Edited by Gaspode:
Removed off-topic comment.
Dear
brantc,
I have read your postings now for a long time and it seems to me that you still have a lot to learn about how plasma physics and its application in space works. There are several very good books on this topic: Kivelson & Russell (Introduction to space physics) and Baumjohann & Treumann (Basic space plasma physics), and naturally there is also the book by Peratt (Physics of the plasma universe) and if you want to go to "historic documents" you can read Alfvén's Cosmic Plasma or Cosmical Electrodynamics, however I would refrain from the latter two until you have read more introductory books.
Now, let's look at what you posted about plasmas (in the laboratory and/or in space):
And before you turned on the current to create the plasma there was no current(no discharge).
Then you turned on the electricity and lo and behold there was a discharge. This discharge did not care what the medium of transfer was.
All it cared about was equalizing the charge imbalance.
brantcare you too fixed on currents! There is no need AT ALL for currents in creating natural plasmas. Just heat up the gas enough and ionization will take place. That is the way it works in nature. Or you can have a source of UV radiation near a neutral gas, and the photoionization will kick the electrons from their atoms and in this way it is rather easy to create a plasma. Naturally, you would have to see whether the constraints on what a plasma is are fulfilled, otherwise you just have an (partially) ionized gas and not a plasma. What these conditions are (i.e. when you can talk about a plasma and not just an ionized gas) can be found in the introductory plasma physics books that I quoted above.
It's only in the laboratory that we have to use electrical methods to create a plasma. Like I did in the Alfvén laboratory in Stockholm (whilst Hannes Alfvén was still walking around) in the double plasma machine.
A part from my paper on how this machine works:
Volwerk 1993 said:
The experiments are performed with a double-plasma machine which was also used by Lindberg [7,8] (figure I), which consists of a heated cathode chamber (C), in which argon gas is inserted and the plasma is created. Connected to this cathode chamber by a glass tube is a grounded middle chamber (M) to which a vacuum pump is connected and in which a Langmuir
probe is situated, so that the density of the ingoing beam of plasma into the glass tube (G) at the anode side of the middle chamber can be measured. At the end of the glass tube (G) is situated the anode to which we can apply a voltage which causes a DL to be created inside the glass tube.
(in case you cannot obtain this paper then I can send you an electronic copy)
Even without a voltage on the anode, the heated gas in the glass tube could be "lit" by using a "Tesla", then no current, just plasma shining in a pretty pink colour. Then I'd turn on the voltage to create an anode sheath and then increase the voltage in order to transform the sheath into a double layer and place it in the middle of the glass tube. THEN current was flowing, but only AFTER I turned on the voltage.
There was also no "charge imbalance" how can there be, because the gas was ionized from neutral, so there never was a chance to get any charge imbalance.
And along as there was a charge imbalance then everything in the path was subject to electrification.
I have to point out that gramatically this is not a sentence. Maybe you can rewrite this in a clear way so we can discuss this point.
Consider a gas in a chamber with an electrode at each end. You introduce one electron of say 2keV into the chamber. The electron hits an atom and dislodges another electron, you have an ion and 2 free elections. These electrons run around until they thermalize and are recaptured. The last electron runs out of energy and is probably captured by the vessel wall.
If you had an electron with enough energy you could make a plasma with that one electron.
That is
one way of creating a plasma, that is correct, the process is happening in luminescent tubes. However, that is not what happens in space, no matter how much you want it to. Then you might want to say, well that is how lightning is working. However, there the path is
not created by an electron, but through electrical breakdown of the atmosphere at several MegaVolts per meter electric fields. From Wiki: Electrical breakdown occurs within a gas (or mixture of gases, such as air) when the dielectric strength of the gas(es) is exceeded. Regions of high electrical stress can cause nearby gas to partially ionize and begin conducting.
And its a discharge because that electron is going from the cathode to ground/anode....
Yes,
in the laboratory, in space, however (and that is still where the sun is, whether it is an metal ball a la Terella or an actual ball of plasma) things happen differently, compress a gas enough, using the ideal gas law PV=NRT and
Saha's equation and then put 1 and 2 together and you find if you compress a gas enough (under gravity for example) the temperature rises and Saha shows you what happens, more and more ionization.
