In this semianalytical research, we present a new ansatz in solving the Störmer problem with numerical findings in graphical representations of solutions where dynamics of the charged particle in the classical dipole magnetic field (here, Earth's magnetic field) was investigated in detail. We have fully solved the Störmer problem for partial class of the charged particle's motion close to the equatorial plane of Earth; this result is the main important theoretical finding presented here with prescribed symmetry. Aforementioned motions, determined by Lorentz force in nonrelativistic case, thereby are explored in polar coordinates to present them in a quasi-periodic motions in a general case (in equatorial plane of Earth). Thus, the system of momentum equations has been successfully solved numerically or semianalytically in each case and the resulting semianalytical solving algorithm can clarify the quasi-periodic structure of such family of solutions (with reduction of their geometric symmetry around the Earth in an equatorial plane).