Did the solar open magnetic field really double in one century?

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1 Did the solar open magnetic field really double in one century? T. Dudok de Wit (LPCE, Orléans) The problem Lockwood et al. (Nature, 1999) : «the solar open magnetic flux has doubled in one century» But This conclusion is based on extrapolation of 25 years of solar wind data The controversy still continues

2 The aa index! Did the level of geomagnetic activity increase more than what the sunspots would suggest? Periodicities in the aa index 11 years : solar cycle 6 months : terrestrial inclination 27 days : solar rotation 1 day : instrumental

3 These periodicities are associated with different mechanisms! Their phase and modulation amplitude should evolve differently Modulation amplitude 27 day modulation: slight drop 6 month modulation: constant (ok) 11 year modulation: drops (?) What did then cause the aa index to increase?

4 Intermediate conclusions Instrumental effects can be excluded But A change in the modulation amplitude cannot explain the secular trend either Modulation phase 11 year modulation: phase vs sunspot number No single mechanism can generate such a phase change

5 Solar origin!! Two concomitant solar mechanisms cause geomagnetic activity Btor Bpol 1) Interplanetary perturbations (CMEs) Cause sudden commencement storms Occur mostly during solar maximum Connected with toroidal component of solar magnetic field Solar origin!! Two concomitant solar mechanisms cause geomagnetic activity Btor Bpol 2) Fast solar winds Cause recurrent storms Occur mostly during declining phase of cycle Connected with poloidal (i.e. open-field) component of solar magnetic field

6 What we know Stix (1958) : these poloidal and toroidal components should be ~180 out of phase Ruzmaikin & Feynman (2001): experimental evidence for such a double driver Could we have? What has been overlooked The aa index has a power-law pdf " Its statistics is biased by large events " We should rather have

7 Adding the two contributions Poloidal field Toroidal field arithmetic sum real global effect 13 The model aa index = double contribution from a Toroidal component (in phase with sunspot number) Poloidal component (out of phase with sunspot number) These two components have been fitted to the aa index with as free parameters : their amplitudes their phase vs sunspot number

Results fit from model toroidal component poloidal component The method is simple yet the fit is better than any one produced so far Conclusions Instrumental effects cannot explain the secular

8 Results fit from model toroidal component poloidal component The method is simple yet the fit is better than any one produced so far Conclusions Instrumental effects cannot explain the secular increase in the aa index This increase is amplified by the phase shift : storms may now occur anytime during the solar cycle Assuming the two contributions reflect the strength of the solar magnetic field: Toroidal field = almost constant Poloidal field = has more than doubled since 1868 Average level of geomagnetic activity can be predicted one cycle ahead.

9 COST Action 724 Athens, 12 October 2005 Appendix 8 WP CME Analysis Status Report V. Bothmer

10 COST724 Working Package 14000, WG 1 Status Report CME Analysis Volker Bothmer Institut für Astrophysik Universität Göttingen Friedrich-Hund-Platz Göttingen Germany

11 Scope of WP for WG 1 of COST724 Coronal Mass Ejection Analysis Specific CME Science Objectives 1: Source regions 2: Precursors and photospheric field evolution 3: CME onsets and post-eruption effects 4: Near-Sun Evolution 5: Interplanetary Evolution 6: Magnetic Field and 3D Structure 7: Space Weather Effects 8: Acceleration of Energetic Particles and Radiation Hazards 9: Theoretical Modeling 10: Solar Cycle Evolution 2

12 I & IV: CME Source Regions & Near-Sun Evolution Collaborators: D.K. Tripathi, Cambridge University, UK H. Cremades, MPS, Katlenbuurg-Lindau, Germany Y. Liu, Stanford University, USA Goal: Using the combined set of SOHO s remote sensing instruments EIT (Extreme Ultraviolett Imaging Telescope, LASCO (Large Angel and Spectrometric Coronagraph) and MDI (Michelson Doppler Interferometer) and complementary ground-based observatory data (H-alpha, etc.), the low corona and photospheric source regions (SRS) of CMEs can be identified. 3

13 Evolution and morphology of a CME The evolution of a CME seen in SOHO/LASCO C2 10:06 UT 10:34 UT 09:54 UT 10:57 UT time 4 11:30 UT Cremades & Bothmer 2002/01/04 09:30 UT

14 CME Source Region and Near-Sun Evolution The onset of a CME seen by EIT 2002/01/04 10:06 UT 2002/01/04 11:01 UT 2002/01/04 9:24 UT time 2002/01/04 8:48 UT 2002/01/04 9:36 UT Neutral line Opposite polarities 2002/01/04 9:24 UT 5 Cremades & Bothmer, A&A, /01/04 9:12 UT

opposite polarities Neutral line Region of opposite polarities N NL

15 Photospheric Source Regions Comparison of Photospheric Field Structure With Coronal Structure MDI contours superposed on EIT 195 Å Region of opposite polarities Neutral line Region of opposite polarities N NL Polarity: Blue=negative Magenta=positive 6 Cremades & Bothmer, A&A, 2004

