KRAMERS ELECTRODYNAMICS AND ELECTRON-ATOMIC RADIATIVE-COLLISIONAL PROCESSES

A new, essentially classical method of description of inelastic atomic processes, both radiative and collisional, caused by electrons of low and moderate energies (typical for most plasmas) is developed and quantum-mechanically substantiated. The essence of the method designated as "Kramers Electrodynamics" (KrED) is that the spectral dependence of the probability of the excitation of a quantum oscillator of frequency-omega by an electron moving (quasi-) classically in an attractive central potential, appears to retain its classical structure (Fourier transform of the respective electron classical trajectory), with increasing-omega and, hence, energy exchange \DELTA-E\ = HBAR-omega, up to very large values of the inelasticity parameter HBAR-omega/E (E is the electron's initial energy). This holds for the excitation of both the electromagnetic field oscillator (i.e. emission of a real photon) and the "atomic" oscillator (i.e. excitation of an atom by the Fermi equivalent photon "emitted" by the exciting electron). The KrED method allows a substantial universalization of the description of radiative-collisional electron-atomic processes, both elementary and kinetic ones. The method is applied to the treatment of the following processes: bremsstrahlung radiation of the electrons on many-electron atoms and ions; photorecombination and line radiation; radiative cascade between Rydberg atomic states; polarizational radiation for free-free, free-bound and bound-bound transitions, both resonant and non-resonant ones; multiphoton processes.