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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. The idea sonofusion (technically known as acoustic inertial confinement fusion) was derived from related phenomenon sonoluminescence. 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.
The standard of living in a society is measured by the amount of energy consumed. In the present scenario where the conventional fuels are getting depleted at a very fast rate the current energy reserves are not expected to last for more than 100 years. Improving the harnessing efficiency of non-conventional energy sources like solar, wind etc. as a substitute for the conventional sources is under research.
One of the conventional methods of producing bulk energy is nuclear power. There are two types of nuclear reactions, namely fission & fusion. They are accompanied by the generation of enormous quantity of energy. The energy comes from a minute fraction of the original mass converting according to Einsteinâ„¢s famous law: E=mc2, where E represents energy, m is the mass and c is the speed of light. In fission reaction, certain heavy atoms, such as uranium is split by neutrons releasing huge amount of energy. It also results in waste products of radioactive elements that take thousands of years to decay. The fusion reactions, in which simple atomic nuclei are fused together to form complex nuclei, are also referred to as thermonuclear reactions. The more important of these fusion reactions are those in which hydrogen isotopes fuse to form helium. The Sunâ„¢s energy is ultimately due to gigantic thermonuclear reaction.The waste products from the fusion plants would be short lived, decaying to non-dangerous levels in a decade or two. It produces more energy than fission but the main problem of fusion reaction is to create an atmosphere of very high temperature and pressure like that in the Sun.
A new step that has developed in this field is ËœBubble Powerâ„¢-the revolutionary new energy source. It is working under the principle of Sonofusion. For several years Sonofusion research team from various organizations have joined forces to create Acoustic Fusion Technology Energy Consortium (AFTEC) to promote the development of sonofusion. It was derived from a related phenomenon known as sonoluminescence. Sonofusion involves tiny bubbles imploded by sound waves that 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.
THE IDEA OF SONOFUSION
It is hard to imagine that mere sound waves can possibly produce in the bubbles, the extreme temperatures and pressures created by the lasers or magnetic fields, which themselves replicate the interior conditions of stars like our sun, where fusion occurs steadily. Nevertheless, three years ago, researchers obtained strong evidence that such a process now known as sonofusion is indeed possible.
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.
Deuterated acetone (C3D6O).
Neutron and gamma ray detector.
Microphone and speaker.
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 flaskâ„¢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 (C3D6O), 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.
ACTION OF VACUUM PUMP:
The naturally occurring gas bubbles cannot withstand high temperature and pressure. All the naturally occurring gas bubbles dissolved in the liquid are removed virtually by attaching a vacuum pump to the flask and acoustically agitating the liquid.
ACTION OF THE WAVE GENERATOR:
To initiate the sonofusion process, we apply an oscillating voltage with a frequency of about 20,000 hertz to the piezoelectric ring. The alternating contractions and expansions of the ring-and there by of the flask-send concentric pressure waves through the liquid. The waves interact, and after a while they set up
an acoustic standing wave that resonates and concentrates a huge amount of sound energy. This wave causes the region at the flaskâ„¢s centre to oscillate between a maximum (1500kpa) and a minimum pressure. (-1500kpa).
ACTION OF THE NEUTRON GENERATOR:
Precisely when the pressure reaches its lowest point, a pulsed neutron generator is fired. This is a commercially available, baseball bat size device that sits next to the flask. The generator emits high-energy neutrons at 14.1 mega electron volts in a burst that lasts about six microseconds and that goes in all directions.
ACTION IN THE FLASK:
Some neutrons go through the liquid, and some collide head on with the Carbon, oxygen and deuterium atoms of the deuterated acetone molecules. The fast moving neutrons may knock the atomâ„¢s nuclei out of their molecules as these nuclei recoil; they give up their kinetic energy to the liquid molecules. This interaction between the nuclei and the molecules create heat in regions a few nanometers in size that results in tiny bubbles of deuterated acetone vapor. Computer simulations, suggest that this process generates clusters of about 1000 bubbles, each with a radius of only tens of nanometers.
By firing the neutron generator during the liquidâ„¢s low pressure phase, the bubbles instantly swell -a process known as cavitation. In these swelling phases, the bubbles balloon out 100,000 times from their nanometer dimensions to about one millimeter in size. To grasp the magnitude of this growth, imagine that the initial bubbles are the size of peas after growing by a factor of 100,000, each bubble would be big enough to contain the Empire State Building.
