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Bubble Power:
In sonofusion a
piezoelectric crystal attached to liquid filled Pyrex flask send pressure waves
through the fluid, exciting the motion of tiny gas bubbles. The bubbles
periodically grow and collapse, producing visible flashes of light. The
researchers studying these light emitting bubbles speculated that their
interiors might reach such high temperature and pressure they could trigger
fusion reaction. Tiny bubbles imploded by sound waves can make hydrogen nuclei
fuse- and may one day become a revolutionary new energy source.
When a gas bubble
in a liquid is excited by ultrasonic acoustic waves it can emit short flashes
of light suggestive of extreme temperatures inside the bubble. These flashes of
light known as sonoluminescence, occur as the bubble implode or cavitates. It
is show that chemical reactions occur during cavitations of a single, isolated
bubble and yield of photons, radicals and ions formed. That is gas bubbles in a
liquid can convert sound energy in to light.
Sonoluminescence
also called single-bubble sonoluminescence involves a single gas bubble that is
trapped inside the flask by a pressure field. For this loud speakers are used
to create pressure waves and for bubbles naturally occurring gas bubbles are
used. These bubbles can not withstand the excitation pressures higher than
about 170 kilopascals. Pressures higher than about 170 kilopascals would always
dislodge the bubble from its stable position and disperse it in the liquid. A
pressure at least ten times that pressure level to implode the bubbles is
necessary to trigger thermonuclear fusion. The idea of sonofusion overcomes
these limitations.
Introduction of Bubble Power
Sonofusion is
technically known as acoustic inertial confinement fusion. In this we have a
bubble cluster (rather than a single bubble) is significant since when the
bubble cluster implodes the pressure within the bubble cluster may be greatly
intensified. The centre of the gas bubble cluster shows a typical pressure
distribution during the bubble cluster implosion process. It can be seen that,
due to converging shock waves within the bubble cluster, there can be
significant pressure intensification in the interior of the bubble cluster.
This large local liquid pressure (P>1000 bar) will strongly compress the
interior bubbles with in the cluster, leading to conditions suitable for
thermonuclear fusion. More over during the expansion phase of the bubble
cluster dynamics, coalescence of some of interior bubbles is expected, and this
will lead to the implosion of fairly large interior bubbles which produce more
energetic implosions.
The apparatus
consists of a cylindrical Pyrex glass flask 100 m.m. in high and 65m.m.in
diameter. A lead-zirconate-titanate ceramic piezoelectric crystal in the form
of a ring is attached to the flask's outer surface. The piezoelectric ring
works like the loud speakers in a sonoluminescence experiment, although it
creates much stronger pressure waves. When a positive voltage is applied to the
piezoelectric ring, it contracts; when the voltage is removed, it expands to
its original size.
The flask is then
filled with commercially available deuterated acetone (C 3 D 6 O), in which
99.9 percent of the hydrogen atoms in the acetone molecules are deuterium (this
isotope of hydrogen has one proton and one neutron in its nucleus). The main
reason to choose deuterated acetone is that atoms of deuterium can undergo
fusion much more easily than ordinary hydrogen atoms. Also the deuterated fluid
can withstand significant tension (stretching) without forming unwanted
bubbles. The substance is also relatively cheap, easy to work with, and not
particularly hazardous.
Applications :
•
Thermonuclear fusion gives a new, safe, environmental friendly way to produce
electrical energy.
• This
technology also could 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 structure 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.
A new technique to
study various phenomenons in cosmology, including the working of neutron star
and black holes.
With the steady
growth of world population and with economic progress in developing countries,
average electricity consumption per person has increased significantly.
There fore seeking
new sources of energy isn't just important, it is necessary. So for more than
half a century, thermonuclear fusion has held out the promise of cheap clean
and virtually limitless energy. Unleashed through a fusion reactor of some
sort, the energy from 1 gram of deuterium, an isotope of hydrogen, would be
equivalent to that produced by burning 7000 liters of gasoline. Deuterium is
abundant in ocean water, and one cubic kilometer of seawater could, in
principle, supply all the world's energy needs for several hundred years.
