On motion of a particle in a strong-field magnetic bottle

Compact astrophysical sources like neutron stars and magnetars possess extremely strong magnetic fields. Radiative cooling of plasma particles in their magnetospheres can be short compared to the plasma dynamical time. Such magnetospheres are observed to produce strong flares, which indicates production of relativistic electrons and, possibly, positrons. How does the particle distribution change as these particles propagate in the magnetospheric 'magnetic bottle'? Here we discuss the motion of a relativistic 'larmor particle' in a straight magnetic bottle subject to synchrotron energy loss.