1 / 48

Coronal loops formed by separator reconnection: The birth & life of AR9574

Coronal loops formed by separator reconnection: The birth & life of AR9574. Dana Longcope Montana State University. Collaborators:. Jonathan Cirtain Dave McKenzie Jason Scott. MSU. Support:. NASA grant NAG5-10489 Isaac Newton Institute, Cambridge. Observations of Reconnection.

vevina
Télécharger la présentation

Coronal loops formed by separator reconnection: The birth & life of AR9574

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Coronal loops formed by separator reconnection:The birth & life of AR9574 Dana LongcopeMontana State University

  2. Collaborators: • Jonathan Cirtain • Dave McKenzie • Jason Scott MSU Support: • NASA grant NAG5-10489 • Isaac Newton Institute, Cambridge

  3. Observations of Reconnection Flare (Sweet) Jet (Shimojo & Shibata) CME (Lin & Forbes)

  4. Outline Flux Emergence: A new setting for studying reconnection • What happened in Aug. 2001 • Cataloging interconnections • Making a magnetic model • Interp’ing data w.r.t. the model • What does it tell us about reconnection

  5. Case study: AR 9574 SoHO MDI SoHO MDI White light Line-of-sight B 2001 Aug 11, 11:15 UT

  6. Case study: AR 9574 SoHO MDI SoHO MDI AR9570 AR9570 White light Line-of-sight B 2001 Aug 11, 11:15 UT

  7. Case study: AR 9574 SoHO MDI SoHO MDI AR9574 AR9574 AR9570 AR9570 White light Line-of-sight B 2001 Aug 11, 11:15 UT

  8. Case study: AR 9574 PHOTOSPHERE AR9574 AR9570 movie 2001-08-10 12:51 UT

  9. The emergence process 2001-08-10 12:51 UT 2001-08-11 17:39 UT white black white black

  10. Case study: AR 9574 PHOTOSPHERE CORONA 2001-08-10 12:51 UT movie TRACE 171A (106 K Plasma)

  11. Timeline of emergence CORONA 7:34 00:00 12:00 00:00 12:00 00:00 Aug 10, 2001 Aug 11, 2001 PHOTOSPHERE

  12. Why this is reconnection Reconnected flux Emerged flux Baum & Bratenahl 1976 Old flux

  13. Interconnecting loops:A catalog Synthetic slit 5139 images @ 28 sec 7:00 Aug10 – 23:59 Aug11 BG subtracted TRACE 171 images:

  14. 11:00 Stack slit pixels… Time after 00:00 Aug10 Position @ 11:00 Aug10

  15. Loops are bright features

  16. Lots of loops: ~9:00  14:00 Gen’l bright’g 1st loop: 12:36

  17. Finding the loops • Identify peaks • in slit-intensity • loop = fw @ hm

  18. Finding the loops • Identify peaks • in slit-intensity • loop = fw @ hm 25 22 23 26 24

  19. Finding the loops Loop = row of peaks Show peaks vs. time

  20. Finding the loops Verify spatial correspond-ence w/ intercon’ing loops

  21. Interconnecting loops:A catalog 43 loops identified total 1st loop: (probably) interconnects loops 171A intensity 1st loop: definitely interconnecting loop flurry ~9:00

  22. Interconnecting loops:A catalog properties of all 43 loops density lower bound

  23. Magnetic Model movie SoHO MDI Identify distinct regions with |Bz| > 45 G

  24. Magnetic evolution

  25. Coronal Field State of least energy: Potential Field

  26. Coronal Field Includes connections AR9574 to AR9570 (P051  N01) …all under separatrix surface

  27. Separatrices enclose loops

  28. Coronal Field Inter-connecting lines enclosed by separator

  29. Coronal Field Inter-connecting flux: P051 AR9574 Potential field: Increasing interconnection

  30. Flux in 171A loops • Assumptions • Each loop is a field-line bundle (flux tube) • Loops/flux tubes : x-section • Loop tracks flux tube for entire life • No flux tube re-appears in 171 A

  31. Flux in 171 A loops 1. Each loop is a field-line bundle (flux tube)

  32. Flux in 171 A loops Y Flux in pot’l model loops Flux if B0 = 30 G Cummulative loop areas

  33. Reconnection observed Y Flux in pot’l model Incomplete reconnection 24 hour delay Burst of reconnection 1016 Mx/sec = 100 MV

  34. P-spheric Trigger? Response? 24 hour delay loop flurry ~9:00

  35. There were no flares Reconnection burst

  36. The story of the loops life time  heating density lower bounds radiative cooling time (upper bound on life) RTV equilibria

  37. The story of the loops TRACE 171 A Yohkoh SXT movie ~3,000,000 K 950,000 K Loops are hot (~3MK) after reconnection… Gradually cool into TRACE pass-band (All of them?)

  38. Model of energy storage Unconstrained minimum: W Wpot Flux Y=Y(v) linking poles 0

  39. Model of energy storage Constrain Flux Y & minimize energy… W Wfce DW Wpot Flux Constrained Equilibrium (Longcope 2002) 0

  40. Model of energy storage Flux Constrained Equilibrium (Longcope 2002) Lowest Energy w/ fixed Y: • Current-free • except …

  41. Model of energy storage Flux Constrained Equilibrium (Longcope 2002) Lowest Energy w/ fixed Y: • Current-free • except … • Current Sheet • @ separator • I(DY) • Mag. Energy • in excess of • potential • DW(DY)

  42. Steady Reconnection? Sweet-Parker: = 4 months

  43. Comparison of scales c/wpi Sweet-Parker: ri

  44. Role(s) of Current Sheet Site of localized reconnection 1018 Mx of newly reconnected flux (1% of DY)

  45. Role(s) of Current Sheet Releases DE ~ I Dy ~ 1028 ergs 1018 Mx of newly reconnected flux (1% of DY)

  46. Role(s) of Current Sheets W Energy storage: W accumulates for 24 hrs. prior to reconn’ burst Wfce DW Wpot Rapidly released via local process 0

  47. Summary • AR 9574: unambiguous reconnection • Reconnection in brief (6 hour) burst after delay of ~24 hours • Separator reconnection • Trigger? … No evidence in p-sphere • Produces scores of ~1018 Mx loops • Observed flux accounts for 10% - 30% of maximum allowed (partial reconnection)

More Related