  We present the first 3D particle-in-cell simulations of laser driven
sheath-based ion acceleration in a kilotesla-level applied magnetic field. The
applied magnetic field creates two distinct stages in the acceleration process
associated with the time-evolving magnetization of the hot electron sheath and
results in a focusing, magnetic field-directed ion source of multiple species
with strongly enhanced energy and number. The benefits of adding the magnetic
field are downplayed in 2D simulations, which strongly suggests the feasibility
of observing magnetic field effects under experimentally relevant conditions.
