Coronal loops formed by separator reconnection the birth life of ar9574
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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.

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

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Coronal loops formed by separator reconnection the birth life of ar9574

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

Dana LongcopeMontana State University


Collaborators

Collaborators:

  • Jonathan Cirtain

  • Dave McKenzie

  • Jason Scott

MSU

Support:

  • NASA grant NAG5-10489

  • Isaac Newton Institute, Cambridge


Observations of reconnection

Observations of Reconnection

Flare (Sweet)

Jet (Shimojo & Shibata)

CME (Lin & Forbes)


Outline

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


Case study ar 9574

Case study: AR 9574

SoHO MDI

SoHO MDI

White light

Line-of-sight B

2001 Aug 11, 11:15 UT


Case study ar 95741

Case study: AR 9574

SoHO MDI

SoHO MDI

AR9570

AR9570

White light

Line-of-sight B

2001 Aug 11, 11:15 UT


Case study ar 95742

Case study: AR 9574

SoHO MDI

SoHO MDI

AR9574

AR9574

AR9570

AR9570

White light

Line-of-sight B

2001 Aug 11, 11:15 UT


Case study ar 95743

Case study: AR 9574

PHOTOSPHERE

AR9574

AR9570

movie

2001-08-10 12:51 UT


The emergence process

The emergence process

2001-08-10 12:51 UT

2001-08-11 17:39 UT

white

black

white

black


Case study ar 95744

Case study: AR 9574

PHOTOSPHERE

CORONA

2001-08-10 12:51 UT

movie

TRACE 171A (106 K Plasma)


Timeline of emergence

Timeline of emergence

CORONA

7:34

00:00

12:00

00:00

12:00

00:00

Aug 10, 2001

Aug 11, 2001

PHOTOSPHERE


Why this is reconnection

Why this is reconnection

Reconnected flux

Emerged flux

Baum &

Bratenahl

1976

Old flux


Interconnecting loops a catalog

Interconnecting loops:A catalog

Synthetic slit

5139 images @ 28 sec

7:00 Aug10 – 23:59 Aug11

BG subtracted

TRACE 171 images:


Coronal loops formed by separator reconnection the birth life of ar9574

11:00

Stack slit

pixels…

Time after

00:00 Aug10

Position @

11:00 Aug10


Coronal loops formed by separator reconnection the birth life of ar9574

Loops are bright

features


Coronal loops formed by separator reconnection the birth life of ar9574

Lots of

loops:

~9:00

 14:00

Gen’l

bright’g

1st loop:

12:36


Finding the loops

Finding the loops

  • Identify peaks

  • in slit-intensity

  • loop = fw @ hm


Finding the loops1

Finding the loops

  • Identify peaks

  • in slit-intensity

  • loop = fw @ hm

25

22

23

26

24


Finding the loops2

Finding the loops

Loop = row

of peaks

Show peaks

vs. time


Finding the loops3

Finding the loops

Verify spatial

correspond-ence w/ intercon’ing

loops


Interconnecting loops a catalog1

Interconnecting loops:A catalog

43 loops

identified

total

1st loop:

(probably)

interconnects

loops

171A intensity

1st loop:

definitely

interconnecting

loop flurry ~9:00


Interconnecting loops a catalog2

Interconnecting loops:A catalog

properties

of all

43 loops

density lower bound


Magnetic model

Magnetic Model

movie

SoHO MDI

Identify distinct regions with |Bz| > 45 G


Magnetic evolution

Magnetic evolution


Coronal field

Coronal Field

State of least energy:

Potential Field


Coronal field1

Coronal Field

Includes connections

AR9574 to AR9570

(P051  N01)

…all under separatrix

surface


Coronal loops formed by separator reconnection the birth life of ar9574

Separatrices

enclose loops


Coronal field2

Coronal Field

Inter-connecting lines

enclosed by

separator


Coronal field3

Coronal Field

Inter-connecting flux:

P051

AR9574

Potential field:

Increasing interconnection


Flux in 171a loops

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


Flux in 171 a loops

Flux in 171 A loops

1. Each loop is a field-line bundle (flux tube)


Flux in 171 a loops1

Flux in 171 A loops

Y Flux in pot’l

model

loops

Flux if B0 = 30 G

Cummulative loop areas


Reconnection observed

Reconnection observed

Y Flux in pot’l

model

Incomplete

reconnection

24 hour delay

Burst of reconnection

1016 Mx/sec = 100 MV


P spheric trigger response

P-spheric Trigger? Response?

24 hour delay

loop flurry ~9:00


There were no flares

There were no flares

Reconnection burst


The story of the loops

The story of the loops

life time

 heating

density lower bounds

radiative cooling time

(upper bound on life)

RTV equilibria


The story of the loops1

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?)


Model of energy storage

Model of energy storage

Unconstrained minimum:

W

Wpot

Flux Y=Y(v) linking poles

0


Model of energy storage1

Model of energy storage

Constrain Flux Y & minimize energy…

W

Wfce

DW

Wpot

Flux Constrained Equilibrium

(Longcope 2002)

0


Model of energy storage2

Model of energy storage

Flux Constrained Equilibrium

(Longcope 2002)

Lowest Energy w/ fixed Y:

  • Current-free

  • except …


Model of energy storage3

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)


Steady reconnection

Steady Reconnection?

Sweet-Parker:

= 4 months


Comparison of scales

Comparison of scales

c/wpi

Sweet-Parker:

ri


Role s of current sheet

Role(s) of Current Sheet

Site of localized

reconnection

1018 Mx of newly

reconnected flux

(1% of DY)


Role s of current sheet1

Role(s) of Current Sheet

Releases

DE ~ I Dy

~ 1028 ergs

1018 Mx of newly

reconnected flux

(1% of DY)


Role s of current sheets

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


Summary

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)


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