Cosmic turbulences result in star and black hole formation

Aug 15, 2013
This image shows an artist's rendering of a protoplanetary disc. Credit: Pat Rawlings / NASA

Just how stars and black holes in the Universe are able to form from rotating matter is one of the big questions of astrophysics. What we do know is that magnetic fields figure prominently into the picture. However, our current understanding is that they only work if matter is electrically well conductive—but in rotating discs this isn't always the case. Now, a new publication by Helmholtz-Zentrum Dresden-Rossendorf physicists in the scientific journal Physical Review Letters shows how magnetic fields can also cause turbulences within "dead zones," thus making an important contribution to our current understanding of just how compact objects form in the cosmos.

When Johannes Kepler first proposed his laws of planetary motion in the early days of the 17th century, he could not have foreseen the central role would play in planetary system formation. Today, we know that in the absence of magnetic fields, mass would not be able to concentrate in compact bodies like stars and black holes. One prominent example is our , which formed 4.6 billion years ago through the collapse of a gigantic cloud of gas, whose concentrated particles in its center, culminating in the formation of a large disc. "These accretion discs are extremely stable from a hydrodynamic perspective as according to Kepler's laws of planetary motion increases from the center towards the periphery," explains HZDR's own Dr. Frank Stefani. "In order to explain the growth rates of stars and black holes, there has to exist a mechanism, which acts to destabilize the rotating disc and which at the same time ensures mass is transported towards the center and angular momentum towards the periphery."

As early as 1959, Evgenij Velikhov conjectured that magnetic fields are capable of prompting turbulences within stable rotating flows. Although it wasn't until 1991 that astrophysicists Steven Balbus and John Hawley fully grasped the fundamental significance of this magneto rotational instability (MRI) in cosmic structure formation. Balbus and Hawley will be this year's recipients of the one million Dollar Shaw Prize for astronomy, which will be given in September 2013. However, în order to ensure the MRI actually works, the discs have to exhibit a minimum degree of electrical conductivity. In areas of low conductivity like the "dead zones" of protoplanetary discs or the far-off regions of accretion discs that surround supermassive , the MRI's effect is numerically difficult to comprehend and is thus a matter of dispute. HZDR scientists, who to date have been mostly concerned with an experimental study of the MRI, have now offered a new theoretical explanation for this phenomenon.

Rivalry between physicists and astrophysicists

If you try and simulate the MRI in a liquid metal experiment with an exclusively vertically oriented magnetic field this field has to be rather strong. At the same time, since the rotational speed has to be very high, these types of experiments are extremely involved and thus far success has eluded them. Back in 2005, for the first time ever, Dr. Stefani and his colleagues at the HZDR and the Leibniz Institute for Astrophysics Potsdam managed to successfully simulate the cosmic process in the lab. By adding a circular magnetic field to a vertical one, they were able to observe the MRI at substantially smaller magnetic fields and rotational speeds. According to Steven Balbus and Hantao Ji per the current August edition of the magazine Physics Today, one of the blemishes of this "helical MRI" is the fact that it only acts to destabilize rotational profiles that are relatively precipitous towards the periphery, which for now does not include rotation profiles obeying Kepler's law.

Magnetic fields and rotating flows reinforce each other

The HZDR scientists are now countering this weighty astrophysics argument with their latest insights. The calculations by Dr. Oleg Kirillov and Dr. Frank Stefani have shown that the helical MRI very much applies to the Keplerian rotation profile if only the circular magnetic field is produced not entirely from the outside but at least partly from within the accretion disc. "This is in fact a much more realistic scenario. In the extreme case that there does not exist a vertical field, we're looking at a problem of what came first – the chicken or the egg. A circular magnetic field acts to destabilize the disc and the resulting turbulence generates components of vertical magnetic fields. They in turn reproduce the circular magnetic field because of the special form of the disc's rotational movement." Regardless of whether with or without a vertical magnetic field, current calculations show that the MRI is possible even in areas of low conductivity like the "dead zones"—something astrophysicists had not previously thought possible.

