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Lab Produces 3.6 Billion Degree Gas
starexplorer2001 writes "LiveScience is reporting how scientists at Sandia's Z laboratory have produced superheated gas exceeding temperatures of 3.6 billion degrees Fahrenheit (2 billion kelvins). That's hotter than the interior of our sun, which is only 15 million degrees F. And they don't know how they did it. Do we want anything that hot on our planet?"
According to the summary, the Sun's interior is 15 million degrees Fahrenheit. According to the article, it's 15 million degrees Kelvin which makes the Sun's interior actually 27 million degrees Fahrenheit.
It says that the record was set for the hottest temperature ever on earth. Unfortunately, the value they list is not the highest value I can obtain for a really hot temperture. The hottest temperature I found occurs at RHIC and that is a trillion degress kelvin not fifteen million. http://www.bnl.gov/RHIC/heavy_ion.htm Could it be a record temperture for a certain type of reaction? Also to answer the question about is this safe. Yes it's safe. The temperatures only occur for such a small tiny tiny tiny fraction of a second that it really doesn't affect anything.
Ooo man the floppy drive is broken. No wait. The computer is just upside down.
http://en.wikipedia.org/wiki/Fusion_energy#Power_p lant_design
Also plasma is not a gas. The article points this out, but the title gets it mixed up. It is a 4th phase of matter associated with high conductivity and separation of ionic components
http://en.wikipedia.org/wiki/Plasma_(physics)
My work involved doing quantum molecular dynamics (QMD) simulations to extract equation of state (EOS) data for the tungsten wires used in the z-pinches. The highest temperatures I remember the simulations reaching, however, were only about 40,000 Kelvin.
All things glow when they heat up, and they do so in a predictable manner.
They may have been able to measure the wavelength of the electromagnetic energy coming off of the gas.
This explains it better than I ever could.
Actually the live science article is missing the most vital info.
I read this article on PhysOrg.com http://www.physorg.com/news11538.html (yes I'm to lazy to HTML'ize that link)
From the PhysOrg article: "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. "
What I don't understand is how these spectrometers even worked at these tempearatures, I would expect most things to go kaput at these temperatures.
From the journal article, emission line optical depth varies inverse squarely with the ion temperature. So they used the k-shell emission spectrum for the stainless steel plasma to determine what temperature would produce the observed lines.
Spectrometers measure the EM radiation. It doesn't need to actually touch the substance being measured.
Social scientists are inspired by theories; scientists are humbled by facts.
The container that holds the experiment is called a holhraum, just a cylindrical metal thingy. In the middle, wires are vertically strung around in a circle (see this pic). When you pass a current through the wires, they want to move towards eachother (Ampere's law). Since the situation is symmetrical, they all move towards the center, and the intense current, motion, and collision, turn the wires into a hot plasma, that doesn't stick around for long. The whole thing is over in well under a second, and the container holding the plasma is destroyed.
The paper with the proposed model explaining these findings is available here for anyone that can understand it. They refer to instabilities (of the Rayleigh-Taylor kind?) causing ion viscous heating as they are dissipated. When an array of wires is heated and implodes, most of the content of the wires remain unmoved at the beginning, with only the outer parts being converted to plasma and moving toward the center. The inner left-overs are eventually converted as well and make the trip, though not necessarily until after the peak energy radiation.
Mit der Dummheit kämpfen Götter selbst vergebens.
Hohlraum. Now Google will give you decent results.
Rather than reading a digest from a science news site (not that it's a bad writeup) here is the press release from Sandia themselves.
Personally, I think the picture of the Z-machine is one of the coolest looking things I've seen. =)
Lost at C:>. Found at C.
For the curious, here's the actual abstract from the research paper, as published in Physical Review Letters:
Ion Viscous Heating in a Magnetohydrodynamically Unstable Z Pinch at Over 2×109 Kelvin
Pulsed power driven metallic wire-array Z pinches are the most powerful and efficient laboratory x-ray sources. Furthermore, under certain conditions the soft x-ray energy radiated in a 5 ns pulse at stagnation can exceed the estimated kinetic energy of the radial implosion phase by a factor of 3 to 4. A theoretical model is developed here to explain this, allowing the rapid conversion of magnetic energy to a very high ion temperature plasma through the generation of fine scale, fast-growing m=0 interchange MHD instabilities at stagnation. These saturate nonlinearly and provide associated ion viscous heating. Next the ion energy is transferred by equipartition to the electrons and thus to soft x-ray radiation. Recent time-resolved iron spectra at Sandia confirm an ion temperature Ti of over 200 keV (2×109 degrees), as predicted by theory. These are believed to be record temperatures for a magnetically confined plasma.
Also, there's a press release from Sandia National Labs.
That's not really that strange of a claim. All that it means is that some of the energy put into creating the reaction induced some of the atoms to let loose some of the energy they contain in their bonds between particles. As the article says, something that "usually only occurs in nuclear reactions".
There is a ginormous difference in 15M degrees F and 15M Kelvin. It's Kelvin and Celcius that are 273.xx something apart. Kelvin starts at absolute zero whereas Celcius starts at the freezing point of water, otherwise they're on the same scale.
"degrees" Kelvin...
Kelvins would be the correct term.
