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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-Region Prominence. Joten Okamoto Kyoto Univ. ／ NAOJ JSPS Research Fellow Saku Tsuneta, Bruce Lites, Masahito Kubo, Takaaki Yokoyama and Japan-US Hinode/SOT team + KD Leka, Tom Metcalf.

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

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  1. Direct Evidence of Emergence of a Helical Flux Rope under an Active-Region Prominence Joten Okamoto Kyoto Univ.／NAOJ JSPS Research Fellow Saku Tsuneta, Bruce Lites, Masahito Kubo, Takaaki Yokoyama and 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.

  2. Hinode satellite EIS • 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 Hinode • Continuous 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 XRT

  3. 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 prominences • Formation process • supply of mass • construction of magnetic field • Fine structures and their evolution • Disappearance and eruption • Coronal Mass Ejection (CME) SMART Hα image (Hida Obs.) Hinode/SOT Ca II H movie （Okamoto et al. 2007)

  4. Structure of prominence magnetic fields • Helical in many cases • Measurement 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 ? prominence helical field line Prominence in the unified model of flares and CMEs (Shibata et al.) QS prominence AR prominence

  5. Formation of prominence magnetic fields prominence How are they made ? helical field line • Theory • Helical flux rope emergence from the photosphere • e.g., Rust, Kumar, Low, Lites… • Shear motion on the photosphere and reconnection in the corona • e.g., Pneuman, van Ballegooijen, Martens, Antiochos, Aulanier, Karpen… • Observation • No clear evidence • lack of accuracy of polarimetric measurement due to seeing • restriction to long-duration observation KEY: Motion and time-evolution of magnetic field on the photosphere Tracking of evolution of AR prominence

  6. Data • Continuous observation of AR • 2007 Apr 28 ～ May 2 • AR 10953 • wavelength (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 field • Milne-Eddington inversion (Yokoyama et al.) • 180°ambiguity solution with AZAM (Lites et al.) • （Current 3,4 (Metcalf et al.)） Ca II H H-alpha ROI

  7. Hα movie with Hinode/SOT • Repetition of formation and deformation during 2 days Hinode/SOT Hα 04.28 11:56 04.28 23:14 04.29 12:09 04.29 18:13 04.29 20:51 formation deformation formation deformation

  8. After that…（Hida/SMART Hα） • Formation of a clear prominence • it looks stable after May 1 05.01 22:27 04.29 22:10 05.02 21:18 05.03 22:09 05.04 21:44 SOT FOV What can we see in SP data ? Evolution of photospheric magnetic field near the PIL during the promninence formation

  9. ＋ － ＋ － ＋ － Result （photosphere） plage sunspot side PIL PIL PIL Interpretation （cross section of photosphere) × × × photosphere （conclusion）Helical flux rope emergence • Observational 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 PIL sunspot side plage

  10. sunspot side （＜－500 G） plage （＞500 G） PIL magneto-gram（1/9） 2007.04.29 11:43 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： boundary of ±500G of Bz

  11. magneto-gram（2/9） 2007.04.29 15:36 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： boundary of ±500G of Bz

  12. magneto-gram（3/9） 2007.04.29 20:16 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： boundary of ±500G of Bz

  13. magneto-gram（4/9） 2007.04.30 01:00 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： boundary of ±500G of Bz

  14. magneto-gram（5/9） 2007.04.30 05:07 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： boundary of ±500G of Bz

  15. magneto-gram（6/9） 2007.04.30 08:56 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： boundary of ±500G of Bz

  16. magneto-gram（7/9） 2007.04.30 15:46 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： boundary of ±500G of Bz

  17. magneto-gram（8/9） 2007.04.30 22:46 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： boundary of ±500G of Bz

  18. magneto-gram（9/9） 2007.05.01 08:16 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： boundary of ±500G of Bz

  19. 15” ~ 10,000 km vertical mag. （color contour）＋horizontal mag.（arrows） ④ ① 2007.04.2911:43 2007.04.3005:07 ⑦ 2007.04.3022:46 ⑧ 2007.05.0102:06 2007.04.3008:56 2007.04.2915:36 ② ⑤ ⑨ 2007.04.2920:16 2007.04.3015:46 ③ ⑥ 2007.05.0108:16

  20. －300 m/s vertical velocity of magnetic components by ME fitting （color contour）＋horizontal mag. （arrows） ④ ① 2007.04.2911:43 2007.04.3005:07 ⑦ 2007.04.3022:46 ⑧ 2007.05.0102:06 2007.04.3008:56 2007.04.2915:36 ② ⑤ ⑨ 2007.04.2920:16 2007.04.3015:46 ③ ⑥ 2007.05.0108:16

  21. normal or inverse ?（1/12） 2007.04.28 21:26 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  22. normal or inverse ?（2/12） 2007.04.29 03:46 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  23. normal or inverse ?（3/12） 2007.04.29 11:43 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  24. normal or inverse ?（4/12） 2007.04.29 15:36 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  25. normal or inverse ?（5/12） 2007.04.29 20:16 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  26. normal or inverse ?（6/12） 2007.04.30 05:07 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  27. normal or inverse ?（7/12） 2007.04.30 08:56 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  28. normal or inverse ?（8/12） 2007.04.30 12:46 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  29. normal or inverse ?（9/12） 2007.04.30 15:46 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  30. normal or inverse ?（10/12） 2007.04.30 22:46 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  31. normal or inverse ?（11/12） 2007.05.01 02:06 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  32. normal or inverse ?（12/12） 2007.05.01 05:16 vertical mag. red ：＋ blue：－ horizontal mag. arrows black line： PIL 度 normal inverse

  33. ＋ － ＋ － ＋ － Result （photosphere） plage sunspot side PIL PIL PIL Interpretation （cross section of photosphere) × × × photosphere Helical flux rope emergence • Observational 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 PIL sunspot side plage

  34. ＋ － ＋ － ＋ － Result （photosphere） plage sunspot side PIL PIL PIL Helical flux rope emergence

  35. Emergence of helical flux ropeand Prominence 2007.04.29 15:36 2007.04.29 20:16 2007.04.30 05:07 2007.04.30 08:56 • Continuous prominence appeared after the emergence of the flux tube • Some remnants of prominence existed before the event • The newly-emerging fields connect with original fields or get rid of those ?

  36. Motion on the photosphere（G-band） 2007.04.30 08:56 Red circle indicates the orientation of the prominence

  37. Motion on the photosphere（G-band） 2007.04.30 08:56 Red circle indicates the orientation of the prominence advective flow: arrows No clear sheared motion, but some mesogranules under the prominence = support to emergence ?

  38. Physical parameters 2007.04.3005:07 10,000 km sunspot side PIL plage • Duration of emergence： 24 – 36 hours • Rising height： ～25,000 km • 24 h ×300 m/s • Mag. field strength of prominence: ～100 G • 650 G ×0.15

  39. Summary • Clear evidence of emerging helical flux rope associated with formation of prominence • Appearance of magnetized region that had weaker field strength along the PIL • After that, prominence was stabilized • No continuous sheared motion along the PIL • Shear/reconnection model is ruleed out ?... No • Our result is one example in an active region • Necessary 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.

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