Effects of alpha particles on the scattering function in CO2laser scattering

It is shown that the alpha-particle contribution to the scattered power can be dominant in the coherent scattering of a CO2laser in a Maxwellian plasma. For Ti= Te= 10 keV, the optimal forward-scattering angle is around 1.0°, with detection of the electron density fluctuation wavenumbers k?>> k||(relative to the toroidal magnetic field). A strong resonance occurs at the lower hybrid frequency. Because of the strong dependence of the scattered signal on the alpha-particle temperature and the alpha distribution function, it seems feasible that CO2laser scattering, using heterodyne techniques, could give detailed local information on fusion alphas.