Dec 9, 2005 AGU Fall 2005, San Francisco

Reconnection in the Reconnection in the Solar CoronaSolar CoronaProbing the Probing the

fundamental scalesfundamental scales

Reconnection in the Reconnection in the Solar CoronaSolar CoronaProbing the Probing the

fundamental scalesfundamental scalesDana LongcopeDana Longcope

Montana State UniversityMontana State University

Work supported by NASA, NSF & DoDWork supported by NASA, NSF & DoD

Thanks: Mark Linton, Thanks: Mark Linton, NRL NRL

Dec 9, 2005 AGU Fall 2005, San Francisco

Driver: Photospheric Driver: Photospheric FieldField

Driver: Photospheric Driver: Photospheric FieldField

00:0000:00 12:0012:00 00:0000:00 12:0012:00

Aug 10, 2001Aug 10, 2001 Aug 11, 2001Aug 11, 200100:0000:00

MDI

TRACE 171A

7:347:34

AR9574

AR9570

moviemovie

Emergence:(Longcope et al. 2005)

Dec 9, 2005 AGU Fall 2005, San Francisco

Coronal ResponseCoronal ResponseCoronal ResponseCoronal ResponsePotential field: minimum energy state

0

WWpotpot

WW

(v)(v)

Flux Flux (v)(v) interconn-ects interconn-ects newnew & & oldold Ars Ars

increases - increases - emerg’ceemerg’ce

Dec 9, 2005 AGU Fall 2005, San Francisco

Estimating Coronal Estimating Coronal ResponseResponse

Estimating Coronal Estimating Coronal ResponseResponse

Constrain interconnecting flux

0

WWfcefce

WWpotpot

WW

WW

I = 1.3 x 10I = 1.3 x 101111 Amps Amps

(v)(v)

~ ~ const.const.

€

I ≈Δψ

L

(v) (v) =10=102121 Mx Mx Minimum energy: FCE

Reconn. dormantReconn. dormant

Dec 9, 2005 AGU Fall 2005, San Francisco

Equilibrium Current Equilibrium Current Sheet…Sheet…

Equilibrium Current Equilibrium Current Sheet…Sheet…

€

Δ =4μo I

π ′ B

€

Bo =′ B Δ

2

€

B⊥ ~ ′ B r⊥Far from CS:Far from CS:

……gross structuregross structuredetermined bydetermined byp-spheric fieldp-spheric field

Dec 9, 2005 AGU Fall 2005, San Francisco

Quasi-static EvolutionQuasi-static EvolutionQuasi-static EvolutionQuasi-static Evolution

I=88 GAI=42 GA

I=5 GANo recon’ionNo recon’ion

Dec 9, 2005 AGU Fall 2005, San Francisco

Internal CS Structure…Internal CS Structure…

€

SCS ≡B0Δ

η 4πρ=

I(ΔΨ)

0.003 A~ 1013 =

Δ

δ

⎛

⎝ ⎜

⎞

⎠ ⎟2

*

… … set by non-ideal set by non-ideal effects*effects*

Sweet-Parker Reconnection

€

~ SCS−1/ 2Δ ~ 8 m outflows

€

ICS =1

4πB ⋅dl∫ =

B0Δ

2π

~ 50 Mm

2/1CSArx Sττ =

ΨΔΨ

= &

= 4 months= 4 months

€

ISP = η ρ /π

Dec 9, 2005 AGU Fall 2005, San Francisco

InstabilitiesInstabilitiesInstabilitiesInstabilities

Δ

• Unstable:Unstable:

ΔΔ > 2> 21. Resistive Tearing 1. Resistive Tearing (Furth et al. 1963)

Dec 9, 2005 AGU Fall 2005, San Francisco

InstabilitiesInstabilitiesInstabilitiesInstabilities1. Resistive Tearing 1. Resistive Tearing (Furth et al. 1963)

• Stabilizing effects:Stabilizing effects:• Sweet-Parker flowSweet-Parker flow (Phan & (Phan & Sonnerup 1991)Sonnerup 1991)

• Para’ll comp. of Para’ll comp. of B B (3(3rdrd dimension)dimension)

• Nonlinear saturation Nonlinear saturation (turbulence)(turbulence)

• Instab. enhances Instab. enhances diffusion … drives CS to diffusion … drives CS to marginal stability marginal stability Δ Δ ~ ~ 1000 1000

Dec 9, 2005 AGU Fall 2005, San Francisco

c/c/pipi

ii

Δ= − 2/1CSSδ

Δ

Dec 9, 2005 AGU Fall 2005, San Francisco

ReconnectionReconnectionReconnectionReconnection

Biernat et al. 1987

• LocalizedLocalized in space & in space & timetime

• Fast rec’n w/ Fast rec’n w/ slow slow shocksshocks

• Creates Creates reconnected reconnected loops loops ΔΔ

• New CSNew CS forms in wake forms in wake

2d2d

Dec 9, 2005 AGU Fall 2005, San Francisco

ReconnectionReconnectionReconnectionReconnection

Linton & Longcope 2006

3d3d

• LocalizedLocalized in space & in space & timetime

• Fast rec’n w/ Fast rec’n w/ slow slow shocksshocks

• Creates Creates reconnected reconnected loops loops ΔΔ

• New CSNew CS forms in wake forms in wake

Dec 9, 2005 AGU Fall 2005, San Francisco

Reconnection ObservedReconnection ObservedReconnection ObservedReconnection Observed

reconnected loops reconnected loops ΔΔQ: How do loop Q: How do loop diameters relate to diameters relate to ReX size? ReX size?

TRACE 171A

Dec 9, 2005 AGU Fall 2005, San Francisco

Reconnection ObservedReconnection ObservedReconnection ObservedReconnection Observed

reconnected loops reconnected loops ΔΔQ: How do Q: How do loop loop diameters diameters relate to relate to ReX sizeReX size? ?

A: Not SimplyA: Not Simply

Dec 9, 2005 AGU Fall 2005, San Francisco

c/c/pipi

ii

Δ= − 2/1CSSδ

RAM

TRACE

Dec 9, 2005 AGU Fall 2005, San Francisco

Summary: Current Summary: Current SheetsSheets

Summary: Current Summary: Current SheetsSheets

• Global structure: Global structure: Set by p-spheric fieldSet by p-spheric field can be estimated can be estimated today today (~ 30 Mm)(~ 30 Mm)• Internal structure:Internal structure: set by non-ideal effects (i.e. set by non-ideal effects (i.e. ))

• reconnection:reconnection: will occur on will occur on internal scales - creating loopsinternal scales - creating loops• Cannot (yet) observed these Cannot (yet) observed these scalesscales

• Estimate: < 30 kmEstimate: < 30 km