Location of Ion-Acoustic Waves from Back and Side Stimulated Brillouin Scattering

Direct observation of the location of ion-acoustic waves (IAWs) explains for the first time the stimulated Brillouin scattering (SBS) spectra in backward and side directions. The regions of SBS activity are limited and smaller than the scale length of the plasma. The IAWs are localized in the front part of the plasma, resulting in blue Doppler shift of the scattered electromagnetic wave, and the distance from the summit changes with the SBS angle.