The HZDR scientists were driven by their long-standing experience with cosmic experiments in the lab, from a model of Earth's dynamo to magneto-rotational instability all the way to Tayler instability. The latter is being debated by astrophysicists with reference to cosmic jets and the formation of neutron stars, among others, but also has to be considered in the construction of large liquid metal batteries, for example. At this time, the scientists are planning a large-scale experiment using liquid sodium, which they are hoping to realize over the next few years as part of the DRESDYN Project. "Once we get this experiment, which for the first time ever will combine the MRI with Tayler instability, up and running, we will much improve our understanding of the interaction between various magnetic cosmic phenomena," says a happy Stefani. Regardless of who is the one to push the envelope in this amicable competition—the experimental physicists or the theoretical astrophysicists—the angular momentum transport in and in the lab will continue to be a hotly contested topic.

Explore further: The largest magnetic fields in the universe

More information: O.N. Kirillov, F. Stefani: Extending the range of the inductionless magnetorotational instability, in Physical Review Letters 111 (2013), S. 061103, DOI-Link: link.aps.org/doi/10.1103/PhysRevLett.111.061103

H. Ji, S. Balbus: Angular momentum transport in astrophysics and in the lab, in Physics Today, August 2013, S. 27 - 33.

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cantdrive85
1 / 5 (15) Aug 15, 2013
Rivalry between physicists and astrophysicists

Say it ain't so, you mean scientist resist interdisciplinary studies? Naaawww.

"Scientists tend to resist interdisciplinary inquiries into their own territory. In many instances, such parochialism is founded on the fear that intrusion from other disciplines would compete unfairly for limited financial resources and thus diminish their own opportunity for research."
[Naming territorial dominance, greed, and fear of the unknown, as some of the influences on the increasing specialization of science]
— Hannes Alfvén
"These accretion discs are extremely stable from a hydrodynamic...

Still using "models we know from experiments to be wrong".

And any idea these magnetic fields are created without the prerequisite electric currents can be dispelled with a single paper.
http://electric-c...OAAJ.pdf
no fate
4.4 / 5 (7) Aug 15, 2013
Scott is patently wrong.

" Magnetic fields are created by and moved around by electric currents – nothing else".

Any "current" flowing in the form of charged particles does so as a result of a flux field or conductive medium (FYI magnetic flux is a conductive medium) focusing and compressing the energy (clearly stated in the article and understood by every experimentally proficient plasma physicist). Once a continuous current is generated, yes, there will be an accompying magnetic field. But the electricity can never come first, you have to have a force (magnetic interaction) to produce an electric current and maintain it. Plasma never does this by itself ( if confined it is a homogenous "cloud" until a field is applied, in free space it rapidly dissipates without a confining field)

Here's a better way to put it, describe any means of generating a current without manipulating the energy that forms it.

Q-Star
4.5 / 5 (8) Aug 15, 2013
Scott is patently wrong.


If ya thought that paper was entertaining, ya should read some of the stuff he co-authored with Dr. Woo.
cantdrive85
1 / 5 (13) Aug 16, 2013
"The Maxwell (Heaviside) equations are based on real experimental measurements. These fundamental expressions clearly link electric current densities, magnetic flux densities, and electric fields into a unified conceptual whole." D. Scott

What induces "magnetic interaction"? What force created the magnetic field which in turn gave the force to the plasma to create an electric current?

cantdrive85
1 / 5 (9) Aug 16, 2013
Get your ideal MHD model over heeere!
thingumbobesquire
1 / 5 (5) Aug 16, 2013
no fate
4.2 / 5 (5) Aug 16, 2013
"These fundamental expressions clearly link electric current densities, magnetic flux densities, and electric fields into a unified conceptual whole." D. Scott

What induces "magnetic interaction"? What force created the magnetic field which in turn gave the force to the plasma to create an electric current?



