Geospace Gap: Issues, Strategy, Progress

1. Geospace Gap:Issues, Strategy, Progress Cosponsored by NASA HTP Lotko - Gap region introduction Lotko - Outflow simulations Melanson - LFM/SuperDARN/Iridium comparisons Murr - GEM Challenge on MI coupling Lyon - Development of Multifluid LFM Wang - Development of CMIT and TING/TIEGCM Merkin - Proposed studies using multifluid LFM/RCM Lotko - Proposed studies using multifluid CMIT

2. Geospace Gap:Issues, Strategy, Progress • A 1-2 RE spatial “gap” exists between the upper boundary of TING (or TIEGCM) and the lower boundary of (LFM). • The gap is a primary site of plasma transport where electromagnetic power is converted into field-aligned electrons, ion outflows and heat. • Modifications of the ionospheric conductivity by the electron precipitation are included in global MHD models via the “Knight relation”; but other crucial physics is missing: • Collisionless dissipation in the gap region; • Heat flux carried by upward accelerated electrons; • Conductivity depletion in downward current regions; • Ion parallel transport outflowing ions, esp. O+. Issues The mediating transport processes occur on spatial scales smaller than the grid sizes of the LFM and TING/TIEGCM global Challenge: Develop models for subgrid processes using dependent, large-scale variables available from the global models as causal drivers.

3. The Geospace:Issues, Strategy, Progress Foster et al. ‘05 Plasma Redistribution

4. The Geospace:Issues, Strategy, Progress Ring Current & Plasma Sheet Composition Nose et al. ‘05

5. The Geospace:Issues, Strategy, Progress Simulated O+/H+ Outflow into Magnetosphere Winglee et al. ‘02

6. Geospace Gap:Issues, Strategy, Progress Paschmann et al., ‘03

7. Geospace Gap:Issues, Strategy, Progress Evans et al., ‘77 Conductivity Modifications

8. Geospace Gap:Issues, Strategy, Progress Simulated Time Variation of Ne Profile in Downward Current Region Cavity formation on bottomside is more efficient than at F-region peak  Bottomside gradient steepens Doe et al. ‘95

9. Geospace Gap:Issues, Strategy, Progress “Knight” Dissipation • Current-voltage relation in regions of downward field-aligned current†; • Collisionless Joule dissipation and electron energization in Alfvénic regions – mainly cusp and auroral BPS regions; • Ion transport in regions 1 and 3; • Ion outflow model in the polar cap (polar wind). Lennartsson et al. ‘04 Keiling et al. ‘03

10. Geospace Gap:Issues, Strategy, Progress Zheng et al. ‘05 Cusp & Auroral-Polar Cap Boundary Region EM Power IN  Ions OUT

11. Geospace Gap:Issues, Strategy, Progress Energy Flux mW/m2 Mean Energy keV J|| A/m2 Alfvén Poynting Flux, mW/m2 Chaston et al. ‘03 Alfvénic Electron Energization Empirical approach? LFM’s large grid annihilates most of the relevant Alfvénic power near its inner boundary

12. Geospace Gap:Issues, Strategy, Progress FO+ = 2.14x107·S||1.265 Strangeway et al. ‘05 r = 0.721 r = 0.755 Empirical approach to ionospheric outflow

13. Geospace Gap:Issues, Strategy, Progress OUTFLOW ALGORITHM Outflows in cusp and auroral polar cap boundary

14. Geospace Gap:Issues, Strategy, Progress IMF Global Effects of O+ Outflow Equatorial plane 0 2 4 1010 O+ / m2-s 6 Northern Outflow 10 No outflow With outflow • Greatest change in lobes and inner magnetosphere • Magnetopause appears more variable 8

15. Geospace Gap:Issues, Strategy, Progress T > 1 keV  > 0.5 n < 0.2/cm3 P < 0.01 nPa Where does the mass go? Ionospheric effects?

16. Geospace Gap:Issues, Strategy, Progress

17. Geospace Gap:Issues, Strategy, Progress Pathways To Upwelling Strangeway et al. ‘05

18. Geospace Gap:Issues, Strategy, Progress

19. Geospace Gap:Issues, Strategy, Progress T > 1 keV  > 0.5 n < 0.2/cm3 P < 0.01 nPa Where does the mass go? Ionospheric effects?