[extropy-chat] Bubble fusion--strong evidence for it.

Robert J. Bradbury bradbury at aeiveos.com
Tue Mar 2 22:51:33 UTC 2004



---------- Forwarded message ----------
Date: Tue, 2 Mar 2004 14:50:50 -0800 (PST)
From: Robert J. Bradbury <bradbury at aeiveos.com>
To: Transhumantech mailing list <transhumantech at egroups.com>
Subject: Bubble fusion--strong evidence for it.


> Date: Tue, 02 Mar 2004 17:58:17 +0000
> From: Tatiana Covington <tatianacovington at hotmail.com>
> Subject: Bubble fusion--strong evidence for it.

Theresa Bourgeois
bourgt at rpi.edu
http://www.rpi.edu/web/News/press_releases/2004/lahey.htm

Researchers Report Bubble Fusion Results Replicated. Physical Review E
publishes paper on fusion experiment conducted with upgraded measurement
system.

TROY, N.Y. — Physical Review E has announced the publication of an article
by a team of researchers from Rensselaer Polytechnic Institute (RPI), Purdue
University, Oak Ridge National Laboratory (ORNL), and the Russian Academy of
Science (RAS) stating that they have replicated and extended previous
experimental results that indicated the occurrence of nuclear fusion using a
novel approach for plasma confinement. This approach, called bubble fusion,
and the new experimental results are being published in an extensively
peer-reviewed article titled “Additional Evidence of Nuclear Emissions
During Acoustic Cavitation,” which is scheduled to be posted on Physical
Review E’s Web site and published in its journal this month.

The research team used a standing ultrasonic wave to help form and then
implode the cavitation bubbles of deuterated acetone vapor. The oscillating
sound waves caused the bubbles to expand and then violently collapse,
creating strong compression shock waves around and inside the bubbles.
Moving at about the speed of sound, the internal shock waves impacted at the
center of the bubbles causing very high compression and accompanying
temperatures of about 100 million K.

These new data were taken with an upgraded instrumentation system that
allowed data acquisition over a much longer time than was possible in the
team’s previous bubble fusion experiments. According to the new data, the
observed neutron emission was several orders of magnitude greater than
background and had extremely high statistical accuracy. Tritium, which also
is produced during the fusion reactions, was measured and the amount
produced was found to be consistent with the observed neutron production
rate. Earlier test data, which were reported in Science (Vol. 295, March
2002), indicated that nuclear fusion had occurred, but these data were
questioned because they were taken with less precise instrumentation.

“These extensive new experiments have replicated and extended our earlier
results and hopefully answer all of the previous questions surrounding our
discovery,” said Richard T. Lahey Jr., the Edward E. Hood Professor of
Engineering at Rensselaer and the director of the analytical part of the
joint research project. Other fusion techniques, such as those that use
strong magnetic fields or lasers to contain the plasma, cannot easily
achieve the necessary compression, Lahey said. In the approach to be
published in Physical Review E, spherical compression of the plasma was
achieved due to the inertia of the liquid surrounding the imploding bubbles.
Professor Lahey also explained that, unlike fission reactors, fusion does
not produce a significant amount of radioactive waste products or decay
heat. Tritium gas, a radioactive by-product of deuterium-deuterium bubble
fusion, is actually a part of the fuel, which can be consumed in
deuterium-tritium fusion reactions.

Researchers Rusi Taleyarkhan, Colin West, and Jae-Seon Cho conducted the
bubble fusion experiments at ORNL. At Rensselaer and in Russia, Professors
Lahey and Robert I. Nigmatulin performed the theoretical analysis of the
bubble dynamics and predicted the shock-induced pressures, temperatures, and
densities in the imploding vapor bubbles. Robert Block, professor emeritus
of nuclear engineering at Rensselaer, helped to design, set up, and
calibrate a state-of-the-art neutron and gamma ray detection system for the
new experiments. Special hydrodynamic shock codes have been developed in
both Russia and at Rensselaer to support and interpret the ORNL experiments.
These computer codes indicated that the peak gas temperatures and densities
in the ORNL experiments were sufficiently high to create fusion reactions.
Indeed, the theoretical shock code predictions of deuterium-deuterium (D-D)
fusion were consistent with the ORNL data.