Then the pressure rapidly reverses, the liquid pushes the bubblesâ„¢ walls inward with tremendous force, and they implode with great violence. The implosion creates spherical shock waves with in the bubbles that travel inward at high speed and significantly strengthen as they converge to their centers.
The result, in terms of energy, is extra ordinary. Hydrodynamic shock-waves create, in a small region at the centre of the collapsing bubble, a peak pressure greater than 10 trillion kPa. For comparison, atmospheric pressure at sea level is101.3 kPa. The peak temperature in this tiny region soars above 100 million degree centigrade about 20.000 times that of the sunâ„¢s surface.
These extreme conditions within the bubbles-especially in the bubbles at the centre of the cluster, where the shock waves are more intense because of the surrounding implosions-cause the deuterium nuclei to collide at high speed. These collisions are so violent that the positively charged nuclei overcome their natural electrostatic repulsion and fuse.
The fusion process creates neutrons which we detect using a scintillator, a device in which the radiation interacts with a liquid that gives off light pulses that can be measured. This process is also accompanied by bursts of photons, which is detected with a photomultiplier. And subsequently, after about 20 microseconds, a shock wave in the liquid reaches the flaskâ„¢s inner wall, resulting in an audible pop, which can be picked up and amplified by a microphone and a speaker.
Deuterium-Deuterium fusion has two probable outputs, helium and a 2.45-MeV neutron or tritium and a proton.
IF TRITIUM IS PRODUCED:
The total neutron output would include not only the neutrons from deuterium-deuterium fusion, but also neutrons from deuterium-tritium fusion, since the tritium produced in sonofusion remains within the liquid and can fuse with deuterium atoms. Compared with deuterium-deuterium fusion, deuterium-tritium fusion occurs 1000 times more easily and produces more energetic neutrons increasing the neutron yield by about three orders of magnitude.
SCHEMATIC OF SONOLUMINESCENE & SONOFUSION PHENOMENON
SEQUENCE OF EVENTS DURING SONOFUSION
THE EVOLUTION OF LIQUID PRESSURE WITH IN BUBBLE CLUSTER
SEPARATION OF DEUTERIUM FROM ORDINARY HYDROGEN (PROTIUM)
SEPARATION FROM ORDINARY HYDROGEN BY DIFFUSION PROCESS:
Deuterium can be isolated from ordinary hydrogen by taking advantage of different rates of diffusion of the two isotopes. Protium, which is lighter, diffuses more readily than deuterium. The diffusion is carried out under reduced pressure. The lower the pressure, the greater is the efficiency of the process.
The process of diffusion is carried out in series of porous diffusion units, known as Hertz diffusion units. Each unit contains a porous membrane represented by dotted portion. As mixture is led into the diffusion units under reduced pressure, say from left to right, with the help of the mercury diffusion pumps P1, P2, P3. etc. The heavier component (deuterium) diffuses less readily and keeps behind while the lighter component (protium) diffusing at a faster move more and more to the right. The process is repeated several times, till ultimately, deuterium collects in the reservoir L on the left. The efficiency of the separation process can be increased by increasing the number of diffusing units.
SEPARATION FROM ORDINARY HYDROGEN BY FRACTIONAL DISTILLATION:
Deuterium can be separated from ordinary hydrogen by careful fractional distillation of liquid hydrogen. Heavy hydrogen boils at -249.5 degree C while protium boils at a lower temperature of -282.5 degree C. Hence fraction distillation of liquid hydrogen can result in enrichment of the last fraction in deuterium, can be used for recovery of deuterium by the diffusion process described above.
SEPARATION FROM ORDINARY HYDROGEN BY ADSORPTION ON CHARCOAL:
Protium is adsorbed more readily and more strongly on solid surfaces in general and on charcoal surface in particular. Thus when a mixture of the two isotopes is led over charcoal kept at liquid air temperature, most of the protium gets adsorbed while most of the deuterium passes out unchanged.
SEPARATION FROM ORDINARY HYDROGEN BY CHEMICAL METHODS:
The lighter isotope (protium) is more reactive than the heavier isotope (deuterium). Thus when ordinary hydrogen is passed over red hot copper oxide, the lighter component is consumed more than the heavier one.
