Abstract
It is shown that in the regions far away from the center of a moving domain wall the distribution of magnetization is the same as in a spin wave of complex wave number. The structure of the moving wall is calculated rigorously for wall velocities v smaller than a certain critical velocity v1. At the critical velocity the derivative of the wall energy with respect to v becomes infinite. The wall mobility in the subcritical region (v < v1) is inversely proportional to the wall energy.