  Husimi functions allow one to obtain sensible and useful phase space
probability distributions from quantumechanical wavefunctions or classical wave
fields, linking them to (semi-)classical methods and intuition. They have been
used in several fields of physics, including electronic transport. We show that
applying Husimi functions to ballistic electron dynamics in magnetic fields
needs special consideration in order for them to obey gauge invariance and
energy conservation. We therefore extend the Husimi function formalism to allow
for magnetic fields making use of magnetic translation operators. We
demonstrate the application in tight-binding magneto-transport calculations in
graphene nanodevices, highlighting connections with Klein tunneling. In
continuation of recent work, with this paper we further pave the way for using
the Husimi function to unravel quantum transport phenomena in nanodevices.
