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Heating from Reconnection QuantifiedPowerPoint Presentation

Heating from Reconnection Quantified

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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 ReconnectionQuantified

Dana LongcopeMontana 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

St. Andrews

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: P [ ergs/sec ]

Reconnection magnetic dissipation

Prx[ ergs/sec ]

P = Prx

[Begging the question?]

Heating from Reconnection

Heating: P [ ergs/sec ]

Reconnection flux transfer

F[ Mx/sec ]

Reconnection

heating

P = CF m

m>0

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 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 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

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

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

emergence begins

enclose loops

Reconnection observed

Y Flux in pot’l

model

(Longcope et al. 2004)

24 hour delay

Burst of reconnection

1016 Mx/sec = 100 MV

Quantifying Reconnection

- Poles
- Converging: v = 218 m/sec
- Potential field:
- bipole

- changing

1.6 MegaVolts

(on separator)

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)

(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

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 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 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

- 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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