Fast Magnetic Reconnection and the Hall Effect

  • Released Thursday, April 28, 2022
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Magnetic reconnection is one of the most complex processes known for converting energy from magnetic fields to particle motion. It takes place in solar flares and regions of planetary (and stellar) magnetospheres. Having been studied since the 1950s, many details of the process are still undergoing study.

One of the key components in magnetic reconnection is the collision of two magnetic field regions with opposite-directed field lines, imbedded in a plasma. The field and plasma combination forms an X-shaped configuration at their closest, and most intense point.

These visualizations are plotted from a reconnection model generated by VPIC (Vector Particle-In-Cell) code. Quantities are plotted in 'dimensionless' coordinates, that are normalized to the ion inertial length (di).

This data visualization illustrates the motion of electrons (red) and ions (cyan) in the x,z plane through the magnetic and current configuration in the 'X-shaped' region of magnetic reconnection. The gold color represents the current density flowing in the y-direction (out of the plane of the plot).


The magnetic vector potential is represented by the blue-green curves which dip inward from the top and sides of the plot. This forms the 'X' region that confines the electric current (gold) which is directed out of the plane of the plot (towards the viewer). The Electron Diffusion Region (EDR) is the intense horizontal oblong blob near the center of the plot.

Electrons and ions (plasma) flow into the region from the top and bottom of the plot, initially moving together. As the plasma moves into regions with less intense magnetic field and stronger electric current, the ion and electron trajectories begin to diverge, driven by the Hall effect (Wikipedia). This accelerates and channels the flow of particles outward, through the left and right wings of the 'X', where the magnetic energy density is lowest. The net process is magnetic energy is converted into particle energy.

Color bar representing current density along the y-axis (out of the plane of the image) in relative model units.

Color bar representing current density along the y-axis (out of the plane of the image) in relative model units.

This data visualization illustrates the flow of packets of energy (orange trajectories and dots) in the x,z plane through the 'X-shaped' region of magnetic reconnection. The background color represents the magnetic energy density, with black representing low energy-density and white as high energy-density.


The incoming magnetic energy is diverted and transported to the downstream region leaving an energy void at the X-line.

Magnetic energy density color bar in model units.

Magnetic energy density color bar in model units.

This data visualization illustrates the motion of electrons (red) and ions (cyan) in the x,z plane through the magnetic configuration in the 'X-shaped' region of magnetic reconnection. In this version, the color lines represent the magnetic field intensity illustrating how the particle motion undergoes the most direction change in regions where the magnetic field change is large.

For More Information

See NASA.gov

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NASA's Scientific Visualization Studio

This page was originally published on Thursday, April 28, 2022.
This page was last updated on Wednesday, May 3, 2023 at 11:44 AM EDT.

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Papers used in this visualization

First-Principles Theory of the Rate of Magnetic Reconnection in Magnetospheric and Solar Plasmas

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