Plasma Can Be So Tubular
Long theorized but never seen, plasma tubes around the earth’s magnetic field lines have been detected at the outskirts of our atmosphere using a novel technique in radio astronomy.
We all know there’s nitrogen, oxygen, and water vapor in our atmosphere. A smaller group has heard there’s also small amounts of argon, carbon dioxide, helium, neon, and methane. There’s also another constituent even fewer are aware of…plasma. This is the part of the upper atmosphere that’s been ionized by the sun ripping electrons away from atomic nuclei making a charged soup of atomic debris. Scientists have suspected for decades that our magnetic field might shape this plasma into tubular structures but have never been able to prove it.
Enter the MWA and a Loi.
The MWA is the Murchison Widefield Array, a radio telescope consisting of 128 separate sections called reciever tiles. Together these tiles image a relatively large swath (30 degrees) of the sky. These images are so rapid fire that it can take movies of the plasma as it dances and shimmers across the sky in radio frequencies.
Loi is Ms Cleo Loi of the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) and the University of Sydney’s School of Physics.
While an undergraduate, she used the MWA to create striking images of the plasma forming alternating dense and rarefied regions aligned with the field lines of earth’s magnetosphere. She knew she was on to something but that achievement paled in comparison to what happened next. She realized that by dividing the radio telescope into two separate telescopes, she would be giving it the equivilent two separate eyes to pear at the upper atmosphere. Like human eyes, since each one would be looking at the same patch of sky with a slightly different perspective, a 3 dimensional image could be constructed that would be far more illuminating than the usual flat 2D representation. This breakthrough and never-before-done technique created for the first time evidence that atmospheric plasma was indeed forming ducts or tubular structures aligned with the field lines of earth’s magnetic field.
This evidence and other details this new 3d technique could flesh out could prove incredibly important in the future. These plasma structures lie between us and satellite (navigation) signals and a host of other radiation from far deeper in space. Anything that’s part of the earth that could potentially distort these signals need to be identified and accounted for if we want to correctly interpret what we’re receiving.
The other icing on this astro-cake was the very impressive Loi herself. As her supervisor Dr Tara Murphy said:
“It is to Cleo’s great credit that she not only discovered this but also convinced the rest of the scientific community. As an undergraduate student with no prior background in this, that is an impressive achievement,”
Plasma Tubes: http://phys.org/news/2015-06-astronomers-real-time-d-movies-plasma.html