What determines the reconnection rate at the dayside magnetosphere

[1] Reconnection between the magnetosphere and magnetosheath at the dayside magnetopause is studied for southward IMF using high-resolution 3-D MHD simulations. The BATSRUS code is run at CCMC with a resistive spot added on the magnetopause to ensure that fast reconnection occurs and to control the reconnection physics. A large range of Mach numbers (1.9–15) are run. The reconnection rate at the nose of the magnetosphere is measured and compared with local plasma parameters and with upstream-solar wind parameters. It is found that the reconnection rate is controlled by four local plasma parameters: Bs (the magnetic field strength in the magnetosheath), Bm (the magnetic field strength in the magnetosphere), ρs (the plasma mass density in the magnetosheath), and ρm (the plasma mass density in the magnetosphere). The Cassak-Shay formula for fast reconnection was tested and found to successfully describe the reconnection rate on the dayside magnetopause. It was found that reconnection itself does not significantly modify the local plasma parameters that control dayside reconnection and argued that reconnection does not significantly alter the flow pattern of the magnetosheath. This means that dayside reconnection is not “driven” in the sense that plasma pileup occurs to change the local parameters to adjust the reconnection rate to balance the driving. A “plasmasphere effect” was observed in the simulations wherein high-density magnetospheric plasma flows into the magnetopause reconnection site and mass loads the reconnection: a spatially localized plume of plasma was observed to locally reduce the reconnection rate by about a factor of 2.

[1]  R. Denton,et al.  The scaling of collisionless, magnetic reconnection for large systems , 1999 .

[2]  R. Gendrin,et al.  Relationships between the solar wind electric field and the magnetospheric convection electric field , 1981 .

[3]  E. Parker.  The reconnection rate of magnetic fields. , 1973 .

[4]  J. Birn,et al.  Forced magnetic reconnection , 2005 .

[5]  Christopher T. Russell,et al.  Plasma depletion layer: its dependence on solar wind conditions and the Earth dipole tilt , 2003 .

[6]  P. Pritchett,et al.  Three‐dimensional collisionless magnetic reconnection in the presence of a guide field , 2004 .

[7]  J. Birn,et al.  Whistler‐mediated magnetic reconnection in large systems: Magnetic flux pileup and the formation of thin current sheets , 2003 .

[8]  F. Mozer,et al.  Comparison of S3-3 polar cap potential drops with the interplanetary magnetic field and models of magnetopause reconnection , 1983 .

[9]  Lou‐Chuang Lee,et al.  Fast magnetic reconnection with small shock angles , 1992 .

[10]  Lou‐Chuang Lee,et al.  Energy coupling function and solar wind‐magnetosphere dynamo , 1979 .

[11]  B. Anderson,et al.  Magnetic pulsations from 0.1 to 4.0 Hz and associated plasma properties in the Earth's subsolar magnetosheath and plasma depletion layer , 1993 .

[12]  J. Birn,et al.  General magnetic reconnection, parallel electric fields, and helicity , 1988 .

[13]  John C. Dorelli,et al.  A new look at driven magnetic reconnection at the terrestrial subsolar magnetopause , 2004 .

[14]  M. Ugai,et al.  Magnetic field-line reconnexion by localized enhancement of resistivity: Part 1. Evolution in a compressible MHD fluid , 1977, Journal of Plasma Physics.

[15]  Dan Winske,et al.  Collisionless reconnection supported by nongyrotropic pressure effects in hybrid and particle simulations , 2001 .

[16]  J. Birn,et al.  A Theory of Solar-Wind/Magnetosphere Coupling Derived from First Principles , 2008 .

[17]  M. Pinnock,et al.  Some comments on transient and steady‐state reconnection at the dayside magnetopause , 2000 .

[18]  C. Wu.  MHD FLOW PAST AN OBSTACLE : LARGE-SCALE FLOW IN THE MAGNETOSHEATH , 1992 .

[19]  B. Sonnerup.  Magnetic-field re-connexion in a highly conducting incompressible fluid , 1970, Journal of Plasma Physics.

[20]  P. Roe,et al.  A Solution-Adaptive Upwind Scheme for Ideal Magnetohydrodynamics , 1999 .

[21]  C. Russell,et al.  An empirical relationship between interplanetary conditions and Dst , 1975 .

[22]  M. Shay,et al.  The scaling of forced collisionless reconnection , 2005 .

[23]  C. Russell,et al.  Comments on a paper by J. P. Heppner, ‘Polar cap electric field distributions related to interplanetary magnetic field direction’ , 1973 .

[24]  D. Hunten,et al.  Depletion of solar wind plasma near a planetary boundary , 1976 .

