The 6th Solar-B Science meeting Kyoto Nov 8 2005

What can we learn from the vector magnetic

field measured in filament channels ?

Arturo López AristeB. Schmieder, G. Aulanier,

THEMIS Observations:Magnetic field vector

Introduction

Chirality and resolution of the 180° ambiguity

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Barbs and feet are related to Minority magnetic polarities (Martin 1994)

Lin , Wiik, Engvold (2004, 2005) 60% of ends are rootedin network boundaries

How is oriented the field vector?Is it horizontal (Chae et al 2005)

or vertical (Lin et al 2005) ?

SST La Palma

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Computations of the dips in each field line in the computation model box

ligne de champ

dH = Hg = 300 km

altitude (z)(B . ) B > 0

Bz = 0

Presence of minority polarities in filament channels

Simulation of the observations of cool plasma visible in multi- (Aulanier and Démoulin 1998, van Ballegooijen 2004, Régnier and Amari 2004)

Dips filled by plasma

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Extrapolation of B from SoHO/MDI

3D magneto-hydrostatic linear model with free parameters constrained by the theory and the observations

08:12 UT 07:52 UT

Lignes de champ

filament

arcades coronales

Matière froide

z > 4 Mm

z < 4 Mm

Topology of B and distribution of the cool matter Aulanier G., Schmieder B., 2002, A&A, 386, 1106-1122

CDS OV

THEMIS

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Modeled dipsAdapted from

Aulanier et al. (1999)

H filament Bz (z=0) & Magnetic dips

Bt (z=0)

Dipsviewed in 3D

–+

barb

The 6th Solar-B Science meeting Kyoto Nov 8 2005

THEMIS

JOP 178 International campaign 16 October 2004

The 6th Solar-B Science meeting Kyoto Nov 8 2005

THEMIS Observations in the Multi lines mode

1. Simulaneously observations of the polarized profiles ofFe I doublet 6301-6302 A, Na I, Hwith beam exchange techniqueData processing (flat field, dark current) SQUV3. Inversion code for the Fe I doublet with a PCA-based algorithmin a Milne-Eddington atmosphere using a grid of models B, Inc., Azi. with error bars in the LOS ref. frame4. Change of the system of reference to local frame5. The 180 ° ambiguity is not resolved, two solutions for incl. and azi.

Criterion used for resolving the ambiguity : the chirality rules for filaments

The 6th Solar-B Science meeting Kyoto Nov 8 2005

SINISTRAL CASE DEXTRAL CASE

According to the directions of the fine structures and the feet (Halpha)

Filament

The 6th Solar-B Science meeting Kyoto Nov 8 2005

I(H)

B (Fe I)

B Sinistral filament

The 6th Solar-B Science meeting Kyoto Nov 8 2005

+

–

Filament axisPhotospheric inversion line (Bz)

SINISTRAL CASE

B horizontal mean direction if the chirality is sinistral

The 6th Solar-B Science meeting Kyoto Nov 8 2005

+

–

B horizontal mean direction if the chirality is dextral

DEXTRAL CASE

Filament axisPhotospheric inversion line (Bz)

The 6th Solar-B Science meeting Kyoto Nov 8 2005

#1#5

#3 #4

#2

#6

The 6th Solar-B Science meeting Kyoto Nov 8 2005

#1#5

#3 #4

#2

#6

The 6th Solar-B Science meeting Kyoto Nov 8 2005

114.7 Mx/cm2 -8.8 Mx/cm2

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Inversion errors (case #1)

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Case #1

–+

3D

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Case #1 3D view

In the filament channel : horizontal dip

Case 2

Case 4

Case 5

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Bz & Bt (z=0)

Lopez Ariste, Aulanier, Schmieder , Sainz A &A 2006

H filament

–+barb

Dipviewed in 3D

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Conclusion

THEMIS/MTR observes simultaneously in multi lines: H, Fe 6302 and 6301, Na D1

High sensitivity of the magnetic flux: -10 Mx/cm2

Magnetic field vector tangential to the photosphere

Photospheric dips = « bald patches » observed

in filament channels

consistent with model of Aulanier & Démoulin (1998)

Needs more cases : SOLAR-B

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Observational evidence of photospheric magnetic dips

in filament channels

Arturo López AristeB. Schmieder, G. Aulanier,

Magnetic loops

filament flux tube

overlaying arcades

Magnetic dips

z > 4 Mm

z < 4 Mm

Adapted from Aulanier & Schmieder (2002)

The 6th Solar-B Science meeting Kyoto Nov 8 2005

EUV filament

A

C

C

ADark, bright threads or no existing

Emission in hot lines

B BOV 105 K

Long extensions

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Case # 6

The 6th Solar-B Science meeting Kyoto Nov 8 2005

Conclusion

THEMIS/MTR observes simultaneously in multi lines: H, Fe 6302 and 6301, Na D1

THEMIS/MSDP H and Na D1 High sensitivity of the magnetic flux: -10 Mx/cm2

Magnetic field vector tangential to the photosphere

Photospheric dips = « bald patches » observed

in filament channelsconsistent with the model of Aulanier & Démoulin (1998)

1.

2. Emerging and cancellation of magnetic fluxFilament disappearance and formation