1. III. APPLICATIONS of RECONNECTION Yohkoh Bright Pts Loops Holes A magnetic world T=few MK 1. Coronal Heating

2. Quiet Sun (XRT on Hinode) 30-sec cadence, 12-hour duration How is the Corona Heated ?

3. Reconnection: likely cause of coronal heating (i) Drive Simple Recon. at nulls by phot c. motions --> X-ray bright point (ii) Nanoflares -- Parker Braiding (iii) Modern version: “Coronal Tectonics” (including magnetic carpet) Supported by TRACE

4. 2. SOLAR FLARES & CME’s SOHO Coronagraph -- Artificial eclipse Discovered huge ejections of plasma

5. Photo- sphere [from SOHO] On October 28, 2003 3rd largest flare

6. Outer Corona [from SOHO] CME 2000 km/s (5 times faster than normal) Snow -- rel c particles

7. Thurs Aurora in St Andrews

8. 1 Week Later (Nov 4 )- Fireworks Continued the biggest solar flare ever recorded !

9. Conjuring trick -- plasma appearing by magic ? Close-up of plasma motions

10. N.B.  Flare & CME are part of 1 magnetic eruptive process (short MHD connection time)  Role of filament/prominence -- indicator of high shear So perhaps eruption is driven more from core, where most energy is stored  Difference 2-ribbon flare & CME --- magnetic field strength

11. Overall Picture of Eruption In core - magnetic tube twisted (energy stored in fff) - erupts (catastrophe or breakout) - drives reconnection

12. Reconnection heats loops/ribbons

13. (Priest and Schrijver 1999) Reconnection heats loops Continues: new loops form & evaporate. Old loops cool & drain Feet move apart

14. Examples of prominences

15. Eruptions:

16. Ex of Cusped Loops Rising

17. Example from SOHO

18. Example from TRACE (171 A) 1 MK (Fe IX) + 20 MK (Fe XVI)

19. Before: twisted sigmoid --> energy stored

20. Cause of Eruption ? (i) Magnetic Catastrophe (Priest & Forbes)

21. (ii) Antiochos et al - breakout model for eruption

22. Emergence of flux rope into a potential arcade Eruption due to magnetic catastrophe when twist > 3.4 Yuhong Fan

23. Tibor Torok Similar model for kink instability, with different flux tube/ overlying field

24. 3. CONCLUSIONS  Understanding how B interacts with plasma: Key to many solar system phenomena  Two main equations: Induction equation -- advection + diffusion Eqn. motion -- magnetic tension + pressure forces  Reconnection - different roles in coronal heating, - Solar flares & CMEs