Chinese Acad Sci, Lab Opt Phys, Inst Phys, Beijing 100080, Peoples R China
; Chinese Acad Sci, Inst High Energ Phys, Beijing 100049, Peoples R China
; China Acad Engn Phys, Res Ctr Laser Fus, Mianyang 621900, Peoples R China
; Univ Sci & Technol China, Dept Modern Phys, Hefei 230027, Peoples R China
; Rutherford Appleton Lab, Cent Laser Facil, Didcot OX1 10QX, Oxon, England
With the effective Thomson scattering diagnostic of the laser plasmas produced under different laser conditions, the distinct asymmetry of the two peaks of the ion-acoustic waves are measured 150 mu m in front of the target surface. The more intense peak appears at shorter wavelength when the electron temperature is higher, and switches to longer wavelength when the electron temperature is lower. The two-peak structure, the asymmetry and the position of the more intensity peak of the ion-acoustic waves can be well interpreted with the Raman scattering effect. This paper, for the first time, establishes the corresponding relationship between Raman scattering of light and Thomson scattering of electons in laser plasmas.