OBSERVATION OF THE LANGMUIR DECAY INSTABILITY DRIVEN BY STIMULATED RAMAN-SCATTERING

Thomson scattering was used to measure the Langmuir wave spectrum driv en by stimulated Raman scattering. The Thomson scattering signals meas ured in the experiment showed Langmuir waves with components both para llel and antiparallel to the incident laser's wave vector, k(0), The p arallel component was attributed to stimulated Raman scattering. Howev er, the Langmuir waves with components antiparallel to k(0), which can not be explained by stimulated Raman scattering, were attributed to th e Langmuir decay instability (LDI), The relative amplitude of the two Langmuir wave features and their angular width supported the conclusio n that the Langmuir waves traveling antiparallel to the incident laser 's wave vector were driven by the Langmuir decay instability. (C) 1997 American Institute of Physics.