EFFECTS OF THE WIGGLER FIELD ON THE TERAHERTZ RADIATION GENERATED BY INTENSE LASER BEAM IN COLLISIONLESS MAGNETOPLASMA

In this paper, relativistic effects of the wiggler field on the terahertz (THz) radiation generated by intense laser beam in collisionless magnetoplasma in the attendance of a planar magnetostatic wiggler is studied. Analytical formulation governing the laser spot-size with respect to competition between diffraction and self-focusing terms of laser beam has been derived and the effects of the wiggler field on the variations of beam width parameter and THz field amplitude has been investigated. Numerical simulations show that increasing of wiggler magnetic field leads to reduces of beam width parameter. Indeed, when we employ the magnetic wiggler field, self-focusing in magnetoplasma improve, appropriately. In addition, it was found that by employing wiggler magnetic field, maximum spot-size of the laser beam decreases as a result of laser beam propagating in magnetoplasma. Moreover, it was shown that the THz conversion efficiency significantly enhanced, with increasing of the wiggler field strength. Also, it was found that self-focusing of the laser beam and wiggler magnetic field play crucial roles in process of conversion efficiency.