Observations of stimulated Brillouin backscattering from a magnetically confined plasma

Abstract

Backscattered laser radiation has been observed from a CO2 laser-produced and heated underdense plasma in a steady solenoid magnetic field, and is attributed to the stimulated Brillouin scattering process. Spectral measurements and observations of the dependence of the backscattered intensity on laser power are presented to support this identification. Backscattered radiation, amounting to as much as 1% of the incident power, was found to be redshifted by 80–100 Å, the shift expected for stimulated Brillouin scattering from a plasma at the measured temperature Te=80±25 eV. Data are also presented on the dependence of backscattered power on the density and convergence angle of incoming radiation.