dec 9, 2005agu fall 2005, san francisco reconnection in the solar corona probing the fundamental...
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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