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Heating from Reconnection Quantified. Dana Longcope Montana State University. Acknowledgments:. Erik Aver Jonathan Cirtain Charles Kankelborg Dave McKenzie Jason Scott Alexei Pevtsov Robert Close Clare Parnell Eric Priest NASA grant NAG5-10489 NSF grant ATM 97227. MSU. NSO Sac Peak.

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heating from reconnection quantified

Heating from ReconnectionQuantified

Dana LongcopeMontana State University

acknowledgments
Acknowledgments:
  • Erik Aver
  • Jonathan Cirtain
  • Charles Kankelborg
  • Dave McKenzie
  • Jason Scott
  • Alexei Pevtsov
  • Robert Close
  • Clare Parnell
  • Eric Priest
  • NASA grant NAG5-10489
  • NSF grant ATM 97227

MSU

NSO Sac Peak

St. Andrews

reconnection heating theory
Reconnection Heating: Theory
  • Parker 1972, Parker1983:

“Topological dissipation”

  • Tucker 1973, Levine 1974

Dissipation @ current sheets

  • Heyvaerts & Priest 1984

Taylor relax’n after QS evol’n

  • van Ballegooijen 1985

Dissipation of turbulent structure

  • Parker 1988, Cargill 1993, 1994, …

Nanoflares

  • Longcope 1996, Aly & Amari 1997

QS Formation + rapid elimination of current sheets

(Parker 1972)

=reconnection?

heating from reconnection
Heating from Reconnection

Heating: P [ ergs/sec ]

Reconnection magnetic dissipation

Prx[ ergs/sec ]

P = Prx

[Begging the question?]

heating from reconnection5
Heating from Reconnection

Heating: P [ ergs/sec ]

Reconnection flux transfer

F[ Mx/sec ]

Reconnection

heating 

P = CF m

m>0

reconnection heating
Reconnection Heating

P = CF m

  • Quasi-static models:

tD << tev

Heyvaerts & Priest 1984

Longcope 1996

Aly & Amari 1997

P ~ v

P = IqrxF

m = 1

Units of constant: Amps

reconnection heating7
Reconnection Heating

P = CF m

2. Resistive dissipation:

Parker 1983, 1988

van Ballegooijen 1985

tD ~ tev

P ~ v2

P =(F)2/ R

m = 2

Units of constant: Mhos

quantifying heating
Quantifying Heating

Pevtsov et al. 2003

ARs

XBPs

quantifying reconnection
Quantifying Reconnection
  • What is F?
  • What is F?
    • Which field lines change?
    • Where does the change occur?

Average Heating  General setting:

assume avg. fieldline is recycled once

in time trcyc

quantifying reconnection10
Quantifying Reconnection

Pevtsov et al. 2003

ARs

XBPs

whither withbroe noyes
Whither Withbroe & Noyes?

Quiet Sun: <|Bz|> ~ 10 Mx/cm2

(Lites 2002)

 Fx ~2 x 104ergs/sec/cm2

(Pevtsov et al. 2003)

F ~ Fx /c=3 x 105ergs/sec/cm2

(Withbroe & Noyes 1977)

c ~ 0.1

specific case ar 9574
Specific Case: AR 9574

Longcope et al. 2004

PHOTOSPHERE

2001 Aug 11, 1:35

CORONA

  • Emerging AR
  • Interconnections
  • How much
  • reconnection?

movie

TRACE 171A (106 K Plasma)

p spheric flux sources
P-spheric flux sources

emergence begins

coronal model
Coronal Model

Interconnecting flux

separator

finding all the loops
Finding all the loops

Peaks in a

“slit”

slide16
Separatrices

enclose loops

reconnection observed
Reconnection observed

Y Flux in pot’l

model

(Longcope et al. 2004)

24 hour delay

Burst of reconnection

1016 Mx/sec = 100 MV

energy release
Energy release

I~ 3 x 1010 A

Transfer flux DF

Liberate energy DW

DW ~ DFIqrx

Dissipation? (NO)

quiet sun case xbp1
Quiet Sun Case: XBP1

TRACE & SOI/MDI observations 6/17/98

(Kankelborg & Longcope 1999)

quantifying reconnection20
Quantifying Reconnection
  • Poles
  • Converging: v = 218 m/sec
  • Potential field:

- bipole

- changing

 1.6 MegaVolts

(on separator)

surveys of xbps
Surveys of XBPs
  • Archival SOHO data
  • EIT + MDI images
  • Visually ID XBPs

in EIT 195A

  • Extract bipole

prop’s from 12 MDI

images (@15min)

(Longcope et al. 2000,

Aver & Longcope 2005)

surveys of xbps22
Surveys of XBPs

149 XBPs

vr

15o

v

d

(Aver & Longcope 2005)

F+

F=(F++F-)/2

t=d/vr

aver longcope 2005
(Aver & Longcope 2005)

P

Diverging

bipoles:

No Corr’n

B0=10 G

Converging

bipoles:

P strongly

correlates

w/ reconn’n

rate proxies

1 G

P

Iqrx=1011 A

F/t

vrF

converging vs diverging
Converging vs. Diverging

convergence

(closing)

divergence

(opening)

time

reconnected flux

coronal recycling time
Coronal recycling time

(Close, Parnell, Longcope & Priest 2004)

240 Mm x 240 Mm

quiet Sun region

  • Identify sources
  • Coronal field from
  • potential extrap’n

50 MDI m-grams @ 15 min

coronal recycling time26
Coronal recycling time

Fa= p-spheric

Flux in source a

yi = interconn-ecting flux in domain i

Flux balance:

“All flux goes somewhere”

Change

over Dt

submergence/emergence

Coronal reconnection

coronal recycling time27
Coronal recycling time

Recycling by emergence or submegence

~ 15 hours

(cf. Hagenaar

et al. 2003)

3 hours

1.4 hours

Recycling by reconnection

2 diff. methods

of elimating Si

summary
Summary
  • Heating of individual structures:P ~F
  • Suggests Quasi-static reconnection heating

P=IqrxFwithIqrx=2 x 105trcyc

  • Emerging AR (9574):
    • Reconnection delayed by ~24 hours
    • F = 260 MV, I=3 x 1010 A
    • Heating after reconnection
  • XBPs: F ~1 MV, I~ 109 A
    • Convergence/divergence dichotemy
    • trcyc ~2 hours
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