Qualitative Analysis of Quantum-Electrodynamic Processes in a Strong Field

We propose a simple method for estimation of the probabilities of elementary processes of quantum electrodynamics in a strong field. It is shown that quantum-electrodynamic processes run in the quasiclassical or quantum regime depending on the ratio of the characteristic scales of the time of particle acceleration by the field (a quasiclassical effect) and energy absorption by charged particles from the field directly during the process (a purely quantum effect). Using simple kinematic considerations and the uncertainty principle for these regimes, it is possible to reproduce the probabilities of the known processes in a strong field, in particular, spontaneous pair creation, photon emission by an electron, pair photoproduction, and radiation mass correction.