Absorption of ultra-intense laser pulses

We use simulations to investigate the interaction of ultra-intense laser pulses with a plasma. With an intensity greater than 10^18 W/cm^2, these pulses have a pressure greater than 10^3 M bar and drive the plasma relativistically. Hole boring by the light beam is a key feature of the interaction. We find substantial absorption into heated electrons with a characteristic temperature of order the pondermotive potential. Other effects include a dependence on the polarization of the incident light, strong magnetic field generation, and a period of intense instability generation in the underdense plasma.