Quantum-mechanical dielectric model of the electron-ion collision frequency in strong laser fields

The electron-ion collision frequency in a strong laser field is calculated in the framework of the quantum Vlasov theory in first-order Born approximation. Using a Wigner representation of the density matrix, the collision frequency can be expressed in terms of the Lindhard dielectric function and a close correspondence between classical and quantum-mechanical approaches can be obtained. Asymptotic formulas for the high-frequency collision frequency in weak and strong electric fields are obtained and compared with complete numerical calculations. The basic strong-field behavior can be explained in terms of the cold plasma model. (C) 2001 American Institute of Physics.