thomson scattering signals also has implications for the saturation amplitude of the Langmuir waves.Peer reviewed: YesNRC publication: Ye