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Orientation of the X-line in asymmetric magnetic reconnection

Published online by Cambridge University Press:  14 July 2016

N. Aunai*
Laboratoire de Physique des Plasmas, CNRS, Ecole Polytechnique, Université Pierre et Marie Curie, Université Paris-Sud, Observatoire de Paris, France
M. Hesse
NASA Goddard Space Flight Center, Heliophysics Division, Greenbelt, MD, USA
B. Lavraud
Institut de Recherche en Astrophysique et Planétologie, CNRS, Université Paul Sabatier, Toulouse, France
J. Dargent
Laboratoire de Physique des Plasmas, CNRS, Ecole Polytechnique, Université Pierre et Marie Curie, Université Paris-Sud, Observatoire de Paris, France
R. Smets
Laboratoire de Physique des Plasmas, CNRS, Ecole Polytechnique, Université Pierre et Marie Curie, Université Paris-Sud, Observatoire de Paris, France
Email address for correspondence:


Magnetic reconnection can occur in current sheets separating magnetic fields sheared by any angle and of arbitrarily different amplitudes. In such asymmetric and non-coplanar systems, it is not yet understood what the orientation of the X-line will be. Studying how this orientation is determined locally by the reconnection process is important to understand systems such as the Earth magnetopause, where reconnection occurs in regions with large differences in upstream plasma and field properties. This study aims at determining what the local X-line orientation is for different upstream magnetic shear angles in an asymmetric set-up relevant to the Earth’s magnetopause. We use two-dimensional hybrid simulations and vary the simulation plane orientation with regard to the fixed magnetic field profile and search for the plane maximizing the reconnection rate. We find that the plane defined by the bisector of upstream fields maximizes the reconnection rate and this appears not to depend on the magnetic shear angle, domain size or upstream plasma and asymmetries.

