  We propose shortcuts to adiabaticity which achieve fast and stable control of
the state of a charged particle in an electromagnetic field. In particular we
design a non-adiabatic change of the magnetic field strength in a Penning trap
which changes the radial spread without final excitations. We apply a
streamlined version of the fast-forward formalism as well as an invariant based
inverse engineering approach. We compare both methods and examine their
stability.
