Highly nonideal classical thermal plasmas: Experimental study of ordered macroparticle structures

The formation of spatially ordered CeO2 particle structures in a thermal plasma at atmospheric pressure and temperatures of 1700-2200 K is studied. The spatial structure of the particles in the plasma is analyzed using laser time-of-flight counting of individual particles. Probe and optical diagnostics are used to determine the parameters of the thermal plasma. The CeO2 particles were positively charged (about 10(3) electronic charges). The resulting Coulomb interaction parameter for the particles is gamma(p)>120, which corresponds to a highly nonideal plasma. (C) 1997 American Institute of Physics.