Signal Intensity Enhancement by Cavity Confinement of Laser-Produced Plasma

The effect of hemispherical cavity confinement on the laser-generated plasma plume has been studied and revealing a fivefold signal intensity enhancement in the spectra of copper. The plasma temperature ( $T$ ) and electron density ( $N_{e}$ ) with and without cavity confinements have been determined. The plasma parameters ( $T$ and $N_{e}$ ) in the cavity confinement configuration remain the same for the first few microseconds and thereafter decay exponentially. The trend of constant plasma parameters for the first few microseconds is attributed to the competition of two processes; compression of the plasma plume by the reflected shock waves and cooling of the plasma plume by losing its kinetic energy due to the collision of the ambient gases. The signal intensity enhancement can be attributed to the reheating or compression of plasma plume by the reflected shock waves.