Research Article
© Cambridge University Press 2016 

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Alexeev, I. I., Sibeck, D. G. & Bobrovnikov, S. Y. 1998 Concerning the location of magnetopause merging as a function of the magnetopause current strength. J. Geophys. Res. 103 (A), 66756684.Google Scholar
Aulanier, G., Pariat, E., Démoulin, P. & Devore, C. R. 2006 Slip-running reconnection in quasi-separatrix layers. Solar Phys. 238 (2), 347376.Google Scholar
Aunai, N., Hesse, M., Black, C., Evans, R. & Kuznetsova, M. 2013a Influence of the dissipation mechanism on collisionless magnetic reconnection in symmetric and asymmetric current layers. Phys. Plasmas 20 (4), 042901.Google Scholar
Aunai, N., Hesse, M., Zenitani, S., Kuznetsova, M., Black, C., Evans, R. & Smets, R. 2013b Comparison between hybrid and fully kinetic models of asymmetric magnetic reconnection: coplanar and guide field configurations. Phys. Plasmas 20 (2), 2902,1–10.Google Scholar
Birn, J., Borovsky, J. E., Hesse, M. & Schindler, K. 2010 Scaling of asymmetric reconnection in compressible plasmas. Phys. Plasmas 17 (5), 2108.Google Scholar
Birn, J., Drake, J. F., Shay, M. A., Rogers, B. N., Denton, R. E., Hesse, M., Kuznetsova, M., Ma, Z. W., Bhattacharjee, A., Otto, A. et al. 2001 Geospace environmental modeling (GEM) magnetic reconnection challenge. J. Geophys. Res. 106 (A), 37153720.Google Scholar
Birn, J. & Priest, E. R. 2007 Reconnection of Magnetic Fields. Cambridge University Press.Google Scholar
Biskamp, D. 2005 Magnetic Reconnection in Plasmas. Cambridge University Press.Google Scholar
Borovsky, J. E. 2013 Physical improvements to the solar wind reconnection control function for the Earth’s magnetosphere. J. Geophys. Res. Space 118 (5), 21132121.Google Scholar
Cassak, P. A. & Shay, M. A. 2007 Scaling of asymmetric magnetic reconnection: general theory and collisional simulations. Phys. Plasmas 14 (1), 2114.Google Scholar
Cowley, S. W. H. 1976 Comments on the merging of nonantiparallel magnetic fields. J. Geophys. Res. 81, 34553458.Google Scholar
Crooker, N. U. 1979 Dayside merging and cusp geometry. J. Geophys. Res. 84 (A3), 951959.Google Scholar
Daughton, W., Roytershteyn, V., Karimabadi, H., Yin, L., Albright, B. J., Bergen, B. & Bowers, K. J. 2011 Role of electron physics in the development of turbulent magnetic reconnection in collisionless plasmas. Nat. Phys. 7 (7), 539542.Google Scholar
Dorelli, J. C., Bhattacharjee, A. & Raeder, J. 2007 Separator reconnection at Earth’s dayside magnetopause under generic northward interplanetary magnetic field conditions. J. Geophys. Res. 112 (A), 02202.Google Scholar
Dunlop, M. W., Taylor, M. G. G. T., Davies, J. A., Owen, C. J., Pitout, F., Fazakerley, A. N., Pu, Z., Laakso, H., Bogdanova, Y. V., Zong, Q.-G. et al. 2005 Coordinated cluster/double star observations of dayside reconnection signatures. Ann. Geophys. 23 (8), 28672875.Google Scholar
Eastwood, J. P., Phan, T. D., Drake, J. F., Shay, M. A., Borg, A. L., Lavraud, B. & Taylor, M. G. G. T. 2013 Energy partition in magnetic reconnection in Earth’s magnetotail. Phys. Rev. Lett. 110 (2), 225001.Google Scholar
Eastwood, J. P., Phan, T. D., Øieroset, M. & Shay, M. A. 2010 Average properties of the magnetic reconnection ion diffusion region in the Earth’s magnetotail: the 2001–2005 cluster observations and comparison with simulations. J. Geophys. Res. 115 (A), 08215.Google Scholar
Fuselier, S. A. & Lewis, W. S. 2011 Properties of near-Earth magnetic reconnection from in-situ observations. Space Sci. Rev. 160 (1), 95121.Google Scholar
Gosling, J. T., Eriksson, S., Blush, L. M., Phan, T. D., Luhmann, J. G., Mccomas, D. J., Skoug, R. M., Acuña, M. H., Russell, C. T. & Simunac, K. D. 2007 Five spacecraft observations of oppositely directed exhaust jets from a magnetic reconnection X-line extending $4.26\times 106$  km in the solar wind at 1 AU. Geophys. Res. Lett. 34 (2), 20108.Google Scholar
Hesse, M., Aunai, N., Zenitani, S., Kuznetsova, M. & Birn, J. 2013 Aspects of collisionless magnetic reconnection in asymmetric systems. Phys. Plasmas 20 (6), 1210.Google Scholar
Hesse, M., Forbes, T. G. & Birn, J. 2005a On the relation between reconnected magnetic flux and parallel electric fields in the solar corona. Astrophys. J. 631 (2), 12271238.Google Scholar
Hesse, M., Kuznetsova, M., Schindler, K. & Birn, J. 2005b Three-dimensional modeling of electron quasiviscous dissipation in guide-field magnetic reconnection. Phys. Plasmas 12 (10), 100704.Google Scholar
Hesse, M. & Schindler, K. 1988 A theoretical foundation of general magnetic reconnection. J. Geophys. Res. 93, 55595567.Google Scholar
