Learning the magnetic ropes

Nov 17, 2006

At the Sun's edge, in a region called the heliosphere, magnetic fields and electrical currents align and twist themselves in massive three-dimensional structures called "magnetic flux ropes." As these ropes kink, they become twisted and unstable.

Occasionally, one of the rope's ends--which was previously "tied" to the Sun's surface--breaks loose, ejecting electrically charged gas, or plasma, and producing solar flares that can wreak havoc with everything from satellites to electrical power grids. Once only observed remotely, flux ropes are now being created in the laboratory, making it possible to tie experimental data to prior theoretical analyses.

In a recent Physical Review Letters paper, members of the Los Alamos Relaxation Scaling Experiment, describe their studies of these bench-top flux ropes. These studies of the magnetic structure of kinking, rotating, and coalescing flux ropes have shown that having a free rope end and a fluid flow along the length of the flux rope substantially reduces the electrical current required to drive a property known as kink stability and induces rotation of the helically unstable flux rope.

According to Tom Intrator, principal investigator for the Relaxation Scaling Experiment, "Because past models of the Sun's coronal field have been based principally on remote observations, this work is valuable as a close-up study of the dynamical behavior of flux ropes. Understanding how the coexistence and alignment of magnetic fields and currents work in flux ropes is an important step in understanding the effects of flux ropes in everything from the Earth's magnetosphere to incredibly distant and huge astrophysical jets."

The Relaxation Scaling Experiment uses a small plasma gun in a vacuum to produce unstable flux ropes in the form of plasma-current filaments, like flexible wires composed of plasma. These "mini ropes" are then photographed and studied with probe measurements as they wind helically around an imaginary central axis. The experimental system provides a relatively simple means for systematically characterizing the evolution of these short-lived rope structures.

In addition to Intrator, the Relaxation Scaling Experiment team includes Ivo Furno, Leonid Dorf, T. Madziwa-Nussinov, Xuan Sun, and Giovanni Lapenta from Los Alamos, and Dmitri Ryutov from Lawrence Livermore National Laboratory. At Los Alamos, the experiment is supported by Laboratory-Directed Research and Development funding.

Source: Los Alamos National Laboratory

Explore further: Calibrating cancer radiotherapy beams using light and sound

add to favorites email to friend print save as pdf

Related Stories

Discovering a hidden source of solar surges

Jun 03, 2014

Cutting-edge observations with the 1.6-meter telescope at Big Bear Solar Observatory (BBSO) in California have taken research into the structure and activity of the Sun to new levels of understanding. Operated ...

Robots inspect cables

Jul 01, 2013

The bearer cables and tethers of bridges, elevators, and cable cars are exposed to high levels of stress. For this reason, their functional reliability must be monitored on a regular basis. A new robot recognizes ...

Scientists 'see' flux rope formation for the first time

Apr 03, 2013

(Phys.org) —Naval Research Laboratory scientists have observed, for the very first time, the formation of solar flux ropes, which are a type of solar magnetic field. Models of flux ropes have been drawn ...

A new state of Venus's ionosphere

Dec 27, 2012

Observations from NASA's Pioneer Venus orbiter, which reached Venus in 1978, suggested that Venus's ionosphere had two states: a magnetized state with a large- scale horizontal magnetic field and an unmagnetized ...

High-frequency flux transfer events detected near Mercury

Nov 13, 2012

The physical process that creates connections between the magnetic fields emanating from the Sun and a planet - a process known as magnetic reconnection - creates a portal through which solar plasma can penetrate ...

Recommended for you

User comments : 0