| Abstract: | Two-dimensional particle simulation is carried out to study the interaction between a high-intensity finite-size spot laser beam and a plasma with linear density profile. The laser is allowed to propagate in underdense corona until it is cut off near the critical surface. The intense laser can drive various instabilities through particle collective motion and result in electron heating, while relativistic effect and ponderomotive force can bring strong energy absorption and electron heating in the overdease region. As the laser beam is nonuniform in the transverse direction, a density channel forms and hole boring effect occurs as a result of strong ponderomotive force pushing particle outwards. These processes can be investigated well by particle simulation. |
