• This is not another 12th May 1997.

• 13th May 2005 is more complex because it follows solar maximum: residue magnetic fields.

12/05/97 13/05/05

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

Coronal dimming analysis of 13th May 2005 event Gemma Attrill CfA/SAO

Complexity reflected in the coronal dimmings

Intensity evolution (35 hr) selected regions

Quiet SunCoronal Hole

Data gap: 17:37 - 22:58 UT

1 2 3 4 5

6 7 8

Away from core 1

Away from core 2

Inte

nsity

Time

1

2

3

45

6

7 8

Existing coronal hole and extended dimming

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

Previous rotation

17th April

Pre-eruption

13th May

Post-eruption:13th May

Extended CH is there all the time.

But obscured by overlying loops pre-eruption.

These loops are removed during the eruption.

QuickTime™ and a decompressor

are needed to see this picture.

1

2

3

45

6

7 8Region + - Absolute Net

1 1.60E+21 -3.10E+21 4.70E+21 -1.50E+212 2.30E+21 -9.50E+20 3.25E+21 1.35E+213 2.10E+21 -1.40E+21 3.50E+21 7.00E+204 3.00E+21 -1.90E+21 4.90E+21 1.10E+215 2.60E+20 -6.20E+20 8.80E+20 -3.60E+206 4.00E+20 -1.30E+20 5.30E+20 2.70E+207 2.70E+20 -4.40E+20 7.10E+20 -1.70E+208 5.20E+19 -6.70E+19 1.19E+20 -1.50E+19

QuickTime™ and a decompressor

are needed to see this picture.

How are these loops involved in the eruption?

- Do they play a crucial role in making the footprint of the eruption so large-scale?

- Need to understand remote, secondary dimmings too.

Old MDI data - not recalibrated:

Small clues…

QuickTime™ and a decompressor

are needed to see this picture.

Plus global-scale coronal wave too!

QuickTime™ and a decompressor

are needed to see this picture.

QuickTime™ and a decompressor

are needed to see this picture.

10th April 8th May

Verification:

Dimming analysis 13/05/05Gemma AttrillMullard Space Science Laboratory

This is not another 12/05/97.

13/05/05 is more complex because it follows solar maximum: residue magnetic fields.

12/05/97 13/05/05

Dimming regions of 13/05/05

Attrill et al., (2006)

Selecting regions for analysis

Intensity evolution (35 hr) selected regions

Quiet SunCoronal Hole

Data gap: 17:37 - 22:58 UT

1 2 3 4 5

6 7 8

Away from core 1

Away from core 2

Inte

nsity

Time

1

2

3

45

6

7 8

Magnetic flux dimmings (20 G filter)

If dimmings 1 and 2 mark flux rope footpoints, then minimum magnetic flux of the flux rope:

((Absolute 1 + Absolute 2) / 2) = 3.98E+21 Mx

c.f. Yurchyshyn et al., (2006) use an Erupting Flux Rope model and Hu et al., (2006) use the Grad-Shafranov model:

Axial (torroidal) flux in ICME = 2.9E+21 Mx, 2.1E+21 Mx

Azimuthal (poloidal) flux in ICME = 4.4E+22 Mx, 4.2E+21 Mx

Our magnetic flux measurement (which is a minimum), is too large to be explained just by the axial (torroidal) magnetic flux. So the azimuthal (poloidal) magnetic flux is also required.

1

2

3

45

6

7 8

Region + - Absolute Net1 1.60E+21 -3.10E+21 4.70E+21 -1.50E+212 2.30E+21 -9.50E+20 3.25E+21 1.35E+213 2.10E+21 -1.40E+21 3.50E+21 7.00E+204 3.00E+21 -1.90E+21 4.90E+21 1.10E+215 2.60E+20 -6.20E+20 8.80E+20 -3.60E+206 4.00E+20 -1.30E+20 5.30E+20 2.70E+207 2.70E+20 -4.40E+20 7.10E+20 -1.70E+208 5.20E+19 -6.70E+19 1.19E+20 -1.50E+19

1

2

3

45

6

7 8

How do the dimmings form?

Region Net polarity1 -2 +3 +4 +5 -6 +7 -8 -

From SolarSoft Latest events archive. PFSS Derosa & Schrijver

3 47

1 2

Analysis of the evolution of the dimmings can give a lot of information (both quantitative & qualitative) regarding

the changing magnetic topology of the CME event.