Optical characterization of lithium plasma produced by laser irradiation.

Abstract

Solid lithium deposited on stainless steel (SS) was irradiated by a CO₂, laser at 10.6 μm, and by a dye laser tuned to 666.4 nm and to the first resonance line of lithium, 670.8 nm. Type 316 SS surfaces were irradiated by a dye laser at 670.8 nm. Power densities ranged from < 0.1-9.4 MW/cm². Optical information from the lithium plasma produced was evaluated using Stark broadening analysis to determine the plasma density, which varied from ~ 2 x 10¹⁶/cm² to over 10 ¹⁷/cm³. Lithium and SS surfaces were observed by an SEM before and after irradiation, and evidence of unipolar arcing was found on both surface types.