1. Kinetic-scale electric field structures at plasma boundaries in the inner magnetosphere (including injection fronts) David Malaspina 1, John Wygant 2, Robert Ergun 1, Geoff Reeves 3, Ruth Skoug 3, and Brian Larsen 3 1 University of Colorado / LASP 2 University of Minnesota 3 Los Alamos National Laboratory RBSP SWG July, 2015 7/29/15

2. Kinetic-scale electric field structures double layers, phase space holes, kinetic-Alfvén wave field line resonances, whistlers with embedded structures 7/29/15 CRRES Waves Plot

3. REPT MagEIS HOPE FGM Vsc E waves B waves Case Study – injection front 23 June, 2013 scB Electron phase space holes 1 7/29/15

4. REPT MagEIS HOPE FGM Vsc E waves B waves Case study - Plasma Sheet Boundary 10 June, 2013 scA Kinetic Alfven Waves [Chaston+ 2014] 7/29/15

5. REPT MagEIS HOPE FGM Vsc E waves B waves Case study - Plasmapause 30 March, 2013 scB Very likely kinetic Alfven waves 7/29/15

6. REPT MagEIS HOPE FGM Vsc E waves B waves Case study – Lobe Crossing 14 November, 2012 scB Electron double layers similar to [Mozer+ 2013] 7/29/15

7. Nearly all boundaries show kinetic structures [dispersionless injections, PS boundary] Nearly all kinetic structures are near boundaries [dispersionless injections, PS boundary] +/- 60 min +/- 30 min +/-10 min +/- 2 min 92.2%88.3%82.6%73.0% % of 5-50 keV e- boundaries w/ broadband E-field activity +/- 60 min +/- 30 min +/-10 min +/- 2 min 91.0%79.5%61.4%31.2% % of broadband E-field activity near 5-50 keV e- boundaries Abrupt 5-50 keV electron flux increase = boundary 7/29/15 Boundaries [Malaspina+ 2015]

8. 7/29/15 Spatial Distribution Radial distances of outer radiation belt, ring current (3 < L < 7) Primarily dawn to dusk Concentrated pre-midnight A few on day side More at MLaT > 10° [Malaspina+ 2015] [Malaspina+ 2014] Highest amplitudes pre-midnight Highest amplitudes at MLaT > 10°

9. 7/29/15 Questions?

10. 7/29/15 Begin Extra I

11. Van Allen Probe B THEMIS-D Propagation delays match (!) Bz, e- flux, Broadband E-fields True for injections and plasma sheet boundary [Malaspina+ 2015] Kinetic structure source region travels with injection fronts Continually generated at injection fronts 7/29/15 Boundaries

12. Classifying Inner Magnetosphere Plasma Boundaries What distinguishes boundaries? Plasma sheet Injection Front Lobe Plasmapause - Other? What Properties Can We Evaluate? - Dispersion - Drift echoes - Change in dispersion across multiple s/c - Whistler waves - flux changes > 100 keV - MLaT - Dipolarization type (transient / permanent) - Other? Distinguishing between plasma sheet crossings and dispersionless injections is non-trivial 7/29/15

13. REPT MagEIS HOPE FGM Vsc E waves B waves Ideal dispersionless Injection (electrons) > 100 keV fluxes not discontinuous (magnetic topology minimally changed) < 100 keV sudden enhancement (some dispersion) ‘Transient’ dipolarization Whistler waves near fce/2 signal Earthward flow (instability driven by μ-conservation) Drift echoes are good Injection indication Near-equatorial MLaT EM broadband power 7/29/15

14. REPT MagEIS HOPE FGM Vsc E waves B waves Ideal Plasma Sheet Boundary (electrons) > 100 keV fluxes Discontinuous No dipolarization at all (spacecraft moves through plasma boundary, not the other way around) Radiation belts no longer observed, looks more like PS 1 – 50 keV only (e- and H+) MLaT > 12 Minimal or no whistler waves near fce/2 ES broadband power (alone) indicates boundary crossing 7/29/15

15. REPT MagEIS HOPE FGM Vsc E waves B waves Plasma Sheet Boundary (electrons) > 100 keV fluxes Discontinuous ‘Permanent’ stair-step dipolarizations Radiation belts no longer observed, looks more like PS 1 – 50 keV only (e- and H+) MLaT > 12 Minimal or no whistler waves near fce/2 No dispersion whatsoever 7/29/15

16. REPT MagEIS HOPE FGM Vsc E waves B waves Plasmapause (electrons) > 100 keV fluxes continuous No dipolarization at all (some ULF waves) Sudden increase in observed e- flux (must be removed Inside PP ?) Broadband waves, but strong electromagnetic component Clear density shelf 7/29/15

17. REPT MagEIS HOPE FGM Vsc E waves B waves Case study – Lobe Crossing 14 November, 2012 scB Electron flux dropout over wide range of energies Ions drop out same energies at the same time B variations strong during Dropouts (|B| increases) Very strong broad-band wave activity Interpretations of this event: [Hwang+ 2015, Dixon+ 2015] 7/29/15

18. Classifying Inner Magnetosphere Plasma Boundaries What distinguishes boundaries? Plasma sheet Injection Front Lobe Plasmapause - Other? What Properties Can We Evaluate? - Dispersion - Drift echoes - Change in dispersion across multiple s/c - Whistler waves - flux changes > 100 keV - MLaT - Dipolarization type (transient / permanent) - Other? Distinguishing between plasma sheet crossings and dispersionless injections is non-trivial 7/29/15

19. Begin Extra II

20. Plasmapaus e LobeInjection Front Plasma Sheet Drift Echoes No MaybeNo Particle Energy Dispersion No High energy first Low energy first (nose) Density gradient LargeSmall MLATanyHigh most likely Low most likely High most likely DipolarizationNoStep-likeTransientStep-like Whistler onsetMaybe YesMaybe (weak) > 100 keV flux changes MaybeYesNo (usually)Yes Summary of Boundary Properties Are these good indicators? What else should we be using for identification? 7/29/15

21. Ambiguities Dai et al. 2015 MeV e- injection April 26, 2013, RB-A Very ambiguous in single-spacecraft data But: Timing of injection matches on multiple s/c (some dispersed, some not) e- flux could be boundary (too abrupt) H+ shows echoes Dipolarizations Unclear (stair-step?) Almost no whistler power MLaT near 12 Note next boundary unlikely to be injection 7/29/15