Astronomers make real-time, 3-D movies of plasma tubes drifting overhead

June 1, 2015, University of Sydney

By creatively using a radio telescope to see in 3D, astronomers have detected the existence of tubular plasma structures in the inner layers of the magnetosphere surrounding the Earth.

"For over 60 years, scientists believed these structures existed but by imaging them for the first time, we've provided visual evidence that they are really there," said Cleo Loi of the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) and School of Physics at the University of Sydney.

Ms Loi is the lead author on this research, undertaken as part of her award-winning undergraduate thesis and recently published in Geophysical Research Letters. In collaboration with international colleagues, she identified the structures.

"The discovery of the structures is important because they cause unwanted signal distortions that could, as one example, affect our civilian and military satellite-based navigation systems. So we need to understand them," Ms Loi said.

The region of space around the Earth occupied by its magnetic field, called the magnetosphere, is filled with plasma that is created by the atmosphere being ionised by sunlight.

The innermost layer of the magnetosphere is the ionosphere, and above that is the plasmasphere. They are embedded with a variety of strangely shaped plasma structures including, as has now been revealed, the tubes.

"We measured their position to be about 600 kilometres above the ground, in the upper ionosphere, and they appear to be continuing upwards into the plasmasphere. This is around where the neutral atmosphere ends, and we are transitioning to the plasma of outer space," explained Ms Loi.

Using the Murchison Widefield Array (MWA), a radio telescope located in the Western Australian desert, Ms Loi found that she could map large patches of the sky and even exploit the MWA's rapid snapshot capabilities to create a movie - effectively capturing the real-time motions of the plasma.

"We saw a striking pattern in the sky where stripes of high-density plasma neatly alternated with stripes of low-density plasma. This pattern drifted slowly and aligned beautifully with the Earth's lines, like aurorae," Ms Loi said.

"We realised we may be onto something big and things got even better when we invented a new way of using the MWA."

The MWA consists of 128 antenna 'tiles' spread over an area roughly three by three kilometres that work together as one instrument - but by separating the signals from tiles in the east from the ones in the west, the astronomers gave the MWA the power to see in 3D.

"This is like turning the telescope into a pair of eyes, and by that we were able to probe the 3D nature of these structures and watch them move around," said Ms Loi.

"We were able to measure the spacing between them, their height above the ground and their steep inclination. This has never been possible before and is a very exciting new technique."

This ability adds yet another accolade to the MWA's name after it had already proven its worth as a powerful precursor instrument to the Square Kilometre Array (SKA), and now the MWA's 3D vision has the potential to provide many more in-depth analyses of the formation of structures.

"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," said Ms Loi's supervisor Dr Tara Murphy, also of CAASTRO and the School of Physics at the University of Sydney.

"When they first saw the data, many of her senior collaborators thought the results were literally 'too good to be true' and that the observation process had somehow corrupted the findings, but over the next few months, Cleo managed to convince them that they were both real and scientifically interesting."

Explore further: Radio astronomy backed by big data projects

More information: "Real-time imaging of density ducts between the plasmasphere and ionosphere" Geophys. Res. Lett., 42, DOI: 10.1002/2015GL063699.

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17 comments

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cantdrive85
1.6 / 5 (7) Jun 01, 2015
Plasma ropes are of course code for Birkeland currents. More and more data daily which continues to confirm the electric nature of our Universe.
RichManJoe
5 / 5 (4) Jun 01, 2015
Give this young woman a doctorate.
Captain Stumpy
5 / 5 (9) Jun 02, 2015
Plasma ropes are of course code for Birkeland currents. More and more data daily which continues to confirm the electric nature of our Universe.
@cd
except that there is absolutely NO reference in the link to birkeland currents
nor is there a reference to them in any of the supplemental materials

the authors do not state that your plasma ropes are code for them either
nor to the plasma physicists who worked on the study
nor do any other reputable plasma physicist from PPPL.gov

guess you will have to go back to your engineers and tell them they made a faux pas
again
or still

physics and nature are FAR more interesting than your religious beliefs anyway, sparky
i prefer to let the science speak for itself
jonesdave
4.1 / 5 (13) Jun 03, 2015
Plasma ropes are of course code for Birkeland currents. More and more data daily which continues to confirm the electric nature of our Universe.


They aren't Birkeland currents. Read and try to understand the paper. They are magnetic flux tubes of the Earth's internal magnetic field above the ionosphere, which are expected to be filled with magnetospheric plasma.
Amazing how many times these EU numpties keep misinterpreting the real science to try to show support for their much derided pseudo-science.
barakn
4.6 / 5 (10) Jun 04, 2015
Since a Birkeland current is a field-directed current, and the magnetic field dives into the atmosphere at both ends, there should be some evidence of this current hitting the atmosphere. Permanent auroral displays at mid-latitude,for example. All cd has to do is provide evidence of this sort of thing happening.
cantdrive85
1 / 5 (5) Jun 04, 2015
And while your at it get CD a life....so that he can stop calling every plasma tube formation a Birkeland current.

