This thread should pertain strictly to the formation and structure of jets.

Do you mean strictly in the EU cosmology (such as cometary jets), or do you accept postings about mainstream research about jets caused by material inflow into highly massive objects with strong magnetic fields?

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Forming opinions as we speak

1) What is a Birkeland current?

2) What is the role of Birkeland currents in the structure & formation of a jet?

3) Do Birkeland currents function as outlined in (2), at all size & time scales? In other words, can they explain jets on both stellar & extragalactic scales?

4) How does the EU explanation differ from the standard, mainstream explanation?

5) Why is the standard, mainstream explanation so poor as to require replacement?

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Don't try this at home - We're what you call "professionals" - MythBusters.

So the mainstream interpetation of intergalactic jets is that they carry an electric current from the source, central BH, to the lobes, emitting radiation and pinching along the way.
So would the MS also say there is an electrical circuit?

Also, everything I've seen on blackholes recently indicates streams of electrons and protons a TEv energies going away from the blackhole. Jets are definately powered by the central object. But its not a blackhole.

Post anything relating to jets, both mainstream and ATM.
The idea is to understand jets because you can see them clearly as opposed to trying to figure out our local circuit, which has proven to be difficult.

Here is M87.
http://www.astronet.ru:8105/db/msg/1172631/eng

From wikipedia "A Birkeland current generally refers to any electric current in a space plasma,"

But originally referred to the currents that powered the aurora.

The jets could be considered a large Birkeland current that transfers kinetic energy from the plasma flow and electrical energy from the field aligned currents.

They would be able to explain any collimated or striated plasma structures.

THe EU explanation clearly states that the jets are a result of a Birkeland current structure, and that there is collimation and pinching from the magnetic fields developed by the field aligned currents.

Not from the twisting of the central blackhole.

A Birkeland current is an effect that can be separated from the central BH object, and now you just have to worry about how that thing in the center is generating a stream of particles(hyper-pinch?), and it explains other filament like structures that have been discussed.

I have been following the Arp discussion with interest. A plasma universe would provide an explanation for the departure from the Hubble relation.

Could you please point out to us, then:
1.) How you think Birkeland currents (BCs) can create jets? Or do you mean that the BCs only collimate the jet, which is created by a central object?
2.) Do the BCs generate all the magnetic fields in the jets, or do the magnetic fields come from somewhere else, another generator region?
3.) What effects have the BCs on the magnetic field of the jet, if the magnetic field is not generated by the BCs?

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Optimism does not change the laws of physics. (T'Pol)
A good scientist has freed himself of concepts and keeps his mind open to what is. (Dao De Jing 27)
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Martin ( http://www.geocities.com/DrMartinV )

Mainstream would say, there have to be field aligned currents in the jets to explain the twisting magnetic fields, because only currents can change the direction of the magnetic field throught the beautiful formula:

rot(B) = mu0 J

__________________
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Optimism does not change the laws of physics. (T'Pol)
A good scientist has freed himself of concepts and keeps his mind open to what is. (Dao De Jing 27)
************************************************** *************************
Martin ( http://www.geocities.com/DrMartinV )

And you base your opinion on this on what??
Just because both positive and negative particles are accelerated away in the jet, from the BH region?
It has been shown clearly that such jets are created by the interaction of a black hole, and accretion disk, magnetic field and rotation. I would have to look up for references, but I think you can use Tim Thompson's referece in the 'table of content' thread.

Just because it is a black hole, does not mean that nothing can escape. Only at reaching the event horizon a particle is lost to our side of the event horizon, everything outside of the event horizon still has a chance of escaping.

__________________
************************************************** *************************
Optimism does not change the laws of physics. (T'Pol)
A good scientist has freed himself of concepts and keeps his mind open to what is. (Dao De Jing 27)
************************************************** *************************
Martin ( http://www.geocities.com/DrMartinV )

if i may intercede.

why is it "clear" that a blackhole is involved at all??

I guess just because the mass of the central object is very high and the size is very small. Just your regular neighbourhood AGN black hole.

__________________
************************************************** *************************
Optimism does not change the laws of physics. (T'Pol)
A good scientist has freed himself of concepts and keeps his mind open to what is. (Dao De Jing 27)
************************************************** *************************
Martin ( http://www.geocities.com/DrMartinV )

Well, this paper and this paper give all the specifics, along with references to other papers for your perusal. What I find especially interesting, is that the papers talk about the interaction of gravitational, plasma, and EM reactions and effects. The last two, the plasma and EU folks usually claim the mainstream doesn't pay any attention to.