The research team leaders are all well known authorities in the fields of
multiphase flow and heat transfer technology and nuclear engineering.
Taleyarkhan, a fellow of the American Nuclear Society (ANS) and the
program’s director, held the position of Distinguished Scientist at ORNL,
and is currently the Ardent Bement Jr. Professor of Nuclear Engineering at
Purdue University. Lahey is a fellow of both the ANS and the American
Society of Mechanical Engineers (ASME), and is a member of the National
Academy of Engineering (NAE). Nigmatulin is a visiting scholar at
Rensselaer, a member of the Russian Duma, and the president of the
Bashkortonstan branch of the Russian Academy of Sciences (RAS). Block is a
fellow of the ANS and is the longtime director of the Gaerttner Linear
Accelerator (LINAC) Laboratory at Rensselaer. The bubble fusion research
program was supported by a grant from the Defense Advanced Research Projects
Agency (DARPA).
*************
Purdue News
http://news.uns.purdue.edu/html4ever/2004/0400302.Taleyarkhan.fusion.html
March 2, 2004

Evidence bubbles over to support tabletop nuclear fusion device
WEST LAFAYETTE, Ind. – Researchers are reporting new evidence supporting
their earlier discovery of an inexpensive "tabletop" device that uses sound
waves to produce nuclear fusion reactions. The researchers believe the new
evidence shows that "sonofusion" generates nuclear reactions by creating
tiny bubbles that implode with tremendous force. Nuclear fusion reactors
have historically required large, multibillion-dollar machines, but
sonofusion devices might be built for a fraction of that cost. "What we are
doing, in effect, is producing nuclear emissions in a simple desktop
apparatus," said Rusi Taleyarkhan, the principal investigator and a
professor of nuclear engineer at Purdue University. "That really is the
magnitude of the discovery – the ability to use simple mechanical force for
the first time in history to initiate conditions comparable to the interior
of stars."

The technology might one day result in a new class of low-cost, compact
detectors for security applications that use neutrons to probe the contents
of suitcases; devices for research that use neutrons to analyze the
molecular structures of materials; machines that cheaply manufacture new
synthetic materials and efficiently produce tritium, which is used for
numerous applications ranging from medical imaging to watch dials; and a new
technique to study various phenomena in cosmology, including the workings of
neutron stars and black holes. Taleyarkhan led the research team while he
was a full-time scientist at the Oak Ridge National Laboratory, and he is
now the Arden L. Bement Jr. Professor of Nuclear Engineering at Purdue.

The new findings are being reported in a paper that will appear this month
in the journal Physical Review E, published by the American Physical
Society. The paper was written by Taleyarkhan; postdoctoral fellow J.S Cho
at Oak Ridge Associated Universities; Colin West, a retired scientist from
Oak Ridge; Richard T. Lahey Jr., the Edward E. Hood Professor of Engineering
at Rensselaer Polytechnic Institute (RPI); R.C. Nigmatulin, a visiting
scholar at RPI and president of the Russian Academy of Sciences'
Bashkortonstan branch; and Robert C. Block, active professor emeritus in the
School of Engineering at RPI and director of RPI's Gaerttner Linear
Accelerator Laboratory. The discovery was first reported in March 2002 in
Science.

Since then the researchers have acquired additional funding from the U.S.
Defense Advanced Research Projects Agency, purchased more precise
instruments and equipment to collect more accurate data, and successfully
reproduced and improved upon the original experiment, Taleyarkhan said. "A
fair amount of very substantial new work was conducted, " Taleyarkhan said.
"And also, this time around I made a conscious decision to involve as many
individuals as possible – top scientists and physicists from around the
world and experts in neutron science – to come to the lab and review our
procedures and findings before we even submitted the manuscript to a journal
for its own independent peer review."

The device is a clear glass canister about the height of two coffee mugs
stacked on top of one another. Inside the canister is a liquid called
deuterated acetone. The acetone contains a form of hydrogen called
deuterium, or heavy hydrogen, which contains one proton and one neutron in
its nucleus. Normal hydrogen contains only one proton in its nucleus. The
researchers expose the clear canister of liquid to pulses of neutrons every
five milliseconds, or thousandths of a second, causing tiny cavities to
form. At the same time, the liquid is bombarded with a specific frequency of
ultrasound, which causes the cavities to form into bubbles that are about 60
nm in diameter. The bubbles then expand to a much larger size, about 6,000
microns, large enough to be seen with the unaided eye.

"The process is analogous to stretching a slingshot from Earth to the
nearest star, our sun, thereby building up a huge amount of energy when
released," Taleyarkhan said. Within nanoseconds these large bubbles contract
with tremendous force, returning to roughly their original size, and release
flashes of light in a well-known phenomenon known as sonoluminescence.
Because the bubbles grow to such a relatively large size before they
implode, their contraction causes extreme temperatures and pressures
comparable to those found in the interiors of stars. Researches estimate
that temperatures inside the imploding bubbles reach 10 million C and
pressures comparable to 10E14 Pa.

At that point, deuterium atoms fuse together, the same way hydrogen atoms
fuse in stars, releasing neutrons and energy in the process. The process
also releases a type of radiation called gamma rays and a radioactive
material called tritium, all of which have been recorded and measured by the
team. In future versions of the experiment, the tritium produced might then
be used as a fuel to drive energy-producing reactions in which it fuses with
deuterium. Whereas conventional nuclear fission reactors produce waste
products that take thousands of years to decay, the waste products from
fusion plants are short-lived, decaying to non-dangerous levels in a decade
or two. The desktop experiment is safe because, although the reactions
generate extremely high pressures and temperatures, those extreme conditions
exist only in small regions of the liquid in the container – within the
collapsing bubbles.

