WEIBEL INSTABILITY ANALYSIS IN LASER-PRODUCED PLASMAS

Analytic analysis of collisionless Weibel modes in laser-created plasm as is presented. The heat flux (HF), the plasma expansion (PE), and th e inverse bremsstrahlung absorption (IBA) sources have been investigat ed. 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 bremsstr ahlung absorption is the most efficient Weibel mechanism for producing strong magnetic fields in the vicinity of the critical layer. For lar ge 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 th ermal transport and the inverse bremsstrahlung absorption mechanisms. Useful scaling laws of convective e-foldings, with respect to the lase r and the plasma parameters, are also derived.