Exploring Reconnection - Guide Field Off

  • Released Thursday, May 18, 2017
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This visualization shows an oblique view of the reconnection region. Magnetic field direction is represented by the cyan lines. The color trail represents an electron moving in the field. Color of the particle trail represents a dimensionless speed of the particle, with blue for slow and red for fast.

One of the aspects of magnetic reconnection which makes it a difficult process to fully understand is the complex interactions between charged particles and the electromagnetic fields that dominate their motion. The electromagnetic fields determine the motion of the particles, but the motion of the particles changes the configuration of the electromagnetic fields.

In the visualizations below, we illustrate the magnetic field (cyan line structures) surrounding a reconnection region, sometimes called the X-line region, because the field lines form an X-like structure with most of the reconnection physics taking place in the center of the 'X'. In this case, the reconnection layer, sometimes called the diffusion region, lies in a thin region above and below the grey grid.

Inside this reconnection layer, there is an electric field that accelerates the charged particle along the y-axis, causing the particle to bounce back and forth between the regions above and below the reconnection layer. In those regions, there is a small magnetic field that is directed in opposite directions above and below the layer. This causes the charged particle to move in a curve, that bounces above and below the layer, creating the sinusiodal motion of the particle as moves along the y-axis. This is the guide-field off configuration.

But if there is a little bit of magnetic field parallel to the electric field (also in the y-direction) - the particle moves in the guide-field on configuration. In this case, the particle picks up a little extra gyro motion, perpendicular to the sinusoidal motion. This creates the loops which appear in the motion when looking along the y-axis. This additional motion pumps additional energy into the charged particle, until its trajectory slips outside the reconnection layer current sheet, and takes a little energy out of the field with it.

Additional References
Particle Trajectories in Model Current Sheets. 1. Analytical Solutions
T. W. Speiser
Journal of Geophysical Research, Volume 70, pp 4219-4226 (1965)

This visualization opens with an oblique view of the reconnection region and then moves to a position with the camera on the Y-axis looking along the reconnection region. Magnetic field direction is represented by the cyan lines. The color trail represents an electron moving in the field. Color of the particle trail represents a dimensionless speed of the particle, with blue for slow and red for fast. The color change illustrates the particle accelerates in small bursts, occasionally slowing down, then speeding back up as it exchanges energy with the surrounding field.

This visualization presents the motion of the particle along the Y-axis, as viewed by a camera along the X-axis.

This visualization presents the motion of the particle along the X-axis, as viewed by a camera along the Y-axis.

This visualization presents the motion of the particle along the X-Y-plane, as viewed by a camera 'above' the reconnection region along the Z-axis.

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NASA's Scientific Visualization Studio

This page was originally published on Thursday, May 18, 2017.
This page was last updated on Wednesday, November 15, 2023 at 12:10 AM EST.

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Papers used in this visualization

Electron diffusion region during magnetopause reconnection with an intermediate guide field: Magnetospheric multiscale observations

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