Experiments discover a 3-D process by which magnetic reconnection can release energyfaster than expected by classical theories.
Scientists at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) have discovered a new process at work in a mysterious magnetic phenomenon that occurs both in the earth's atmosphere and in space, playing a role in events such as the aurora borealis and solar flares.
In a series of experiments on a device known as the Magnetic Reconnection Experiment (MRX), which replicates magnetic reconnection in the laboratory, a team of researchers found that many important plasma quantities are found to have strong variations in three dimensions very early in the process. This variation may aid in the formation of regions of high electric current with characteristics similar to what have been called "flux ropes."
Experiments show that when the reconnection rate spikes in this 3-D configuration, the high current ropes are ejected out of the reconnection region, leading to a sudden decrease in the current density. The researchers have termed this process a "current layer disruption."
This science visualization shows a magnetospheric substorm, during which, magnetic reconnection causes energy to be rapidly released along the field lines in the magnetotail, that part of the magnetosphere that stretches out behind Earth. This released energy is focused down at the poles and the resulting flood of solar particles into the atmosphere, causes the auroras at the North and South Poles.
Scientists believe that magnetic reconnection is behind the extraordinary bursts of radiation that have emerged from the center of the Crab nebula, the remains of an exploded star. The device allows PPPL researchers to recreate the magnetic reconnection process in a controlled setting. (Photo by Elle Starkman)
William Slavin (center), head of PPPL's safety division, gives graduate students a tour of the MRX device, which resembles a large steel barrel attached to arrays of tubes and wires. The device allows PPPL researchers to recreate the magnetic reconnection process in a controlled setting. (Photo by Elle Starkman)