1 / 23

Small Scale Magnetic Reconnection in the Solar Wind.

UCL DEPARTMENT OF SPACE & CLIMATE PHYSICS MULLARD SPACE SCIENCE LABORATORY. Small Scale Magnetic Reconnection in the Solar Wind. A.C. Foster 1 , C.J. Owen 1 , A.N. Fazakerley 1 , I. J. Rae 1 , C. Forsyth 1 , E. Lucek 2 , H. Rème 3 UCL, Mullard Space Science Laboratory, Surrey, UK

mason-rose
Télécharger la présentation

Small Scale Magnetic Reconnection in the Solar Wind.

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. UCL DEPARTMENT OF SPACE & CLIMATE PHYSICS MULLARD SPACE SCIENCE LABORATORY Small Scale Magnetic Reconnection in the Solar Wind. A.C. Foster1, C.J. Owen1, A.N. Fazakerley1, I. J. Rae1, C. Forsyth1, E. Lucek2, H. Rème3 UCL, Mullard Space Science Laboratory, Surrey, UK Imperial College, London, UK CNRS, IRAP, Toulouse, France Cluster Active Archive

  2. First published study of solar wind reconnection made by Gosling, 2005. Bifurcated current sheet Magnetic field rotations over current sheets Enhanced plasma jet / reconnection exhaust Magnetic Reconnection Observables Reconnection Exhaust B A1 A2 Inflow Inflow Magnetic Field Lines Current Sheet Inflow Inflow B Reconnection Exhaust Adapted from Gosling, J.T. (2005)

  3. Advantages in studying Reconnection in the Solar Wind • Unconstrained boundary conditions • Multiple spacecraft observations • Time scales ≤ few hours • Length scales ~100s RE • Different plasma conditions than frequently studied (e.g. Magnetopause / magnetotail) Jet BM ACE To Sun Exhaust Earth Cluster Wind Solar Wind Direction Phan, T.D (2006) Jet

  4. Previous study of reconnection event 02/02/2002 Phan, T.D (2006)

  5. Previous results have suggested that reconnection in the solar wind is fundamentally extended and non patchy. Is this always the case? Study magnetic reconnection structures Test the consistency of the temporal and spatial structure of magnetic reconnection from large scales to small scales using the 4 Cluster spacecraft; multi-scale capacity Aim of Project

  6. Case Study: Event 2/3/2006 Cluster 3 magnetic field and ion velocity data in GSE 8 6 |B| (nT) B (nT) 4 Total -- X --Y --Z -- 2 0 4 2 0 -2 40 400 -370 Vx (km/s) 30 -380 390 |V| (km/s) -390 20 380 10 -400 370 10 0 Vz (nT) Vy (nT) -10 -20 37m00s 38m00s 38m30s 39m00s 39m30s 40m00s 37m30s Universal Time

  7. Event 2/3/2006: Characteristics • Magnetic rotation over the event: 71° Total -- X --Y --Z -- 37m00s 38m00s 38m30s 39m00s 39m30s 40m00s 37m30s Universal Time

  8. Event 2/3/2006: Characteristics • Magnetic rotation over the event: 71° • Angle between two main current sheets: 33° Inflow B Inflow Inflow Current Sheet A1 33° Reconnection Exhaust A2 Magnetic Field Lines Inflow B Inflow Adapted from Gosling, J.T. (2005)

  9. Event 2/3/2006: Characteristics • Magnetic rotation over the event: 71° • Angle between two main current sheets: 33° • Low plasma βeither side of the event Cluster 3 plasma β 3 2 Plasma β 1 0 37m30s 37m00s 38m30s 38m00s 39m30s Universal Time

  10. Event 2/3/2006: Characteristics • Magnetic rotation over the event: 71° • Angle between two main current sheets: 33° • Low plasma βeither side of the event • Alfvènspeed approximately 43km/s Cluster 3 Alfvèn Velocity 50 48 46 Alfvèn Velocity km/s 44 42 40 37m30s 37m00s 38m30s 38m00s 39m30s Universal Time

  11. Event 2/3/2006: Consistency • Consistent with previous results • Double magnetic field rotation that bounds an ion velocity increase. Cluster 3 magnetic field in GSE co-ordinates and ion Velocity B (nT) |V| km/s 1

  12. Event 2/3/2006: Consistency • Consistent with previous results • The changes in V and B are correlated on one edge of the exhaust and anti-correlated on the other. Cluster 3 magnetic field in GSE co-ordinates and ion Velocity B (nT) |V| km/s 1

  13. Event 2/3/2006: Consistency • Consistent with previous results • The Walen test is satisfied for the two rotations seen at Cluster 3.

  14. Magnetic field in GSE co-ordinates for the 4 Cluster spacecraft C1 ∆C1 = 0.00 C2 ∆C2 = 35.50 C3 ∆C3 = -0.09 C4 ∆C4 = 16.6

  15. Also seen at ACE and Wind 6 6 6 4 4 4 B (nT) 2 2 2 0 0 0 -2 -2 -2 -4 -4 -4 440 420 420 |V| (kms-1 400 400 420 400 380 380 360 360 380 B (nT) |V| (kms-1 B (nT) |V| (kms-1 15m00s 16m00s 15m30s 16m30s 17m00s Universal Time

  16. Conclusion and Discussion • In the solar wind the current picture is of large-scale non-patchy events • This study looks at the small scale structure • Reconnection seen at Cluster. Similar current sheets at ACE and Wind but no evidence for ion velocity enhancements. • Large overall structure current sheet structure (100s RE) but there are small scale differences on the 10,000km scale.

  17. Baumjohann, W. (1997): Wolfgang Baumjohann and Rudolf A. Treumann. Basics of Space Plasma Physics. Imperial College Press, 1997. Priest, E. R. (1984): Priest, E. R. (1984), Solar Magneto-Hydrodynamics, Geophys. Astrophys.Monogr. Ser., Springer, New York. Gosling, J.T (2005): J.T. Gosling, R.M. Skoug, D.J. McComas, C.W. Smith, J. Geophys. Res. 110, A01107, 2005 Phan, T. D. (2006): T. D. Phan, J. T. Gosling, M. S. Davis, R. M. Skoug, M. Øieroset, R. P. Lin, R. P. Lepping, D. J.McComas, C. W. Smith, H. Reme, and A. Balogh. A magnetic reconnection X-line extending more than 390 Earth radii in the solar wind. Nature, 439:175–178, January 2006. Gosling (2007): J. T. Gosling, S. Eriksson,L. M. Blush,T. D. Phan,J. G. Luhmann,D. J. McComas,R. M. Skoug,M. H. Acuna,C. T. Russell, and K. D. Simunac. Five spacecraft observations of oppositely directed exhaust jets from a magnetic reconnection X-line extending > 4.26 106km in the solar wind at 1 AU References UCL DEPARTMENT OF SPACE & CLIMATE PHYSICS MULLARD SPACE SCIENCE LABORATORY

  18. UCL DEPARTMENT OF SPACE & CLIMATE PHYSICS MULLARD SPACE SCIENCE LABORATORY

  19. Event 2/3/2006: Visualisation Minimum Variance Direction Minimum Variance Direction 4000 5000 -5000 -4000 0 10000 -10000 10000 -10000 0 Maximum Variance Direction Maximum Variance Direction

  20. Cluster Configuration

  21. 2/3/2006

More Related