  We argue that it is generally nonstationary Laguerre-Gaussian states (NSLG)
rather than the Landau ones that appropriately describe electrons with orbital
angular momentum both in their dynamics at a hard-edge boundary between a
solenoid and vacuum and inside the magnetic field. It is shown that the r.m.s.
radius of the NSLG state oscillates in time and its period-averaged value can
significantly exceed the r.m.s. radius of the Landau state, even far from the
boundary. We propose to study the unconventional features of quantum dynamics
inside a solenoid in several experimental scenarios with vortex electrons
described by the NSLG states. Relevance for processes in scanning and
transmission electron microscopes, as well as for particle accelerators with
relativistic beams is emphasized.