OTHER APPROACHES OF FUSION REACTION
There are mainly two approaches on fusion reactions other than bubble power. They are
1. Laser Beam Technique.
2. Magnetic Confinement Fusion.
LASER BEAM TECHNIQUE
In this process extremely energetic laser beams converge on a tiny solid pellet of deuterium-deuterium fuel. The result is a shock wave that propagates towards the centre of the pellet and creates an enormous increase in temperature and density.
One of the drawbacks of this approach is the amount of power lasers required. This techniqueâ„¢s main goal is not producing energy but rather producing thermonuclear weapons.
MAGNETIC CONFINEMENT FUSION
It uses powerful magnetic fields to create immense heat and pressure in hydrogen plasma contained in a large, toroidal device known as a tokamak. The fusion produces high energy by neutrons that escape the plasma and hit a liquid filled blanket surrounding it. The idea is to use the heat produced in the blanket to generate vapor to drive a turbine and thus generate electricity.
It is very much difficult to hold the plasma in place while increasing temperature and pressure. It is a very unstable process that has been proved difficult to control.
EVIDENCE TO SUPPORT TABLE TOP NUCLEAR FUSION DEVICE
There are two kinds of evidence that deuterium is fusing. The first neutron emission detected by the neutron scintillator. The device registers two clearly distinct bursts of neutron that are about 30 microseconds apart. The first is at 14.1 MeV, from the pulsed neutron generator; the second, how ever, is at 2.45 MeV. This is the exact energy level a neutron produced in a deuterium-deuterium fusion reaction is expected to have. These 2.45MeV neutrons are detected at about the same time that the photomultiplier detects a burst of light, indicating that both events take place during the implosion of the bubbles.
There is a second fusion fingerprint by measuring levels of another hydrogen isotope, tritium, in the deuterated acetone. The reason is that deuterium-deuterium fusion is a reaction with two possible outputs at almost equal probability. On possibility gives 2.45 MeV neutrone plus helium, and the other gives tritium plus a proton. Thus, the build-up of tritium above the measured initial levels is an independent and strong, indication that fusion has taken place, since tritium can not be produced with out a nuclear reaction.
The desktop experiment is safe because although the reactions generate extremely high pressures and temperature those extreme conditions exist only in small regions of the liquid in the container-within the collapsing bubbles.
ADVANTAGES OF BUBBLE POWER OVER OTHER APPROACHES
1. It is self sustainable.
2. Easily controllable.
3. It consistently produces more energy than it consumes.
4. Low cost.
5. Easily available raw materials.
6. Environmental friendly.
1) Thermonuclear fusion gives a new, safe, environmental friendly way to produce electrical energy.
2) 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.
3) Devices for research that use neutrons to analyze the molecular structure of materials.
4) Machines that cheaply manufacture new synthetic materials and efficiently produce tritium, which is used for numerous applications ranging from medical imaging to watch dials.
5) A new technique to study various phenomenons in cosmology, including the working of neutron star and black holes.
FULLY SELF SUSTAINED:
To make the fusion reaction fully self-sustaining arranging the setup so it produces a continuous neutron output without requiring the external neutron generator. One of the possible ways is to put two complete apparatuses side by side so that they would exchange neutrons and drive each otherâ„¢s fusion reactions. Imagine two adjacent sonofusion setups with just one difference: when the liquid pressure is low in one, it is high in the other. That is, their pressure oscillations are 180 degrees out of phase. Suppose hit the first apparatus with neutrons from the external neutron generator, causing the bubble cluster to form inside the first flask. Then turn off the neutron generator permanently. As the bubble cluster grows and then implodes, it will give off neutrons, some of which will hit the neighboring flask. If all is right, the neutrons will hit the second flask at the exact moment when it is at the lowest pressure, so that it creates a bubble cluster there. If the process repeats, get a self-sustaining chain reaction.
TO CREATE A FULL-SIZE ELECTRICITY PRODUCING NUCLEAR GENERATOR:
A table top single apparatus yields about 400000 per second. The neutrons are an important measure of the output of the process because they carry most of the energy released in the fusion reaction. Yet that yield corresponds to a negligible fraction of a watt of power.
