Pre-flare%20Energy%20Storage

1
Pre-flare Energy Storage

• Current sheets (YES)
• Reconnection (NO then YES)

Dana Longcope Montana State University
Thanks Dave McKenzie Jonathan Cirtain Jason Scott
Work supported by NASA NAG5-10489
2
The Photospheric Field
2001-08-10 1251 UT
2001-08-11 1739 UT

• distribution of isolated
• sources
• evolution over days
• anchors coronal field

3
The Coronal Field
coronal connections
P10
P07
N05
y49
N09
y71
P04
y41
N01
Total flux connecting Pi ? Nj yij
4
The Coronal Field
sources
sources
Potential Field
5
Quantifying Flux
separator
null
null

• All flux connecting P07?N01
• enclosed by 2 separatices
• Intersect at separator

6
Quantifying Flux
separator
close path

• All flux connecting P07?N01
• enclosed by 2 separatices
• Intersect at separator

• All P07?N01 lines enclosed

7
Model of energy storage
Unconstrained minimum
W
Wpot
Flux yy(v) linking poles
0
8
Model of energy storage
Constrain Flux y minimize energy
W
Wfce
DW
Wpot
Flux Constrained Equilibrium (Longcope 2002)
Potential iff Dyy-y(v) 0
0
9
Model of energy storage
Flux Constrained Equilibrium (Longcope 2002)
Lowest Energy w/ fixed y

• Current-free
• except

10
Model of energy storage
Flux Constrained Equilibrium (Longcope 2002)
Lowest Energy w/ fixed y

• Current-free
• except
• Current Sheet
• _at_ separator
• I(Dy)
• Mag. Energy
• in excess of
• potential
• DW(Dy)

11
Role(s) of Current Sheets
W
Energy storage DW accumulates prior to
reconn burst
Wfce
DW
Wpot
Stored globally
0
12
Steady Reconnection?
Sweet-Parker
4 months
13
Role(s) of Current Sheets
W
Energy RELEASE DW accumulates prior to
reconn burst latency
Wfce
DW
Wpot
Rapidly released via local E field
0
14
Role(s) of Current Sheet
Site of localized reconnection
2 X 1018 Mx of newly reconnected flux (1 of Dy)
15
Role(s) of Current Sheet
Releases DE I Dy 1031 ergs
2 X 1018 Mx of newly reconnected flux (1 of Dy)
16
Flux emergence
AR9574 begins emerging _at_ 734 2001-08-10
AR9570 remains
Coronal response
17
Evidence of reconnn latency
Stack plot of inter- connecting loops
loops
18
Evidence of reconnn latency
GOES 1-8 A
TRACE 171 A
loops
EUV
loop EUV
emergence
19
Evidence of reconnn latency
reconnection
latency
cooling
emergence
20
Evidence of reconnn latency
latency 24 hrs flux transfer 3.5 hrs Dy 1021
Mx dy/dt 109 V
from potential model
y(v)
latency
y
from observed loops
21
Consequence of latency
Dy 1021 Mx
I 1.3 x 1011 Amps
DWFCE 1.4 x 1031 ergs
22
Consequence of latency
GOES 1-8 A
GOES 0.5-4 A
Radiated power P 5 x 1026 erg/sec
Radiated energy1031 ergs
DWFCE 1031