Science Case for a Global Ionospheric Outflow Mission

Abstract

400-character short descriptionA mission is needed to observe the spatial pattern of ionospheric outflow and its relation to geospace driving conditions. Initial cost estimates suggest that such a mission could be achieved within the constraints of the Small Explorer mission line with minimal instrumentation (i.e., only low-energy ions), or at the Mid-sized Explorer line with additional contextual measurements. Synopsis of High-Level RecommendationsIonospheric outflow supplies the magnetosphere with nearly all of the heavy ions observed there, as well as a significant fraction of the proton density. While much is known about upflow and outflow energization processes, the full spatial pattern of outflow is only known statistically or through numerical modeling. Because of the dominant role of heavy ions in several key physical processes, this ambiguity of the full outflow pattern leads to significant uncertainty in understanding geospace dynamics, especially during storm intervals. That is, global models do not always accurately reproduce intense space storms because the global dynamics and amount of ionospheric outflow are only poorly characterized. It is recommended that a mission be flown to observe ionospheric outflow from several platforms, allowing for a reasonable reconstruction of the full outflow pattern on an orbital cadence. Initial cost estimates suggest that such a mission could be achieved within the constraints of the Small Explorer mission line with minimal instrumentation (i.e., only a low-energy ion spectrometer), or at the Mid-sized Explorer line with additional contextual instrumentation on each satellite. This mission should:• Reveal the global structure of ionospheric outflow • Relate outflow patterns to geomagnetic activity level • Determine the spatial and temporal nature of outflow composition An ancillary modeling task that should be associated with this mission is mapping the outflow through the magnetosphere and connecting the outflow patterns to any available relevant measurements elsewhere in geospace.

Reconstruction Analysis of Global Ionospheric Outflow Patterns

“…Since they are taken over some period of time (a few minutes), it does not allow the determination of the temporal and spatial variation of ion outflow in response to variable solar wind and interplanetary magnetic field (IMF) conditions during the progression of geomagnetic storms. As argued by Liemohn et al (2022), it is important to understand event-specific spatial and temporal variability in order to quantify the impact of outflow on the geospace system. The community lacks this capability with respect to the structure of outflow for any particular disturbed time.…”

“…As argued by Liemohn et al. (2022), it is important to understand event‐specific spatial and temporal variability in order to quantify the impact of outflow on the geospace system. The community lacks this capability with respect to the structure of outflow for any particular disturbed time.…”