Mechanisms of carbon dimer formation in colliding laser-produced carbon plasmas

摘要

It has been demonstrated that the hot stagnation region formed during the collision of laser-produced carbon plasmas is rich with carbon dimers which have been shown to be synthesized into large carbon macromolecules such as carbon fullerene onions and nanotubes. In this study, we developed and integrated experimental and multidimensional modeling techniques to access the temporal and spatial resolution of colliding plasma characteristics that elucidated the mechanism for early carbon dimer formation. Plume evolution imaging, monochromatic imaging, and optical emission spectroscopy of graphite-produced, carbon plasmas were performed. Experimental results were compared with the results of the 3D comprehensive modeling using our HEIGHTS simulation package. The results are explained based on a fundamental analysis of plasma evolution, colliding layer formation, stagnation, and expansion. The precise mechanisms of the plasma collision, plume propagation, and particle formation are discussed based on the experimental and modeling results.