3-D Neutral Polar Wind Model

The high-latitude polar-cap region is an extremely dynamic region with many interesting phenomena associated with it, including: the ion and neutral polar winds, plasma patches, polar holes, etc. In order to better understand the coupling between the ionosphere and magnetosphere via the high-latitudes a new 3-D hydrodynamic model has been developed that solves the continuity, momentum, and simplified energy equations for five species (H⁺, O⁺, H_s, O_s, and e^-). The early studies conducted using a 1-D version of the model show a high outflow flux of neutral hydrogen in the polar cap, which is on the order of 10⁹ cm^-2s^-1 at 1000 km. The new 3-D model also shows a substantial outflow flux of neutral hydrogen, on the order of 10⁹ cm^-2s^-1, over the whole polar cap region. The neutral oxygen, on the other hand, has a relatively small, or negative, outflow flux. However, the new 3-D model shows that there is a substantial vertical flux at 1000 km, which is on the order of 10⁹ cm^-2s^-1. This suggests a continual flow of hydrogen ions and neutrals into the magnetosphere from the ionosphere, while the oxygen ions and neutrals need some form of energization, such as auroral energization, frictional heating, or some other source, in order to escape into the magnetosphere. With the inclusion of particle precipitation and magnetospheric electric fields, the 3-D model indicates an increased outflow of ions in areas of increased auroral heating, and that the neutrals produced in charge exchange reactions flow in all directions due to the convection electric fields.