Laser-produced carbon plasma in an ambient gas

We report a detailed investigation of the double-peak structure in the temporal profile of the C i i transition 3d ${}_{}{}^2{}_{}{}^{}$D–4f ${}_{}{}^2{}_{}{}^{}$ ${\mathit{F}}^{\mathit{o}}$ at 426.7 nm in a laser-produced carbon plasma at various air pressures. An estimate of the plasma expansion velocity from the temporal behavior at various distances from the target for C i i, C i i i, and C i v species and electron density from the Stark broadened transition is also reported. It is proposed that the second peak in temporal profiles originates mainly due to stratification of the plasma into fast and slow ion components at the interface where the occurrence of the Rayleigh-Taylor instability causes deceleration of the laser plasma front by ambient gas.