1. Field-aligned currents associated with interchange injections at Saturn Anna DeJong, James Burch and Roberto Livi Southwest Research Institute

2. Interchange injections Burch et al. 2005

3. Ions and electrons during interchange injections UT Temperature increase Density decreases Electrons Ions

4. Field-aligned and trapped electrons during injections Trapped = 70°-110° pitch angles Field-aligned = 0°-20° and 160°-180° pitch angles DeJong et al. 2010 Fluxes peak in the 10-100 eV range

5. Statistics of Average Flux for 10-100 eV SLS3 DeJong 2010 More injections close to 330° SLS3? But others have not seen SLS3 dependence in injection location.

6. Local Time Asymmetry LT DeJong 2011 10-100 eV electrons penetrate deeper on nightside. Elliptical rotation (Thomsen this meeting) Stronger injections on the nightside due to larger pressure differences (DeJong 2011 GRL) Trapped Field-aligned Carbary 2009 and Paranicas 2010 see similar local time differences in high energy electrons.

7. Currents associated with injections Field-aligned currents on the edges of the injection drive the flux tube inward. From Rymer et al. 2009

8. FACs using Magnetometer Data ΔB ϕ ΔB r ΔB FA FAC UT L ≈ 6.7 LT ≈17.5 SLS3 ≈ 100L ≈ 7.1 LT ≈2.3 SLS3 ≈172

9. FACs using ELS FAC FAC ELS (>10eV) FAC ELS (>10ev) FAC Mag Anode 4 UT L ≈ 6.7 LT ≈17.5 SLS3 ≈ 100L ≈ 7.1 LT ≈2.3 SLS3 ≈172

10. Conclusions Calculations of field-aligned current using ELS give similar results to the FACs calculated using the Mag data. Not only are the cool electrons (10-100eV) related to injections they carry most of the current. Schippers (This meeting) found that inside 9 Rs electrons less than 100 eV carry the current.

11. What’s next? Find more events with good pitch angle coverage. Account for spacecraft potential. Compare the FAC dayside and nightside FACs in order to further investigate the penetration of electrons deeper into the inner magnetosphere on the nightside (DeJong 2010) Calculate velocities and flux tube content using the ion moments.