Charge induces magnetic interaction. Charge isn't current, it is magnetic orientation. You're missing the point, electricity isn't an emergent property of energy until the energy is directed to align in the form of a current. This is accomplished with a field- always. The field that is generated electrically disappears if the electricity does, however energy concentrated in some forms of matter will also produce an external flux field with proper atomic alignment, in this case there is no electric current despite the existence of a field.

If the EU theory was valid, we'd all be plugging devices into magnets for power.
no fate
3.7 / 5 (3) Aug 16, 2013
"Today, we know that in the absence of magnetic fields, mass would not be able to concentrate in compact bodies like stars and black holes."

When they say "we" in the above statement they apparently mean everyone outside the EU. Asking what force creates a field, Tesla would make you wear a white cone shaped hat made out of paper and tell you to go stand in the corner.
cantdrive85
1 / 5 (11) Aug 16, 2013
If the EU theory was valid, we'd all be plugging devices into magnets for power.

That's what you are suggesting, first there was a magnetic field, them things can happen.
Charge induces magnetic interaction.

So the electric charge of the particles causes those particle to interact magnetically. The question arises, how to induce an electric charge to enable "magnetic interaction"?
IronhorseA
1 / 5 (2) Aug 16, 2013
"So the electric charge of the particles causes those particle to interact magnetically. The question arises, how to induce an electric charge to enable "magnetic interaction"?"

Strip some electrons off of some of the atoms in the cloud and their motion--caused by gravity-- will cause localized currents which in turn will induce a magnetic field. When the motion of the matter in the cloud or disk is sufficiently organized, so will be the magnetic field. The trick here is to strip some electrons off of the atoms and for that ionizing radiation will do just fine.
HannesAlfven
1 / 5 (8) Aug 18, 2013
Re: "If the EU theory was valid, we'd all be plugging devices into magnets for power."

The real problem here is that rather than engaging the actual theorists in such speculations in order to ensure against creating unnecessary confusion, people frequently imagine that the claims can be debunked without ever having to talk to the theorists. And at the end of the day, what you have is a bunch of people justifying to one another their decisions to not take the ideas seriously enough to authentically learn them.

Those of us who have engaged the theorists directly have not only found that serious questions by people who take them seriously are frequently engaged, but it also appears to be the norm for people to run into issues when trying to comprehend a completely new paradigm. The tendency is to unintentionally mix the claims of competing paradigms, and what results is then nonsense that is oftentimes passed as debunking.
HannesAlfven
1 / 5 (8) Aug 18, 2013
What people seem to consistently fail to realize is that the EU body of knowledge and claims is by now rather extensive. It very obviously remains a work in progress, but just getting up to speed on it can easily take a person a number of years.

What I generally see online is a very obvious desire to debunk the claims without having to learn the theory. The debunking is actually motivated by the desire to not actually learn the theory. In practice, what this oftentimes looks like is a bunch of people sending each other URL's to Tom Bridgman's website, which is rarely followed up with any actual clarification or discussion of the details -- as if decades-old arguments which have in numerous instances rolled from the lips of a Nobel laureate are so obviously wrong that a person can deduce it in less than 5 minutes of investigation.

Just as obvious is that this approach, which tilts all of the authentic learning to mainstream theory, and all of the debunking to the EU, is biased.
no fate
1 / 5 (1) Aug 19, 2013
If the EU theory was valid, we'd all be plugging devices into magnets for power.
That's what you are suggesting, first there was a magnetic field, them things can happen.




No it is what you are suggesting. First comes electricity, then the magnetic field. Therefore you are saying in order for the field to be present, a current must be flowing somewhere inside the magnet to generate the flux field. You don't know what a flux field is. There is no current in a flux field unless there are particles present in sufficient density in order to form one. We know there is magnetic flux in space because of the directionality of particle flow, but there aren't enough particles to form an actual current. If either of you EU guys can describe the process by which enough particle density is accumulated in order for currents to form without a magnetic field, I'll eat crow and admit I am wrong.

Actually, I'll eat crow shit and admit I am wrong.
no fate
4 / 5 (4) Aug 19, 2013
Charge induces magnetic interaction.

