Z-pinch Sunspots

[robinson]

Err, I don't think that is correct.

 

[Reality Check]

RC, you will find that BAC does not answer direct questions, he will point some way and spin but not usually answer.

Hi DD. I have seen BAC on other threads and he does have a tendency to spin questions. He has been fairly reasonable on this thread but at least he has admitted that the sun is "mostly fusion powered".
I suspect (please tell me that I am wrong BAC!) that the electrically-powered sun will reappear from him in the future.
In any case this is a useful exercise for me since it enables me to reconnect with my physics background after 20 years in IT.

 

[Reality Check]

Err, I don't think that is correct.

"The core of the sun is basically a lot of hydrogen bombs" is simplistic but not totally wrong. Another analogy would be 1 enormous hydrogen bomb that has been exploding for the last few billion years.

 

[sol invictus]

"The core of the sun is basically a lot of hydrogen bombs" is simplistic but not totally wrong. Another analogy would be 1 enormous hydrogen bomb that has been exploding for the last few billion years.

Yes, that's basically correct. It's only in the core (which ends maybe 1/4 of the way out from the center) that the fusion is taking place, and it's not exactly the same set of reactions used in modern hydrogen bombs, but those are relatively minor points.

In both cases the primary power source is the fusion of hydrogen into helium.

 

[BeAChooser]

Magnetic fields come from electric currents.

You don't say?

You'd be surprised at the number of mainstream papers and articles that forget to mention that little fact ... that act like the magnetic fields just appeared out of nowhere.

Solar magnetic fields have a important role in stars but little role beyond the surface of a star.

Well how far do solar magnetic fields extend above the surface of the sun? To the corona? A little beyond that?

They do have a role in flares and solar winds but these are minor phenomena, i.e. do not affect a stellar system as a whole.

Surely you aren't saying that flares and solar winds are minor phenomena and do not affect the stellar system as a whole. Surely.

The solar wind today is a minor effect - when was the last time that a planet was blown out of its orbit by the solar wind?

Oh, I guess you are!

No pinch (zeta, theta or other) in the laboratory has produced fusion.

http://tech.groups.yahoo.com/group/undernetphysics/message/230 "The big news out of the April APS Meeting in Philadelphia this week (as reported by ScienceNow) is the report out of Sandia National Lab of the first ever hydrogen fusion using the Z pinch machine."

http://sciencenow.sciencemag.org/cgi/content/citation/2003/408/2 "Electrical Pinch Fuses Hydrogen"

 

[BeAChooser]

The parameters are simple - temperature and pressure.

You forgot at least one. Time.

We know the parameters because we have done it - ever hear of the hydrogen bomb ?

So you think a hydrogen bomb is a sustained fusion reaction? Do you know how long fusion actually lasts in a hydrogen bomb?

The core of the sun is basically a lot of hydrogen bombs.

But that doesn't really describe the approach that mainstream physicists have been trying in controlled fusion experiments the last 40 years, does it?

http://query.nytimes.com/gst/fullpage.html?res=9805E0D71338F93BA35757C0A9659C8B63 " New Fusion Method Offers Hope of New Energy Source, By KENNETH CHANG
Published: April 8, 2003, With a blast of X-rays compressing a capsule of hydrogen to conditions approaching those at the center of the Sun, scientists from Sandia National Laboratories reported today that they had achieved thermonuclear fusion, in essence detonating a tiny hydrogen bomb. "It's the first observation of fusion for a pulsed power source,'' said Dr. Ramon J. Leeper, manager of the target physics department at Sandia, in Albuquerque, who presented the findings at a meeting of the American Physical Society here. Most fusion efforts have tried to use magnetic fields to compress hydrogen to temperatures hot enough for fusion to occur continuously, as it does in the Sun. But sustaining a dense hot cloud of hydrogen gas has proved trickier than scientists thought when they started fusion experiments 50 years ago."

On the other hand, a hydrogen bomb does describe the z-pinch approach. And you've heard of those, haven't you?

 

[BeAChooser]

Originally Posted by Reality Check
"The core of the sun is basically a lot of hydrogen bombs" is simplistic but not totally wrong. Another analogy would be 1 enormous hydrogen bomb that has been exploding for the last few billion years.

Yes, that's basically correct. ... snip ... it's not exactly the same set of reactions used in modern hydrogen bombs, but those are relatively minor points.

ROTFLOL! If they are so minor, sol, why haven't they been able to sustain fusion in the lab ... after 50 years of trying ... and billions and billions of dollars spent in research?

 

[Ziggurat]

So you think a hydrogen bomb is a sustained fusion reaction?

I don't believe he made that claim.

Do you know how long fusion actually lasts in a hydrogen bomb?

Do you know how long you can sustain high pressure in a hydrogen bomb?

But that doesn't really describe the approach that mainstream physicists have been trying in controlled fusion experiments the last 40 years, does it?

Well, duh. That's because we have no possible mechanism available on earth for maintaining such high pressures. They tend to, you know... explode.

