[1] It is widely accepted that the ionosphere is an important source of ions in the magnetosphere and until recently this population has largely been neglected from many global simulations. In this study, a causally regulated cusp O + outflow is added to the multifluid version of the Lyon-Fedder-Mobarry (LFM) global simulation. The cusp outflow algorithm uses empirical relationships to regulate the outflow flux with further conditioning to isolate the outflow spatially to a dynamic cusp. The impact cusp O + outflow has on the magnetosphere-ionosphere (MI) system is investigated for a moderate storm on 31 August 2005. It is found the MI system response depends upon the specification of the outflow velocity and temperature. More energetic outflow tends to flow downtail whilst colder, slower outflow fills the inner magnetosphere. High O + densities in the inner magnetosphere can increase the strength of the ring current, reducing Dst and inflating the magnetosphere. This effect is mostly found for the less energetic outflow specification. O + outflow is found to reduce the access of solar wind ions to the inner magnetosphere, which, through the MI coupling in LFM reduces the precipitating electron power, conductance and field-aligned currents. The effect outflow has on the cross polar cap potential (CPCP) depends upon two competing factors. The reduction in Region I currents when outflow is present appears to increase the CPCP whilst the inflation of the magnetosphere due to an enhanced ring current decreases the CPCP.

[1] A multifluid version of the Lyon-Fedder-Mobarry global simulation model has been used to investigate the effects of outflowing ionospheric O + on the magnetosphereionosphere system. To quantify these effects, we specify the number density, upward parallel velocity, and temperature of the O + outflow in a limited area of the low-altitude simulation boundary representing the projection of cusp, cleft, and low-latitude boundary layer. A baseline simulation without O + outflow is compared with simulations with a range of fluxes and initial velocities. In the cases with high fluxes, it is shown that the configuration of the magnetosphere is dramatically changed. In particular, the cross-polar cap potential is reduced, the polar cap area is increased, and the nightside reconnection line is moved earthward. Furthermore, in one case, the O + outflow leads to the onset of a second substorm not seen in the other simulation runs.

Electron acceleration by dispersive scale Alfvén waves at Jupiter is investigated using a Gyrofluid‐Kinetic‐Electron model. Specifically, the simulations consider the propagation of an Alfvén wave perturbation from the center of the Io plasma torus to high‐latitude regions that are consistent with recent Juno satellite observations (e.g., Allegrini et al., 2017, https://doi.org/10.1002/2017GL073180; Mauk, et al., 2017a, https://doi.org/10.1038/nature23648; Mauk, et al., 2017b, https://doi.org/10.1002/2016GL072286; Szalay et al., 2018, https://doi.org/10.1029/2018JE005752). As in those observations, the energized electron spectra is broadband in nature and the majority of the energization is under the interaction of inertial Alfvén waves at high latitudes. The extent of the energization associated with these waves is proportional to both the magnitude of the wave perturbation and the ratio of the torus to high‐latitude density.

A new 2‐D self‐consistent hybrid gyrofluid‐kinetic electron model in dipolar coordinates is presented and used to simulate dispersive‐scale Alfvén wave pulse propagation from the equator to the ionosphere along an L = 10 magnetic field line. The model is an extension of the hybrid MHD‐kinetic electron model that incorporates ion Larmor radius corrections via the kinetic fluid model of Cheng and Johnson (1999). It is found that consideration of a realistic ion to electron temperature ratio decreases the propagation time of the wave from the plasma sheet to the ionosphere by several seconds relative to a ρi=0 case (which also implies shorter timing for a substorm onset signal) and leads to significant dispersion of wave energy perpendicular to the ambient magnetic field. Additionally, ion temperature effects reduce the parallel current and electron energization all along the field line for the same magnitude perpendicular electric field perturbation.