A novel fast electron beam emitting along the surface of a target irradiated by intense laser pulses is observed. The beam is found to appear only when the plasma density scale length is small. Numerical simulations reveal that the electron beam is formed due to the confinement of the surface quasistatic electromagnetic fields. The results are of interest for potential applications of fast electron beams and deep understanding of the cone-target physics in the fast ignition related experiments.

Filamentation formed by self-focusing of intense laser pulses propagating in air is investigated. It is found that the position of filamentation can be controlled continuously by changing the laser power and divergence angle of the laser beam. An analytical model for the process is given.

The scattering of ultrashort and ultraintensie laser pulses by single electrons has been investigated theoretically and numerically by use of the classical theory of Thomson scattering by free electrons. The results indicate that attosecond pulse trains are emitted during the interaction. The temporal and spatial characteristics of the radiation are presented for different laser parameters(including intensity, pulse duration, initial phases and polarizations) and initial states of the electron(including different initial velocities and positions). Usually, with the increase of the incident laser intensity, the radiation becomes more powerful, its central frequency becomes higher, its duration becomes shorter, and its angular distribution becomes smaller. The radiation produced by the electron under a linearly polarized laser has a higher amplitude than under a circularly polarized laser pulse with the same intensity. In both cases, the polarization state of the radiation is very complicated, which depends n the observation direction. In spite of its initial energy and moving direction, the radiation produced by relativistic energetic electrons tends to be predominantly along the moving direction of the electron.

We report a plasma-based strong THz source generated in intense laser-solid interactions at relativistic intensities >1018 W/cm2. Energies up to 50 μJ/sr per THz pulse is observed when the laser pulses are incident onto a copper foil at 67.5°. The temporal properties of the THz radiation are measured by a single shot, electro-optic sampling method with a chirped laser pulse. The THz radiation is attributed to the self-organized transient fast electron currents formed along the target surface. Such a source allows potential applications in THz nonlinear physics and provides a diagnostic of transient currents generated in intense laser-solid interactions.