 

[Reality Check]

The links are a bit old (2003) but looking up Google does show that Sandia have has success.
So it looks like z-pinches can create fusion under laboratory conditions. Of course the sun is not a laboratory and so it would be nice to see proof of z-pinches and fusion from them on the sun.

 

[BeAChooser]

Originally Posted by BeAChooser
So you think a hydrogen bomb is a sustained fusion reaction?

I don't believe he made that claim.

So when I wrote "they still haven't been able to produce a 'sustained' fusion reaction in the lab." and he responded "We do not have to observe the core of the sun to know it exists. The parameters are simple - temperature and pressure. We know the parameters because we have done it - ever hear of the hydrogen bomb ?", you don't think he was claiming a hydrogen bomb is a sustained fusion reaction? Ok, suit yourself, Ziggurat.

Well, duh. That's because we have no possible mechanism available on earth for maintaining such high pressures. They tend to, you know... explode.

Looks to me like you are saying its *obvious to you* that nuclear physicists have wasted 40 years and billions and billions of dollars pursuing an approach that was doomed from the start ... where there is "NO POSSIBLE MECHANISM" available on earth to maintain the required pressures? Is that right, Ziggurat? Are you calling all those researchers incompetent or so eager to get the billions that they ignored the obvious? I'm frankly surprised to hear that sort of statement coming from you.

 

[ben m]

Looks to me like you are saying its *obvious to you* that nuclear physicists have wasted 40 years and billions and billions of dollars pursuing an approach that was doomed from the start ... where there is "NO POSSIBLE MECHANISM" available on earth to maintain the required pressures? Is that right, Ziggurat? Are you calling all those researchers incompetent or so eager to get the billions that they ignored the obvious? I'm frankly surprised to hear that sort of statement coming from you.

Holy cow, BAC, that's the kind of nonsense that makes me keep you on "ignore". I clicked "view post" once and won't do it again.

Did he say "no possible mechanism"? No, you're just making up things to argue with. We haven't done sustained fusion on Earth because we need a pressure/temperature containment mechanism here---as opposed to on the sun, where confinement is provided naturally---and so far the invented mechanisms (tokamaks, stellerators, pinches, NIF) present difficult engineering problems. Physicists are attempting to solve those engineering problems. Did you not know that, or did you pretend not to for the sake of something to sneer about? I don't know which is worse. Back to ignore.

 

[Reality Check]

So when I wrote "they still haven't been able to produce a 'sustained' fusion reaction in the lab." and he responded "We do not have to observe the core of the sun to know it exists. The parameters are simple - temperature and pressure. We know the parameters because we have done it - ever hear of the hydrogen bomb ?", you don't think he was claiming a hydrogen bomb is a sustained fusion reaction? Ok, suit yourself, Ziggurat.

You should have noted the smiley at the end of the comment. It was an analogy not an assertion. I will make my post more explicit:

1. We know that the sun has a core since it cannot be hollow given that it is composed of plasma.
2. We know that the core is under high pressure since the sun's gravity is pulling in the plasma. The pressure can be calculated.
3. We know that the core is at a high temperature because if it was not then it would not be comprised of plasma. The temperature can be calculated.

Therefore we find that the temperature and pressure at the core is sufficient for various fusion reactions to occur and it is this that powers the sun. Our understanding of solar fusion is as complete as the science that lead to the hydrogen bomb.

 

[The Man]

The links are a bit old (2003) but looking up Google does show that Sandia have has success.
So it looks like z-pinches can create fusion under laboratory conditions. Of course the sun is not a laboratory and so it would be nice to see proof of z-pinches and fusion from them on the sun.

Actually in Sandia National Lab’s Z-machine the Z-pinch does not directly generate fusion but acts as an X-ray source for indirect inertial confinement fusion, the same process used in a hydrogen bomb. The only difference is that in a hydrogen bomb a fast fission device is used as the radiant energy source and not a Z-pinch.

But that doesn't really describe the approach that mainstream physicists have been trying in controlled fusion experiments the last 40 years, does it?

Yes it does, the basic methods for obtaining fusion in laboratory research are magnetic confinement (Tokomak and direct Z-pinched fusion) and inertial confinement (Z-machine, laser and ion beam fusion). Fusion from gravity is a form of inertial confinement fusion.

On the other hand, a hydrogen bomb does describe the z-pinch approach. And you've heard of those, haven't you?

No, it does not, it describes the Z-machine approach where the Z-pinch is just a radiant energy source for indirect inertial confinement fusion. Direct Z-pinched fusion is a form of magnetic confinement and differs from the inertial confinement approach used in the Z-machine, the hydrogen bomb and considered to power the sun.

 

[Ziggurat]

Looks to me like you are saying its *obvious to you* that nuclear physicists have wasted 40 years and billions and billions of dollars pursuing an approach that was doomed from the start

I'm saying nothing of the sort.

... where there is "NO POSSIBLE MECHANISM" available on earth to maintain the required pressures?

There is indeed no possible method available to us on earth to maintain the pressures that occur in the heart of the sun. Do you dispute that? Can you tell me how we can maintain such pressures? No, you can't. Nor did you even try.

Are you calling all those researchers incompetent or so eager to get the billions that they ignored the obvious?

