In Coulomb drag propulsion, a long high voltage tether or system of tethers gathers momentum from a natural plasma stream such as solar wind or ionospheric plasma ram flow. A positively polarised tether in the solar wind can be used for efficient general-purpose interplanetary propellantless propulsion (the electric solar wind sail or E-sail), whereas a negatively polarised tether in LEO can be used for efficient deorbiting of satellites (the plasma brake). Aalto-1 is a 3-U cubesat to be launched in May 2016. The satellite carries three scientific experiments including 100 m long Coulomb drag tether experiment. The tether is made of four 25 and 50 micrometre diameter aluminium wires that are ultrasonically bonded together every few centimetre intervals. The tether can be charged by an onboard voltage source up to one kilovolt positive and negative. The Coulomb drag is measured by monitoring the spin rate.
- Posts: 83
- Joined: Wed Jan 29, 2014 8:09 am
- Posts: 1255
- Joined: Sat Apr 18, 2009 4:01 am
- Location: The Netherlands
There was a thread about the concept here>http://www.thunderbolts.info/forum/phpB ... =3&t=16154
- Posts: 250
- Joined: Mon Sep 02, 2013 6:16 am
- Location: Liverpool, UK
The European Space Agency’s (ESA) Swarm spacecraft have encountered a ‘strange ribbon of purple light’ called Steve.
One of the Swarm satellites found that; ‘The temperature 300 km above Earth’s surface jumped by 3000°C and the data revealed a 25 km-wide ribbon of gas flowing westwards at about 6 km/s compared to a speed of about 10 m/s either side of the ribbon.’
A ‘ribbon of gas’ or a Birkeland Current?
http://www.esa.int/Our_Activities/Obser ... _met_Steve
- Posts: 6
- Joined: Thu Mar 30, 2017 1:17 pm
- Posts: 1372
- Joined: Mon Mar 17, 2008 3:05 am
Supersonic Plasma Jets Discovered
Swarm Detects Assymetry
For more detailed info just visit: Swarm Documents and Publications
The latest Space News covers Swarm with Dr. D. Scott: Plasma Jets and the Electric Earth
- Posts: 341
- Joined: Sun Aug 31, 2008 1:06 am
A video of the phenomenon. Looks like the aurora twisting into a double strand current tube?
- Posts: 10
- Joined: Tue Jul 05, 2016 6:02 pm
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?
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?
Thanks for the basic knowledge insights (as I'm sure it's pretty basic knowledge).
- Posts: 1372
- Joined: Mon Mar 17, 2008 3:05 am
Correct. This particular display of the Aurora had never been observed.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?
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:
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.… 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
“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.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?
Some Aurora are not visible. They are called “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.]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
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.
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 Photography
1-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.
- Posts: 4433
- Joined: Fri Apr 04, 2008 2:54 pm
http://www.thunderbolts.info/forum/phpB ... 61#p119561
That includes E.U. data. Please see that thread.
I told my brother, Steve, about that plasma string. I told him it seems that scientists consider anything unusual to be Steve.
Who is online
Users browsing this forum: No registered users and 3 guests