Observations of an Eruptive Flux Rope, CME Formation, and Associated Blast Wave

1. Observations of an Eruptive Flux Rope, CME Formation, and Associated Blast Wave V.Grechnev1, A.Uralov1, I.Kuzmenko2, A.Kochanov1, V.Fainshtein1, Ya.Egorov1, D.Prosovetsky1 1Institute of Solar-Terrestrial Physics (Irkutsk, Russia) 2Ussuriysk Astrophysical Observatory (Ussuriysk, Russia) 2010-06-13 SDO/AIA 193 Å From Gopalswamy et al.: 2012, ApJ 744, 72

2. 2010 June 13 Event A number of aspects were previously addressed by: • Patsourakos, Vourlidas, Stenborg: 2010, ApJL 724, L188 • Kozarev et al.: 2011,ApJL 733, L25 • Ma et al.: 2011,ApJ 738, 160 • Gopalswamy et al.: 2012, ApJ 744, 72 • Downs et al.: 2012, ApJ 750, 134 • Eselevich & Eselevich: 2012, ApJ 761, 68 • Vasanth et al.: 2014, Solar Phys. 289, 251 • Kouloumvakos et al.: 2014, Solar Phys. 289, 2123, etc… • Genesis of the flux rope and its properties • How was the CME formed? • Where and how was the wave excited? Major unanswered questions - Common issues for many similar events

3. Looks mainly similar in 171, 193, 211, and 304 Å a) Usual representation: fixed field of view b) Resizing images to compensate for expansion CME Lift-off in 171 Å. Outer boundary green What drove the CME?

4. 1 2 3 4 SDO/AIA 131 Å images • Initial dark prominence • Prominence activates and brightens up  heating up to ~10 MK • Transforms into bundles of loops, which erupt • Rope expands, turns aside by 20, and rotates Visible only • in 131 Å (10 MK) faint • in 94 Å (6.3 MK) still poorer

5. Top: SDO/AIA 131 Å Bottom: acceleration Initial dark prominence Brightens  heats Transforms into bundles of loops, i.e., flux rope Rope sharply erupts, 3 km/s2 Rope turns aside by 20, rotates, and decelerates, -1 km/s2 Flux rope in resized movie Red arcoutlines the top

6. Flare onset Kinematics of the Flux Rope • Hot ~10 MK flux rope developed from structures initially associated with compact prominence • Flux rope appeared as a bundle of intertwisted loops • It sharply erupted with an acceleration up to  3 km/s21 min before HXR burst and earlier than any other structures, • reached a speed of 450 km/s • then decelerated to  70 km/s

7. 193 Å CME development • CME was driven by flux rope expanding inside it. Arcade loops above the rope • were sequentially involved into expansion from below upwards, • approached each other, and • apparently merged, constituting the visible rim • Flux rope rotated inside the rim, which has become an outer boundary of the cavity • Different event led Cheng et al. (2011, ApJL 732, L25) to similar conclusions

8. Images are resized to keep rim fixed 131 Å 171 Å CME formation. Development of Rim

9. The rim: red Below rim (304 & 171 Å): blue Above rim (211 Å): green different orientations: rim was associated with a separatrix surface Not permeable, like a membrane Expanding separatrix surface swept up structures & plasmas ahead left rarefied volume behind dimming Formation of rim: due to successive compression of structures above active region into CME’s frontal structure When the rim was formed completely, it looked like a piston 304 Å LPS 40 171 Å 211 Å What was the Rim?

10. Disturbance responsible for consecutive CME formation episodes was excited by flux rope inside the rim propagated outward Structures at different heights accelerated, when their trajectories were crossed by trajectory of this disturbance Flux rope transmitted part of its energy to structures above it 193 Å Wave 193 Å arc sec ‘elastic collision’ -36 Distance–Time History

11. Wave with v0 1000km/s was excited by a subsonic piston, vP = 240 km/s v0 1000km/s is usual Alfvén speed above an active region Acceleration of the piston was 3 km/s2 at that time Impulsively excited wave decelerated like a blast wave Kinematics of Rope, Loops and Wave

12. Method: Grechnev et al. (2011, Sol. Phys., 273, 433 & 461) Type II burst • Wave signatures were leading portion of the EUV wave and type II radio burst • Also wave traces: onset of dm bursts recorded at fixed frequencies (white) • Outline: power-law density model and fit • Shock: see cited papers and talk by Fainshtein & Egorov

