Parametric Survey of Inner Magnetosphere FLRs in the Pc4 Range

Abstract:

Due to their effective interaction with ring current and radiation belt particles, waves in the Pc4 band (1-2 minute period) are a topic of ongoing interest. We discuss the response of such waves to sinusoidal driving under an ensemble of conditions. Multiple driving mechanisms, ionospheric conductivity profiles, and azimuthal modenumbers are considered. Runs are carried out using a two-and-a-half dimensional model of the inner magnetosphere. The model includes height-resolved conductivity and permittivity profiles for the ionosphere and plasmasphere, as well as a conducting ground and an insulating atmosphere. Results from this model show a novel dichotomy between the poloidal and toroidal Pc4 modes when driving is delivered through modulation of the ring current.The toroidal mode depends only weakly on the azimuthal modenumber. On the other hand, the poloidal mode becomes significantly stronger and more structured as the modenumber increases.