Plasma characteristics of CNTP composites under nanosecond pulsed laser ablation

Carbon nanotube paper (CNTP) is a promising material for pulsed laser propulsion, yet the relationship between species-resolved plasma dynamics and momentum generation remains poorly understood. Here, time-resolved imaging was employed to investigate C₂ and CN plasmas generated from four CNTP composites under nanosecond laser ablation. Plasma front evolution, expansion velocity, emission intensity, and temperature were analyzed. C₂ dominates the early-stage expansion, and its initial expansion velocity (v₀) strongly correlates with the impulse coupling coefficient (C_m), identifying early-stage C₂ dynamics as an important kinetic indicator of momentum transfer. Highly graphitized single-walled CNTP generates stronger C₂ emission but lower plume velocity, whereas multi-walled CNTP composites exhibited faster expansion and higher C_m. These findings establish a direct link between CNTP composite and plasma momentum evolution, providing guidance for the design of high-performance laser propulsion materials.