Weibel instability analysis in laser-produced plasmas

Analytic analysis of collisionless Weibel modes in laser-created plasmas is presented. The heat flux (HF), the plasma expansion (PE), and the inverse bremsstrahlung absorption (IBA) sources have been investigated. It has been shown that for short laser wavelengths (lambda(L) < 1 mu m) and high laser fluxes (I > 10(14) W/cm(2)), the inverse bremsstrahlung absorption is the most efficient Weibel mechanism for producing strong magnetic fields in the vicinity of the critical layer. For large laser wavelengths (lambda(L) similar to 10 mu m), the production of the magnetic fields in the vicinity of the critical layer, due to the plasma expansion mechanism, is as important as the ones due to the thermal transport and the inverse bremsstrahlung absorption mechanisms. Useful scaling laws of convective e-foldings, with respect to the laser and the plasma parameters, are also derived.