For operating a few thousand mega watts of thermal power, in terms of neutron-per-second, output of 10^22 neutrons per second needed. For this we will improve various parameters of Sonofusion process, such as the size of the liquid flask, the size of the bubbles before implosion and the pressure compressing the bubbles etc. then we installed a liquid filled blanket system around the reactor. All those high-energy neutrons would collide with it, raising its temperature. So that it heat could used to boil a fluid to drive a turbine and thus generate electricity.
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 isnâ„¢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 worldâ„¢s energy needs for several hundred years.
Richard T. Lahey Jr., Rusi P. Taleyarkhan & Robert I. Nigmatulin, bubble power, IEEE spectrum, page no: 30-35, may 2005.
Fuels and combustion, author Samir Sarkar.
Principles of Inorganic chemistry, authors â€œ Puri, Sharma, Kalia.
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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 of 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 sea water, could, in principle, supply the entire world’s energy needs for several hundred years.
Such reactor haven’t bean built basically because after spending billion of dollars on research, we have yet to identify an economically viable fusion reactor technology that can consistently produce more energy than it consumes. Today researchers have using enormous lasers or powerful magnetic fields to trigger limited fusion reactions among deuterium and other hydrogen isotopes. Results are promising-yet still the challenge remains.
Cold fusion is the general name given to processes that fuse atomic nuclei at or near room temperature. In theory these would provide useful energy without complex apparatus required to emulate the nuclear fusion that powers the stars. The later needs temperatures approaching 100 million degrees.
However if you mention cold fusion to most scientists, the tend to back off. Stanley Pons and Martins Fleischman have almost relegated the subject to pseudoscience some 15 years ago. But recent event suggest the idea is gaining respectability once again. The US Department of Energy is to review the evidence from more recent research, which claims to provide a theoretical basis for the idea. Some type of cold fusion is certainly known to be possible, such as the one normally called muon-catalysed cold fusion.
The situation is now complicated by a report by Rusi P Taleyarkhan of Purdue University in a journal of the American physical society, which is causing controversy among specialists. For several years, Dr Taleyarkhan has been working on experiments that combine burst of high-frequency sound waves (ultrasound) with pulses of neutron in a process as he describes as sonofusion or tabletop fusion. He claims to have detected fusion reactions taking place, through other experiments dispute his results.
The research groups at Perdue University in West Lafayatte, Indiana; Renesselear Polytechnic institute in Troy, N.Y and Russian Academy of Sciences branch in Ufa have been worked on a new way to create a fusion reactions. By applying sound waves to a deuterium-rich liquid, we create pressure oscillations that implode tiny bubbles filled with deuterium vapor.
The bubbles’ violent collapse can cause some of the deuterium nuclei to undergo fusion.
It is hard to imagine that mere sound wave can possibly produce, in the bubbles. Even briefly, the extreme temperature and pressures created by the lasers or magnetic fields which themselves replicate the interior conditions of stars like our sun, where fusion occurs steadily. Nevertheless, researchers have obtained strong evidence that such a process-now known, as ‘Sonofusion’ is indeed possible!
The idea of sonofusion , technically known as acoustic inertial confinement fusion, was derived from a related phenomenon , sonoluminescence, a process widely used by chemists and also a science-fair staple, loudspeakers attached to a liquid – filled flask send pressure waves through the fluid , exciting the motion of tiny gas bubble. The bubbles’ periodically grows and collapse, producing visible flashes of light that last less than 50 pico seconds.
After successive failures of the early implementation of sonofusion through enhanced sonoluminescence , a group of three researchers , Rusi P Taleyarkhan, Richard T Lahey and Robert I Nigmatulin were successful in their work and published their result in the journal Physical Review E in march 2004. It is their work and result that is explained in detail this.
The earliest reference to the term “sonofusion” seems to be by Steven E. Jones, a professor at Brigham Young University. A graduate student of his at BYU, jeannette Lawler was involved in a search for “sonofusion” in D2O as early as December 10, 1992. Terry Bollinger gave a theoretical discussion in 1992. Jones provided another overview in 1995.
