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Studying Solar Wind Magnetic Reconnection Events using Cluster.

UCL DEPARTMENT OF SPACE & CLIMATE PHYSICS MULLARD SPACE SCIENCE LABORATORY. Studying Solar Wind Magnetic Reconnection Events using Cluster. 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

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Studying Solar Wind Magnetic Reconnection Events using Cluster.

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  1. UCL DEPARTMENT OF SPACE & CLIMATE PHYSICS MULLARD SPACE SCIENCE LABORATORY Studying Solar Wind Magnetic Reconnection Events using Cluster. 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

  2. First 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 Data from Cluster 3 in GSE Total -- X -- Y --Z -- Magnetic rotation at current sheets |B| (nT) B (nT) |velocity| (km/s) |velocity| (km/s) velocity (km/s) Phan, T.D (2006) Universal Time

  5. 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 |B| (nT) B (nT) Total -- X --Y --Z -- |Velocity| (km/s) Velocity_x (km/s) Velocity_z (nT) Velocity_y (km/s) Density

  7. 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. • The Walen test has been satisfied.

  8. Event 2/3/2006: Characteristics • Magnetic rotation over the event: 550 • Angle between two main current sheets: 330 • Low plasma βeither side of the event, increase of plasma β during the event • Alfven speed approximately 43km/s

  9. Event 2/3/2006: Visualisation CS1-- CS2 – residual velocity B Field CS1-- CS2 – residual velocity B Field 10000 10000 0 0 Minimum Variance Direction Minimum Variance Direction -10000 Configuration with 2% alteration in background solar wind speed -10000 Initial configuration 0 -10000 10000 -10000 0 10000 Maximum Variance Direction Maximum Variance Direction Courtesy of C. Forsyth, C.Owen, I.J. Rae

  10. Event 2/3/2006 8 8 |B| (nT) |B| (nT) Total -- X --Y --Z -- 0 0 4 4 B (nT) B (nT) C1 C2 -2 -2 37m30s Universal Time 40m00s 37m30s 40m00s Universal Time 8 8 |B| (nT) |B| (nT) 0 0 4 4 B (nT) B (nT) C3 C4 -2 -2 40m00s 37m30s Universal Time Universal Time 40m00s 37m30s

  11. Also seen at ACE

  12. Discussion • Similar current sheets seen at ACE. Situated approximately 200RE away from the Cluster spacecraft • Large overall structure (100s RE) but there are small scale differences on the 10,000km scale.

  13. Conclusions • Small scale differences. In the solar wind the picture is of large scale, non patchy events • Not all of the reconnection events fit the simple gosling bifurcated current sheet with the reconnection outflow between the two.

  14. 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

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

  16. Cluster Configuration

  17. 2/3/2006

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