Laser Scattering Measurements of Thermal Ion-Acoustic Fluctuations in Collisional Plasmas

Phys. Rev. Lett. 53, 1563 (1984)https://ireap.umd.edu/10.1103/PhysRevLett.53.15631984Journal ArticlePlasma, Accelerator, and Nuclear Physics

The thermal ion-acoustic fluctuation spectrum of a high-density, low-temperature (2 eV, 10¹⁷ cm⁻³), collisional plasma was measured in a CO₂-laser scattering experiment. The measured spectra differed substantially from spectra observed in collisionless plasmas. Fluctuations at the ion-acoustic frequency were strongly enhanced and the width of the resonance was significantly narrowed in comparison to the collisionless case. The Bhatnagar-Gross-Krook theory proved most successful in describing the data.