May
13
The Hope In Ultra Dense Deuterium
May 13, 2009 | 10 Comments
Ultra Dense Deuterium has made news, blogs and articles for a couple of days now since Leif Holmlid from the Atmospheric Science, Department of Chemistry, the University of Gothenburg published in Science Direct asserting that his team has proven that an ultra-dense deuterium material exists. The University of Gothenberg press release is much more enthused than the stolid Swedish stereotype would suggest.
Now the futurecasting is supporting ultra dense deuterium as a fuel with Holmlid saying, “One important justification for our research is that ultra-dense deuterium may be a very efficient fuel in laser driven nuclear fusion. It is possible to achieve nuclear fusion between deuterium nuclei using high-power lasers, releasing vast amounts of energy.” That’s just the thing to snap the heads around at the U.S. National Ignition Facility with their 192 lasers setup.
What is this stuff that generated such excitement? Deuterium is the heavy form of hydrogen, readily found in water most everywhere on the planet, not in particularly short supply and refined for in earnest since the Second World War. Ultra heavy deuterium is formed by Holmid such that it is a million times more dense than frozen deuterium. The weight is a spectacular >130 kg / cm3 that worked out to the thrilling quote “a material so heavy that a cube with sides of length 10 cm weighs 130 tons.” At this point the stuff is metallic and the spaces between the atoms is extremely small, some 2.3 times of the Bohr radius about 121 picometers. That’s small as a picometer is a thousandth of the famed nanometer. Things are really close together at picometer ranges.
Ultra Dense Deuterium. Click image for more info.
Just how Holmlid is getting the stuff made isn’t out yet. But the effort to build a fuel for fusion reactions has been quietly going on for years. Holmid just popped the cap with success and hard proof. At a hundred thousand times heavier than water and denser than the core of the sun, the scientists working with this material are aiming for an energy process that is both more sustainable and less damaging to the environment than the nuclear power used today.
As noted above ultra dense deuterium would be just the thing for laser driven fusion. Holmlid explains that laser technology has long been tested on frozen deuterium, known as “deuterium ice”, but results have been poor. It has proved to be very difficult to compress the deuterium ice sufficiently for it to attain the high temperature required to ignite the fusion.
Many believe with good math and well-reasoned thinking that high deuterium densities would fuel a laser driven fusion breakthrough. “If we can produce large quantities of ultra-dense deuterium, the fusion process may become the energy source of the future. And it may become available much earlier than we have thought possible”, says Holmlid. “Further, we believe that we can design the deuterium fusion such that it produces only helium and hydrogen as its products, both of which are completely non-hazardous. It will not be necessary to deal with the highly radioactive tritium that is planned for use in other types of future fusion reactors, and this means that laser-driven nuclear fusion as we envisage it will be both more sustainable and less damaging to the environment than other methods that are being developed.”
There are just a slew of “buts” coming. First off is as Holmlid notes, just making the deuterium so dense in any volume is an issue and must be worked quite cold. Next, the matter of stability comes to mind, as in the paper’s graphs the time to live is short, shorter than even nanoseconds. That makes the foreseeable production essentially within a laser fusion reactor. Making the ultra dense deuterium and moving it seems out of the question for now. The time of life seems impractical for any laser ignition anytime soon. Finally, the fusion reaction would have to be rather, well, counter intuitive, yielding harmless helium and hydrogen. One would expect a wider range of new materials from the fusion including tritium, which can be nasty radioactive stuff. Lots of supposition, but experimentation is in order.
All that said, it is by every objective view – a great success. Metallic hydrogen has been worked on for several years with less than useful results. The heavier ultra dense deuterium with the atoms already very close might just spark some engineering to see if the new fuel candidate has potential. But it’s a long climb up a tall mountain.
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I’m skeptical. Sounds like a hopelessly exotic material and a scientist’s attempt to grab the spotlight and get funding.
A great finding, if true. I still haven’t found the scientific papers supporting it and I breathlessly await confirmatory experiments.
If you can make it in enough quantity, it seems to be a near-perfect inertial-confinement fusion fuel. 130 kg/cc means you would have = 300 g/cm^2 for a 20 micron-radius ball. ( is areal density, and is the key factor of interest in igniting fusion burn. For those who don’t know, deuterium-tritium fusion aims for a ~ 3 g/cm^2; but D-D fusion is about 100 times harder)
Note that the 192 lasers on NIF are primarily to compress the fuel: if the fuel can be made compressed in another way (i.e. more efficiently!) that puts fusion much closer — even if you have to figure out how to create these high-density states in the target chamber, due to short lifetime.
Just so you know, 1 nanosecond is around the same timescale as an ICF fusion bang.
Waiting to hear more!!
er, redo of my second paragraph:
If you can make it in enough quantity, it seems to be a near-perfect inertial-confinement fusion fuel. 130 kg/cc means you would have rho-r = 300 g/cm^2 for a 20 micron-radius ball. (rho-r is areal density, and is the key factor of interest in igniting fusion burn. For those who don’t know, deuterium-tritium fusion aims for a rho-r ~ 3 g/cm^2; but D-D fusion is about 100 times harder)
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reading about the early experiments at livermore on the use of diamond synthesis to augment thier measurement of conductivity using designer diamond anvil cells was inspirational, as it may apply to scale in the creation of chambers large enough for the the compression of super-dense hydrogen.i believe it shows that layers of synthetic diamond can be sucsessfully fused to the 1/3 carot natural diamonds used in the experiments.just a thought from a dilitante.