Can flux cancellation build-up magnetic flux ropes? - Yardley

UCL DEPARTMENT OF SPACE AND CLIMATE PHYSICS
MULLARD SPACE SCIENCE LABORATORY
Can Flux Cancellation Build-up
Magnetic Flux Ropes?
Stephanie L. Yardley1, Lucie M. Green1,
David R. Williams1, Lidia van DrielGesztelyi1,2,3 & Antonia Savcheva4
1Mullard
Space Science Laboratory, University College London
2LESIA-Observatoire de Paris
3Konkoly Observatory
4Harvard-Smithsonian Centre for Astrophysics
June 7 2011 Eruption
• CME ≈ 1250 kms-1
• EUV coronal wave
• M2.5 flare
• Filament material
Flux Rope Model
PIL
van Ballegooijen & Martens, 1989
Flux Rope Model
van Ballegooijen & Martens, 1989
Flux Rope Model
van Ballegooijen & Martens, 1989
Flux Rope Model
van Ballegooijen & Martens, 1989
Flux Rope Model
van Ballegooijen & Martens, 1989
Flux rope Model
van Ballegooijen & Martens, 1989
Flux rope configuration
≈ 34% (7.1 × 1020 Mx) of the AR
flux cancels over a 2.5 day period
Green et al., 2011
Non-Linear Force Free Field (NLFFF)
Flux Rope Insertion Method
Flux rope contains 30 – 50 % of the AR flux
Savcheva et al., 2012
Neighbouring ARs
Magnetic Flux Algorithm
Input
Inclination
Submap
Conditions
Contours
(100 G)
Track
Region
Grow
(30 G)
Output
Magnetic Flux Algorithm
Previous Work
≈ 10% (1× 1021 Mx) of the AR flux cancels over a 24 hour period
Sterling et al., 2010
Previous Work
≈ 10% (1× 1021 Mx) of the AR flux cancels per day
Baker et al., 2012
Results
Total absolute positive magnetic flux – AR 11226
4th
5th
6th
Time of
eruption
16%
16%
33%
Results
Total absolute positive magnetic flux – AR 11227 & 11233
AR 11233
AR 11227
4th
5th
6th
4th
5th
6th
7%
14%
26%
12%
26%
29%
Results
Flux cancellation during 4 – 7 June
Active Region
Total Flux Cancelled
11227
1.91 × 1021 Mx
11233
1 × 1021 Mx
11226
6.73 × 1021 Mx
Concluding Remarks
• Flux cancellation is important in the formation
of flux ropes and filaments
• Automated magnetic flux algorithm to
quantify flux cancellation
• Equivalent to an entire medium sized AR flux
built into the flux rope
– 6.73 × 1021 Mx over 3 days!
• Full vector magnetic field data required
• NLFFF modelling

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