Quasistatic magnetic field generation in initially inhomogeneous plasma

Abstract

We consider the interaction of arbitrary amplitude circularly polarized (c.p.) laser pulses with under-dense, cold, unmagnetized, initially inhomogeneous electron plasmas. Confirming the applicability of the formalism given in our recent paper and deriving the correct expression for the LF drag current we have shown the possibility of strong QSM field generation by spatially uniform c.p. laser radiation in initially strongly inhomogeneous underdense plasma. Investigating the different initial density profiles for laser-produced plasmas, where the density scale length is typically of the order of that of the laser beam amplitude and taking into account the electron cavitation by relativistically strong short laser pulses, we have shown the advantage of the convex initial density profile compared to the concave one (or to the initially homogeneous plasma) to generate immense magnetic fields (∼200 MG and greater) in the self-channelling regime by the currently available intense laser pulses.