Fluid theory of magnetic-field generation in intense laser-plasma interaction

¹ Graduate School of China Academy of Engineering Physics P. O. Box 2101, Beijing 100088, PRC
² Institute of Applied Physics and Computational Mathematics P. O. Box 8009, Beijing 100088, PRC
³ Department of Physics, Zhejiang University - Hangzhou 310027, PRC

Received: 11 July 2005
Accepted: 14 October 2005

Abstract

Using the ten-moment Grad system of hydrodynamic equations, a self-consistent fluid model is presented for the generation of spontaneous magnetic fields in intense laser-plasma interaction. The generalized vorticity is not conserved as opposed to previous studies, for the nondiagonal stress force is considered. Equations for both the axial magnetic field B_z and the azimuthal one are simultaneously derived from a fluid scheme for the first time in the quasi-static approximation, where the low-frequency phase speed v_p is much smaller than the electron thermal speed v_te. It is found that the condition , widely used as cold-fluid approximation, where B_z is incomplete, is improper. The profiles of B_z and as well as the plasma density cavitation are analyzed. Their dependences on the laser intensity are also discussed.