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 II transition 3d2D - 4f2F0 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 d istances from the target for C II, C III, and C IV species and electro n density from the Stark broadened transition is also reported. It is proposed that the second peak in temporal profiles originates mainly d ue to stratification of the plasma into fast and slow ion components a t the interface where the occurrence of the Rayleigh-Taylor instabilit y causes deceleration of the laser plasma front by ambient gas.