Now would either you or upriver care to link to anything explaining how plasma or EU ideas show the jets are formed? And please have those links and papers show the mathematical and physical detail that is in the references I provided.

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Some try to tell me, thoughts they cannot defend,... - Moody Blues.

Okay, I am no expert on jets, but let me make the following model of what I think is happening, with a view from the early nineties

A supermassive object (black hole) is surrounded by an accretion disk. In this disk there is very turbulent plasma, because of differential rotation in the disk the mechanism of the so-called alpha-dynamo works very well. Strong magnetic fields are created, that are transported inwards, but will also balloon above the disk, creating a "magnetosphere".
Now the mass from the accreation disk crossing the last stable orbit will spiral into the supermassive object, but because of spin and whatever-you-got (guess I should read Tim Thompson's quoted paper and the ones by Tensor) instead of falling into the object, the mass (neutral magnetized plasma) is ejected away from the central object along its axis of rotation.
Note, that there is no reason why the magnetic field in the plasma that gets ejected should be "self-contained", it can easily be that there is a magnetic loop on the disk of which only one footpoint crosses the last stable orbit. This means that one side of the magnetic loop is flying away along the rotational axis of the system and the other side remains in the disk, rotating with it.
This rotation of the one side gets communicated to the other side by e.g. Alfven waves, which makes the field lines bend around. (Experiment take very looooong spaghetti, cooked, and hold one end up and let someone else rotate the hanging end, and see how the rotation takes time to reach your hand.) Now, the funny thing is, that magnetic field lines are not corpuscular, they are just mathematical objects that follow the direction of the magnetic field. So, the magnetic field needs to be changed direction, and in this case in the direction perpendicular to the magnetic field itself. The only way to do that is to have currents along the magnetic field (field aligned current, and if you really need to hear it Birkeland currents, although I consider the last to exist only in planetary magnetospheres). So the fact that the magnetic field gets twisted because of the rotation of the accretion disk, from which the magnetic field stems, causes magnetic field aligned currents to exist.
Now, it totally depends on what the jet does at its end. Usually there is a very turbulent region at the end, and a definite answer to what closes the current circuit I cannot give here. But there, I may point to the observations of the current with the VLBA that is mentioned somewhere above.

So, astrophysics says that the parallel currents are needed to twist the field lines. Now, I think biknewb in the "table of content" thread supposed that electrical engineers assume there is just a blow out of hot gas, ionized in jets, and that a possible difference in velocity in the positiv and negative particles is the cause of current and will confine the jet. However, I have trouble to see here how he creates the magnetic field along the jet in this fashion, it can only create "strapping" magnetic field circling around the jet.

__________________
************************************************** *************************
Optimism does not change the laws of physics. (T'Pol)
A good scientist has freed himself of concepts and keeps his mind open to what is. (Dao De Jing 27)
************************************************** *************************
Martin ( http://www.geocities.com/DrMartinV )

Wow, Tussenfem this image of magnetic field lines twisting an turning is somewhat beyond my current level of understanding. I'd have to study that.
I would like to clarify what I said (had to look for my post in the multithreaded environment):
Electrical engineers do not think about blowing gas. They see a current so they assume a potential difference as cause of the current. No blowing, just current flowing.
The controversial part is the assumed electric potential as opposed to the mainstream's assumed gravitational potential.

gerards regards

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Es gibt keine Tatsachen, es gibt nur Interpretationen. (There are no facts, only interpretations.) Friedrich Wilhelm Nietzsche

Guess I got the quote wrong then, I could not find it anymore, but I do remember reading it. Sorry that I misquoted you biknewb.