16 Bipolar Magnetic Regions as CME Sources All CME source regions can be traced back to individual regions of opposite polarities, as identified in MDI synoptic charts. April 2000 SRs of CMEs Positive Polarity 7 Negative Polarity Cremades & Bothmer, A&A, 2004

17 How does the CME activity depends on the photospheric field evolution what are the precursors? 8

18 10: Solar Cycle Evolution Collaborators: D.K. Tripathi, Cambridge University, UK H. Cremades, MPS, Katlenbuurg-Lindau, Germany Y. Liu, Stanford University, USA D. Hathaway, NASA/GSFC, USA Goal: Study the solar cycle variation of identified CME photospheric source regions over the course of the solar cycle, also with respect to active and quiet regions as well as the evolution of spatial and time variations of the photospheric field and the Sun s global field reversal and activity maximum. 9

19 CME Source Regions Over the Solar Cycle Longitudinally averaged magnetic field in time, compared with the latitude evolution in time of the structured CMEs SRs. 10 Cremades, Bothmer, Tripathi, 2005.

20 2 & 3: Precursors and photospheric field evolution, CME onsets and post-eruption effects Collaborators: D.K. Tripathi, Cambridge University, UK Y. Liu, Stanford University, USA A. Zhukov (link to EU-Intas project coordinated by V. Bothmer) Goal: Study the evolution of the photospheric field in the source regions of CMEs. Investigate CME-rate and physical properties solar cycle variation of identified CME photospheric source regions over the course of the solar cycle, also with respect to active and quiet regions as well as the evolution of spatial and time variations of the photospheric field and the Sun s global field reversal and activity maximum. 11

21 Erupting Filaments, Arcades and Magnetic Flux Evolution 12

22 Erupting Filament and CME 13 Bothmer, 2003

23 The big flare and post-eruptive arcade on 14 July 2000 SOHO/EIT and TRACE Observations 14

24 5 & 6: Interplanetary evolution, magnetic field and 3D-structure Collaborators: G. Poletto, Arcetri Astrophysical Observatory, Firenze, Italy D.K. Tripathi, Cambridge University, UK Y. Liu, Stanford University, USA (tbc) A. Zhukov (link to EU-Intas project coordinated by V. Bothmer) E. Huttunen, University of Helsinki, Finnland (tbc) I. Veselovsky, Moscow State University, Russia (Intas) E. Romashets, Izmiran, Russia (Intas) M. Vandas, Astrophysical Institute of Prague, Czech Republic (Intas) 15 R. Schwenn, MPS, Germany Goal: Study the internal magnetic field characteristics of CMEs and their evolution between Sun and Earth. Develop bases for quantitative modeling and forecasting.

25 Structured CMEs The Basic Scheme The topology of the three-part system is basically consistent with the orientation of the neutral line and its position on the solar disk. N NL S EIT 195Å 16 LASCO C2 Cremades & Bothmer, A&A, 2004

26 Relationship between the magnetic structure of filaments at the Sun and the structure of helical flux rope CMEs (magnetic clouds) in the solar wind Bothmer und Schwenn,

27 Solar cycle variation of the magnetic structures of filaments and helical flux rope CMEs in the solar wind 18 Involves findings on filament structures by Martin and Rust Bothmer und Rust, 1997; Bothmer and Schwenn, 1998

28 Implications for CME Modeling The presented scheme agrees with MHD models of large-scale flux ropes. An interplanetary flux rope (Bothmer & Schwenn, 1998) 19

29 The CME on 14 July 2000 caused the strongest geomagnetic storm of the current solar cycle Cause: superfast SEN helical flux rope CME S E N B Bx By Bz 20 Bothmer, 2003.

30 Magnetic Field Properties of the Solar Source Region of the July 2000 CME Expected flux-rope type: SEN (left-handed) Bothmer, 2003.

31 7,8: Space Weather Effects, Particle Acceleration and Radiation Hazards 22 Collaborators: M. Storini, Italy A. Zhukov (link to EU-Intas project coordinated by V. Bothmer) I. Veselovsky, Moscow State University, Russia (Intas), A. Dmitriev E. Romashets, Izmiran, Russia (Intas) M. Vandas, Astrophysical Institute of Prague, Czech Republic (Intas) Collaboration with EADS/Astrium, Wolfgang Keil, A. Zaglauer on effects on satellite systems N. Jakowski, DLR, Germany: Effects on navigation systems, GPS, Implications for Galileo Contract with Springer/Praxis: Space Weather Physics and Effects (to be publ. in 2006) Goal: Study the solar/interplanetary causes of space weather effects and the specific impacts on different technical systems on the ground and in space. Study the origin and causes of solar energetic particle events.

