# Presentation: 409762

## Global Ionospheric Ion Outflow (During Substorm Recovery)

- Stephen A. Fuselier
*Lockheed Martin Advanced Technology Center*

## Outline

- Global Ionosphere Outflow – What we need
- Imaging ion outflow using neutral atoms and in situ measurements
- Local time distribution
- Total ionospheric outflow

## Determining Total Ionospheric Outflow

- Need 3 input quantities
- Ion outflow intensity
- In situ measurements – instantaneous intensity at a specific MLT – or use electron precipitation as a proxy
- Ion outflow latitudinal range
- In situ measurements – “instantaneous” latitudinal range at a specific MLT – or use electron precipitation as a proxy
- Ion outflow MLT range
- In situ measurements – “statistical average” MLT range (typically >6 months of data)
**Imaging – “instantaneous” MLT range**

## Outflow Over a 2.5 Hour Time Period

- 27 Nov 2000
- ion outflow

- Use DMSP passes to determine latitudinal extent of the outflow and the total outflow at a specific local time
- Use IMAGE/LENA to determine the local time extent

## Outflow Is Correlated With Auroral Activity

## Ray Tracing Used To Determine Local Time Extent

## Local Time Compared To AE

- _As AE decreases:_
-   MLT extent of outflow varies
-   dramatically
-   MLT location of outflow is
-   constant except near the
-   end of the interval

## DMSP Electrons Used To Determine Latitudinal Extent and Outflow Flux

- Strangeway et al 2005
- correlate outflow with
- precipitating electron density

## Total Outflow – MLT, Lat Extent and Flux

- DMSP Electrons
-   provide ion outflow
-   flux
-   assume constant
-   over outflow MLT
-   observed by IMAGE
-   Compute the outflow
-   in a latitudinal “strip”
-   and add up the strips

## Results:  Ion Outflow Dependence On AE

- Outflow decreases with time, but so does AE – Outflow
-  is strongly correlated with AE on a substorm timescale

## Future Work

- 133 Outflow Intervals from IMAGE
- ~34 are “substorm growth phase”
- ~78 are “substorm recovery phase”
- Determine if the AE correlation persists for both growth and recovery

## Backup

## Ion Outflow Change Associated With Change in Local Time of Outflow

## Three Auroral Regions & Three Outflow Regions

- Carlson et al. 1998; Auroral Plasma Physics, Kluwer, 2003

## Ion Outflow Regions: An Example

- Upward Current
- Energetic electrons
- >1 keV
- Weak outflow, narrow conics
- “middle of the auroral oval”
- Alfven wave region
- Intense low energy electrons
- Intense outflow, broad conics
- “Thin region” at the poleward edge of the auroral oval

- PA    flux    PA    flux

- ions      electrons

- ion outflow
- intensity

- in Auroral Plasma Physics, Kluwer, 2003

## Outflow: Local Time Occurrence

- Outflow and wave events have broad MLT distribution
- Peak on the dawnside
- Second peak near midnight
- Broad latitudinal distribution
- Artifact of the statistical sampling?

- Norqvist et al. 1998
- ion outflow: high Kp

- Øieroset et al. 1999
- Ion outflow: high AE

- Chaston et al., 2003 “Alfven Wave Events”

## Imaging Ion Outflow - Conics

- Energetic Neutral atom (ENA) imaging of outflow favors energetic ion conics
- Flux peaks off the magnetic field direction
- Imaging favors outflow from Alfvenic wave acceleration regions
- Large pitch angle extent
- Most intense outflow
- Imaging favors intense events
- Imager has limited dynamic range