Observation of ion acoustic waves associated with plasma-induced incoherence of laser beams using Thomson scattering

The physical processes responsible for the plasma-induced incoherence (PII) of a laser beam, were investigated. A Thomson scattering diagnostic was used to observe ion acoustic waves (IAW) having wave vectors transverse to the interaction beam spectral and temporal characteristics. It was found that for the high plasma density the Thomson scatter spectra show a red feature that is shifted by 1.5 Å. The spectral characteristics of these ion waves were in agreement with numerical simulations in the case of low plasma density.