The chemistry and kinetics of the plasma were investigated for different pO2 at total pressures of 2*10−2 and 1*10−1 mbar. Figure 5 presents the front position versus delay time of the plasma plume at pressures of 2*10−2 and 1*10−1 mbar O2. The plasmas propagated differently in both pressures. At 2*10−2 mbar, the plasma arrived at the substrate 6 μs after ablation, with a velocity of 5 km/s. The propagation could be fitted with a simple kinetic drag model28. In this model, the plasma has a ballistic like propagation, while minor deceleration occurs due to drag forces on the particles in the plasma. At 1*10−1 mbar, the plasma front position changed linearly with delay time after 12 μs, which indicates propagation by diffusion. The plasma reached the substrate after 20 μs with a velocity of 1 km/s. The plasma propagation behavior and arriving velocities were very similar to other oxide plasmas24.Figure 5Plot of plasma front positions versus delay times at 2*10−2 and 1*10−1 mbar O2. The solid lines represent a drag model fit, the dashed curve is a linear fit indicating diffusive propagation. The blue line is the substrate position.