So the electric charge of the particles causes those particle to interact magnetically. The question arises, how to induce an electric charge to enable "magnetic interaction"?

Again: " Charge isn't current, it is magnetic orientation. "

It is not an electrical property when speaking atomically and sub- atomically and cannot be induced. It is a property that is particle dependant and is THE property which dictates it's interaction with other particles and fields.
cantdrive85
1 / 5 (9) Aug 19, 2013
A flux field cannot "just exist", something needs to create the flux, i.e., something needs to create that energy.

Any time electric charges move, they generate magnetic fields. Without moving electric charges, magnetic fields cannot exist. Ampère's Law states that a moving charge generates a magnetic field with circular lines of force, on a plane that is perpendicular to the movement of the charge.

cantdrive85
1 / 5 (9) Aug 19, 2013
In addition, from volumes of supportive laboratory research on plasma, those particles tend to naturally self organize into filamentary and cellular structures. Those filaments produce an electromotive force and are what transmits electric current in plasmas over all scales throughout the universe and produce the large scale magnetic fields we observe.
no fate
4.2 / 5 (5) Aug 19, 2013
A flux field cannot "just exist", something needs to create the flux, i.e., something needs to create that energy.


That is correct. But to pinpoint the source of all interstellar and intergalactic magnetic flux you are venturing into creation theory of the universe. The same physics still applies post inflation, you have to get the particles to align in a current prior to a magnetic field existing.

Anytime magnetic charges align, they create a flux field...no electricity present. It is called ferromagnetism.

In addition, from volumes of supportive laboratory research on plasma, those particles tend to naturally self organize into filamentary and cellular structures.


Just one example of this occuring without application of a field to a homogenous plasma will get me the same unpleasant meal I mention above.
no fate
3.7 / 5 (3) Aug 19, 2013
"you have to get the particles to align in a current prior to a magnetic field existing".

The words, "in order for the EU theory to be valid" should have followed this.
cantdrive85
1 / 5 (7) Aug 19, 2013
But to pinpoint the source of all interstellar and intergalactic magnetic flux you are venturing into creation theory of the universe.

God did it?

Anytime magnetic charges align, they create a flux field...no electricity present. It is called ferromagnetism.

Are we still talking about plasma? That sounds suspiciously like the theories and models based upon "ideal" ionized gases that "experiment has shown to be wrong". What you are proposing is a hypothetical construct or a metal.

Just one example of this occuring without application of a field to a homogenous plasma will get me the same unpleasant meal I mention above.

Are you suggesting the Universe is homogeneous? How do you pose a question and then constrain the parameters that don't reflect reality. You assume all the necessary factors to produce your outcomes, is it too much to assume there will be ions and electrons present in the EU model?
Fleetfoot
5 / 5 (3) Aug 20, 2013
A flux field cannot "just exist", something needs to create the flux, i.e., something needs to create that energy.


You are forgetting that a bar magnet has a field even though it has no source of energy.

However, you are also right in that, if you want to take energy from the field, you need a source to replace it otherwise the field decays. This is a conversation we have had several times before, the EU model has no such source. That's why it is treated as pseudo-science and will continue to be until the cranks promoting it bite the bullet and tackle that problem.
no fate
3.7 / 5 (3) Aug 20, 2013
But to pinpoint the source of all interstellar and intergalactic magnetic flux you are venturing into creation theory of the universe.

God did it?

Anytime magnetic charges align, they create a flux field...no electricity present. It is called ferromagnetism.

Are we still talking about plasma? That sounds suspiciously like the theories and models based upon "ideal" ionized gases that "experiment has shown to be wrong". What you are proposing is a hypothetical construct or a metal.

Just one example of this occuring without application of a field to a homogenous plasma will get me the same unpleasant meal I mention above.

Are you suggesting the Universe is homogeneous? How do you pose a question and then constrain the parameters that don't reflect reality. You assume all the necessary factors to produce your outcomes, is it too much to assume there will be ions and electrons present in the EU model?


