Efficiency of generation of highly ionised atoms under resonance absorption of CO2-laser radiation

We consider the generation of beams of highly ionised atoms in solid targets irradiated with CO₂-laser pulses. We present experimental results on generation of Mg and Pb ions from laser plasma at a radiation flux density q ≈ 10¹⁴ W cm^-2. We have developed a theoretical model describing the plasma heating by CO₂-laser radiation at a high pulse intensity on the target, taking into account the ponderomotive forces affecting the behaviour of the interaction of light with the plasma. It is shown that in the case of resonance absorption of laser radiation by the plasma, the efficiency of generation of highly ionised atoms of the target substance is higher than the efficiency of generation in the case of classical absorption. The results of the numerical calculation by the developed model are in good agreement with the experiment.