MAGNETIC-FIELD GENERATED IN A PLASMA BY A SHORT, CIRCULARLY-POLARIZEDLASER-PULSE

We study the generation of a quasistatic magnetic field by a short, ci rcularly polarized laser pulse in a tenuous cold uniform plasma. It is shown that two physical mechanisms are responsible for the generation of the various components of the magnetic field. One mechanism is due to the ponderomotive forces and governs the generation of the azimuth al component of the magnetic field. The other is similar to the invers e Faraday effect (IFE) in a nonuniform plasma and gives rise to axial and radial components of the magnetic field. At moderate radiative int ensities, all magnetic field components are proportional to the square d intensity. The spatial structure of the magnetic field depends stron gly on the pulse shape and the plasma density. (C) 1998 American Insti tute of Physics. [S1063-7761(98)00709-4].