Playing dodgeball?
no fate
4.2 / 5 (5) Aug 20, 2013
You brought up the filaments plasma forms, you just refuse to acknowledge what is required for them to form. You can release any volume of plasma into a vacuum chamber you want to, it won't form any structure by itself. Try it.

I am not suggesting the universe is homogenous, but it would be if we we were relying on plasma to form the first structure by itself.

Ferromagnetism obviously doesn't apply to plasma, it is an example of a magnetic flux field formed without electricity...that is why it isn't called electromagnetism.

One more time: Describe the process of aligning the particles to create a current without using a magnetic field. If you can do this no one can dispute the EU model.
cantdrive85
1 / 5 (10) Aug 20, 2013
A flux field cannot "just exist", something needs to create the flux, i.e., something needs to create that energy.


You are forgetting that a bar magnet has a field even though it has no source of energy.

However, you are also right in that, if you want to take energy from the field, you need a source to replace it otherwise the field decays. This is a conversation we have had several times before, the EU model has no such source. That's why it is treated as pseudo-science and will continue to be until the cranks promoting it bite the bullet and tackle that problem.

I guess I can call you a crank since you haven't found 96% of your universe. For the EU, the structures are apparent for Birkeland currents, and the magnetic fields are present for the currents. The only thing not measured is the actual current, that would however require a Langmuir probe inserted directly. Or we understand those fields are NOT magical, but created by an electric current.
cantdrive85
1 / 5 (8) Aug 20, 2013
Here's a piece of evidence for intergalactic BC, just for you Fleet.
http://arxiv.org/abs/1106.1397
cantdrive85
1 / 5 (9) Aug 20, 2013
You brought up the filaments plasma forms, you just refuse to acknowledge what is required for them to form.

You are setting constraints that don't match reality.
I am not suggesting the universe is homogenous, but it would be if we we were relying on plasma to form the first structure by itself.

I, nor any EU theorist are proposing a "creation event", as scientists one can only see as it is and try and work back from there. What can be seen however, is a filamentary and cellular structure from the smallest scales to the largest, seems foolish to ignore such an obvious plasma morphology.
Ferromagnetism obviously doesn't apply to plasma, it is an example of a magnetic flux field formed without electricity[/]q
How do you achieve a ferromagnetic metal w/o first supplying the energy to align the electrons? If you remove the magnetic properties of a bar magnet, it doesn't naturally reattain it's magnetism. Only an electric current can "recharge" the magnet.

cantdrive85
1 / 5 (9) Aug 20, 2013
One more time: Describe the process of aligning the particles to create a current without using a magnetic field.

How about electrostatic forces? Take a quasi-neutral "cloud" of plasma, within that cloud the particles will arrange themselves into "homogeneous" clouds. Around those clouds a sheath will appear naturally to protect the clouds from each other. That sheath is in fact a double layer with it's requisite electric field. In order to "equalize" the two clouds, force free currents will naturally arise. Those currents will form magnetic fields, DL's, and more electric fields, which in turn create a feedback mechanism which will further complicate the system. There is also other interesting things happening in the DL's, such as particle acceleration and synchrotron radiation which also adds complexity.


If you can do this no one can dispute the EU model.

