Issues A 2 R E spatial “gap” exists between the upper boundary of TING and 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 is included in global 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 +. M-I Coupling Physics: Issues, Strategy, Progress William Lotko, John Gagne, David Murr, John Lyon, Paul Melanson Alfvénic Electron Energization Energization Regions Ionospheric Parameters (issues!) Where does the mass go? Percent Change in Mass Density The mediating transport processes occur on spatial scales smaller than the grid sizes of the LFM and TING/TIEGCM global models. Challenge: Develop models for subgrid processes using the dependent, large-scale variables available from the global models as causal drivers. Strategy (four transport models) 1.Current-voltage relation in regions of downward field-aligned current; 2.Electron energization and collisionless Joule dissipation in Alfvénic regions – mainly cusp and the auroral BPS regions; 3.Ion transport in regions 1 and 2 above; and 4.Ion outflow in the polar cap, essentially a polar wind. Progress Reconciled E  mapping and collisionless Joule dissipation with Knight relation in LFM Developed and implemented empirical outflow model – O+ flux indexed to EM power and electron precipitation flowing into gap from LFM (S ||  F e|| ) Initiated validation of LFM Poynting fluxes with global statistical results from DE, Astrid, Polar and Iridium/SuperDARN events (Gagne thesis + student poster by Melanson) Evans et al., ‘77 Paschmann et al., ‘03 Conductivity Modifications Dartmouth founded 1769 Energy Flux Mean Energy J || mW/m 2 keV  A/m 2 Alfvén Poynting Flux, mW/m 2 Alfvénic Ion Energization “Knight” Dissipation EM Power In  Ions Out Priorities Implement multifluid LFM (!) Implement CMW (2005) current-voltage relation in downward currents Include electron exodus from ionosphere  conductivity depletion Accommodate upward electron energy flux into LFM Advance empirical outflow model Develop model for particle energization in Alfvénic regions (scale issues!) Need to explore frequency dependence of fluctuation spectrum at LFM inner boundary Parallel transport model for gap region (long term) Chaston et al. ‘03 Keiling et al. ‘03 Lennartsson et al. ‘04 Zheng et al. ‘05 Equatorial plane Global Effects of O + Outflow IMF Empirical “Causal” Relations Strangeway et al. ‘05 r = F O+ = 2.14x10 7 ·S || r = :00 UT IMF O + / m 2 -s 68 Northern Outflow With outflow No outflow T > 1 keV  > 0.5 n < 0.2/cm 3 P < 0.01 nPa Chaston, C.C., J. W. Bonnell, C. W. Carlson, J. P. McFadden, R. E. Ergun, and R. J. Strangeway, Properties of small-scale Alfvén waves and accelerated electrons from FAST, J. Geophys. Res. 108(A4), 8003, doi: /2002JA009420, 2003  Cran-McGreehin, A.P., and A.N. Wright, Current-voltage relationship in downward field-aligned current region, J. Geophys. Res. 110, A10S10, doi: /2004JA010870, 2005  Evans, D.S., N. Maynard, J. Trøim, T. Jacobsen, and A. Egeland, A., Auroral vector electric field and particle comparisons 2. Electrodynamics of an arc, J. Geophys. Res. 82(16), 2235–2249, 1977  Keiling, A., J.R. Wygant, C.A. Cattell, F.S. Mozer, and C.T. Russell, The global morphology of wave Poynting flux: Powering the aurora, Science 299, , 2003  Lennartsson, O.W., and H.L. Collin, W.K. Peterson, Solar wind control of Earth’s H+ and O+ outflow rates in the 15-eV to 33-keV energy range, J. Geophys. Res. 109, A12212, doi: /2004JA010690, 2004  Paschmann, G., S. Haaland and R. Treumann, Auroral Plasma Physics, Kluwer Academic Publishers, Boston/Dordrecht/London, 2003  Strangeway, R.J., R. E. Ergun, Y.-J. Su, C. W. Carlson, and R. C. Elphic, Factors controlling ionospheric outflows as observed at intermediate altitudes, J. Geophys. Res. 110, A03221, doi: /2004JA010829, 2005  Zheng, Y., T.E. Moore, F.S. Mozer, C.T. Russell and R.J. Strangeway, Polar study of ionospheric ion outflow versus energy input, J. Geophys. Res. 110, A07210, doi: /2004JA010995, 2005 Cosponsored by NASA SECTP The “Gap”