Feasibility of alpha-particle measurement by CO2 laser Thomson scattering

The feasibility of CO2 laser Thomson scattering from a multicomponent burning plasma has been evaluated for the measurement of the velocity distribution of D–T-produced alpha particles. The density and velocity distribution of the alpha particles from their initial energy of 3.5 MeV down to near-thermal energies may be measured by small-angle (<1°) Thomson scattering. A computer simulation of the experiment indicates that a 100-MW pulsed laser combined with a bank of heterodyne receivers will be able to measure a scattered signal from the alpha particles with a postdetection signal-to-noise ratio of 75 for an assumed alpha density of 7.5×1011 cm−3.