In this work, a model is proposed to provide an estimation of the temporal and spatial changes of the potential within the interaction zone between laser and metal surface. The model depends on the real experimental data which were measured around the interaction zone. This model provides an estimation of the charge involved and considers the presence of the hole created by the interaction. For the first time, it provides the spatial and the temporal variation of the potential which reflects the electric forces and temperature at the interaction zone. It also gives a clear insight of the position of the Knudsen layer. The estimated maximum potential is more than ten times the potential at the surface boundary. This implies that surface potential is due to the interaction of the surface with the plasma rather than the usually believed thermionic emission.

Laser-solid interaction --- Poisson's equation --- Knudsen layer --- Plasma dynamics

In this article, advanced laser diagnostics have been used in combination with modeling to study fundamental non-equilibrium low temperature Plasma Assisted Combustion kinetics. We also discuss recent advances in ultra-high frame rate imaging, which provides new capability for capturing the dynamic evolution of high speed, unsteady flow fields, and/or increasing the data collection rate in short run time “impulse” facilities.

Thermal equilibrium --- Optical measurements --- Plasma dynamics --- Raman spectroscopy