The earliest reference found on a sonofusion-type process is a patent by Hugh G. Flynn, a professor at the University of Rochester. Flynn passed away in 1997. He put forward a method of generating energy by acoustically induced cavitation fusion and reactor therefore. Nuclear fusion energy production by liquid cavitatoin – using acoustic device to produce alternating pressure pulses in liquid metal containing hydrogen isotopes.
Two different cavitation fusion reactors (CFR’s) are disclosed. Each comprises a chamber containing a liquid (host) metal such as lithium or an alloy of thereof. Acoustical horns in the chamber wall operate to vary the ambient pressure in the liquid metal, creating therein-small bubbles, which are caused to grow to maximum sizes and then collapse violently in two steps. In the first stage the bubble contents remains at the temperature of the host liquid, but in the second stage the increasing speed of collapse causes an adiabatic compression of the bubble content, and of the thin shell of liquid surrounding the bubble. Application of a positive pressure on the bubble accelerates this adiabatic stage, and causes the bubble to contract to smaller radius, thus increasing maximum temperature and pressure reached within the bubble. At or near its minimum radius the bubble generates a very intense shock wave, creating high pressures and temperature in the host liquid. These extremely high pressures and temperature occure both within the bubble and in the host liquid, and cause hydrogen isotope in the bubbles and liquid to undergo thermonuclear reactions. in one of CFR the thermonuclear reaction is generated by cavitations within thw liquid metal itself, and in the other type the reaction takes place primarily within the bubbles . The fusion reaction generates energy that is absorbed as heat by the liquid metal, and this heat is removed from the liquid by conduction through the acoustical horns to an external heat exchanger, without any pumping of the liquid material.
Larry Crum has given a discussion of this patent.
In 1992, Seth Putterman of UCLA indicated that his group had reached 100,000 C in sonoluminescence experiments, and thought 1 million C was possible. Roger Stringham claimed to have produced confined nuclear fusion via ultrasound in 1993. Also in 1993 Fukushima and Yamamoto wrote an article entitled “Sonofusion: Maximum Temperature Hot Spots”.
Seth Putterman applied for a patent for a sonofusion device in 1994, which was granted in 1997. This was converting acoustic energy into useful other energy forms.
Inventors: Seth J Putterman, Bradley Paul Barber, Robert Anthony Hiller, and Ritva Maire Johanna Lofstedt.
Converting acoustic energy to different form – by applying controlled resonant acoustic energy to gas bubble in the liquid.
Sonoluminescence in an off-equilibrium phenomenon in which the energy of a resonant sound wave in liquid is highly concentrated so as to generate flashes of light. The conversion of sound to light represents an energy amplification of eleven orders of magnitude. The flashes can be compromised over one million photons and last for less 100 Pico seconds. The emission displays a clock like synchronicity; the jitter in between consecutive flashes is less than 50 pico seconds. The emission is blue to the eye and has a broadband spectrum increasing from 700 nm to 200 nm. The peak power is about 100 mill watts. The initial stage of the energy focusing is affected by the nonlinear oscillations of a gas bubble trapped in the liquid. For sufficiently high drive pressures an imploding shock wave is launched into the gas by the collapsing bubble. The reflection of the shock from its local point results in high temperatures and pressures. The sonoluminescence light emission can be sustained by sensing a characteristic of the emission and feeding back changes into the driving mechanism. The liquid is in a sealed container and the seeding of the gas bubble is effected by locally heating the liquid after sealing the container. Different energy forms than light can be obtained from the converted acoustic energy. When the gas contains deuterium and tritium there is the feasibility of the other energy form being fusion, namely including the generation of the neutrons.
Putterman later (2005) developed a pyroelectric crystal fusion device. In 1994, William C Moss examined simulations of sonoluminescence that could theoretically produce deuterium fusion reactions.
Joseph A Clark of the US Navy received a patent that teaches a method of sonoluminescence . the patent refers to Hugh Flynn’s earlier patent , but does not make any reference to fusion in the abstract. George, D.R, and Stringham, R.S. (1996) got patent on “Technical report on the demonstration of mew technology producing heat and nuclear products via cavitation induced micro-fusion in the E-Quest Scientist Mark II research device”, EPRI Project Final Report.