No. But it's clear that you're clueless about what I am saying. We don't need to produce sustained pressures like the sun in order to produce fusion. We can go to higher temperatures instead (tokamak), or we can do pulsed fusion. The Z-pinch fusion power concept doesn't rely on sustaining fusion, in case you weren't aware. It relies on essentially pulsing mini-hydrogen bomb explosions. That's not sustained fusion, that's just repeated fusion.

 

[Belz...]

You'd be surprised at the number of mainstream papers and articles that forget to mention that little fact ... that act like the magnetic fields just appeared out of nowhere.

Maybe it's because it's implicitely understood how they do arise.

ROTFLOL! If they are so minor, sol, why haven't they been able to sustain fusion in the lab ... after 50 years of trying ... and billions and billions of dollars spent in research?

Aren't they using magnetic "pinch" to create nuclear fusion ?

The sun is gravity-powered, when you think about it. It requires very large amounts of gas for the whole thing to work.

 

[Zeuzzz]

The sun is gravity-powered, when you think about it. It requires very large amounts of gas for the whole thing to work.

The sun isn't gas, technically, its nearly entirely plasma, which is a different state of matter all together from gas.

 

[BeAChooser]

Did he say "no possible mechanism"? No, you're just making up things to argue with.

You mean to say you can't see his post where he stated "we have no possible mechanism available on earth for maintaining such high pressures." Do you have Ziggurat on ignore too, edd? Or are you just trying to embarrass yourself?

We haven't done sustained fusion on Earth because we need a pressure/temperature containment mechanism here---as opposed to on the sun, where confinement is provided naturally---and so far the invented mechanisms (tokamaks, stellerators, pinches, NIF) present difficult engineering problems.

But Ziggurat seemed to suggest that such a confinement system isn't possible here on earth. Hence my question about whether physicists were just wasting our money trying to do it.

Back to ignore.

Bye bye ben.

 

[BeAChooser]

Our understanding of solar fusion is as complete as the science that lead to the hydrogen bomb.

Well then by now don't you think we should have free energy for all?

 

[Ziggurat]

But Ziggurat seemed to suggest that such a confinement system isn't possible here on earth.

I said you couldn't maintain such pressures on earth. You can't. Nothing you've said precludes that. Nothing I've said precludes that, nor does it preclude producing fusion on earth. I didn't say you couldn't confine the constituents by other (non-pressure) means. And I didn't say you couldn't pulse the fusion (as in the Z-machine).

Look, the highest pressures we can produce sustainably on earth (ie, NOT in an explosion) are around 20 GPa, or 2x10¹⁰ Pa, inside diamond anvil cells. Aside from the fact that you can't bring such a cell to very high temperature, that's nowhere near as high pressure as the core of the sun. The sun's core pressure is about 2.5x10¹¹ atmospheres, or about 2.5x10¹⁶ Pa. That's 6 orders of magnitude between the highest steady pressures we can produce and the pressure at the center of the sun. God damned straight we can't maintain that kind of pressure. Will you conceed the point? Will you admit you were wrong to contest it? No, I don't expect you will. Because you've never been honest about this debate.

 

[BeAChooser]

Originally Posted by BeAChooser
Looks to me like you are saying its *obvious to you* that nuclear physicists have wasted 40 years and billions and billions of dollars pursuing an approach that was doomed from the start

I'm saying nothing of the sort.

Really? Well that seems a little at odds with your very next statement:

There is indeed no possible method available to us on earth to maintain the pressures that occur in the heart of the sun.

According to what I've read, scientists here on earth have been struggling for 50 years to duplicate the temperatures and pressures on the sun so we'd have plentiful controlled fusion electricity and do away with the need to burn oil. But now you are telling us that there is "no possible method" on earth to maintain those pressures so it seems to me you are saying that effort started 50 years ago was sort of a waste of time and money.

That's not sustained fusion, that's just repeated fusion.

Oh. I see. All these researchers are just being *sloppy* with their language:

https://www.llnl.gov/str/Hill.html "Much of the renewed interest in spheromaks is focused on a research effort at Lawrence Livermore called the Sustained Spheromak Physics Experiment (SSPX). ... snip ... According to SSPX leader David Hill, the tokamak concept is considered the leading contender to generate sustained fusion reactions".

http://news.bbc.co.uk/2/hi/science/nature/4328597.stm "Achieving stable and sustained reactions on Earth, however, present an immense challenge. The Iter design is for the reactions to take place inside a 100-million-degree gas (plasma) suspended in an intense doughnut-shaped magnetic field. Iter will consolidate all that has been learnt over many decades of study. It is expected to produce 500MW of fusion power during pulses of at least 400 seconds."

400 second long pulses? And you don't think that's "sustained", Ziggurat?

And note that ITER's objective isn't just 400 second long pulses.

http://www.iter.org/a/index_faq.htm "This also explains ITER's interest in extending pulses to steady state. A reactor operating for only 7 minutes every 30 minutes is not attractive, since little electricity can be produced during much of the "dwell" time, but some plant power is nevertheless consumed then."

Guess you'd better tell them it's NOT POSSIBLE and save us all some development costs.