LAUSR

The dynamics of invariant magnetic surfaces is considered with examples of axially symmetric magnetic systems. The inner trap (magnetic mirror) and the outer trap (dipole) are distinguished in a system formed by two coils with current. The dynamics of noninteracting particles moving in the plane of the magnetic equator is considered in the drift approximation for the perturbation vector satisfying the third invariant conservation condition. The results are extended to the equator of the geomagnetic trap, in which the external perturbing field is given by the ring current. It is shown that the real effect of the ring current on plasma dynamics in the bounded magnetosphere of the Earth in the approximation of constancy of the third invariant differs from conventional model calculations based on dipole representations of the geomagnetic field. In this case, it is not the magnetic flux that makes practical sense but only its change, which is equal to the difference between the final and initial fluxes calculated by the parameters of the real field. The minimum values of the energies of charged particles in the radiation belts required to satisfy the third condition of adiabatic invariant conservation are estimated for the main phase of a particular magnetic storm.