Storm-Time Ion Velocity Distributions in the Generalized Polar Wind

At high latitudes the plasma escapes along geomagnetic field lines from the high pressure ionosphere into the low pressure magnetosphere. As the plasma flows upwards, it goes through transitions from collision-dominated to collisionless conditions, from subsonic to supersonic flows, and form O+-dominated to H+-dominated compositions. Meanwhile, the plasma E×B drifts across the cusp, the polar cap, the auroral oval, and the subauroral regions, where it is exposed to different intensities of physical factors, e.g. wave-particle interactions, magnetospheric particle precipitation, and centrifugal acceleration. Moreover, during geomagnetic activity these effects vary significantly with time. We used a 3-D generalized polar wind (GPW) model in order to simulate the plasma behavior during a geomagnetic storm. The northern polar region was modeled with 1000 convecting trajectories and about one billion simulation particles. Special attention was given to investigating the interplay between the different mechanisms regarding their influence on the velocity distributions of the O+ and H+ ions at different altitudes, latitudes and storm phases. We present the evolution of the ion velocity distributions and how they depend on space and time. The results will be compared with previous results from simpler models.