Paul Bellan's textbook, Fundamentals of Plasma Physics, Cambridge Press 2006, discusses particle motion on fields in plasma extensively.  He notes [3.5.2] that in a more general situation, "a charged particle will gyrate around B (local mag field line direction], stream parallel to B, have ExB drifts across B, and may also have force based drifts.  This is under the assumption that "these various motions are well separated and related to the requirement that the [E and B and other F fields] fields vary slowly and also to the concept of adiabatic invariance".

Bellan gets into drift equations quite extensively in Ch. 3, and leads into the concept of "magnetic mirrors" in Section 3.5.6.  Understanding magnetic mirrors and that they may be able to act as trajectory guides for particle motion, even at relativistic velocities, where synchrotron radiation can cause emission of pulsed light trains may give insight into Healey and Peratt's paper on the theory and lab experiments regarding the origin of very fast light pulses from pulsars, that *contradicts* the present view, that posits that a pulsar mass actually physically spins at the pulse rate in the "lighthouse" analogy. {Ref: "Radiation Properties of Pulsar Magnetospheres: Observation, Theory and Experiment", Kevin Healey (VLA Ops Center, NRAO), Anthony Peratt (Physics Division, Los Alamos National Laboratory), 1995.