Rusi P Teleyarkhan, currently of Purdue University, has made the most recent stir about sonofusion. It appears that Taleyarkhan and Lahey were interested in sonoluminescence prior to the first sonofusion paper, and were making an effort to increase the energy released via the process. Teleyarkhan first published on sonofusion phenomenon in science. It is rumored that there was controversy among 13 or 14 reviewers over its publication.
DETAILS OF SONOFUSION APPARATUS
In 2002, evidence was obtained that sonofusion could actually work and its apparatus was modified to suit into some experimental conditions. This apparatus evolved since those initial experiments in 1996, but it continues to be relatively simple . it consists of:
► Cylindrical in shape
► 65 mm diameters
► 100 mm lengths
► Contains commercially viable deuerated acetone, in which 99.9% of hydrogen atoms in the acetone molecules are deuterium.
► Lead-zirconate-titanate ceramic piezo-electric crystal in the form of a ring.
► Works like loudspeaker in sonoluminescence experiment, although creates much stronger pressure waves.
► When a positive voltage is applied to it, it contracts and when the voltage is removed it expands to its original size.
Wave Generator &Amplifier
► Creates an oscillating voltage with a frequency of about 20 khz to drive the piezoelectric crystal.
► The amplifier amplifies the signal from the wave generator and feeds it to the piezoelectric crystal.
► It is a baseball bat size device , which sits next to the flask.
► It emits a burst of high-energy neutrons at 14.1 mega electron volt that lasts for 6 µs and goes in all directions.
Neutron and gamma ray detector
► Registers neutrons and gamma ray emitted during the experiment.
► Detects the photon produced during the collapse of the bubbles
► Creates a vacuum with in the flask to remove gas from the acetone.
Microphone and Loudspeaker
► Audible ‘pop’ produced by bubbles’ implosion is picked up and amplified by the microphone and speaker
The main reason why deuterated acetone is chosen 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 particularly hazardous.
Fig. 3.1 Sonofusion Works
OPERATION OF SONOFUSION APPARATUS
To initiate sonofusion process, we apply an oscillating voltage with a frequency of about 20 KHz to the piezoelectric crystal ring. The alternating contractions and expansion of the ring and thereby of the flask send concentric pressure waves through the liquid. The waves interact , and after a while they setup acoustic standing waves that resonate and concentrate a huge amount of sound energy. This wave causes the region at the center of the flask to oscillate between a maximum of 1500Kpa and a minimum of -1500Kpa pressure. During the positive pressure cycle , the liquid is being compressed and during the negative pressure cycle, it is being stretched.
Precisely when the pressure reaches its lowest point , we fire a pulsed neutron generator. The generator emits neutron at 14.1 mega electron volts in a burst that lasts about 6 micro seconds and that goes in all directions. Some neutrons go through the liquid and some collide head on with the carbon, oxygen and deuterium atoms of the deuterated acetone molecules. In these collisions, the fast moving neutrons may knock the atoms’ nuclei out of their molecules. As these nuclei recoil, they give their kinetic energy to the liquid molecules. This interaction between the nuclei and the molecules creates heat in regions a few nanometers in size that result in tiny bubbles of deuterated acetone vapour. It generates clusters about 1000 bubbles, each with a radius of only tens of nanometers.
By firing the neutron generator during the liquid’s low pressure phase, the bubbles’ instantly swell-a process known as cavitation. In this swelling phase , the bubbles balloon out 100000 times from nanometer size to about 1mm in size. After growing a factor of 100000,each bubble would be big enough. Then the pressure rapidly reverses , the liquid pushes the bubbles’ wall inward with tremendous force, and they implode with great violence.
The implosion creates spherical shock waves within the bubbles’ that travel inward at high speeds and significantly strengthens as they converge to their centers. The result in terms of energy is extra ordinary-a peak pressure greater than 10 trillion Kpa. The peak temperature in this tiny region is above 100 million ºC.
These extreme conditions within the bubbles-especially at the center of the cluster , where the shock waves are more intense because of the surrounding implosion cause the deuterium nuclei to collide at high speed. These collisions are so violent that the positively charge nuclei overcome their natural electrostatic repulsion and fuse. The fusion process creates neutrons , which detected using a scintillator , a device in which radiation interacts with a liquid that gives off light pulses that can be measured. The process is also accompanied by bursts of photons , which we detect using a photo multiplier.
