Two Billion Kelvin ...

[phongn]

Sandia’s Z machine exceeds two billion degrees Kelvin

Temperatures hotter than the interiors of stars

ALBUQUERQUE, N.M. — Sandia’s Z machine has produced plasmas that exceed temperatures of 2 billion degrees Kelvin — hotter than the interiors of stars.

The unexpectedly hot output, if its cause were understood and harnessed, could eventually mean that smaller, less costly nuclear fusion plants would produce the same amount of energy as larger plants.

The phenomena also may explain how astrophysical entities like solar flares maintain their extreme temperatures.

The very high radiation output also creates new experimental environments to help validate computer codes responsible for maintaining a reliable nuclear weapons stockpile safely and securely — the principal mission of the Z facility.

“At first, we were disbelieving,” says Sandia project lead Chris Deeney. “We repeated the experiment many times to make sure we had a true result and not an ‘Ooops’!”

The results, recorded by spectrometers and confirmed by computer models created by John Apruzese and colleagues at Naval Research Laboratory, have held up over 14 months of additional tests.

A description of the achievement, as well as a possible explanation by Sandia consultant Malcolm Haines, well-known for his work in Z pinches at the Imperial College in London, appeared in the Feb. 24 Physical Review Letters.

Sandia is a National Nuclear Security Administration laboratory.

What happened and why?
Z’s energies in these experiments raised several questions.

First, the radiated x-ray output was as much as four times the expected kinetic energy input.

Ordinarily, in non-nuclear reactions, output energies are less — not greater — than the total input energies. More energy had to be getting in to balance the books, but from where could it come?

Second, and more unusually, high ion temperatures were sustained after the plasma had stagnated — that is, after its ions had presumably lost motion and therefore energy and therefore heat — as though yet again some unknown agent was providing an additional energy source to the ions.

Sandia’s Z machine normally works like this: 20 million amps of electricity pass through a small core of vertical tungsten wires finer than human hairs. The core is about the size of a spool of thread. The wires dissolve instantly into a cloud of charged particles called a plasma.

The plasma, caught in the grip of the very strong magnetic field accompanying the electrical current, is compressed to the thickness of a pencil lead. This happens very rapidly, at a velocity that would fly a plane from New York to San Francisco in several seconds.

At that point, the ions and electrons have nowhere further to go. Like a speeding car hitting a brick wall, they stop suddenly, releasing energy in the form of X-rays that reach temperatures of several million degrees — the temperature of solar flares.

The new achievement — temperatures of billions of degrees — was obtained in part by substituting steel wires in cylindrical arrays 55 mm to 80 mm in diameter for the more typical tungsten wire arrays, approximately only 20 mm in diameter. The higher velocities achieved over these longer distances were part of the reason for the higher temperatures.

(The use of steel allowed for detailed spectroscopic measurements of these temperatures impossible to obtain with tungsten.)

Haines theorized that the rapid conversion of magnetic energy to a very high ion plasma temperature was achieved by unexpected instabilities at the point of ordinary stagnation: that is, the point at which ions and electrons should have been unable to travel further. The plasma should have collapsed, its internal energy radiated away. But for approximately 10 nanoseconds, some unknown energy was still pushing back against the magnetic field.

Haines’ explanation theorizes that Z’s magnetic energies create microturbulences that increase the kinetic energies of ions caught in the field’s grip. Already hot, the extra jolt of kinetic energy then produces increased heat, as ions and their accompanying electrons release energy through friction-like viscous mixing even after they should have been exhausted.

High temperatures previously had been assumed to be produced entirely by the kinetic flight and intersection of ions and electrons, unaided by accompanying microturbulent fields.

Z is housed in a flat-roofed building about the size and shape of an aging high-school gymnasium.

This work has already prompted other studies at Sandia and at the University of Nevada at Reno.

[wautd]

Interesting to say the least

[SirNitram]

I love the Z Machine. It's so neat.

[Admiral Valdemar]

Article is inaccurate. Kelvin temperatures are not measured in degrees. Interesting nontheless, though anything above 100 degrees C is unimaginable anyway.

[Faram]

Article is inaccurate. Kelvin temperatures are not measured in degrees. Interesting nontheless, though anything above 100 degrees C is unimaginable anyway.

Ehh, my owen can do 250C easy so 100C is nothing special.

