Starship Asterisk*

Regarding: http://antwrp.gsfc.nasa.gov/apod/ap060313.html

The March 13, 2006 APOD caption states, "The plasma reached a temperature in excess of two billion Kelvin, making it the hottest thing ever in the history of the Earth." [edit: I see that the authors have inserted the word "arguably" into that sentence; thanks ] Those of us who study nuclear collisions would disagree. At the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, we routinely produce matter at well over one trillion Kelvins (10^12), albeit for a very small system of particles (a few thousand hadrons - we're talking about temperatures so high that nuclei of atoms melt into their constituents) and for an even shorter period of time than the Z Machine (the system blows apart after approximately 10^-23 seconds). Note that we are still not quite sure just how hot we really do make things, simply that it has cooled to ~10^12 Kelvins by the time it "freezes out"!

But we should not restrict ourselves to what humans do: high energy cosmic rays collide with nuclei in Earth's atmosphere continually, and many collisions are at much high energies than we can create in the laboratory. It is hard to say just what temperatures can be reached in such collisions!

So two billion may be hot, and much hotter than stars, but it's not so hot
-Gene

2 billion K and over a trillion K. Wow! I'm impressed. But how can we really measure anything that hot?
Orin

I am fascinated about the picture and the numbers beneath the picture but on the Z-Machine page http://www.sandia.gov/media/z290.htm (link is under the picture) I cant find 2 billion K. I can only find 2 million.
Is it my mistake?

Soenke

Soenke, I see that the wikipedia entry for the Z Machine lists 2 billion, which is probably where they grabbed that number:
http://en.wikipedia.org/wiki/Z_machine

Orin, you asked how we measure something that hot. For us, we have two methods: 1) chemistry and 2) kinetics. They both assume equilibration, which is difficult to conceive on the short time scales we are discussing. But the data shows amazingly strong support for it.

With chemistry, particle abundances are proportional to their fugacity, which is a term involving mass and temperature. Think of it this way: the hotter it is, the more energy is available to produce heavier species. On a parallel vein, consider a volume with gaseous hydrogen, oxygen, and water vapor formed from combining hydrogen and oxygen atoms; the number of hydrogen and oxygen atoms that combine to form water depends again on the fugacities which involve temperature. It's then a simple matter of determining ratios of abundances. The agreement between over a dozen ratios from RHIC's nuclear collisions and the chemical thermal expectation is astounding!

With kinetics, the momentum distribution of particles is related to the temperature. Again, hotter temps provide higher average momenta. This is actually why a star, a light bulb, and an electric stove element all emit light similarly: the spectrum of light emitted is a distribution of photons at different momenta, and the mean of that distribution changes with changing temperature (we only discern something like a mean color with our eyes, but there is really a full spectrum of wavelengths/frequencies which are proportional to the photon momenta). Crank up the heat and the peak of the light frequency distribution goes from infrared, to red, to yellow, to blue, to ultraviolight, etc.

For chemistry to change, the temperatures must be hot enough to at least allow particles to interact and change species. We find from the chemistry a temperature of ~2e12 K. It is probable that this describes the coolest temperature at which the species could change. We call this the observed "chemical freeze out" temperature, but we don't (yet) know how hot it was before the freeze out.

For momenta to change, the particles must be close enough to scatter off each other and redistribute their momenta. In our collisions, nothing is containing these particles, so they are blowing apart and cooling rapidly. We observe temperatures of ~1.6e12 K from this technique for the "kinetic freeze out", and it is likely that it occurs later than the chemical freeze out: particles are still scattering off each other for a short time even though it isn't hot enough for them to change species.

I hope that helps give some understanding,
-Gene

Thanks Gene; It's a little deep for this layman; but I get the drift. Very impressive
Orin

The Z Machine link in APOD is from 1998, that's why the lower temps.

Gene,

Is this why the cylindrical tungsten wire array, to keep the momenta bouncing off each other and maintain a longer and more contained locale for the test?

I've recently run across a new theory of matter that postulates it is entirely pure energy. All things result from the presence of energy, in nodes of amplitude if you will; inertia and gravity are results of energy density.

Are you making your calculations of temperature as a result of momentum transference using a model that the components involved are energy packets? You don't think of neuclei as material objects do you?

