  The structure of stellar atmospheres can be modified if they include embedded
diverging magnetic fields. This is due to the presence of speed filters. Here
we examine some of the relevant effects through the numerical simulation of the
motion of charged particles. We introduce the concept of "floating" particles
and point out the relevance of the diamagnetic effet (DME) to the evolution of
Maxwellian velocity distributions into Non-Maxwellian.