[Admiral Valdemar]

ANY oven can do that. The point is, stick your hand in 100 degree C water or air, then stick it in a couple billion degrees C heat. You won't notice much, aside from your hand being vapour with the second one. Anything above boiling point of water is excessive pain, beyond that it doesn't matter what temperature you're at.

[kheegster]

Article is inaccurate. Kelvin temperatures are not measured in degrees. Interesting nontheless, though anything above 100 degrees C is unimaginable anyway.

It's not wrong to say '5 degrees Kelvin'....and even when one just says 'degrees' in a scientific context, it's generally understood that it is the Kelvin scale that is being referred to.

There's one phenomenon in daily life which easily exceeds 100 C, and that's a naked flame. Above that, I would indeed agree that temperatures are difficult to imagine for a layperson.

[Faram]

ANY oven can do that. The point is, stick your hand in 100 degree C water or air, then stick it in a couple billion degrees C heat. You won't notice much, aside from your hand being vapour with the second one. Anything above boiling point of water is excessive pain, beyond that it doesn't matter what temperature you're at.

Ahh I misunderstod you at first, now I know what you mean.

[Admiral Valdemar]

It's not wrong to say '5 degrees Kelvin'....and even when one just says 'degrees' in a scientific context, it's generally understood that it is the Kelvin scale that is being referred to.

Because of the way kelvin (it is an SI unit that's not capitalised except as the capital symbol "K") is used in science, there is no need for degrees as you would write "2 billion kelvins". Kelvin is a noun, not an adjective like Celsius and the defunct (it is, you damn Yanks) Fahrenheit. As a grammar Nazi and scientist, I have to object strongly by hitting you upside the head with a fish.

[kheegster]

It's not wrong to say '5 degrees Kelvin'....and even when one just says 'degrees' in a scientific context, it's generally understood that it is the Kelvin scale that is being referred to.

Because of the way kelvin (it is an SI unit that's not capitalised except as the capital symbol "K") is used in science, there is no need for degrees as you would write "2 billion kelvins". Kelvin is a noun, not an adjective like Celsius and the defunct (it is, you damn Yanks) Fahrenheit. As a grammar Nazi and scientist, I have to object strongly by hitting you upside the head with a fish.

I was merely referring to the usual convention. I hear scientists say 'degrees' far more than 'kelvins' when discussing temperatures. Point taken about the spelling though.

[dragon]

Article is inaccurate. Kelvin temperatures are not measured in degrees. Interesting nontheless, though anything above 100 degrees C is unimaginable anyway.

It's not wrong to say '5 degrees Kelvin'....and even when one just says 'degrees' in a scientific context, it's generally understood that it is the Kelvin scale that is being referred to.

There's one phenomenon in daily life which easily exceeds 100 C, and that's a naked flame. Above that, I would indeed agree that temperatures are difficult to imagine for a layperson.

Hell go to some of the saunas here in Germany and they get up to 110 C, normally supposed to be set at 90-100 c, as long as there is no moisture in the air its not to unbarable for a few minutes.

[Admiral Valdemar]

Sitting in that water would surely kill you after those few minutes, if only because your internal temperature goes out-of-control and your enzymes denature. Though I expect having your skin scolded would prevent you from being that stupid.

[GSV Use Psychology]

Hell go to some of the saunas here in Germany and they get up to 110 C, normally supposed to be set at 90-100 c, as long as there is no moisture in the air its not to unbarable for a few minutes.

Yeah, the warmest I've experienced is about 130C, although warming it that high was accidental. The air itself wasn't any problem but you couldn't touch anything since the floor and wooden were burning hot.

[Edi]

Article is inaccurate. Kelvin temperatures are not measured in degrees. Interesting nontheless, though anything above 100 degrees C is unimaginable anyway.

It's not wrong to say '5 degrees Kelvin'....and even when one just says 'degrees' in a scientific context, it's generally understood that it is the Kelvin scale that is being referred to.

There's one phenomenon in daily life which easily exceeds 100 C, and that's a naked flame. Above that, I would indeed agree that temperatures are difficult to imagine for a layperson.

Hell go to some of the saunas here in Germany and they get up to 110 C, normally supposed to be set at 90-100 c, as long as there is no moisture in the air its not to unbarable for a few minutes.

