  We present an analysis of particle motion in fields of a relativistic neutral
electron-positron current sheet in the case when radiative effects must be
accounted for. In the Landau-Lifshitz radiation reaction force model, when
quantum effects are negligible, a high-precision analytical solution for
particle trajectories is derived. Based on this solution, for the case when
quantum effects are significant an averaged quantum solution in the
semiclassical approach is obtained. The applicability region of the solutions
is determined and analytical trajectories are found to be in good agreement
with those of numerical simulations with account for radiative effects.
