An investigation of the potential of optically thick line profiles for determining laser-produced plasma parameters

A method of determining laser-produced plasma conditions from the shape of a single optically thick line profile is investigated. The parameters of a model of the plasma emissivity, absorption coefficient and ion velocity are adjusted until a close fit between the profile computed from the model and the observed profile is obtained. The technique is shown to be capable of obtaining accurate plasma parameters from synthetic profiles (where the exact parameters producing the line profile are known) and to be numerically stable in the presence of noise superimposed on a synthetic profile. Ion streaming velocities in expanding plasmas can be determined, for example, to an accuracy within 10%. Plasma parameters are also deduced from a recently published C VI L alpha line profile emitted from a slab polyethylene target laser-produced plasma.