1. Atmosphere-Ionosphere Wave Coupling as Revealed in Swarm Plasma Densities and Drifts
Jeffrey M. Forbes
Department of Aerospace Engineering Sciences, University of Colorado
Stephan Buchert
Swedish Institute of Space Physics, University of Uppsala
David Knudsen and Jonathan Burchill
Department of Physics and Astronomy, University of Calgary
Atmosphere-ionosphere coupling mechanisms
Swarm-CHAMP comparisons
Variability of Swarm electron densities and attributions
Conclusions

2. Atmosphere-Ionosphere Coupling by Tides & Planetary Waves
Pole
Equator
Ionosphere-Thermosphere (IT)
Lower Atmosphere
Mesopause
0 km
500 km
Tides
Atmosphere-Ionosphere Coupling by Tides & Planetary Waves
plasma
flow
tidal penetration B E
tidal
dynamo
dissipation O3
H2O
Atmosphere-Space
Interaction Region
PWs
equatorial anomaly
composition changes
wind transport
Wave Spectrum
Gravity Waves
min
10’s – 1000 km
Planetary Waves
2-20 days
1000’s to 10,000 km
Tides
24, 12, 8 hours
1000’s to 10,000 km
The primary mechanism through which energy and momentum are transferred from the lower atmosphere to the upper atmosphere and ionosphere is through the generation and propagation of waves.

3. Swarm-CHAMP comparisons – 1
Monthly-mean total [e-] from Langmuir Probe (LP) measurements
Plotted in geographic coordinates
Swarm: Dec 2013
F10.7 = 148
CHAMP: 1-31 Dec 2006
F10.7 = 91
Dec 2005-May 2006, Dec 2013-May 2014 only periods where Swarm-CHAMP local times and months coincide.

4. Swarm-CHAMP Comparisons – 2
% residuals from longitude mean
Moderates differences in F10.7
Moderates latitude differences
Temporal variability of the tide-PW spectrum (days, weeks, seasonal, inter-annual)
Longitude variability of the tide-PW spectrum
Wave-wave interactions within the tide-PW spectrum
Solar modulation of ionospheric conductivity in the dynamo region
Global magnetic field configuration
Complexity due to Atmosphere-Ionosphere Coupling by Tides and Planetary Waves (PW)

5. Day-to-Day Variability of Swarm Electron Density Residuals – Ionospheric “Weather”

6. Quantifying the Variability: Periodicities in Time and Longitude
distinct peaks
eastward- and westward-propagating waves
significant differences in latitude and local time

7. Quantifying the Variability:
Separating Responses due to Forcing from “Above” and “Below”
Kp and F10.7 spectra for Dec 2013-May 2014
Kp peaks near 6d and 10d also characteristic of PW
Kp peaks possibly connected with recurrent geomagnetic activity due to high-speed streams and coronal hole distribution.

8. closely related to zonal E-field
Plasma Drifts from EFI add Additional Guidance and Constraints Concerning Atmosphere-Ionosphere Coupling by Tides and Planetary Waves
Vi parallel to B
Vi perpendicular to B, meridional plane
closely related to neutral wind along B
closely related to zonal E-field
perpendicular to B
Above plotted in geographic coordinates

9. CONCLUSIONS
Swarm reveals significant day-to-day variability, or ionospheric weather, in plasma densities at low to middle latitudes.
Much of this variability is due to plasma drifts driven by tidal and planetary wave winds, either indirectly through dynamo generation or directly through collisional transport along B-field lines.
Care must be taken to account for variability at PW periods (2-20 days) due to recurrent geomagnetic activity (~7d, 9d, 13.5d) or solar ionizing flux due to rotation of the Sun (~13.5d, 27d).
The combined availability of electron densities, plasma drifts, perturbation magnetic fields and neutral densities from Swarm will enable an integrated self-consistent perspective on atmosphere-ionosphere coupling due to tides and PW.
The same data will serve to challenge first-principles models of the atmosphere-ionosphere system.