Coronal loops formed by separator reconnection The birth

Coronal loops formed by separator reconnection: The birth & life of AR 9574 Dana Longcope Aug 16, 2004 Montana State University

Collaborators: • • • Jonathan Cirtain Dave Mc. Kenzie Jason Scott MSU Support: • NASA grant NAG 5 -10489 • Isaac Newton Institute, Cambridge Aug 16, 2004

Outline • • • 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 Aug 16, 2004

Case study: AR 9574 So. HO MDI White light So. HO MDI Line-of-sight B 2001 Aug 11, 11: 15 UT Aug 16, 2004

Case study: AR 9574 So. HO MDI AR 9570 White light Line-of-sight B 2001 Aug 11, 11: 15 UT Aug 16, 2004

Case study: AR 9574 So. HO MDI AR 9574 AR 9570 White light Line-of-sight B 2001 Aug 11, 11: 15 UT Aug 16, 2004

Case study: AR 9574 PHOTOSPHERE AR 9574 AR 9570 movie 2001 -08 -10 12: 51 UT Aug 16, 2004

Case study: AR 9574 PHOTOSPHERE CORONA 2001 -08 -10 12: 51 UT movie TRACE 171 A (106 K Plasma) Aug 16, 2004

The emergence process 2001 -08 -10 12: 51 UT white Aug 16, 2004 black 2001 -08 -11 17: 39 UT white black

Timeline of emergence CORONA 00: 00 7: 34 12: 00 00: 00 Aug 10, 2001 Aug 16, 2004 PHOTOSPHERE 12: 00 Aug 11, 2001 00: 00

Why this is reconnection Reconnected flux Emerged flux Old flux Aug 16, 2004

Interconnecting loops: A catalog Synthetic slit TRACE 171 images: Aug 16, 2004 5139 images @ 28 sec 7: 00 Aug 10 – 23: 59 Aug 11 BG subtracted

11: 00 Stack slit pixels… Time after 00: 00 Aug 10 Position @ 11: 00 Aug 16, 2004

Loops are bright features Aug 16, 2004

Lots of loops: ~9: 00 14: 00 Gen’l bright’g 1 st loop: 12: 36 Aug 16, 2004

Finding the loops • Identify peaks in slit-intensity • loop = fw @ hm Aug 16, 2004

Finding the loops • Identify peaks in slit-intensity • loop = fw @ hm 25 26 24 Aug 16, 2004 22 23

Finding the loops Loop = row of peaks Aug 16, 2004 Show peaks vs. time

Finding the loops Verify spatial correspondence w/ intercon’ing loops Aug 16, 2004

43 loops identified 1 st loop: (probably) interconnects 171 A intensity Interconnecting loops: A catalog total loops loop: definitely interconnects Aug 16, 2004 loop flurry ~9: 00

Interconnecting loops: A catalog properties of all 43 loops density lower bound Aug 16, 2004

Magnetic Model So. HO MDI Aug 16, 2004 movie Identify distinct regions with |Bz| > 45 G

Magnetic evolution Aug 16, 2004

Aug 16, 2004

Coronal Field State of least energy: Potential Field Aug 16, 2004

Coronal Field Includes connections AR 9574 to AR 9570 (P 051 N 01) …all under separatrix surface Aug 16, 2004

Separatrices enclose loops Aug 16, 2004

Coronal Field Inter-connecting lines enclosed by separator Aug 16, 2004

Coronal Field Inter-connecting flux: P 051 AR 9574 Potential field: Increasing interconnection Aug 16, 2004

Flux in 171 A loops 1. 2. 3. 4. Aug 16, 2004 Assumptions Each loop is a field-line bundle (flux tube) Loops/flux tubes : x-section Loop track flux tube for entire life No flux tube re-appears in 171 A

Flux in 171 A loops 1. Each loop is a field-line bundle (flux tube) Aug 16, 2004

Flux in 171 A loops Y Flux in pot’l model loops Flux if B 0 = 30 G Cummulative loop areas Aug 16, 2004

Reconnection observed Y Flux in pot’l model Incomplete reconnection 24 hour delay Aug 16, 2004 Burst of reconnection 1016 Mx/sec = 100 MV

life time The story of the loops heating density lower bounds RTV equilibria Aug 16, 2004 radiative cooling time (upper bound on life)

The story of the loops Yohkoh SXT TRACE 171 A movie ~3, 000 K 950, 000 K Loops are hot (~3 MK) after reconnection… Gradually cool into TRACE pass-band Aug 16, 2004 (All of them? )

There were no flares Reconnection burst Aug 16, 2004

Model of energy storage Unconstrained minimum: W Wpot Flux Y=Y(v) linking poles Aug 16, 2004 0

Model of energy storage Constrain Flux Y & minimize energy… W Wfce DW Wpot Flux Constrained Equilibrium (Longcope 2002) Aug 16, 2004 0

Model of energy storage Lowest Energy w/ fixed Y: Flux Constrained Equilibrium (Longcope 2002) • Current-free except … Aug 16, 2004

Model of energy storage Lowest Energy w/ fixed Y: Aug 16, 2004 Flux Constrained Equilibrium (Longcope 2002) • Current-free except … • Current Sheet @ separator I(DY) • Mag. Energy in excess of potential DW(DY)

Steady Reconnection? Sweet-Parker: = 4 months Aug 16, 2004

Comparison of scales c/wpi Sweet-Parker: r Aug 16, 2004 i

Role(s) of Current Sheet Site of localized reconnection 1018 Mx of newly reconnected flux (1% of DY) Aug 16, 2004

Role(s) of Current Sheet Releases DE ~ I Dy ~ 1028 ergs 1018 Mx of newly reconnected flux (1% of DY) Aug 16, 2004

Role(s) of Current Sheets Energy storage: W accumulates for 24 hrs. prior to reconn’ burst Rapidly released via local process Aug 16, 2004 W Wfce DW Wpot 0

Summary 1. AR 9574: Example of reconnection between new & old active regions 2. Reconnection occurs in brief (6 hour) burst after delay of ~24 hours 3. Produces dozens of ~1018 Mx loops 4. Observed flux accounts for 10% - 30% of maximum allowed (partial reconn. ) Aug 16, 2004