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

Geospace Gap: Issues, Strategy, Progress A 1-2 R E 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 +. The mediating transport processes occur on spatial scales smaller than the grid sizes of the LFM and TING/TIEGCM global Issues Challenge: Develop models for subgrid processes using dependent, large-scale variables available from the global models as causal drivers.

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

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

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

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

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

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

Geospace Gap: Issues, Strategy, Progress “Knight” Dissipation 1.Current-voltage relation in regions of downward field-aligned current † ; 2.Collisionless Joule dissipation and electron energization in Alfvénic regions – mainly cusp and auroral BPS regions; 3.Ion transport in regions 1 and 3; 4.Ion outflow model in the polar cap (polar wind). Keiling et al. ‘03 Lennartsson et al. ‘04

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

Geospace Gap: Issues, Strategy, Progress Alfvénic Electron Energization Energy Flux Mean Energy J || mW/m 2 keV  A/m 2 Alfvén Poynting Flux, mW/m 2 Chaston et al. ‘03 Empirical approach? LFM’s large grid annihilates most of the relevant Alfvénic power near its inner boundary

Geospace Gap: Issues, Strategy, Progress Empirical approach to ionospheric outflow r = F O+ = 2.14x10 7 ·S || r = Strangeway et al. ‘05

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

Geospace Gap: Issues, Strategy, Progress Greatest change in lobes and inner magnetosphere Magnetopause appears more variable O + / m 2 -s Northern Outflow Equatorial plane Global Effects of O+ Outflow IMF With outflow No outflow

Geospace Gap: Issues, Strategy, Progress Where does the mass go? T > 1 keV  > 0.5 n < 0.2/cm 3 P < 0.01 nPa Ionospheric effects?

Geospace Gap: Issues, Strategy, Progress

Pathways To Upwelling Strangeway et al. ‘05

Geospace Gap: Issues, Strategy, Progress

Where does the mass go? T > 1 keV  > 0.5 n < 0.2/cm 3 P < 0.01 nPa Ionospheric effects?