People seem to be confusing this with fusion. This is not fusion. This plasma is a method for heating a capsule to produce fusion. No fusion occurs in the plasma itself. It is not coming from strong force interactions either. This is just an unexpected but well understood method of heating.
It's ion viscous heating, something not nearly as exciting.
There are indirect ways of measuring temperature. You can measure the energy emitted by radiation, and use that to calculate temperature via Boltzman's law.
A deep unwavering belief is a sure sign you're missing something...
A spectrometer can easily measure the temperature of an object. the laws governing black body radiation (http://en.wikipedia.org/wiki/Black_body_radiation ) are dependent only on temperature. If you can sort out the radiation peaks you see representing quantum energy level transitions, which is easy, since they look like peaks and black body is a curve, you can find the temperature of a radiating body.
For thermal radiation from a blackbody, the wavelength at which the radiation is brightest is inversely proportional to the temperature. This is known as Wien's law. So the temperature of the x-ray source can be inferred from the intensity, as a function of frrequency, or the emitted x-rays.
Look at this
"Housed at Sandia National Laboratories, the Z machine attracted a lot of attention eight years ago when its energy output more than quadrupled - raising hopes that the reactions in the Z could provide a new source of clean, abundant power. To help further progress towards this end, the machine is getting a $61.7 million upgrade, officials announced recently."
If you ask me that sounds like the Z-Machine did that eight years before ago.
"I'd expect that some of the iron was converted to energy,"
IIRC, Fe is that magical break-even point where the energy it takes to fuse it is about even with the energy produced by the fusion (which is why blue supergiant stars go BOOM when they reach this stage). Beyond Fe, you're better off with fission I believe.
I scanned the article. The article does not say that total energy observed was greater than the total input energy.
What the article says, and it's easy to be confused by this, is that the observed energy was greater than the kinetic energy of the implosion. However, one has to realize that the kinetic energy isn't the only significant source of energy in the system. There is also the energy in the magnetic field. The article goes on to elucidate a mechanism by which magnetic field energy is converted to thermal energy ions, which is then transferred to electrons to produce soft X-Rays.
Thus, the bottom line here is, unfortunately, that what happened in this experiment was that one component of the total energy input, magnetic energy, which normally is not converted into heat, was converted into heat by a new mechanism. This is what the authors meant by a new energy source. In other words:
NO FUSION.
Okay, time to move along folks, nothing to see here other than some really really really really hot plasma, which probably don't have the density to achieve sustained fusion...yet. =)
When I said that I read the article, what I meant was that I scanned the original PRL article.
because neutral iron has one spare electron in it's outer shell. therefore, based on the spin of that electron's orbit, the iron atom becomes a tiny magnet. In normal iron, these atoms point every which way, largely cancelling each other. When they get lined up, they become very strong.
Once it's in a plasma, all bets are off. However, there's a nifty effect that could be at work here. IN the presence of very strong (5gigagauss or better) magnetic fields, the electron energy levels in the plasma become highly quantized. Since the rest of the ions (the reactants for the fusion process) can't possibly pass their energy to the electrons anymore, (or will do so only rarely, 10^-19 or so), you effectively eliminate fusion power losses due to electron heating or brehmstralung, making the reaction much more efficient. There's a very sharp point where the field strength is high enough to make this happen, and if Sandia's setup is past that, yay! net fusion power. It's the holy grail, here, guys. We're going to go turn all the lights on.
It's spelled Hohlraum and Bremsstrahlung :)
:)
And yes, it's german - but only because much of the physics (and mathematics, think of "Eigenvektor") of the beginning of the 20th century was published in german. English became the dominant science language after the Nazis rose to power and drove out many, many german (jewish) scientists.
So no Gruppenführer
That would be Wein's Law, not Planck's Law.
For a given temperature T, the peak wavelength of emitted radiation is at 0.0029/T nm. For example, our sun's surface temp is what, about 5800 K? So the peak is around 500nm, which is in the green spectrum. Betcha didn't know that...
I spent three summers working in a trailer less than 50 meters from this machine. It always creeped me out a little. Several times a day, the sirens and flashy lights would go off outside the building, then about a minute later, we'd hear this huge "WUMPH". Our whole trailer would shake and the monitors vibrate. Despite understanding what was going on, I couldn't help but wonder about the safety of sitting next to an array of giant capacitors which get rapidly discharged all at once.
However, I must admit it does make cool pictures. The bright lines you see on most pictures are supposedly spare charge arcing across the giant pool in which they have to keep the whole thing submerged.
2400x1586 JPEG of Z
"Go to CNN [for a] spell-checked, fact-checked summary" -- CmdrTaco
Actually, "degrees Kelvin" has been replaced by "kelvins" (note the lower case "k"), while the abbreviation remains an upper case "K". That makes "degrees Celsius" the only SI unit of measure with an upper case letter in its English name. Also, centigrade and the modern Celsius scale aren't just different names for the same thing; whereas the centigrade scale was based on the freezing and boiling points of water, 0.01 degrees Celsius is, by definition, the triple point of water, and one Celsius degree is 1/273.16 of the difference between the triple point and absolute zero.
(Facts shamefully stolen from the Wikipedia article.)
If you can read this sig, you're too close.
Of course, iron sits at the bottom of the nuclear binding energy saddle, so you would get little energy from either fusing or fissing an iron nucleus. Anything nuclear happening here is likely from some other element in the reaction or in the vicinity of the reaction.