Kovil

Yes
Thanks, Gene, for that excellent synopsis of where current research is on the temperature front.

I'm sticking with my kitchen stove though.
Thanks

if these guys don't watch it, they will start a nuclear reaxction

Kovil, I know little about the operations of the Z Machine. I study nuclear collisions at RHIC as I mentioned in the first post in this thread.

ta152h0 mentions starting a nuclear reaction (well, reaxction ), and I assume he's talking about fission reactions. Fission doesn't require high temperatures, but it does require using nuclei that are metastable to breaking apart (which is generally only true of some isotopes of heavier elements). The experiments in the Z Machine don't use such elements. While we could hypothetically use such elements in nuclear collisions studies, we don't bring anywhere near enough of them together to start a chain reaction.

Fusion reactions are yet a different story. For fusion, nuclei must be forced close enough to each other to overcome their electric charge repulsion (a long-range force) to the point where the attractive strong nuclear force (a very short range force) holds them together. For this, you need extremely high pressures (such as under the immense gravity inside a star). Again, high temperatures are not necessary. In fact, it's preferrable not to have temperatures too high, or nuclei won't even stick together any more (the protons and neutrons will have too much motion for the nuclear force to bind them). If you look up fusion experiments, they are all about generating extremely high pressures.

In both fission and fusion, energy is released, which can result in an increase in temperature. So high temperatures are an effect, not a cause.

In nuclear collisions, we do achieve very high pressures when we bang two nuclei together very hard. In this case, energy that was in the form of directed motion to begin with (each nucleus is moving very fast towards the other), can become heat as the particles begin hitting each other and scattering around (heat is in essence random motion of constituent particles), raising the temperature very high. But we collide things so hard that we're in the regime I said you don't want for fusion: the nuclei break apart! We destroy the nuclei. In fact, at RHIC, we collide them so hard that we destroy individual protons and neutrons, breaking them apart into still smaller particles.

So, to recap, in nuclear collisions:
1) We collide too hard for fusion to occur.
2) We don't have a lot of ready-to-break-apart elements around for fission chain reactions to occur.
3) And, even if we do make microscopic black holes (an uncertainty at this point), they're too small to attract any nearby matter, and too hot to live for more than 10^-23 seconds (remember that collisions like these happen in nature all the time: cosmic rays striking our atmosphere, and no black holes have swallowed the earth).

-Gene

Scandia Labs http://www.sandia.gov/media/z290 wrote:

"The most recent advance resulted in an output X-ray power of about 290 trillion watts -- for billionths of a second, about 80 times the entire world's output of electricity. Strangely, the power used in each trial is only enough to provide electricity to about 100 houses for two minutes. Electricity is provided by ordinary wall current from a local utility company."

Reading about low power creating such incrediblly high temperatures makes me wonder if electromagnetic energy in the neucleosynthesis of elements has been underestimated? given possible superconducting layers characteristic of compressed matter say.. in gas giants, dwarf stars or other gravity wells?

Thanks Gene,

I'd not understood the difference between pressure and temperature.
Temp would actually work to keep things apart.
It holds the sun up from further collapse at one point in its life.
I hadn't thought quite this way about solar fusion preferring a lower temp (11 M C and + ?) to get the neuclei to be larger. There would be a too high temp for best results ! How interesting, and how sensible. Like baking a cake, several conditions have their ranges for best overall results.
Warm neutrons are more easily caught than cold neutrons, and hot ones discorporate.

Is there a favorite neuclei or particle at RHIC for experiments ?
It would have to have an electric charge? As how would one accellerate a neutron with a magnetic field ? haha
Tho there's probably some way to bundle and then separate.

Yes, kinetic energy oft turns to heat. Energy is so fungible it goes morphing all over the place. That's why I view all these big tables of different particles; as combinations and permutations of energy intersection nodes, like an interference pattern of waves; and not really particles, just patterns of reflections of momentum scattering like the energy it is. Would an equasion for fractals express how decay particles move and change species.

Yes, the search for the W boson takes large energies I remember, in the '70's they weren't there yet.

Make a really hard collision and watch the patterns that emerge in the way the high energy cascades down to levels closer to entropy, time length has a corelation to energy, the higher the energy the faster it changes species in decay?

