The dynamic properties of shock-waves formed during laser ablation at sub-atmospheric pressures
Clarendon Laboratory, Department of Physics, University of Oxford
Oxford OX1 3PU, UK
Accepted: 24 October 2001
The Sedov-Taylor-von Neumann (STN) theory has been shown to accurately describe the dynamic properties of shock-waves generated during pulsed-laser ablation of solid aluminium targets at visible wavelengths (510/578 nm) with 40 ns pulses with energies up to 3.5 mJ. A ballistic pendulum is used to measure the integrated recoil pressure in various inert atmospheres (He, Ne, Ar, Kr, Xe, N2, CO2, SF6) with pressures of mbar. This recoil momentum is found to scale linearly with the background gas pressure P1 and with the square root of the molecular weight . More interestingly, the scaling with the ratio of heat capacities γ is verified to be a monotonically increasing function dependent on the form factor of the shock-wave. The validity of a modified STN theory which accounts for the piston mass is assessed.
PACS: 52.50.Jm – Plasma production and heating by laser beams (laser-foil, laser-cluster, etc.) / 52.35.Tc – Shock-waves and discontinuities / 47.40.Nm – Shock-wave interactions and shock effects
© EDP Sciences, 2002