Thomson scattering in both the collective and non-collective regime in a laser produced plasma

We present Thomson-scattering measurements of light scattered from ion-acoustic and electron plasma fluctuations in an N$_2$ gas jet plasma. The transition from the collective regime to the non-collective regime for the electron feature is observed by varying the plasma density from 2.5$\times 10^{18}$ cm$^{-3}$ to 1.7$\times 10^{19}$ cm$^{-3}$ and the temperature from 100 eV to 300 eV. These measurements allow an accurate local measurement of both temperature and density. A discussion on the sensitivity to non-maxwellian electron distribution functions will be presented. This work was performed under the auspices of the U.S. Department of Energy by the Lawrence Livermore Nation Laboratory under Contract No. W-7405-ENG-48. UCRL-ABS-223005.