Interpretation of the observed anomalous transmission of intense laser radiation through an overdense plasma

An explanation is provided to the experimental results of Rockett et al. (Phys. Rev. Lett. 40, 649 (1978)) on the anomalous transmission of a ring-shaped laser beam through an overdense plasma. The laser beam heats the electrons of the illuminated region which in turn heat the electrons of the central region through thermal conduction. In order to equalize the pressure everywhere, a density depletion of the spot size of the laser beam is created which paves the way for the beam to be transmitted.