1. Introducing POMME Potsdam Magnetic Model of the Earth Star camera calibration Ring current field Static and annually varying external fields Internal field Stefan Maus smaus@gfz-potsdam.de Stefan Maus, George Balasis, Hermann Lühr and Martin Rother, GFZ Mioara Mandea, IPGP

2. POMME main field model Internal field: Gauss coefficients g n m to degree 15  t g n m to degree 15  t  t g n m to degree 10 External field: Dst dependent external dipole aligned with internal field dipole Gauss coefficients k n m to degree 2 in Geocentric Solar Magnetic (GSM) coordinates Star camera angle: corrections for 6 time intervals

3. Oersted data before/after median filter

4. Residuals against initial field model

5. Calibration for the angle between the star sensor and the vector magnetometer Fluxgate vector magnetometer Starsensor

7. Z residuals against Pomme 1.4

9. Dst dependence of earlier field models

10. Dst dependence of Pomme

11. Dst versus induced RC field of Pomme

13. Magneto- sphere

15. A constant external field in GSM: Annual variation seen by an Earth fixed observer at 0 degree longitude, 30 degree latitude

16. A constant external field in GSM: Comparison with CO2’s external field (observer at 0 degree longitude, 30 degree latitude)

18. Main field model power spectrum

19. Model with 3 rd time derivative

20. Conclusions Stefan Maus smaus@gfz-potsdam.de Data errors: Important to take instrument errors, star camera mis-alignment and F-Region currents into account New features in POMME: Includes co-estimated star camera angles for CHAMP Imposed realistic Dst dependence of RC field Describes magnetospheric fields in GSM coordinates Includes secular acceleration See: www.gfz-potsdam.de/pb2/pb23/SatMag/model.html

21. Examples of Instrument Problems

22. Examples of genuine magnetic disturbances

23. Diamagnetic effect at 20:00 local time

24. Night side F region currents

25. E - Region B Regions of enhanced plasma density

26. E - Region B Regions of enhanced plasma density

28. CHAMP electron density, 23-23 Oct 2001, 20 LT

29. Diamagnetic effect at 20:00 local time

30. Satellites POGO (1967-1971) MAGSAT (1979-1980) –350 – 650 km altitude –mission duration: 6 months Oersted (since 1999) SAC-C (since 2001) –600 – 800 km altitude CHAMP (since 2000) –450 km altitude, decending –5 year mission