THEMIS Update and a Review of the Science Behind Magnetometer Signatures By Laura Peticolas 2. Outline 3. Satellites Update 4. Ground-based Update 5. Earth’s magnetic fields 6. Magnetic Field Strength 7. Coordinate Systems 8. Geomagnetic (GEONS) 9. Compass-type (HDZ) 10. The GEONS Data 11. Earth’s Magnetic Field 12. Different Latitudes 13. Magnetosphere 14. Magnetosphere currents 15. Solar Wind (SW) 16. Effects of Ring Current on the Mag Data 17. Auroral Currents 18. Magnetic signatures of auroral substorms 19. Kp Index 20. Kp Index = 1 21. Kp Index = 7 22. Space Weather Effects 23. Storm and Substorms 24. THEMIS will determine which competing model is correct 25. Daytime (Sq) Currents 26. Ionosphere Effects     Space Weather Effects          Alaska    South Dakota    Oregon    Nevada   (Kp=1)   X (nT):   13490  19000 17835 21630 (Kp=7)   X (nT):  ? 18940 17745 21585 Difference (nT): ? 60 90 45   Remember, we said at the beginning that • Earth’s magnetic field is       0.000 052T = 52,000 nanotesla (nT) = 0.5 gauss (G) • 1 nanotesla = 10-9 • Changes in Earth’s magnetic field are typically 5-100 nT Slide 22 of 26