  An analytical approach to quantum mechanical wave packet dynamics of
laser-driven particles is presented. The time-dependent Schroedinger equation
is solved for an electron exposed to a linearly polarized plane wave of
arbitrary shape. The calculation goes beyond the dipole approximation, such
that magnetic field effects like wave packet shearing are included. Analytical
expressions for the time-dependent widths of the wave packet and its
orientation are established. These allow for a simple understanding of the wave
packet dynamics.
