High Density Laser Wakefield Acceleration

High density Laser Wakefield Acceleration (HD-LWFA) is studied in simulation using both beatwave and subcycle lasers near the critical density (ref.1).  In contrast to the underdense regime of LWFA, the maximum electron energy in HD-LWFA is shown to increase as the electron density increases toward the critical density.  Energy transfer from the laser to the electrons obeys the same trend, indicating an increase in energy efficiency in the high density regime. These phenomena are potentially relevant for applications of HD-LWFA in the fields of medical radiation therapy, sterilization, and microscopy.