New techniques for laser scattering in plasmas

We report novel techniques for the scattering of laser light from plasmas to measure density and temperature. Subnanosecond laser pulses are used with fast optical streak cameras to monitor the dispersed scattered light. The spectra are recorded on photographic film. Time resolution down to 100 ps is obtained and stray light problems are eliminated so that the unshifted scattered light can be observed. The techniques have been used to measure densities in the range ne≊1016–1018 cm−3 and electron temperatures in the range Te≊5–35 eV with an accuracy of better than 10%. Laser pulses at 5265 Å with an energy of about 10 J are used and give little plasma heating.