How are the N+ Ions Affecting the Transport and Acceleration of
Ionospheric Outflowing Ions?
Abstract
Changes in the heavy ion composition in the terrestrial ionosphere and
magnetosphere can have significant impact on particle dynamics in the
Earth’s magnetosphere-ionosphere system. Most instruments flying in
space, such as MMS and Van Allen Probes, lack the possibility to
distinguish N+ from O+ due to their close masses. However, observations
of N+ both in the ionosphere and magnetosphere indicate that N+ is a
constant companion of O+ , especially during the storm time. Because N+
originates from the Earth’s ionosphere, we further develop the Polar
Wind Outflow Model (PWOM) to investigate the behavior and acceleration
mechanisms of heavy ions in Earth’s ionosphere. The PWOM solves the
particle dynamics of O+, H+ and He+ in the ionospheric outflow and the
modified PWOM can further simulate the behavior of N+ and N2+ in Earth’s
polar wind. The escape of heavy ions from the Earth atmosphere is
consequences of energization and transport mechanisms, including photo
ionization, electron precipitation, ion-electron-neutral chemistry and
collisions. The modified PWOM is coupled with a two-stream model of
superthermal electrons (GLobal airglow, or GLOW) to deal with attenuated
radiation, electron beam energy dissipation, and secondary electron
impact. In this study, we show that during various solar conditions, the
ion-electron-neutral densities in the ionospheric outflow show
significant difference when we consider N+ ions in the polar wind.
Furthermore, we will compare the simulation results of the modified PWOM
with observation data for validation.