"It is possible to produce a plasma which is not quasineutral. An electron beam, for example, has only negative charges. The density of a non-neutral plasma must generally be very low, or it must be very small, otherwise it will be dissipated by the repulsive electrostatic force."
Wiki
I imagine that its also possible to produce proton plasma....LHC?
There is such a field as the physics of non-neutral plasmas, and it is rather complicated. And yes an electron beam (or a proton beam for that matter, a bit more difficult to produce) can be considered such plasmas. Electron guns usually have strong magnetic fields to bind the electrons so that they don't fly away.
However, I would challenge you to find significantly non-neutral plasmas in space.
I guess you could consider vacuum a medium but I dont. I consider any matter to be the medium and you can measure the K of any medium.
They have some conductivity so all you are really doing is specifying a macroscopic (vs a microscopic) amount of electrons during some condition, a "discharge".
Take capacitors in an audio circuit. Dielectric yet there is a signal in the circuit due to the "field". Everything conducts to some degree...
Yeah, everything conducts,
brantc, to some degree and often the degree is zero. I feel that is just a very childish way of getting what you want, without having to really think about the (plasma)physics that is involved in the electrical break down of a isolator.
Where do you think the magnetic field comes from? Go back and read the reconnection thread again. Especially the part about flux transfer events and CLUSTER observations.
Specifically the flux tube forms with a magnetic field following the right hand rule. Then there is a flux transfer event and you are left with the collapsing field around the flux tube which creates a field aligned current flow down the center. A flux tube is. highly dynamic.
Unfortunately you give a very bad description of what an FTE is and I feel you have the wrong impression of how they work and are created. It is not your fault, because usually press releases do not really go into details well enough or dumb the physics down for the general public.
FTEs are something very specific at the Earth's magnetopause, where fluxtube/ropes enter into the Earth's magnetosphere through reconnection processes. It is really quite interesting
In a flux tube
there is already field aligned flow or else how would you get the twisted magnetic fields. And then "collapsing field around the flux tube which creates currenst" this is pure and utter drivel.
To anyone who is interested in FTEs please follow this link to ADS.
Now the reason for the formation of a flux tube, specifically in an existing plasma, is that the discharge current exceeds the plasmas current carrying capability at that moment in time. Kinda like lightning.
No, that is not how a flux tube is created. You can find how they are created in books on solar plasma physics. A good book to start would be Kirk, Melrose & Priest
Plasma Astrophysics.
If there is a current in a plasma that exceeds the "thermal current" that can be carried by the plasma, then
a double layer is formed and NOT a flux tube. This process is nothing like lightning at all, like you claim. And then again, you'd be hard pressed to find an unmagnetized plasma in space, it is rather unclear from your description if you are talking about a magnetized or unmagnetized plasma in which you want to let these currents flow.
Over what time frame?? When you light up a plasma you can see the chamber take a certain amount of time to light up all the plasma, seconds if its big..
Charge imbalance wants to balance at the speed of light. It forms a flux tube to achieve that goal.
Naturally, it CANNOT balance a charge imbalance "at the speed of light" because plasma consists of massive particles which cannot move at the speed of light, but that is only nitpicking. Furthermore, there are specific speeds in plasmas at which signals can be transmitted, most of the time this will be the Alfvén velocity.
This one is of particular interest. Electricity has a speed associated with it. Over large distances, 30000Km, you will get a charge imbalance. The solar surface is constantly discharging electrons and ions into the plasma surrounding the sun. The solar surface has and elevated surface temperature at some points leading to greater emission leading to unbalanced charges at the surface. Plasma on the other hand is an even better conductor than iron some there is less of a chance of structures forming unless there were some sort of high current discharges.
Maunder's Butterfly Diagram is a map of the surface charge imbalance.
Why the pattern? I dont know, nobody knows although I believe it has to do with the way current flows in and around the sun.
This is going much further than we can discuss right now, because I still have the feeling that you have some difficulties with the basics of plasma physics and electrodynamics. Until we have cleared these problems up, we cannot go any further as that will hamper the descriptions that we have to make of the processes happening on the sun. Naturally, we are here for you if you have any specific questions on the topic, don't hesitate to ask.
Looking forward to a good and fruitful (though slightly timelike hampered) discussion.
Best regards
1005