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     Effects of Ring Current on the Mag Data Charged particles circle Earth at about 10 Re (60,000 km) from Earth’s surface near the equator. The electrons and the ions move in opposite directions, creating the ring current Does this add to (strengthen) or subtract from (weaken) Earth’s core magnetic field at Carson City? This is mostly in the x-direction. When disturbed, the ring current weakens Earth’s magnetic field even more. This is called a magnetic storm. Slide 16 of 26