Direct Evidence of Emergence of a Helical Flux Rope under an Active-Region Prominence

Direct Evidence of Emergence of a Helical Flux Rope under an Active-Reg

ion Prominence

Joten OkamotoKyoto Univ. ／ NAOJ JSPS Research Fellow

Saku Tsuneta, Bruce Lites, Masahito Kubo, Takaaki Yokoyamaand Japan-US Hinode/SOT team + KD Leka, Tom Metcalf

This work is my PhD thesis topic. I am provided limited protection for the data sets.(see http://solarb.msfc.nasa.gov/for_scientists/topics.html, http://solar-b.nao.ac.jp/hsc_e/OnGoing_top.shtml )I have submitted the former part of this work to ApJL. The latter part (not included in this PPT) will be submitted.

http://solarb.msfc.nasa.gov/for_scientists/topics.html

http://solar-b.nao.ac.jp/hsc_e/OnGoing_top.shtml

Hinode satellite

Hinode was launched in Sep. 2006.3 instruments

SOT (Soalr Optical Telescope)– photosphere, chromosphere

XRT (X-ray Telescope)– corona

EIS (EUV Imaging Spectrometer)– transition region, corona

Advantage of HinodeContinuous high-quality movie Small scale structures and time variation of solar phenomena

granules, small magnetic elements, spicules, prominences, …

In this talk, we focus on prominence observation.

SOT

EIS

XRT

Prominence

Cool plasma in the corona~ 10,000 K

over polarity inversion lines (PILs)

“filament” on disk

supported by coronal magnetic filed lines

Questions about prominencesFormation process

supply of mass

construction of magnetic field

Fine structures and their evolution

Disappearance and eruptionCoronal Mass Ejection (CME)

SMART Hα image (Hida Obs.)

Hinode/SOT Ca II H movie（ Okamoto et al. 2007)

Structure of prominence magnetic fields

Helical in many casesMeasurement with polarization

e.g., Tandberg-Hanssen, Leroy

Extrapolation from eruption e.g., CME taken by SOHO/LASCO

How to make this ?same or difference of QS and AR prominences ?

AR prominence QS prominence

prominence

helical field line

Prominence in the unified modelof flares and CMEs (Shibata et al.)

Formation of prominence magnetic fields

TheoryHelical flux rope emergence from the

photospheree.g., Rust, Kumar, Low, Lites…

Shear motion on the photosphere and reconnection in the corona

e.g., Pneuman, van Ballegooijen, Martens, Antiochos, Aulanier, Karpen…

ObservationNo clear evidence

lack of accuracy of polarimetric measurement due to seeingrestriction to long-duration observation

How are they made ?

KEY: Motion and time-evolution of magnetic field on the photosphere

Tracking of evolution of AR prominence

prominence

helical field line

Data

Continuous observation of AR2007 Apr 28 ～ May 2AR 10953wavelength (Hinode)

SpectroPolarimeter (SP) fast map (160”x160”, 3 ～ 6-hour cadence )

Hα (160”x160”, 1-min cadence)G-band 、 Ca II H (108”x108”, 1-min cadence)X-ray (512”x512”, 1-min cadence)

Estimation of magnetic fieldMilne-Eddington inversion (Yokoyama et al.)180°ambiguity solution with AZAM

　　 (Lites et al.)（ Current 3,4 (Metcalf et al.) ）

H-alpha

Ca II H

ROI

Hα movie with Hinode/SOT

deformation

Hinode/SOT Hα

formation

Repetition of formation and deformation during 2 days

04.28 11:56 04.28 23:14 04.29 12:09 04.29 18:13 04.29 20:51

deformation formation

After that… （ Hida/SMART Hα ）

Formation of a clear prominenceit looks stable after May 1

05.01 22:27 05.02 21:18 05.03 22:09 05.04 21:4404.29 22:10

What can we see in SP data ?Evolution of photospheric magnetic field

near the PIL during the promninence formation

SOT FOV

（ conclusion ） Helical flux rope emergence

Observational results (on the PIL)Changing direction of horizontal magnetic fieldSimultaneous appearance of a region having weak vertical magnetic fieldSimultaneous upflow in the same region

plage

sunspotside

×

Interpretation（ cross sectionof photosphere)