One key to the process is the large difference between the original size of
the bubbles and their expanded size. Going from 60 nm to 6,000 microns is
about 100,000 times larger, compared to the bubbles usually formed in
sonoluminescence, which grow only about 10 times larger before they implode.
"This means you've got about a trillion times more energy potentially
available for compression of the bubbles than you do with conventional
sonoluminescence," Taleyarkhan said. "When the light flashes are emitted,
it's getting extremely hot, and if your liquid has deuterium atoms compared
to ordinary hydrogen atoms, the conditions are hot enough to produce nuclear
fusion." The ultrasound switches on and off about 20,000 times a second as
the liquid is being bombarded by neutrons. The researchers compared their
results using normal acetone and deuterated acetone, showing no evidence of
fusion in the former.

Each five-millisecond pulse of neutrons is followed by a five-millisecond
gap, during which time the bubbles implode, release light and emit a surge
of about 1 million neutrons per second. In the first experiments, with the
less sophisticated equipment, the team was only able to collect data during
a small portion of the five-millisecond intervals between neutron pulses.
The new equipment enabled the researchers to see what was happening over the
entire course of the experiment. The data clearly show surges in neutrons
emitted in precise timing with the light flashes, meaning the neutron
emissions are produced by the collapsing bubbles responsible for the flashes
of light, Taleyarkhan said. "We see neutrons being emitted each time the
bubble is imploding with sufficient violence," Taleyarkhan said.

Fusion of deuterium atoms emits neutrons that fall within a specific energy
range of 2.5 mega-electron volts or below, which was the level of energy
seen in neutrons produced in the experiment. The production of tritium also
can only be attributed to fusion, and it was never observed in any of the
control experiments in which normal acetone was used, he said. Whereas data
from the previous experiment had roughly a one in 100 chance of being
attributed to some phenomena other than nuclear fusion, the new, more
precise results represent more like a one in a trillion chance of being
wrong, Taleyarkhan said. "There is only one way to produce tritium – through
nuclear processes," he said. The results also agree with mathematical theory
and modeling.

Future work will focus on studying ways to scale up the device, which is
needed before it could be used in practical applications, and creating
portable devices that operate without the need for the expensive equipment
now used to bombard the canister with pulses of neutrons. "That takes it to
the next level because then it's a standalone generator," Taleyarkhan said.
"These will be little nuclear reactors by themselves that are producing
neutrons and energy." Such an advance could lead to the development of
extremely accurate portable detectors that use neutrons for a wide variety
of applications. "If you have a neutron source you can detect virtually
anything because neutrons interact with atomic nuclei in such a way that
each material shows a clear-cut signature," Taleyarkhan said.

The technique also might be used to synthesize materials inexpensively. "For
example, carbon is turned into diamond using extreme heat and temperature
over many years," Taleyarkhan said. "You wouldn't have to wait years to
convert carbon to diamond. In chemistry, most reactions grow exponentially
with temperature. Now we might have a way to synthesize certain chemicals
that were otherwise difficult to do economically. Several applications in
the field of medicine also appear feasible, such as tumor treatment."

Before such a system could be used as a new energy source, however,
researchers must reach beyond the "break-even" point, in which more energy
is released from the reaction than the amount of energy it takes to drive
the reaction. "We are not yet at break-even," Taleyarkhan said. "That would
be the ultimate. I don't know if it will ever happen, but we are hopeful
that it will and don't see any clear reason why not. In the future we will
attempt to scale up this system and see how far we can go."

Writer: Emil Venere, (765) 494-4709, venere at purdue.edu
Source: Rusi P. Taleyarkhan, (765) 494-0198, rusi at purdue.edu
Purdue News Service: (765) 494-2096; purduenews at purdue.edu
ABSTRACT

Additional Evidence of nuclear emissions during acoustic cavitation

R.P. Taleyarkhan1, J.S. Cho2, C.D. West3, R. T. Lahey3, Jr., R.I.
Nigmatulin4, and R.C. Block3

1Purdue University, West Lafayette, Indiana 47907, 2Oak Ridge Associated
Universities, Oak Ridge, Tennessee 37830, 3Rensselaer Polytechnic Institute,
Troy, New York 12180,
4Russian Academy of Sciences,
6 Karl Marx Street, Ufa 450000, Russia

Time spectra of neutron and sonoluminescence emissions were measured in
cavitation experiments with chilled deuterated acetone. Statistically
significant neutron and gamma ray emissions were measured with a calibrated
liquid-scintillation detector, and sonoluminescence emissions were measured
with a photomultiplier tube. The neutron emission energy corresponded to
<2.5 MeV and had an emission rate of up to ~4X10E5 n/s. Measurements of
tritium production were also performed and these data implied a neutron
emission rate due to D-D fusion which agreed with what was measured. In
contrast, control experiments using normal acetone did not result in
statistically significant tritium activity, or neutron or gamma ray
emissions.

[Ho hum, deuterium at room temperature again!! T]

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