Tail – Inner Magnetosphere Interactions

1. Tail – Inner Magnetosphere Interactions Lauren Blum University of Colorado GEM Student Tutorial, June 2012

2. What is the Magnetotail? Why is it so important? Lauren Blum, GEM Student Tutorial, June 2012

3. What: Lauren Blum, GEM Student Tutorial, June 2012

4. Lauren Blum, GEM Student Tutorial, June 2012

5. Tail lobes: • nearly parallel, open magnetic field lines • field lines likely ultimately connect to the solar wind, somewhere far downstream from Earth • extremely low density ( ~.01 per cc ), magnetic pressure dominates Lauren Blum, GEM Student Tutorial, June 2012

6. Plasma Sheet • layer of weaker magnetic field and denser plasma (~.1-1 per cc) • centered on the equator and typically 2-6 Earth radii thick • composed of H+, He+, He++, and O+ • composition varies with geomagnetic activity, ion species indicative of source (ionospheric vs. solar wind) Lauren Blum, GEM Student Tutorial, June 2012

7. Current Sheet • cross-tail current flowing across the plasma sheet from dawn to dusk McComas et al. 1986 Lauren Blum, GEM Student Tutorial, June 2012

8. Tail Dynamics Lauren Blum, GEM Student Tutorial, June 2012

9. Tail Dynamics Lauren Blum, GEM Student Tutorial, June 2012

10. The Substorm Debate Lauren Blum, GEM Student Tutorial, June 2012

11. Tail – Inner Magnetosphere Connection • The tail is the energy and plasma source for the inner magnetosphere! • Substorm injections (aurora, ionospheric currents, etc) • Plasma Sheet is the source for the Ring Current • Linked to the Radiation Belts through this as well Lauren Blum, GEM Student Tutorial, June 2012

12. Influence on the Ring Current • Plasma sheet controls both composition and strength of ring current Nosé et al., 2009 Lavraud and Jordanova 2007 Lauren Blum, GEM Student Tutorial, June 2012

13. Influence on the Radiation Belts • Anisotropies in ring current electrons and protons can generate EMIC and whistler-mode waves, respectively • Wave-particle interactions can accelerate and scatter electrons -> radiation belt enhancements and depletions Summers et al. 1998 Lauren Blum, GEM Student Tutorial, June 2012

14. Tail-Inner Magnetosphere Measurements Geosynchronous Satellites THEMIS Shue et al. 2000 L-90, LANL 1990-095; L-91, LANL 1991-080; L-94, LANL 1994-084; GO-8, GOES 8; GO-9, GOES 9; T-401, Telstar 401; GE, Geotail; I-1, Interball 1; GM-4, GMS 4 Lauren Blum, GEM Student Tutorial, June 2012

15. Summary • Magnetotail: a highly dynamic region of the magnetosphere • Extends up to ~200 RE from the Earth • Energy stored in the stretched magnetic field – released via dipolarization, trapped plasma energization, and plasmoid ejection • Energy deposited in ring current and aurora via enhanced convection, substorms, and storms • Tail the energy and particle source for the inner magnetosphere • Influential in ring current, radiation belt, plasmaspheric, and ionospheric dynamics Lauren Blum, GEM Student Tutorial, June 2012

16. backup

17. What: • extended magnetotail results from the energy stored in the planet's magnetic field. At times this energy is released and the magnetic field becomes temporarily more dipole-like. As it does so that stored energy goes to energize plasma trapped on the involved magnetic field lines. Some of that plasma is driven tailward and into the distant solar wind. The rest is injected into the inner magnetosphere where it results in the aurora and the ring current plasma population Lauren Blum, GEM Student Tutorial, June 2012

18. Tail Dynamics 1. 2. Lauren Blum, GEM Student Tutorial, June 2012

19. Tail Dynamics 3. Lauren Blum, GEM Student Tutorial, June 2012