××

photosphere

PIL

Result（ photosphere ）

－＋

plage sunspot side

－＋－＋

PIL PILPIL

magneto-gram （ 1/

9 ）

2007.04.2911:43

vertical mag.　 red ：＋　 blue ：－

horizontal mag.　 arrows

black line ：boundary of±500G of Bz

plage（＞ 500 G ） PIL

sunspot side（＜－ 500 G ）

2007.04.2915:36

magneto-gram （ 2/

9 ）




2007.04.2920:16

magneto-gram （ 3/

9 ）




2007.04.3001:00

magneto-gram （ 4/

9 ）




2007.04.3005:07

magneto-gram （ 5/

9 ）




2007.04.3008:56

magneto-gram （ 6/

9 ）




2007.04.3015:46

magneto-gram （ 7/

9 ）




2007.04.3022:46

magneto-gram （ 8/

9 ）




2007.05.0108:16

magneto-gram （ 9/

9 ）




2007.04.29 　 11:43

2007.04.29 　 15:36

2007.04.29 　 20:16

2007.04.30 　 05:07

2007.04.30 　 15:46

2007.05.01 　 08:16

2007.05.01 　 02:06

2007.04.30 　 22:46

2007.04.30 　 08:56

vertical mag. （ color contour ）＋ horizontal mag. （ arrows ）

15” ~ 10,000 km

①

②

③

④

⑤

⑥

⑦

⑧

⑨

2007.04.29 　 11:43

2007.04.29 　 15:36

2007.04.29 　 20:16

2007.04.30 　 05:07

2007.04.30 　 15:46

2007.05.01 　 08:16

2007.05.01 　 02:06

2007.04.30 　 22:46

2007.04.30 　 08:56

vertical velocity of magnetic components by ME fitting （ color contour ）＋ horizontal mag. （ arrows ）

－ 300 m/s

①

②

③

④

⑤

⑥

⑦

⑧

⑨

2007.04.2821:26



black line ：　 PIL

normal or inverse ?（ 1/12 ）

normal

inverse

度

2007.04.2903:46


normal

inverse

度




2007.04.2911:43


normal

inverse

度




2007.04.2915:36


normal

inverse

度




2007.04.2920:16


normal

inverse

度




2007.04.3005:07


normal

inverse

度




2007.04.3008:56


normal

inverse

度




2007.04.3012:46


normal

inverse

度




2007.04.3015:46


normal

inverse

度




2007.04.3022:46

normal or inverse ?（ 10/1

2 ）

normal

inverse

度




2007.05.0102:06


2 ）

normal

inverse

度




2007.05.0105:16


2 ）

normal

inverse

度




Helical flux rope emergenceObservational results (on the PIL)

Changing direction of horizontal magnetic field

Simultaneous appearance of a region having weak vertical magnetic field

Simultaneous upflow in the same region plage

sunspotside

×

Interpretation（ cross sectionof photosphere)

××

photosphere

PIL


－＋

plage sunspot side

－＋－＋

PIL PILPIL

Helical flux rope emergence


－＋

plage sunspot side

－＋－＋

PIL PILPIL

Emergence of helical flux ropeand Prominence2007.04.29

20:162007.04.30

05:072007.04.30

08:562007.04.29

15:36

Continuous prominence appeared after the emergence of the flux tubeSome remnants of prominence existed before the eventThe newly-emerging fields connect with original fields or get rid of those ?

Motion on the photosphere （ G-band ）

2007.04.3008:56

Red circle indicates the orientation of the prominence

advective flow: arrows

2007.04.3008:56

No clear sheared motion, but some mesogranules under the prominence= support to emergence ?

Red circle indicates the orientation of the prominence

Motion on the photosphere （ G-band ）

Physical parameters

plage

（＋）

PIL sunspot side

（－）

Bz(G)

＋ 1100±400

0±200

－ 1000±400

Bxy(G)

400±200

650±150

650±200

Vz(m/s)

＋ 200±500

－ 300±200

－ 100±700

filling

factor0.23±0.20

0.15±0.05

0.30±0.20

Mag. field strength of prominence: ～ 100 G

650 G ×0.15

10,000 km

2007.04.30 　 05:07

plage

PIL

sunspotside

Duration of emergence ： 24 – 36 hours

Rising height ：～ 25,000 km24 h ×300 m/s

Summary

Clear evidence of emerging helical flux rope associated with formation of prominence

Appearance of magnetized region that had weaker field strength along the PILAfter that, prominence was stabilizedNo continuous sheared motion along the PIL

Shear/reconnection model is ruleed out ?... NoOur result is one example in an active regionNecessary to observe active/quiescent prominences quantitatively

How to emerge ?Possible to emerge a whole long rope whose length is several tens of thousand km ?Why is it located along the PIL ?

Mechanism of mass supply ? … We don’t know.It supplied only helical magnetic field to the corona.

Documents

Direct Evidence of Emergence of a Helical Flux Rope under an Active-Region Prominence