What you actually experience isn't quite that hot unless you make the mistake of throwing water on the stove. The body tends to retain an envelope of slightly cooler air around it, which is what makes sauna bearable. But when the temp hits 100 and above, even that gets uncomfortably hot very fast. Throwing water on the stove causes it to vaporize and sets an air current in motion that breaks the cooler envelope, which is why it feels so much hotter. I can say from experience that throwing water on the stove when sitting on the top tier in a 120 degree sauna is a NOT a good idea. And like GSV said, there are otehr complications as well.

Edi

[Admiral Valdemar]

I find it hard to believe that people sit in saunas where water is, literally, boiling. Do they enjoy scolding their skin or something? The usual sauna is bad enough for me, though I prefer hot tubs to saunas anyway (and there's no fucking way anyone sits in boiling water).

[kheegster]

I find it hard to believe that people sit in saunas where water is, literally, boiling. Do they enjoy scolding their skin or something? The usual sauna is bad enough for me, though I prefer hot tubs to saunas anyway (and there's no fucking way anyone sits in boiling water).

The Japanese regularly bathe in 40+ degree Celsius water, and I can assure you that at this temperature it feels like boiling water....

[His Divine Shadow]

I find it hard to believe that people sit in saunas where water is, literally, boiling. Do they enjoy scolding their skin or something? The usual sauna is bad enough for me, though I prefer hot tubs to saunas anyway (and there's no fucking way anyone sits in boiling water).

According to the temp in the sauna it was at 130 C one time, oh man oh man that was something alright. Then run out and jump in the lake, it's like nothing you ever seen!

[His Divine Shadow]

P.S. It doesn't scold me but you want to keep pouring cold water over your noggin once in a while, thats really pleasurable too, first it's really hot, then cold as hell then almost instantly pleasantly warm again. Ahhh the sauna.

[Kuroneko]

The point is, stick your hand in 100 degree C water or air, then stick it in a couple billion degrees C heat. You won't notice much, aside from your hand being vapour with the second one. Anything above boiling point of water is excessive pain, beyond that it doesn't matter what temperature you're at.

That's definitely not necessarily true. Even something like 2e9K or more may do almost no heat damage to your hand if the molar density is low enough. That raises the question--just what was the density (or pressure) at the given temperature?

[kheegster]

The point is, stick your hand in 100 degree C water or air, then stick it in a couple billion degrees C heat. You won't notice much, aside from your hand being vapour with the second one. Anything above boiling point of water is excessive pain, beyond that it doesn't matter what temperature you're at.

That's definitely not necessarily true. Even something like 2e9K or more may do almost no heat damage to your hand if the molar density is low enough. That raises the question--just what was the density (or pressure) at the given temperature?

Yes, but your hand would have suffered all the effects of what is effectively a vacuum by then.

[drachefly]

Hello, we have mysterious energy source and you can only talk about saunas?

[Kuroneko]

Yes, but your hand would have suffered all the effects of what is effectively a vacuum by then.

Well, hence the qualifier 'heat damage', but even so, it's quite possible for this to be false. If the pressure and volume stay constant, increasing the temperature of a gas (thus necessarily decreasing density) does not change the internal energy of the system at all according to the ideal gas law. This is because the molar density should decrease by the exact same factor that the temperature was increased and internal energy is directly proportional to temperature.

[Solauren]

I wonder if it could cook the Birito so hot, even god himself could not eat it...

But seriously, that's pretty cool (pun intended)

[Admiral Valdemar]

Well, hence the qualifier 'heat damage', but even so, it's quite possible for this to be false. If the pressure and volume stay constant, increasing the temperature of a gas (thus necessarily decreasing density) does not change the internal energy of the system at all according to the ideal gas law. This is because the molar density should decrease by the exact same factor that the temperature was increased and internal energy is directly proportional to temperature.

I was under the impression the Z-machine, and the original Oxford version, worked with denser plasmas than you'd see in a tokamak if only due to their sizes. Course, if it is really not that dense, then the plasma will be fairly useless, certainly it would cool practically instantly without input (not that sci-fi accepts this with explosive fusion reactors).

[Xon]

Yes, but your hand would have suffered all the effects of what is effectively a vacuum by then.

Human skin handles quite well in vacuum, it is the soft membranes and your lungs packed with air which are the problem.