Abstract
A threedimensional particleincell simulation of magnetic reconnection in an asymmetric configuration without a guide field and with temperature ratio demonstrates that intense perpendicular electric fields are produced on the lowdensity side of the current layer where there is a strong gradient in the plasma density. The simulation shows that the 3D reconnection rate is unaffected by these intense electric fields, that the electron current layer near the X line remains coherent and does not break up, but that localized regions of strong energy dissipation exist along the lowdensity separatrices. Near the X line the dominant term in the generalized Ohm's law for the reconnection electric field remains the offdiagonal electron pressure gradient . On the lowbeta separatrix, however, the anomalous drag makes an equally important contribution to that of the pressure gradient to the average Ey field.
This research was supported by NASA Grant NNX11AD74G. The computations in this work were made possible by an allocation of advanced computing resources by the National Science Foundation on Kraken (a Cray XT5) at the National Institute for Computational Sciences (http://www.nics.tennessee.edu).
I. INTRODUCTION
II. SIMULATION MODEL
III. SIMULATION RESULTS
A. Intense electric fields
B. The electron current layer
C. Ohm's law
D. Energy dissipation
IV. SUMMARY AND DISCUSSION
Key Topics
 Electric fields
 30.0
 Magnetic reconnection
 24.0
 Magnetic fields
 10.0
 Magnetopause
 9.0
 Particleincell method
 9.0
Figures
The yaveraged magnitude (without regard to sign) of the Ey field projected onto the x, z plane from the 3D simulation at time ; the average magnetic field lines are superimposed in white.
The yaveraged magnitude (without regard to sign) of the Ey field projected onto the x, z plane from the 3D simulation at time ; the average magnetic field lines are superimposed in white.
Structure in the x, y plane at at time for (a) the plasma density , (b) the magnetic field , (c) the electric field , and (d) the electric field . The dashed black line in each panel indicates the location of the magnetospheric separatrix (x = 1.5) at this value of z.
Structure in the x, y plane at at time for (a) the plasma density , (b) the magnetic field , (c) the electric field , and (d) the electric field . The dashed black line in each panel indicates the location of the magnetospheric separatrix (x = 1.5) at this value of z.
Structure of the electric field at time in (a) the y, z plane at , (b) the yaveraged field , and (c) the x profile of at with the value at the X line marked by an O. (d) Time history of the reconnected flux function from a 2D simulation of reconnection in the same asymmetric configuration (red/solid curve); the slope of the dashed black tangent line gives the value of the reconnection electric field.
Structure of the electric field at time in (a) the y, z plane at , (b) the yaveraged field , and (c) the x profile of at with the value at the X line marked by an O. (d) Time history of the reconnected flux function from a 2D simulation of reconnection in the same asymmetric configuration (red/solid curve); the slope of the dashed black tangent line gives the value of the reconnection electric field.
Structure of the electron current density at time in (a) the y, z plane at x = 1.1, (b) the y, z plane at x = 1.5, and (c) the x, y equatorial plane (z = 0).
Structure of the electron current density at time in (a) the y, z plane at x = 1.1, (b) the y, z plane at x = 1.5, and (c) the x, y equatorial plane (z = 0).
Contributions of the electron pressure tensor derivatives to the electric field at time : (a) in the plane and (b) in the y, z plane at x = 1.1; (c), (d) the corresponding yaveraged profiles as a function of x or of z.
Contributions of the electron pressure tensor derivatives to the electric field at time : (a) in the plane and (b) in the y, z plane at x = 1.1; (c), (d) the corresponding yaveraged profiles as a function of x or of z.
Contributions to the electric field in the x, y plane at at time for (a) the inertial term and (b) the inertial term; (c), (d) the corresponding yaveraged profiles as a function of x.
Contributions to the electric field in the x, y plane at at time for (a) the inertial term and (b) the inertial term; (c), (d) the corresponding yaveraged profiles as a function of x.
Time histories of yaveraged fields: (a) at x = 1.1, z = 0, (b) Dy at x = 1.1, z = 0, (d) at x = 1.5, , and (e) Dy at x = 1.5, ; spatial profiles in y computed from a temporal average over 2 of (blue curves) and Dy (red curves, multiplied by a factor of five for clarity) at (c) x = 1.1, z = 0 and (f) at x = 1.5, .
Time histories of yaveraged fields: (a) at x = 1.1, z = 0, (b) Dy at x = 1.1, z = 0, (d) at x = 1.5, , and (e) Dy at x = 1.5, ; spatial profiles in y computed from a temporal average over 2 of (blue curves) and Dy (red curves, multiplied by a factor of five for clarity) at (c) x = 1.1, z = 0 and (f) at x = 1.5, .
Contributions to the electric field at time for (a) in the x, y plane at , (b) the corresponding yaveraged profile as a function of x, (c) in the y, z plane at x = 1.5, (d) the yaveraged profiles as a function of z for (blue curve), (red curve) and (green curve).
Contributions to the electric field at time for (a) in the x, y plane at , (b) the corresponding yaveraged profile as a function of x, (c) in the y, z plane at x = 1.5, (d) the yaveraged profiles as a function of z for (blue curve), (red curve) and (green curve).
The electron frame dissipation measure at time (a) averaged over all y and displayed in the x, z plane (with average field lines superimposed in black), (b) displayed in the y, z plane at x = 1.1, (c) displayed in the y, z plane at x = 1.3, and (d) displayed in the y, z plane at x = 1.5.
The electron frame dissipation measure at time (a) averaged over all y and displayed in the x, z plane (with average field lines superimposed in black), (b) displayed in the y, z plane at x = 1.1, (c) displayed in the y, z plane at x = 1.3, and (d) displayed in the y, z plane at x = 1.5.
Article metrics loading...
Full text loading...
Most read this month
Most cited this month










Electron, photon, and ion beams from the relativistic interaction of Petawatt laser pulses with solid targets
Stephen P. Hatchett, Curtis G. Brown, Thomas E. Cowan, Eugene A. Henry, Joy S. Johnson, Michael H. Key, Jeffrey A. Koch, A. Bruce Langdon, Barbara F. Lasinski, Richard W. Lee, Andrew J. Mackinnon, Deanna M. Pennington, Michael D. Perry, Thomas W. Phillips, Markus Roth, T. Craig Sangster, Mike S. Singh, Richard A. Snavely, Mark A. Stoyer, Scott C. Wilks and Kazuhito Yasuike

Commenting has been disabled for this content