DEPOLARIZATION RAYLEIGH-SCATTERING AS A MEANS OF MOLECULAR CONCENTRATION DETERMINATION IN PLASMAS

The difference in polarization for Rayleigh scattered radiation on spherically and nonspherically symmetric scattering objects has been used to obtain molecular species concentrations in plasmas of simple composition. Using a Rayleigh scattering diagnostic, the depolarized component of the scattered signal, proportional to the density of molecules in the plasma, was measured. This new method has been used to locally determine molecular species densities in pure nitrogen and pure hydrogen expanding plasmas. The results were used to obtain the dissociation degree of an expanding hydrogen plasma.