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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

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:

slide14

11:00

Stack slit

pixels…

Time after

00:00 Aug10

Position @

11:00 Aug10

slide16

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

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

slide28

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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