1. National Space Institute Technical University of Denmark TLEs: Combining Observations, Simulations, Theory and Instrument Technical Aspects Torsten Neubert National Space Institute Technical University of Denmark

2. National Space Institute Technical University of Denmark Overview Introduction –CAL/Europe –Space missions –Ground Campaigns Highlights of studies since last workshop –The source of sprites –The process of sprites –Effects of sprites on the atmosphere Lessons learned –Combinations of new instrumentation –The Internet is marvellous –Where are the blue jets? Preparations for TARANIS and ASIM –Models –Lab experiments –Campaigns

3. National Space Institute Technical University of Denmark Overview Introduction –CAL/Europe –Space missions –Ground Campaigns Highlights of studies since last workshop –The source of sprites –The discharge process of sprites –Effects of sprites on the atmosphere Lessons learned –Combinations of new instrumentation –The Internet is marvellous –Where are the blue jets? Preparations for TARANIS and ASIM –Models –Lab experiments –Campaigns

4. National Space Institute Technical University of Denmark Coupling of Atmospheric Layers EU Research Training Network –2002-2006 –10 young scientists –11 research institutions in Europe Theme: –”Do sprites affect the atmosphere or are they just beautifull like rainbows” Strategy: –To combine new combinations of instrumentation and methods Outcome: –New science –Establish collaborations across Europe and across disciplines –The ASIM and TARANIS space missions

5. National Space Institute Technical University of Denmark ASIM and TARANIS Complementaty missions for studies of thunderstorm processes in the stratosphere and mesosphere ASIM: for the International Space Station (ESA) TARANIS: microsatellite (CNES) Both: Launch 2012

6. National Space Institute Technical University of Denmark Ground Observations

7. National Space Institute Technical University of Denmark Overview Introduction –CAL/Europe –Space missions –Ground Campaigns Highlights of studies since last workshop –The source of sprites –The discharge process of sprites –Effects of sprites on the atmosphere Lessons learned –Combinations of new instrumentation –The Internet is marvellous –Where are the blue jets? Preparations for TARANIS and ASIM –Models –Lab experiments –Campaigns Neubert. T. et al., Recent Results from Studies of Electric Discharges in the Mesosphere, submitted to Surveys in Geophysics

8. National Space Institute Technical University of Denmark Overview Introduction –CAL/Europe –Space missions –Ground Campaigns Highlights of studies since last workshop –The source of sprites –The discharge process of sprites –Effects of sprites on the atmosphere Lessons learned –Combinations of new instrumentation –The Internet is marvellous –Where are the blue jets? Preparations for TARANIS and ASIM –Models –Lab experiments –Campaigns Neubert. T. et al., Recent Results from Studies of Electric Discharges in the Mesosphere, submitted to Surveys in Geophysics

9. National Space Institute Technical University of Denmark VLF signatures and Sprites

10. National Space Institute Technical University of Denmark IC discharges

11. National Space Institute Technical University of Denmark The E- field in the Mesosphere (A) 110 kA, 0.2 ms; 20 C; 200 Ckm (B) 30 kA, 0.2 ms + 2 kA, 90 ms; 70 C; 700 Ckm

12. National Space Institute Technical University of Denmark Source summary The complete cloud discharge, including the IC components, are important for sprite morphology and location Modelling of the E-field in mesosphere is well underway Valdivia, Cho and Rycroft, Steve Cummer... and others

13. National Space Institute Technical University of Denmark Overview Introduction –CAL/Europe –Space missions –Ground Campaigns Highlights of studies since last workshop –The source of sprites –The discharge process of sprites –Effects of sprites on the atmosphere Lessons learned –Combinations of new instrumentation –The Internet is marvellous –Where are the blue jets? Preparations for TARANIS and ASIM –Models –Lab experiments –Campaigns

14. National Space Institute Technical University of Denmark 10 kHz (Stenbaek-Nielsen) Sprite at High Speed 20 Hz

15. National Space Institute Technical University of Denmark Field Amplification in Streamers The electric field is amplified in streamer tips E k = background threshold field for streamer ignition Streamers may propagate in fields smaller than E k E cr - ~E k / 2.5 E cr + ~E k / 6

16. National Space Institute Technical University of Denmark Comparison of Optical Luminosity From 10 kHz imaging: –Streamer head: 10 9 - 10 11 R PIC: –E=1.5 E k –Streamer head: 1.4 x 10 9 R Simulations are consistent with observatiions of the initial stage of the discharge. Log Max Emisson Rate [R] 98769876 2P 1P 1N PIC 0-40  s Stenbaek-Nielsen, grl 2008 0-2200  s