I know, I have the problem of calling every duck a duck too.
barakn
4.5 / 5 (8) Jun 05, 2015
The duck comment suggest you have no evidence that there are currents in these things. Thanks for wasting our time.
Captain Stumpy
5 / 5 (4) Jun 05, 2015
I know, I have the problem of calling every duck a duck too.
@cd
actually, you would show a link to a JPG of a random pitted scar on a piece of metal during a plasma experiment and state that it is plasma discharge which generated the duck, despite all the evidence with eggs and mating rituals, thus the birkeland currents demonstrate that peratt and alfven are correct in their belief that astrophysicists can't play gin-rummy

(satirical hyperbole)

Uncle Ira
4.3 / 5 (6) Jun 11, 2015
@mark_mnarkwynne


@ Jean-Skippette. How you are Chere? I am good today, thanks. Ol mark-Skippy got shown the door and locked behind him so he can't answer you until he gets a new puppet name.
cantdrive85
1 / 5 (2) Jun 12, 2015
The duck comment suggest you have no evidence that there are currents in these things. Thanks for wasting our time.

You suggested that, I didn't do such a thing. You're wasting your own time in making such a stupid comment.

there should be some evidence of this current hitting the atmosphere. Permanent auroral displays at mid-latitude,for example


The "tube-like" structure is enough to show there is a current present, if you had the slightest inkling of understanding of plasma physics this would be obvious. Do we need to explain to you why ducks are called ducks as well? And due to your extreme ignorance of plasma physics, you should probably refrain from pontificating what you think "should" be evidence. To that point, we know that the polar BC's are always there, strangely there is no permanent polar aural displays are there. How can that be? Once again, if you had a clue, you'd understand it had something to do with current density.

Uncle Ira
4 / 5 (4) Jun 12, 2015
Please excuse my ignorance, but what are "polar BC's"?


@ Jean-Skippette. They are polar bear cubs, cute little baby bears that are white and fuzzy. What you should be asking him about it is the foolishment with the electrical machinist digging out the Grand Canyon. Or is it the Grand Couyon? Yeah that would make more sense, grand couyon.
cantdrive85
1 / 5 (2) Jun 13, 2015
@cantdrive85:
The "tube-like" structure is enough to show there is a current present,
Really? Would you please explain why, preferably with primary references?

Well, a duck is a duck because....
It's quite obvious, the only way to create the magnetic field which holds the tube together is to have a current flowing through it. If you need a paper to understand this, we'll go ahead and look it up yourself. There is plenty of literature discussing field aligned currents available. If you're going to argue against something you should at least have a basic understanding of the physics. Clearly none of the posters in this thread arguing against my comments have the slightest clue about the objects of the discussion.
cantdrive85
1 / 5 (2) Jun 13, 2015
You may be right, or you may be wrong.

However, that is not an answer to my question! :-O

And you have the ability to answer your question. Unless of course you only rely on others to "teach" you.

For example, "the only way to create the magnetic field which holds the tube together" - where is the DIRECT evidence that it is a magnetic field which "holds the tube together"?

We're discussing plasma here, what else do you expect to drive these plasma properties? Magic?

For example: "holds the tube together": where is the DIRECT evidence that the tubes are stable structures (in some long term)?

How long do they need to exist to be real for you? How about long enough that they can be measured and "probed in 3D".

Finally: "the *only* way to create ..." REALLY!?!

How do you expect magnetic fields to be created? Ask your neighborhood electrical engineer, but avoid astrophysicists at all costs. They believe magnetic fields are magical.
TechnoCreed
5 / 5 (3) Jun 13, 2015
@JeanTate
It's quite obvious, the only way to create the magnetic field which holds the tube together is to have a current flowing through it. If you need a paper to understand this, we'll go ahead and look it up yourself.

You may be right, or you may be wrong.
Just totally wrong; those tubes follows geomagnetic lines. Charged particle in the ionosphere will naturally follow those lines.

There is no need to maintain an electrical current to have a magnetic field; once a magnetic domain is created it can keep its state indefinitely. The Moon and Mars have remnant magnetism. The earth's field is induced by current generated by magmatic thermal convection.

A similar answer was given by another new and excellent poster 'jonesdave'. Thank you! Your contribution is highly appreciated.
cantdrive85
1 / 5 (2) Jun 13, 2015
Just totally wrong; those tubes follows geomagnetic lines. Charged particle in the ionosphere will naturally follow those lines.

Except, those charged particles following the "field lines" constitute an electric current, hence the plasma tubes.
There is no need to maintain an electrical current to have a magnetic field; once a magnetic domain is created it can keep its state indefinitely.

That is a completely asinine statement, and "just totally wrong"! Strangely enough, the machinery in my manufacturing business needs electricity to operate today even though there was a "magnetic domain" in operation yesterday.
The Moon and Mars have remnant magnetism.

Ferromagnetic properties of material exposed to electric currents.
cantdrive85
1 / 5 (2) Jun 13, 2015
The earth's field is induced by current generated by magmatic thermal convection

That is the theory, sadly completely unsupported by any laboratory evidence despite years of attempts. According to that nonsensical theory salt water in a blender should induce a magnetic field but once again complete fail.
TechnoCreed
5 / 5 (3) Jun 14, 2015
@cd
Except, those charged particles following the "field lines" constitute an electric current, hence the plasma tubes.
Electrons do not flow along those lines nor do they have a preferred polarity so no electric current. Electrons get in a perpendicular 'cyclotron motion' around those lines as if it would be flowing inside a coil and this, until positive ions intersects their paths; that is all there is to it.
That is a completely asinine statement, and "just totally wrong"! Strangely enough, the machinery in my manufacturing business needs electricity to operate today even though there was a "magnetic domain" in operation yesterday.
This answer tell me that you do not know what a magnetic domain is. In a nut shell, let's say that binary infotmation in your hard drive (if it is a mechanic drive) are stored in magnetic domains.

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