The Z Machine has so little heat, regardless of how high the temp gets, it couldn't light a match. Well, it couldn't boil a pot of water !

Can they collide two particles so hard they destroy the energy they are made of ?
(yes this is a trick question ! )

((or was that the hidden agenda of the mad scientist who devised the device ? )) LOL

And all they found was a scintillation of energy refraction patterns
and interference matricies.

Darn we wanted to see the Infinite and know It, but it squirted away like a watermellon seed the harder we squeezed it.

Kovil

When I see things like the Z machine I wonder what sort of external scrutiny is involved to ensure that physicists don't do something everyone will later regret?

Zordan wrote:I am fascinated about the picture and the numbers beneath the picture but on the Z-Machine page http://www.sandia.gov/media/z290.htm (link is under the picture) I cant find 2 billion K. I can only find 2 million.
Is it my mistake?
Soenke

The link near the picture leads you to the 1998 (or 1999?) writeup, but there is a later official announcement at http://www.sandia.gov/news-center/news- ... utput.html
It is amazing to me that (1) there was a thousandfold increase in obtained temperature in those few years (and 1000 times original objective), (2) they admit to not understanding why the temperature was higher than expected, and (3) the output power exceeded the input power. I believe there is a great possibility that a significant new understanding may be developing.

Bill Halberstadt

One Larry Spring has came up with a unique explanation for electro magnetism... which you might find entertaining?

http://www.larryspring.com/electromagnetism.html

Mr. Spring is 91 years old and lives on the No. Cal coast.

Maybe i watch too many sci fi mad scientist movies...

Aqua
interesting thought but how do you account for amplitude in that scenario?You need bigger balls to be brighter, right ???

Hello Gene

Can you expalin to me how Ultra Dense plasma come about.

Aqua wrote:One Larry Spring has came up with a unique explanation for electro magnetism... which you might find entertaining?

http://www.larryspring.com/electromagnetism.html

Mr. Spring is 91 years old and lives on the No. Cal coast.

His atomic theory is pretty entertaining too: he draws anagolies with teardrop-shaped drops of rain.

gene wrote:(remember that collisions like these happen in nature all the time: cosmic rays striking our atmosphere, and no black holes have swallowed the earth)

a "cosmic ray" particle having enough energy to create a black hole able to swallow an earth, upon being absorbed by something, would have to be at least that heavy itself, wouldn't it?

Haven’t heard a thing about this situation since the post, anyone have any further info in the matter / why the plasma was reaching such extreme temperatures?

Explanation: Why is this plasma so hot? Physicists aren't sure. What is known for sure is that the Z Machine running at Sandia National Laboratories created a plasma that was unexpectedly hot. The plasma reached a temperature in excess of two billion Kelvin, making it arguably the hottest human made thing ever in the history of the Earth and, for a brief time, hotter than the interiors of stars. The Z Machine experiment, pictured above, purposely creates high temperatures by focusing 20 million amps of electricity into a small region further confined by a magnetic field. Vertical wires give the Z Machine its name. During the unexpected powerful contained explosion, the Z machine released about 80 times the world's entire electrical power usage for a brief fraction of a second. Experiments with the Z Machine are helping to explain the physics of Solar flares, design more efficient nuclear fusion plants, test materials under extreme heat, and gather data for the computer modeling of nuclear explosions.

That particular spike remains unexplained, though some plausible ideas have been proposed. You can read much more about the Z Machine on its Wikipedia page.

Rob

This was previously posted!
http://asterisk.apod.com/viewtopic.php?f=9&t=1047

Thanks for the replies all / as for the advice to visit wikipedia for answers, yes that is certainly an option and I did consider doing so but due to the fact that I have seen a great many actual hands on astronomers and etc, etc scientists browsing this site and taking the time to answer questions posted here at APOD I posted this question here all the while hoping that someone from the sandia laboratory might happen across it and fill me / us all in on the most current information.
Good day all


I never met a weapon I didn’t like, Ronald Regan (circa 1987)

fremantlebiz wrote:When I see things like the Z machine I wonder what sort of external scrutiny is involved to ensure that physicists don't do something everyone will later regret?

They don't think about the upcoming consequences