Knowledge Bank

Many interesting phenomena occur when a high intensity laser interacts with matter. Much research has been done at ultra high intensities which drastically alter or destroy targets, and much has been done at lower intensities which do not modify the plasma surface at all. However, there is much left to be explored in the realm of intensities at which the plasma surface is just modified, but the target is not destroyed. Particle-in-Cell (PIC) simulations have traditionally been used to model hot, sparse plasma, but not to model the transition between solid density and cold, dense plasma. Through PIC simulations, we investigate the interaction between light at high and copper targets. Of specific interest is the radiation response from a target at frequencies lower than that of the illuminating laser. Many challenges present themselves while modelling such interactions. At the higher temperatures caused by ultra high intensities, the target may represent a more idea plasma, making it easier to model PIC simulations. We have successfully modeled this interaction to 500 fs and are working to expand our simulation to larger time regimes by using multiple simulations to eliminate high frequency noise.