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III. APPLICATIONS of RECONNECTION

Explore the mechanisms of coronal heating and solar flares through reconnection processes, magnetic fields, plasma interactions, and eruptive events. Witness the dynamic nature of the sun's outer corona, featuring X-ray bright points, magnetic loops, CMEs, and solar flares. Delve into the intricate interplay of magnetic forces, plasma dynamics, and magnetic reconnection in shaping the solar atmosphere. Understand the pivotal role of reconnection in heating coronal loops and driving explosive solar activities. Unravel the mysteries of solar eruptions and their impact on the space weather environment. This comprehensive overview sheds light on fundamental solar physics phenomena and their implications for our understanding of the sun's behavior.

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III. APPLICATIONS of RECONNECTION

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

  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 photc. motions --> X-ray bright point Supported by TRACE (ii) Nanoflares -- Parker Braiding (iii) Modern version: “Coronal Tectonics”(including magnetic carpet)

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

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

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

  7. Aurora in St Andrews Thurs

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

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

  10. N.B. • Flare & CME are part of1 magnetic eruptive process • (short MHD connection time) • Difference 2-ribbon flare & CME --- magnetic field strength • Role of filament/prominence -- indicator of high shear So perhaps eruption is driven more from core, where most energy is stored

  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: twistedsigmoid --> energy stored

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

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

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

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

  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

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