Sharing three thoughts on this:
Part 1: Citizen's Contribute
Tansi wrote:What I, an 'ordinary' person would like to know is - when they say 'discovered' does that mean they never have ever clapped eyes on a plasma stream like this? Why?
Correct. This particular display of the Aurora had never been observed.
Over the years science simply didn't have enough space craft, and probably not enough people, specifically dedicated to the study of the Aurora. As a result, this particular feature slipped by the observations. As explained:
… Eric Donovan from the University of Calgary explained how this new finding couldn’t have happened 20 years.
“
In 1997 we had just one all-sky imager in North America to observe the aurora borealis from the ground,” said Prof. Donovan.
“
Back then we would be lucky if we got one photograph a night of the aurora taken from the ground that coincides with an observation from a satellite.
Now we have many more all-sky imagers and satellite missions like Swarm so
we get more than 100 a night.”
And now, social media and citizen scientists also have an increasingly important role.-
When Swarm Met Steve
Good on Prof. Donovan for keeping his ear to the ground with an eye to the sky. The interesting part is that the SWAM spacecraft made a match with something that scientist had not seen – correlated with something people on the ground saw regularly. That's a fun thing.
Part 2:Energy and Light
Tansi wrote:Is there a point where they become visible - like more energy? And if so, where or why is there more energy for this stream now?
“Energy” does that. Any increase in energy (electric fields, magnetic fields, gravitational fields, Motion) can cause some particles to emit light. So can "collisions" between some particles. Particles like to be at a certain "energy level" called a "rest state". If you pump them with extra energy from these fields they get "excited" However, they still want to return their normal "rest state". So they shed the excess energy by emitting Light (photons). Aurora are said to be a collision based excitation. The Sun is the biggest nearest source of these increases in energy.
Some Aurora are not visible. They are called “Black Aurora”:
]
The black aurora isn't actually an aurora at all; it's a lack of auroral activity in a region where electrons are 'sucked' from the ionosphere,"
(…)
Aligned like a string of pearls flying 100 seconds apart, the first three spacecraft (Rumba, Salsa and Samba) detected an increase in the energy of the upward-moving electrons, coinciding with an increase in the electric field that was accelerating the electrons, and a stable electric current. However, the electric field had vanished and no evidence of a structure could be seen by the time the fourth spacecraft (Tango) flew over the aurora. -
CLUSTER QUARTET PROBES THE SECRETS OF THE BLACK AURORA
So: Sometimes, when the normal Aurora has a dark hole, or dark curling effect, or perhaps long a dark band, or a dark gap – it *does not* mean that nothing is there. It
can mean that electric currents in “dark mode” are outbound from Earth. Think of electricity as a two lane highway with "particle" traffic (electrons & ions etc) simultaneously moving in opposite directions.
That is why the image in the top left-hand corner from
SWARM shows bidirectional (or “plasma jets”) more properly
Birkeland Currents. Better still, Nature's electric currents.
Part 3: Nature's Electric currents
Here is a fun thing to do:Electric currents take several forms. Looking up from the ground one can see organized “steams”. Looking at things from a different angle one can see “
current sheets.” Sometimes beads of “ball lightning” can occur during storms.
However, probably the most familiar and favored form is the “filament” of electric current (also recognized as the Lightning Bolt). If you do the following very carefully you can watch the “plasma stream” known as “Steve” undertake the most fantastic form of a filament.
At the video link:
Vanexus Photography1-Hit the ”play” button. Watch the counter start at 00:00.
2- You must “Pause” the video counter at 00:01. The video space between 00:00 and 00:01 is what you want to focus on.
3-Next to the "Play" button you should now see a little blue section in the video progress bar.
4- Click and hold your cursor
within that little blue space. Then, VERY slowly slide your cursor left and right **ONLY** within the little blue section of the progress bar between 00:00-00:01.
You can then pause at the briefest of moments and freeze the "plasma stream" while it adopts the very familiar serpentine entwined tubular shape of Nature's very own electric current filament.
"Our laws of force tend to be applied in the Newtonian sense in that for every action there is an equal reaction, and yet, in the real world, where many-body gravitational effects or electrodynamic actions prevail, we do not have every action paired with an equal reaction." — Harold Aspden