Laser Wakefield Near Critical Density

Laser wakefield acceleration (LWFA) in increased plasma density up to near critical densities shows stronger laser coupling with the bulk plasma. In consequence, the long, coherent, and smooth wake structures found in conventional, underdense LWFA are replaced by multiple modes of low phase velocity wakes. 1-D relativistic Particle-In-Cell code (PIC) simulations were conducted to differentiate between conventional and high-density regimes. The parameters that were varied include the plasma density and laser intensity. We show that these low phase velocity wakes are able to trap a large bunch of electrons from the bulk low temperature, thermal distribution and accelerate them. This analysis has the potential to be extended to experimental results using targets at near critical density or nanomaterials.