And subsequently after about 20 µs of a shock wave in the liquid reaches the flask’s innerwall , resulting in an audible ‘pop’, which can be picked up and amplified by the microphone and speaker.
Deuterium-deuterium fusion has two equally probable outputs,helium and a 2.45 MeV neutron or tritium and a proton. The energy of the 2.45 MeV neutrons can be harnessed in a reactor to create water vapor and drive an electricity generator.
Fig 4.1 Deuterium-Deuterium Fusion
4.1 THE ACTION IN THE FLASK:
1. Neutrons flying through the flask create a bubble cluster in the deuterated acetone liquid.
2. The negative pressure in the liquid makes the bubble swell 100000 times in size( from nano to millimeter scale).
3. The liquid pressure turns positive and compresses the bubbles, causing them to implode with great violence.
4. The implosion creates an instantaneous pressure of 10 trillion Kpa and temperature more than 100 million degree centigrade, making the deuterium fuse.
The above figures show the fusion of deuterium under the condition specified.
Fig. 4.2 Action in the Flask
EVIDENCE FOR FUSION
In the first experiment, Taleyarkhan and colleagues fired neutrons at a tank of chilled acetone to creat tiny bubbles. The hydrogen in the acetone had been switched with deuterium, a heavier form of hydrogen with an added neutron. Blasted sound waves caused the bubble to expand and then collapse many times.
The researchers argued that as the bubbles imploded, the temperature inside would rise to millions of degrees, hot enough for two deuterium nuclei to fuse together. This fusion would produce either tritium – an isotop of hydrogen – and a proton , or a helium- 3 nucleus and a neutron with 2.5 MeV of energy.
The team found evidence for both reactions, but other researchers pointed out discrepancies with the amount of neutrons and tritium detected, and the fact that the detector was set up to screen out 2.5 MeV neutrons.
Taleyarkhan says he has since revamped the equipment so that it is better at detecting neutrons. He claims the evidence for fusion is even stronger this time: the neutrons show the right energy and their levels match the amount of tritium detected.
We gather two kinds of evidence that the deuterium is fusing:
The first is neutron emission detected by the neutron scintillator. The device registers two clearly distinct bursts of neuron that are about 30 microseconds apart. The first is at 14.1 MeV , from pulsed neutron generator; the second ,however ,is at 2.45 MeV. This is the exact energy level a neutron produced in a deuterium-deuterium fusion reaction is expected to have. These 2.45 MeV neutrons are detected at about the same time that the photo multiplier detects a burst of light, indicating that both events take place during implosion of the bubbles.
Measuring levels of another hydrogen isotope , tritium , found the second fusion fingerprint in the deuterated acetone. The reason is that deuterium-deuterium fusion is a reaction with two possible outputs at almost equal probability. One probability gives you 2.45 MeV neutron plus helium and the other gives you tritium plus a proton. The build up of tritium above the measured initial level is independent, and strong, indication that fusion has taken place, since tritium can not be produced without a nuclear reaction.
There are two main challenges . the biggest is for Rusi Taleyarkhan’s result to be independently reproduced. Until now, no one but Horizon has published data on replicating Taleyarkhan’s results and many scientists remain highly skeptical about this set of results, although they do not dispute the principle that sonofusion is potentially achievable.
Their skepticism focuses on Taleyarkhan’s use of scientific neutrons in his experiment. Neutrons are one of the key signatures that fusion has taken place so using synthetic neutrons in the experiments means that neutron detection has to be extra ordinarily good. Horizon used the best neutron detection system available for the project and implimentations specifically like this and we found no fusion electrons.
The second main challenge facing sonofusion will come when and if the work is successfully replicated. Then it will ace he same “break even” problem has occur nuclear fusion systems. Scientists are hopeful that this could be overcome because in principle, it would be thermonuclear fusion , which is the right kind of fusion for energy production . one idea put forward is that sonofusion could be a route towards a more efficient , second generation of nuclear fusion.
The energy released by the fusion reaction has to be controlled. Each individual fusion reaction is very brief- it last only about a pico second – and it is confined to a very small region. As a result , the energy output is relatively small , and that is why despite the miniature ‘stars’ within the bubble, the fusion reaction don’t melt down the whole apparatus. To obtain something interesting in terms of energy, the next step is to scale up the apparatus and make the fusion reaction self-sustaining. This is the greatest challenge not only for sonofusion but also for all other fusion methods.