Komar, C. M., Fermo, R. L. & Cassak, P. A. 2015 Comparative analysis of dayside magnetic reconnection models in global magnetosphere simulations. J. Geophys. Res. Space 120 (1), 276294.Google Scholar
Le, A., Daughton, W., Karimabadi, H. & Egedal, J. 2016 Hybrid simulations of magnetic reconnection with kinetic ions and fluid electron pressure anisotropy. Phys. Plasmas 23 (3), 032114.Google Scholar
Liu, Y.-H., Hesse, M. & Kuznetsova, M. 2015 Orientation of X lines in asymmetric magnetic reconnection—mass ratio dependency. J. Geophys. Res. Space 120 (9), 73317341.Google Scholar
Moore, T. E., Fok, M. C. & Chandler, M. O. 2002 The dayside reconnection X line. J. Geophys. Res. Space 107 (A), 1332.Google Scholar
Parker, E. N. 1957 Sweet’s mechanism for merging magnetic fields in conducting fluids. J. Geophys. Res. 62, 509520.Google Scholar
Paschmann, G. 2008 Recent in-situ observations of magnetic reconnection in near-Earth space. Geophys. Res. Lett. 35 (1), 19109.Google Scholar
Phan, T. D., Gosling, J. T., Davis, M. S., Skoug, R. M., Øieroset, M., Lin, R. P., Lepping, R. P., Mccomas, D. J., Smith, C. W., Rème, H. et al. 2006a A magnetic reconnection X-line extending more than 390 Earth radii in the solar wind. Nature 439 (7), 175178.Google Scholar
Phan, T. D., Hasegawa, H., Fujimoto, M., Øieroset, M., Mukai, T., Lin, R. P. & Paterson, W. 2006b Simultaneous geotail and wind observations of reconnection at the subsolar and tail flank magnetopause. Geophys. Res. Lett. 33 (9), 09104.Google Scholar
Phan, T. D., Shay, M. A., Gosling, J. T., Fujimoto, M., Drake, J. F., Paschmann, G., Øieroset, M., Eastwood, J. P. & Angelopoulos, V. 2013 Electron bulk heating in magnetic reconnection at Earth’s magnetopause: dependence on the inflow Alfvén speed and magnetic shear. Geophys. Res. Lett. 40 (1), 44754480.Google Scholar
Priest, E. & Forbes, T. 2007 Magnetic Reconnection. Cambridge University Press.Google Scholar
Pritchett, P. L. & Mozer, F. S. 2009 Asymmetric magnetic reconnection in the presence of a guide field. J. Geophys. Res. 114 (A), 11210.Google Scholar
Schreier, R., Swisdak, M., Drake, J. F. & Cassak, P. A. 2010 Three-dimensional simulations of the orientation and structure of reconnection X-lines. Phys. Plasmas 17 (1), 0704.Google Scholar
Scurry, L., Russell, C. T. & Gosling, J. T. 1994 A statistical study of accelerated flow events at the dayside magnetopause. J. Geophys. Res. 99, 14815.Google Scholar
Siscoe, G. L., Erickson, G. M., Sonnerup, B. U. O., Maynard, N. C., Siebert, K. D., Weimer, D. R. & White, W. W. 2001 Global role of E parallel in magnetopause reconnection: an explicit demonstration. J. Geophys. Res. 106 (A), 1301513022.Google Scholar
Sonnerup, B. U. O. 1974 Magnetopause reconnection rate. J. Geophys. Res. 79 (1), 1546.Google Scholar
Swisdak, M. & Drake, J. F. 2007 Orientation of the reconnection X-line. Geophys. Res. Lett. 34 (1), 11106.Google Scholar
Swisdak, M., Opher, M., Drake, J. F. & Alouani Bibi, F. 2010 The vector direction of the interstellar magnetic field outside the heliosphere. Astrophys. J. 710 (2), 17691775.Google Scholar
Swisdak, M., Rogers, B. N., Drake, J. F. & Shay, M. A. 2003 Diamagnetic suppression of component magnetic reconnection at the magnetopause. J. Geophys. Res. Space 108 (A), 1218.Google Scholar
Teh, W.-L. & Sonnerup, B. U. O. 2008 First results from ideal 2-D MHD reconstruction: magnetopause reconnection event seen by cluster. Ann. Geophys. 26 (9), 26732684.Google Scholar
Teh, W.-L., Sonnerup, B. U. O., Hu, Q. & Farrugia, C. J. 2009 Reconstruction of a large-scale reconnection exhaust structure in the solar wind. Ann. Geophys. 27 (2), 807822.Google Scholar
Trattner, K. J., Mulcock, J. S., Petrinec, S. M. & Fuselier, S. A. 2007a Location of the reconnection line at the magnetopause during southward IMF conditions. Geophys. Res. Lett. 34 (3), 03108.Google Scholar
Trattner, K. J., Mulcock, J. S., Petrinec, S. M. & Fuselier, S. A. 2007b Probing the boundary between antiparallel and component reconnection during southward interplanetary magnetic field conditions. J. Geophys. Res. 112 (A), 08210.Google Scholar
Trenchi, L., Marcucci, M. F., Pallocchia, G., Consolini, G., Bavassano Cattaneo, M. B., Di Lellis, A. M., Rème, H., Kistler, L., Carr, C. M. & Cao, J.-B. 2008 Occurrence of reconnection jets at the dayside magnetopause: double star observations. J. Geophys. Res. 113 (A).Google Scholar
Wyper, P. F. & Hesse, M. 2015 Quantifying three dimensional reconnection in fragmented current layers. Phys. Plasmas 22 (4), 042117.Google Scholar