Ponderomotive effects and magnetic field generation in radiation plasma interaction

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Abstract
A kinetic theory of ponderomotive effects and magnetic field generation is presented. For a comparison with standard fluid theories, explicit equations for momentum and energy conservations are established. As an example, it is shown that collisions do not lead to the usual resistive drag. In the important case of magnetic field generation via resonant absorption, three regimes with different behavior are found. In the collision‐dominated regime of the parameters, the main source of the magnetic field is the off‐diagonal terms of the particle pressure tensor. An intermediate regime appears when the nonlinear effects are collisionless and the amplitude of electromagnetic field due to the resonance absorption mechanism is limited by the plasma resistivity. In the collisionless regime, the validity of published results is extended by a self‐consistent nonlinear calculation. As a result, the distribution function of electrons may include suprathermal tails, and the magnetic field generated does not appear explicitly in the formula.