  We investigate the effects of a Stern-Gerlach-type addition to the Lorentz
force on electrons in a laser wakefield accelerator. The Stern-Gerlach-type
terms are found to generate a family of trajectories describing electrons that
surf along the plasma density wave driven by a laser pulse. Such trajectories
could lead to an increase in the size of an electron bunch, which may have
implications for attempts to exploit such bunches in future free electron
lasers.
