1. Seasonal dependence of LEP observed on DEMETER Erin S. Gemelos 1, Umran S. Inan 1, Martin Walt 1, Jean-Andre Sauvaud 2, Michel Parrot 3 February 18, 2009 1 STAR Laboratory, Stanford University, USA 2 CESR/CNRS, Toulouse, France 3 LPCE/CNRS, Orléans, France

2. Motivation  Lightning-induced electron precipitation (LEP) an important loss process at L<2.5  Ground measurements: ionospheric effects of LEP observed via associated D-region ionization (e.g. Inan et al., 1988; Peter and Inan, 2004)  In-situ measurements  Stimulated Emissions of Energetic Particles (SEEP): measurements of LEP into the loss cone [Voss et al., 1984]  DEMETER detection of LEP in the loss cone [Inan et al., 2007]  Goal: Long term effect of lightning and drift loss cone enhancements using in-situ data

3. Outline  (Motivation)  DEMETER  Lightning and wave data  Seasonal precipitation  Conclusions

4. DEMETER  730 km sun-synchronous orbit  10:30 or 22:30 local time  Instrument for Particle Detection (IDP)  Measures local pitch angles near 90, ~30 degree detector width  4/1 second resolution (survey/burst mode)  ~20/10 keV spectral resolution (survey/burst mode) in range 70keV – 2.35 MeV  Istrument Capteur Electrique (ICE)  VLF power spectrum (1 E component)

5. Energy Resonance

6. Energy Resonance [Blake et al., 2001]

7. Resonant Energy [Inan et al., 2007]

8. Fluxes and Lightning

9. 2006-7 Seasonal Lightning

10. 2006-8 Seasonal Fluxes

12. Seasonal Variation

14. U.S. unique  Location in drift loss cone

15. US unique  Location in drift loss cone  Geomagnetic conjugate in ocean

16. US unique  Location in drift loss cone  Geomagnetic conjugate in ocean  VLF wave activity Courtesy of M. Parrot [UNPUBLISHED RESULT]

17. Seasonal Fluxes over Pacific 2006-8

18. Seasonal fluxes over U.S. Conjugate 2006-2008

19. Conclusions  Drift loss cone observations  Seasonal variation consistent with LEP  US uniquely located

20. Global difference