32 Storms Storm peak interval Peak a p Interplanetary structure CME (1 st appearance in LASCO C2 FOV) Source observed by the EIT (start time and and location) Peak of accompanying flare :00 09:00 2nd peak 18: : Shock ~ 06: , sheath with Bz<0. MC followed with NS orientation, H? 10: , halo, 2125 km/s Travel time: 20 hrs, Expected Oct. 29, 07 UT Dimmings and EIT wave, 11: , 0486 X17.2, 11: :00 24: Shock ~ 16: , followed by tsn MC? 20: , halo, 1950 km/s, Travel time: 21 hrs, expected Oct. 30, 18 UT Dimmings and EIT wave, 20: , 0486 X10.0, 20: :00 21: Shock ~ 07: , MC ESW, RH, S 08: , halo, 1175 km/s, Travel time: 36 hrs, expected Nov. 19, 21 UT Dimmings and EIT wave, 07: , 0501 M3.2, 07: All times in this Table are UT 2Although the source of this CME is located behind the E limb, the CME still appeared as halo due to the propagating shock (?) wave (?) seen in LASCO C2. It is difficult to estimate the speed of this weak propagating disturbance. 3NOAA AR numeration. 4A flare could have happened behind the limb. 5Source AR was situated close to the W limb, so the corresponding CME missed the Earth and only sheath was observed.

33 CMEs are the causes of all major space storms 24

34 The Star-Trackers of Rosetta have been contaminated for several days due to solar energetic particle events 25 ESA Science & Technology 20-Sep :03:28 Solar Flare Interacts with Rosetta 19 Sep 2005 Report for Period 26 August to 16 September 2005 The reporting period covers three weeks of passive cruise, with no major activities planned and weekly ground contact with the spacecraft. Apart for routine monitoring activities and the upload of a software patch to the Star Tracker B (on 8 September), a major unexpected event was a solar flare on 8 and 9 September, which hit the spacecraft at the beginning of the weekly non-coverage period. When the signal was acquired for the weekly contact on 15 September the spacecraft was found with the active Star Tracker crashed in INIT mode, and the second Star Tracker (not used for attitude control) in Standby mode. AOCS had determined the attitude over a period of 6 days using gyroscopes only, and accumulated therefore a drift of about 0.7 degrees, of which 0.3 degrees offset in the High Gain Antenna pointing direction, small enough to allow the RF signal to be received on ground. The recovery activities took most of the ground station pass on 15 September. At the end both Star Trackers were back in Tracking mode and the nominal attitude reacquired. No payload operations were carried out in the reporting period, and all instruments are switched off, except for SREM which is kept active in the background for radiation monitoring. A total of 3 New Norcia passes of maximum 10 hours commanding duration were taken over the reporting period. At the end of the reporting period (DOY 259) Rosetta was at million km from the Earth (1.23 AU; one-way signal travel time was 8 min 07 sec). The distance to Sun was million Km (1.64 AU) NNO Pass Date DOY Main Activity Monitor pass - update TM mode OBCP, dump STR B Monitor pass - patch STR B (hot pixel event) Monitor pass - solar flare: STR recovery For further information please contact: SciTech.editorial@esa.int

35 SEPs caused in the 14. July 2000 storm Data: SOHO/COSTEP 26 Bothmer, ESA-SP, 1999.

36 SOHO Solar Array Degradation on July 14, Courtesy: ESA/NASA

37 Proton Snowstorm observed by SOHO Effects of ~ 100 MeV Protons on LASCO CCDs The largest solar particle events appear to result from shock associated coronal mass ejections (CMEs) 28 Bothmer, ESA-SP, 1999.

38 9: Theoretical Modeling Collaborators: A. Zhukov (link to EU-Intas project coordinated by V. Bothmer) I. Veselovsky, Moscow State University, Russia (Intas), A. Dmitriev E. Romashets, Izmiran, Russia (Intas) M. Vandas, Astrophysical Institute of Prague, Czech Republic (Intas) J. Schmidt, IUB, Germany (tbc) I. Roussev, Univ. of Michigan, USA (tbc) R. Schwenn, MPS, Germany J. Büchner, MPS, Germany Goal: Model internal field structure and evolution of CMEs between Sun and Earth. Help establish bases for realistic magnetic storm prediction. Help develop CME onset models. Predict CME arrival time at Earth. 29

Forecas(ng the Magne(c Field Configura(on of CMEs

Volker Bothmer University of Göttingen Institute for Astrophysics 26 October 2015 ISEST Workshop, UNAM, Mexico City Forecas(ng the Magne(c Field Configura(on of CMEs Outline 1. Magnetic field configuration