1. Localized Thermospheric Energy Deposition Observed by DMSP Spacecraft D. J. Knipp 1,2, 1 Unversity of Colorado, Boulder, CO, USA 2 High Altitude Observatory, NCAR Boulder, CO, USA with contributions from: Y. Deng, L. Kilcommons, W. Li, J.Raeder, G. Crowley Data provided by E. Sutton, F Rich, G Wilson B Anderson

2. Outline Dayside Energy Deposition Background – Influence of IMF B y on Poynting flux – Influence of low energy electrons Local Combined influence of Poynting flux and Particles (outside of standard indices) Future work – Global Combined Poynting Flux and Particle Flux Observations Models

3. Rentz 2009 and Forster, 2010 CHAMP Cusp Neutral Density Enhancement (2002-2005) North South

4. Poynting Flux -Neutral Density Comparisons Southern Hemisphere Nov 2001- Feb 2002 Slow Flow CMEs & Transients High Speed Flow Poynting Flux mW/m 2 CHAMP Neutral Density X 10 --11 kg/m 3

5. Ionosphere-Thermosphere Energy Dissipation Courtesy of Jeff Thayer, CU ~ 75% ~ 25%

6. Poynting Vector and Particles from Defense Meteorological Satellite Program S/C DMSP instruments sense Electric and Magnetic Fields Y X Z Spacecraft track e-e- e-e-

7. DMSP Poynting Flux Changing IMF By Knipp et al, GRL, 2011 Poynting flux exceeds that reported for intense substorms within a superstorm

8. DMSP Poynting Flux Joule Heating from AMIE Neutral Density from TIEGCM Crowley et al., 2010 Localized Energy Associated with Neutral Density Upheaval TIEGCM Neutral Density compared to CHAMP satellite Flank Reconnection Contributes to Neutral Density Enhancement IMF By is large Northern Hemisphere Example--Cont

9. IMF By + Nov 7 2004 Li et al (2011) Northern Hemisphere Southern Hemisphere Flank Reconnection Contributes Poynting Flux when IMF By is large Northern Hemisphere Example 2

10. By-N By+SBy+N By- S 2000-2005 |By| > 10 Bz < 0 DMSP Extreme Poynting Flux mW/m 2 Each dot represents the maximum value of the of the pass Colored dots show Poynting flux in excess of 75 mW/m 2 ~ 1500 passes are shown

11. By-N By+S 2000-2005By+N By-S DMSP Extreme Poynting Flux |By| > 10 Bz >0 mW/m 2 Each dot represents the maximum value of the of the pass Colored dots show Poynting flux in excess of 75 mW/m 2 ~ 1500 passes are shown

12. Strangeway et al., 2005 Field Aligned Currents in the Cusp

13. -10 nT < Bz< -5 nT |By| < 5 nT -5 nT < Bz< 0 nT |By| < 5 nT Poynting Flux mW/m 2 DMSP Poynting Flux B z < 0 Poynting Flux mW/m 2 Fewer extreme values; Maybe associated with flow channel persistence

14. Effects of Large East West IMF on the Cusp OPENGGCM MHD models and DMSP data show that east-west IMF promotes flank and or lobe merging that maps to cusp regions Movement of the open field lines resulting from this reconnection produces a pair of neighboring opposite FACs in the dayside ionosphere cusp region Closure of the FACs results in Joule heating in the ionospheric flow channel between the currents FAC locations are mainly controlled by the IMF clock angle. High speed solar wind flow enhances the Joule heating Joule heating in narrow, elongated channels may exceed 170mW/m 2 When IMF By > 10 nT typical values of Poynting flux ~ 75mW/m 2

15. DMSP Medium and Low Energy Particles (2004 Location of maximum energy deposition during each polar pass electrons 962-679 eV 462-317 eV 213-145 eV 100- 68 eV 46-32 eV 5-10nT By + Bz- 5-10nT By – Bz - South North Particles with energies < 300 eV often ignored Soft Particle Effects in Cusp

16. Difference in the thermosphere 3 hours after adding in the Poynting flux ( 75 mW/m 2 ) At 400 km: 29% increase in T n At 400 km: rise and fall of neutral mass GTM simulation by Deng et al 2011 At 400 km: 31% increase in ρ n At 200 km: 7% decrease in ρ n Poynting Flux-Density Relations in the Cusp

17. Difference in the thermosphere 3 hours after adding in the soft particle flux (100 eV, 2 mW/m 2 ) GITM simulation (Deng et al. 2011) At 400 km: 35% increase in ρ n At 200 km: 2% decrease in ρ n Soft Particle Effects in Cusp

18. At 400 km: 50% increase in ρ n At 200 km: 4% decrease in ρ n Poynting Flux and Soft Particle Effects in Cusp Difference in the thermosphere 3 hours after adding in Poynting Flux and the soft particle flux (PF = 75 mW/m 2, 2keV 0.3 mW/m 2, 100 eV, 2 mW/m 2 ) GITM simulation (Deng et al. 2011)

19. Poynting Flux and Soft Particle Effects in Cusp Deng et al. 2011 50% increase is < 31%+35%+5%, because the Poynting Flux and Particle Precipitation Effects are not Co-located ~50% neutral density enhancement is consistent with CHAMP obs

20. Global Currents Magnetosphere-Ionosphere Thermosphere Cusp Energy NorthSouth

21. Summary and Conclusions Persistent near cusp CHAMP neutral density enhancement – Cusp Enhanced Poynting Flux (order of magnitude) IMF By, solar wind flow speed & variability, pressure – Cusp Soft Particle Precipitation IMF, solar wind flow speed & variability, pressure These are NOT well described by geomagnetic indices Global observations and modeling are key to future progress