13. AIA 211 Å base diff. AIA 171 Å no subtraction Eruption and Wave

14. Plots of CME & Wave and LASCO data • Symbols: measurements from CME catalog • Lines: analytic fit • Main part of EUVtransient became CME’s frontal structure (FS) • consisted of 1.8 MK coronal loops on top of the expanding rim • Wave strongly dampened and decayed into weak disturbance, being not driven by trailing piston, which slowed down

15. Conclusion… • Hot flux rope developed from structures associated with a compact prominence. • It sharply erupted earlier than any other structures and strongly accelerated. Then it decelerated, having transmitted a part of its energy to the CME structures above it. The relaxed flux rope became the CME core. • CME development was driven from inside by the expanding flux rope. Arcade loops above it were sequentially involved into expansion being compressed from below. They apparently approached each other, constituting the visible rim. The rim was separated from the active flux rope by a cavity. The rim was not pronounced in the white-light CME. Contd…

16. …Conclusion • The rim was associated with an expanding separatrix surface. It swept up magnetoplasmas ahead, forming the main part of EUV transient (future CMEfrontal structure) and left rarefied volume behind, producing dimming. • The impulsively erupting flux rope produced inside the forming CME a disturbance, which propagated outward like a blast wave. Being not driven by the decelerating piston, it dampened and decayed into weak disturbance. • A number of events demonstrates a similar history of a wave. If a CME is fast, then such a blast-like wave should transform into bow shock afterwards. • Scenario of Hirayama (1974, Sol. Phys. 34, 323) appears to match the event.

17. Thanks • For your attention • To organizers of this meeting for the opportunity to attend it and support • To the instrumental teams of SDO/AIA, SOHO (ESA & NASA), USAF RSTN, NICT (Japan), STEREO • To the team maintaining the SOHO/LASCO CME Catalog • To L. Kashapova and S. Anfinogentov for their assistance in data handling • To A. Kouloumvakos & co-authors for useful discussion

18. Comments

19. Scenario of T. Hirayama (1974, Sol. Phys. 34, 323). Our colored comments blink Rising filament causes • Shock wave • Flare cusp

20. Inhester, Birn, Hesse 1992, Solar Phys. 138, 257 van Ballegooijen & Martens 1989, ApJ 343, 971 Longcope & Beveridge 2007, ApJ 669, 621 3D CSHKP model • + Toroidal force

21. Toroidal force 3D curvature – toroidal force: • Anzer (1978, Sol. Phys. 57, 111) • Chen (1989, ApJ 338, 453; JGR 1996, 101, A12, 27499)

22. Cf. Simulations by Kliem et al.

23. N S Impulsive Acceleration Stage One of possible scenarios: • Reconnection between filament threads and in envelope arcade increases poloidal flux and plasma pressure • Propelling toroidal force develops • Filament transforms into “mainspring” • Torus instability, possible kink-like instability: mainspring straightens Synchronously with HXR burst Field lines tend to straighten Toroidal force develops Zhang et al. (2001, ApJ 559, 452), Temmer et al. (2008, ApJ 673, L95; 2010, ApJ 712, L1410); etc. Reconnection  twist increases  flux rope completely forms Sheared field of initial filaments van Ballegooijen & Martens 1989, ApJ 343, 971; Inhester, Birn, Hesse 1992, Sol. Phys. 138, 257; Qiu et al. 2007, ApJ 659, 758;etc.

24. Pre-eruptive filaments High Vfast domain Arcade Compression region Eruptive filaments Arcade Low Vfast environment Development of shock waves • Waves are excited by sharply erupting filaments as impulsive pistons at ~50 Mm during rise of HXR/microwave bursts, butnot by flares • Waves rapidly steepen into shocks in region of steep falloff of Vfast in AR • Waves are transmitted by arcades, enveloping filaments, as monopole acoustic antennas • Then waves propagate like decelerating blast waves (cf. Parker 1961; Pomoell et al. 2008) Not easy to recognize expanding arcade and appearing wave

25. Type II

26. Top: yellow ellipses represent circular surface trail of the expanding spheroidal wave front Bottom: surface wave speed Wave in STEREO-A/EUVI 195 Å images

27. Flux rope red, Frontal structure white, Wave yellow CME & Wave in LASCO images