__________________
************************************************** *************************
Optimism does not change the laws of physics. (T'Pol)
A good scientist has freed himself of concepts and keeps his mind open to what is. (Dao De Jing 27)
************************************************** *************************
Martin ( http://www.geocities.com/DrMartinV )

No problem, Tussenfem. It looks like the original thread was under electrical stress and gave birth to a second one, to share the load. It took some posts with it.

gerards regards

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Es gibt keine Tatsachen, es gibt nur Interpretationen. (There are no facts, only interpretations.) Friedrich Wilhelm Nietzsche

The EU model is pretty simple.
In the Galactic Center there is a structure that is a plasma emitter in that it emits or accelerates protons(ions) and electrons. See attachment.
There seems to be a preferential direction of emission.
As the plasma is moving it will naturaly form a filament as it collimates from the magnetic field generated by the electric field from the moving plasma. It is self generating in that the more plasma that flows the longer and more collimated the Birkeland current will be from the stronger electrc field.
http://en.wikipedia.org/wiki/Birkeland_current


Here is the latest mainstream article I could find on blackhole jets.

" For Immediate Release
April 24, 2006 "
" The study results, which will appear in an upcoming issue of the Monthly Notices of the Royal Astronomical Society, also shed new light on how black holes so efficiently produce such particle jets. A significant portion of the gas pulled into black holes must approach the event horizon where it is used with high efficiency to produce the jets.

"Though we don't definitely know the mechanism by which these jets are produced, our findings are supportive of the idea that magnetic field lines interact in a way that causes them to work like the elastic bands of a giant sling shot throwing incoming material back out from the black hole," said Reynolds."
http://www.newsdesk.umd.edu/scitech/...ArticleID=1257

No where do they even mention plasma, and we all know there is probably not much "gas" around a "blackhole".

And the only way I could think of moving magnetic fields is with an electric current.

Have you ever played with a bar magnet and iron filings. The magnetic field never twisted but the filings looked liked it did because they did not move perfectly with the magnetic field.



Here is the conclusion of the latest observations for the galactic center.
I agree with what they say. No where in their paper is there anything that leads me to believe there is a black hole in the GC. Only a high energy particle source.

"To be faced with data from observations that cannot be readily explained nor understood is stimulating and inspiring. This is the kind of puzzle that we face in trying to understand the nature of the emission detected from the direction of the Galactic nucleus with Integral and Hess."

"A Persistent High-Energy Flux from the Heart of the Milky Way : Integral's view of the Galactic Center"
"These observations lend crucial support to the idea that acceleration of particles to very high energies is taking place at the gc (Crocker et al. 2005). Furthermore, all of them agree on the apparent absence of variability from the central source. "
http://clusterlaunch.esa.int/science...bjectid=37891#
Link at bottom of page for full article.

SO that leads us to jets. As this paper says there is no way you can have a column of plasma without the pinch effect.

"High Energy Hadronic Acceleration in Extragalactic Radio Jets"
http://arxiv.org/PS_cache/astro-ph/pdf/0106/0106530.pdf
See attachment for circuit diagram.

And here is the other one again.
http://adsabs.harvard.edu/abs/1986ApJ...306..451B

At this point I think that the Eu model has shown that it has a viable jet model based on simple, known, experimental plasma physics.

Attached Images

	GC.jpg (130.9 KB, 8 views)
	jetcircuit.jpg (34.1 KB, 9 views)

Upriver, have you even read the whole discussion since your last message?

As I have already mentioned above, in this way you only get a current in the direction of the jet, and you cannot generate the guiding field that you need for your jet, and which is observed by the way.

Ah, now we are doing science again using press releases, which we know you have to take with a handfull of salt. No, they will not use the word plasma because, like it or not, most people have no idea what a plasma is (apart from blood plasma) and calling a plasma a gas is no problem, it still adheres to a lot of gas laws, only the adiabatic constant is not 5/3 but 4/3 (if I remember correctly).

And what is with the bar magnet and the magnetic field never twisting? Sure, playing with a bar magnet and filings will not generate currents (well not on an observalble scale). But take e.g. a look at the magnetic field of the Earth in the magnetotail, and you will see that the field is not nicely dipolar (like a bar magnet) but stretched, tilted, twisted, etc. And every change in magnetic field is created by the appropriate currents.

And I think the EU plasma emitter (that you forget to define!) is just the magnetic slingshot effect of main stream physics, which then basically turns the whole of the EU view of jets to regular main stream physics (apart from that you doubt that there is a black hole, but that is an aside, because we are dealing with jets).

__________________
************************************************** *************************
Optimism does not change the laws of physics. (T'Pol)
A good scientist has freed himself of concepts and keeps his mind open to what is. (Dao De Jing 27)
************************************************** *************************
Martin ( http://www.geocities.com/DrMartinV )