[25]  M. Lester,et al.  Solar–wind–magnetosphere–ionosphere interactions in the Earth's plasma environment , 2003, Philosophical Transactions of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[26]  M. Freeman,et al.  Solar wind input between substorm onsets during and after the October 18–20, 1995, magnetic cloud , 1999 .

[27]  J. Huba.  Hall magnetic reconnection: Guide field dependence , 2005 .

[28]  Tamas I. Gombosi,et al.  Ionospheric control of the magnetosphere: conductance , 2004 .

[29]  C. Russell,et al.  Intrinsic time scale for reconnection on the dayside magnetopause , 1997 .

[30]  J. Sauvaud,et al.  Spatial and Temporal Cusp Structures Observed by Multiple Spacecraft and Ground Based Observations , 2005 .

[31]  Michelle F. Thomsen,et al.  Observations of the density profile in the magnetosheath near the stagnation streamline , 1990 .

[32]  Michael Hesse,et al.  Geospace Environment Modeling (GEM) magnetic reconnection challenge: Resistive tearing, anisotropic pressure and Hall effects , 2001 .

[33]  B. Sonnerup,et al.  Magnetopause reconnection rate , 1974 .

[34]  Christopher T. Russell,et al.  The solar wind interaction with the Earth's magnetosphere: a tutorial , 2000 .

[35]  Michael Hesse,et al.  Geospace Environmental Modeling (GEM) magnetic reconnection challenge , 2001 .

[36]  Antonius Otto,et al.  Geospace Environment Modeling (GEM) magnetic reconnection challenge: MHD and Hall MHD—constant and current dependent resistivity models , 2001 .

[37]  L. Rudakov,et al.  Hall magnetic reconnection rate. , 2004, Physical review letters.

[38]  J. Borovsky,et al.  The reconnection of magnetic fields between plasmas with different densities: Scaling relations , 2007 .

[39]  K. Powell,et al.  Magnetospheric configuration for Parker-spiral IMF conditions: Results of a 3D AMR MHD simulation , 2000 .

[40]  E. Parker.  Comments on the reconnexion rate of magnetic fields , 1973, Journal of Plasma Physics.

[41]  R. A. Smith,et al.  Prediction of geomagnetic activity , 1993 .

[42]  Joachim Raeder,et al.  Flux Transfer Events: 1. generation mechanism for strong southward IMF , 2006 .

[43]  F. Mozer,et al.  A quantitative model for the potential resulting from reconnection with an arbitrary interplanetary magnetic field , 1974 .

[44]  Michael Hesse,et al.  Collisionless magnetic reconnection: Electron processes and transport modeling , 2001 .

[45]  M. Shay,et al.  Transition from antiparallel to component magnetic reconnection , 2005, physics/0503064.

[46]  G. Siscoe,et al.  A theoretical relation between Dst and the solar wind merging electric field , 1974 .

[47]  A strong limitation on the rapidity of flux-pile-up reconnection , 1996 .

[48]  Joseph E. Borovsky,et al.  Effect of plasmaspheric drainage plumes on solar‐wind/magnetosphere coupling , 2006 .

[49]  J. Dungey.  Interplanetary Magnetic Field and the Auroral Zones , 1961 .

[50]  James F. Drake,et al.  Alfvénic collisionless magnetic reconnection and the Hall term , 2001 .

[51]  J. Birn,et al.  Properties of asymmetric magnetic reconnection , 2008 .

[52]  B. Sonnerup.  Magnetic field reconnection , 1979 .

[53]  P. Pritchett,et al.  Geospace Environment Modeling magnetic reconnection challenge: Simulations with a full particle electromagnetic code , 2001 .

[54]  Takaya Hayashi,et al.  Externally driven magnetic reconnection and a powerful magnetic energy converter , 1979 .

[55]  Harry E. Petschek,et al.  Magnetic Field Annihilation , 1963 .

[56]  G. Siscoe,et al.  MHD properties of magnetosheath flow , 2002 .

[57]  W. I. Axford.  Driven and Non-Driven Reconnection; Boundary Conditions , 1984 .

[58]  P. Cassak,et al.  Asymmetric Magnetic Reconnection: General Theory and Collisional Simulations , 2007 .

[59]  J. Steinberg,et al.  The Calm before the Storm in CIR/Magnetosphere Interactions , 2006 .

[60]  I. Craig,et al.  Flare-like energy release by flux pile-up reconnection , 2000 .

[61]  Quentin F. Stout,et al.  An adaptive MHD method for global space weather simulations , 2000 .

[62]  E. Priest,et al.  Resistive MHD stagnation-point flows at a current sheet , 1975, Journal of Plasma Physics.