The structure of standing Alfvén waves in a dipole magnetosphere with moving plasma

The structure and spectrum of standing Alfv́n waves were theoretically investigated in a dipole magnetosphere with moving plasma. Plasma motion was simulated with its azimuthal rotation. The model's scope allowed for describing a transition from the inner plasmasphere at rest to the outer magnetosphere with convecting plasma and, through the magnetopause, to the moving plasma of the solar wind. Solutions were found to equations describing longitudinal and transverse (those formed, respectively, along field lines and across magnetic shells) structures of standing Alfv́n waves with high azimuthal wave numbers m>>1. Spectra were constructed for a number of first harmonics of poloidal and toroidal standing Alfv́n waves inside the magnetosphere. For charged particles with velocities greatly exceeding the velocity of the background plasma, an effective parallel wave component of the electric field appears in the region occupied by such waves. This results in structured high-energy-particle flows and in the appearance of multiband aurorae. The transverse structure of the standing Alfv́n waves' basic harmonic was shown to be analogous to the structure of a discrete auroral arc.