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Aim and Outline of the Study

Tracking intense geomagnetic storms to the interplanetary medium and solar source. A case of study.

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Aim and Outline of the Study

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  1. Tracking intense geomagnetic storms to the interplanetary medium and solar source. A case of study Dasso S.1,2, C.H. Mandrini1, B. Schmieder3, A.N. Zhukov4, A. Aran5, Y. Cerrato6, C. Cid6, H. Cremades7, M. Menvielle8, S. Poedts9, L. Rodriguez4, E. Saiz6 1 Instituto de Astronomía y Física del Espacio (IAFE, UBA/CONICET), Argentina 2 Departamento de Física (FCEN, UBA) Argentina 3 Observatoire de Paris, FRE 2461 (CNRS), F-92195, LESIA, Meudon, France 4 Royal Observatory of Belgium, Belgium 5 Universitat de Barcelona (Departament d’Astronomia i Meteorología), Spain 6 Universidad de Alcalá (Space Research Group), Spain 7 NASA/Goddard Space Flight Center (GSFC), Maryland, USA 8 Centre d’Etudes des Enviroments Terrestre et Planétaires, Paris, France 9 The Centre for Plasma Astrophysics (CPA) of the K.U., Leuven, Belgium

  2. Aim and Outline of the Study *We study the geoeffective ‘May 13-17, 2005’ success, tracking it from Sun to Earth*We explore two possible scenarios: ONE or TWO ejections/clouds/geomagnetic-answers* This event corresponds to one of the most geoeffective ones (Dstmin~-300nT) observed at Earth, and it corresponds to observations of one of the most intense (~50nT) and faster (~900 Km/sec) Interplanetary Coronal Mass Ejection at 1AU. We analyze:Solar Atmosphere (r<30Rsun)  HASTA, EIT, TRACE, LASCO (C2/C3)Solar Wind at one Astronomical Unit  ACE (MAG and SWEPAM)Effects on Geomagnetism  Dst, SYM-H, ASY-H, am, and PCn indexes

  3. The events at the Sun Are two eruptions seen in H? The first starting at ~16:30 UT and accompanied by an M8.0 two ribbon flare. A much smaller one starting at ~ 17:00 UT at the South of AR 10759. Theta=50 degree HASTA – May 13, 2005

  4. Envol du filament le 13Mai à 13:02UT TRACE 171A

  5. The events at the Sun EIT 195 Å image on 13 May at 11:42 UT. Magnetic linear force free model of AR 10759 before the M 8.0 flare  = -1.6 10-2 Mm-1 TRACE 195 Å image on 14 May at 12:45 UT. Two post-flare arcades are visible: one corresponding to the two-ribbon flare, the second one probably associated to the small eruption at the South.

  6. The events at the Sun LASCO C2 at 17:22 UT and a corresponding difference image. A full halo CME is observed. Or it is 2CMEs? LASCO C3 at 17:42 UT and a corresponding difference image. A faint edge can be distinguished, suggesting either the presence of a shock or of a fainter ejection with similar geometry. the orientation of its main axis is of ~55˚ from the N-S line

  7. The intense Southern component of IMF (of the order of 40 nT) duringtwo hours and a half, joint to a high velocity (close to 900 km/s) are the responsible of reconnection between thesolar wind and terrestrialmagnetosphere. Then, the different models used to forecast Dst thatarebased on the reconnection mechanism, provide a very accurate response. Dst indexfrom the Kyoto World Data Center and theoretical Dst from different models (see legend)

  8. Very low level of the magnetic activity before the event. The ssc (+ 62 nT in 4 minutes) observed at 02:38 am on May 15th marks the beginning of a 12-hour long period of very intense magnetic activity (am>100 nT, with a 500 nT peak value). This event is followed about six hours later by another period of magnetic activity that may correspond to a second event in the solar wind. Let focus on the first 12-hour long intense magnetic storm. The ssc is followed by a period of high ASY-H with values ranging typically between 50 and 75 nT. The end of this period is marked by a very sharp decrease in SYM-H values and a significant increase in the ASY-H values; it corresponds to the am peak value. The dayside merging (PCn) mostly occurs during the period of intense magnetic activity, while the magnetosphere activity lasts up to ~07:40 pm on May 17th.

  9. Two possible Magnetic Clouds at L1 (ACE) 1rst Cloud? 2nd Cloud? Plasma data gap Time (in Hours) after May 15, 2005, 00UT Magnetic intensity (nT), magnetic field components (GSE, nT), magnetic latitude (degrees), bulk plasma velocity (Km/sec), and proton density (cm-3). Sheath (2:00UT–5:40UT), first cloud (non expansive, high speed, 5:40UT-10:20UT), second cloud (expansive, 10:20UT-04:00UT May 16th)

  10. Magnetic Cloud Frame (Mininum Variance analysis) First MC Second MC Non expanding Left Handed (LH) Flux rope. MV to B: Expanding LH Flux rope, large p/R MV to b=B/|B| (normalized field): : Angle between the cloud axis and the ecliptic plane : Angle between projection of MC axis on ecliptic plane and XGSE (counterclockwise)

  11. ACE data (L1) 15 May at 02 UT : shock followed by sheath At 6 UT discontinuity of V, T and B From 6 to 9: V high, T increases, structures in B From 9 T low, Vlow , B high and rotation (until the green line) After 12 low V, low T low B.

  12. One Cloud with highly elliptical section theta= 59.5, phi=120 degree Between May 15.-9 – May 15- 12 Courtesy of C.Cid Other one cloud fits: Lepping theta=94, Phi=67 MVA theta=49, phi= 246

  13. 2 CMEs (from May 11 and May 13 2005) 11 May LASCO C2 at 20:13 UT above the SWW limb PA 231 = 470 km s-1 13 May LASCO C2 at 17:22 1640 km s-1. Poedts computations

  14. Preliminar Conclusions • Sign of Magnetic Helicity of the AR 10759 before the ejection is negative • One clear 1st ejection (HASTA) and a possible 2nd one • Clear full HALO CME in LASCO C2 (May 13 at 17:22UT) and in C3 (17:42UT), may be a CME on May 11 at 22 UT participate • First possible magnetic cloud (MC) has very high speed (~894Km/sec) and it is not in expansion. Second one is in strongly expansion. Both are left handed, but they seem to have different axis orientation. • Another possibility is only one large from 9 UT, May 15 to 12:00UT, May 16 (very asymmetric with a non typical shape in its first half, strongly distorted perhaps because its interaction with SW in its front, near the Sun) Acknowledgments The authors would like to thank to the International Space Science Institute (ISSI, Bern, Switzerland) to support the project ‘The Stages of Sun-Earth Connection’, leaded by Dr. Consuelo Cid. C. Cid would like to acknowledge financial support from COST 724.

  15. Second MC elliptical model ACE Magnetic field components (GSE, black dots).Red lines correspond to the fitting model (Hidalgo et al. 2004), which consider an elliptical cross section for the cloud The helicity obtained from the fitting is left handed Orientation from model: =55º, =299º

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