17. National Space Institute Technical University of Denmark Properties of streamers at 70 km from PIC simulations Electric field: ~1.5 – 3.0 Ek Conductivity: ~1 mS/m Initial phase: –Current density: ~100 mA/m 2 –Energy deposition:~10 -5 J/m 3 /s Grown phase: ~100 times larger current (Steenbæk-N) Sprite current = 1 kAEnergy deposition: ~1 J/m Sprite current = 10 kAEnergy deposition: ~100 J/m

18. National Space Institute Technical University of Denmark Energetic electrons in Streamers

19. National Space Institute Technical University of Denmark Overview Introduction –CAL/Europe –Space missions –Ground Campaigns Highlights of studies since last workshop –The source of sprites –The discharge process of sprites –Effects of sprites on the atmosphere Lessons learned –Combinations of new instrumentation –The Internet is marvellous –Where are the blue jets? Preparations for TARANIS and ASIM –Models –Lab experiments –Campaigns

20. National Space Institute Technical University of Denmark Infra sound from sprites Infra sound (1-10 Hz) observations give information on energy deposition into the neutral atmosphere Global network is part of Comprehensive Nuclear Testban Treaty Verification Programme Several stations are in France

21. National Space Institute Technical University of Denmark Sprite thunder at 1500 km distance Sprite observed over Corsica on August 25 at 21:50:22.065 (I p = +59.5 kA, +63.2 kA). Pressure perturbations and sonogram of infrasound observed at the Flers station 300 km North-West of Paris.

22. National Space Institute Technical University of Denmark Energy deposition Estimates have varied from MJ – GJ Comparison with BOMB calculations: GJ Pasko et al. based on infrasound obs: MJ-range PIC simulations suggest MJ range

23. National Space Institute Technical University of Denmark Probing the mesosphere and lower ionosphere

24. National Space Institute Technical University of Denmark EMP/ELVE pertubations Early fast Caused by lightning EMP

25. National Space Institute Technical University of Denmark IC/sprite perturbations Early-slow perturbation Caused by IC lightning electric fields and sprite

26. National Space Institute Technical University of Denmark Perturbations to the mesosphere/ionosphere Models of perturbations from EMP and elves quite good (Inan group) IC discharges again showing up Difficult to distinguish between effects of sprites and fields radiated by the causative lightning activity.

27. National Space Institute Technical University of Denmark Perturbations to the Chemistry

28. National Space Institute Technical University of Denmark Chemical effects of Sprites Significant effects of NO (and ozone) inside streamers Small regional effects above severe thunderstorms Negligable global effects

29. National Space Institute Technical University of Denmark Overview Introduction –CAL/Europe –Space missions –Ground Campaigns Highlights of studies since last workshop –The source of sprites –The discharge process of sprites –Effects of sprites on the atmosphere Lessons learned –Combinations of new instrumentation –The Internet is marvellous –Where are the blue jets? Preparations for TARANIS and ASIM –Models –Lab experiments –Campaigns

30. National Space Institute Technical University of Denmark Lessons learned Combinations of new instrumentation The Internet is marvellous Where are the blue jets?

31. National Space Institute Technical University of Denmark Overview Introduction –CAL/Europe –Space missions –Ground Campaigns Highlights of studies since last workshop –The source of sprites –The discharge process of sprites –Effects of sprites on the atmosphere Lessons learned –Combinations of new instrumentation –The Internet is marvellous –Where are the blue jets? Preparations for TARANIS and ASIM –Models –Lab experiments –Campaigns

32. National Space Institute Technical University of Denmark Is our understanding of the mesosphere above thunderstorms adequate? 100-200 km 10-15 km 70 km In situ measurements in the mesosphere are difficult Density and conductivity profiles? Small-scale irregularities?

33. National Space Institute Technical University of Denmark Some model development Electric field –EMP+QE –IC+CG The discharge process –Small scale coupled to large scale –Relativistic Effects on small-scale perturbations

34. National Space Institute Technical University of Denmark Laboratory X- and Gamma-rays from discharges

35. National Space Institute Technical University of Denmark Campaigns IC+CG lightning mapping High-speed optical observations Spectral observations of chemistry Observations of ionisation/conductivity perturbations Triangulation Observations above thunderclouds

36. National Space Institute Technical University of Denmark New Science Already new insights into the nature of electric discharges Lightning represents and ”active” experiment probing the stratosphere and mesosphere. Understanding TLEs will give us a new tool to study the mesosphere, the least known region of the atmosphere