ROTFLMAO! Max Plank said it best, something about people dying and a new generation who are familiar...
no fate
4.3 / 5 (6) Aug 20, 2013
In a quasi neutral "cloud" of plasma, the reactions are temperature and field dependant. Current sheaths don't form on their own because electrons and protons dont align with each other unless they are exposed to an external field, their first interaction is to form atoms which is temperature dependant. Your description of events above isn't what happens in a plasma chamber, or in space. "Force free" doesn't apply to electrical currents.
cantdrive85
1 / 5 (9) Aug 20, 2013
It's seems we'll go back and forth endlessly, what it comes down to is whether the "standard" theoretical model of ideal ionized gases is correct, or whether the behavior of plasma as described by plasma physicists based upon experimentation along with theory is correct. I tend to side with Alfven's POV;
"The cosmical plasma physics of today is far less advanced than the thermonuclear research physics. It is to some extent the playground of theoreticians who have never seen a plasma in a laboratory. Many of them still believe in formulae which we know from laboratory experiments to be wrong. The astrophysical correspondence to the thermonuclear crisis has not yet come."
Until astrophysics experiences their own "thermonuclear crisis", there is little hope for any real understanding of the physics involved. Here's a start;
http://www.plasma...se.info/
There are numerous peer-reviewed articles, books, and a number of presentations linked along with some general info, the crisis begins
no fate
4.2 / 5 (5) Aug 21, 2013
It's seems we'll go back and forth endlessly, what it comes down to is whether the "standard" theoretical model of ideal ionized gases is correct, or whether the behavior of plasma as described by plasma physicists based upon experimentation along with theory is correct.



Only one of us is speaking from a theoretical standpoint. Nothing I have posted here falls outside the realm of being experimentally verified.
cantdrive85
1.1 / 5 (8) Aug 21, 2013
It's seems we'll go back and forth endlessly, what it comes down to is whether the "standard" theoretical model of ideal ionized gases is correct, or whether the behavior of plasma as described by plasma physicists based upon experimentation along with theory is correct.



Only one of us is speaking from a theoretical standpoint. Nothing I have posted here falls outside the realm of being experimentally verified.

You keep thinking that, and the nuclear scientists will continue to chuckle from afar. Can you possibly point me in the direction to an experiment which shows this ferromagnetic plasma you're describing?
no fate
4.2 / 5 (5) Aug 21, 2013
It's seems we'll go back and forth endlessly, what it comes down to is whether the "standard" theoretical model of ideal ionized gases is correct, or whether the behavior of plasma as described by plasma physicists based upon experimentation along with theory is correct.



Only one of us is speaking from a theoretical standpoint. Nothing I have posted here falls outside the realm of being experimentally verified.

You keep thinking that, and the nuclear scientists will continue to chuckle from afar. Can you possibly point me in the direction to an experiment which shows this ferromagnetic plasma you're describing?


If anything, you are applying ferromagnetic attributes to plasma. You are the one suggesting a field free charge alignment that then creates a magnetic field. Still waiting for your example of that.....
cantdrive85
1 / 5 (7) Aug 21, 2013
Try retreading the post, btw I'm still waiting on the explanation of your magical, god induced magnetic fields. Tick, tock...
no fate
4 / 5 (4) Aug 21, 2013
Try retreading the post, btw I'm still waiting on the explanation of your magical, god induced magnetic fields. Tick, tock...


Ok, I will continue through life observing plasma illusions, and I will await the outcome of the Sapphire project or which ever one manages to get plasma to do anything by itself. For now, since it works, I'll stick with the whole fields thing because I am impatient and don't want to stare at plasma soup unti lit does something by itself.

As to what I think about where the fields came from. Prior to inflation, one electron. If that is it, where did it come from? Probably the same place the hydrogen ions did. My opinion about the source of the flux doesn't matter, it is present in all space regardless of particle density. Coupled with the physics you claim the universe is based on never being observed in recorded experimental history, I will be eating a double serving when you prove you EU guys nailed it.

If it is to be my last meal I'll live forever.
Fleetfoot
5 / 5 (4) Sep 06, 2013
Here's a piece of evidence for intergalactic BC, just for you Fleet.
http://arxiv.org/abs/1106.1397


Good paper, it clearly shows how they have reached their conclusions from the observations. From the abstract:

"We present radio emission, polarization, and Faraday rotation maps of the radio jet of the galaxy 3C303. From this data we derive ..."

That is the sort of evidence you should be presenting, observable evidence of the effects of currents, not your usual "it looks like a filament therefore there must be a current" nonsense.

From the first page of the paper:

"An equal but opposite 'return current' flows inward (or outward) at much larger distances from the jet axis so that the net current outflow from the source is zero."

No Birkeland current there then. You need to learn a lot more about what you are trying to claim.

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