For this research groups throughout the world have concentrated on two approaches. In one, extremely energetic laser beams coverage on a tiny solid pellet of deuterium-tritium fuel the result is a shock wave that propagates towards the center of the pellet and creates an enormous increase in temperature and density. One of the drawbacks of this approach is the amount of power that the laser requires.
The second approach called magnetic confinement fusion uses powerful magnetic fields to create immense heat and pressure in hydrogen plasma contained in large toroidal device known as tokamask. The fusion produces high energy neutrons that escape the plasma and hit the liquid filled blanket surrounding it. The idea is to use the heat produced in the blanket to generate vapor to drive a turbine and thus generate electricity. Yet tremendous challenges remains such as holding the plasma in place while increasing temperature and pressure. It is very unstable process that has proved very difficult to control.
A possible way of self sustaining the fusion reaction would be simply to put two complete apparatuses side by side so that they would exchange neutrons and drives each other fusion reactions. When the liquid pressure is low in one, it is high in the other. That is their pressure oscillations are 180 degrees out of phase. The first apparatus is hit with neutrons from the external neutron generator causing the cluster to form inside the first flask. The neutron generator then is turned off after initiating the fusion reaction. As the bubble cluster grows and then implodes it will give off neutrons, some of which will hit the neighboring flask. If all is right, the neutron will hit the flask at the exact moment when it is at the lowest pressure so that it creates a bubble cluster there. If the process repeats you get a self-sustaining chain reaction.
Next it would necessary to scale up the apparatus so it could produce more energy than it consumes. So far a single apparatus is about 400000 neutrons per second. The neutrons are an important measure of the output of the process because they most of the energy released in the fusion reaction. Yet that yield corresponds to a negligible fraction of watt of power.
With improvement of several parameters of the sonofusion process such as the size of the liquid flask, the type liquid in it, the size of the bubble before implosion and the pressure compressing the bubbles, we should be able to reach a neutron input sufficient for net power production.
It’s one of those assertions that a reasonable person might immediately dismiss—sound waves can make bubbles in liquid blow up such a way that they produce temperatures and pressures equivalent to the inside of the sun. Sonoluminascence is a well-known phenomenon since 1934;physicist have known that pulsing low-density sound waves through a liquid medium can causes flashes of light. Now a group physicist at Purdue University have concluded that, under the right conditions, pulsing sound through liquid can result in sufficient energy to produce nuclear fusion.
They are still plenty of questions about the discovery but the paper reporting work apparently went through a far greater-than-usual checking process at physical review E, where it will be published. Unlike Cold Fusion, the sonofusion work seems to have both good data and an explanation for the mechanism that doesn’t require rewriting any physical laws. Skeptics are (quite correctly) waiting other labs to be able to replicate the experiment before celebrating the find.
Assuming the discovery validated , what does it mean for the world? At minimum much more work. The sonofusion research is still in the earliest of stages, and requires much more power to produce the effect than is produced—the so-called “Breakeven” level required for fusion to be useful. Even if break even is achieved, there’s no guarantee that it could scale to a point where it would be competitive with other methods. But what this discovery does do right now is provide us with a friendly reminder that we can’t assume that all the tools we will have for fighting global problems have already been invented. New discoveries , new technological or social innovations add to our response capabilities. While we certainly should not be assuming that a dues ex machine is going to save us all,neither should we despair that our current abilities are insufficient for the task at hand.
The device is a clear glass canister about the height of 2 coffee mugs stacked on top of one another. Inside the canister is a liquid called dueterated acetone. The acetone contains a form of hydrogen called deuterium , or heavy hydrogen, which contains one proton and one nutron in its nucleus. Normal hydrogen contains only one proton in its nucleus.
Development of a low-cost thermonuclear fusion generator would offer potential for a new, relatively safe and low polluting energy source. Where as conventional nuclear fission reactors make waste products that take thousand of years to decay, the waste products from fusions would be short leaved, decaying to non-dangerous levels in a decayed or two. For the same unit mass of fuel , a fusion power plant would produce ten times more energy than a fission reactor , and because deuterium is contained in sea water, a fusion reactor’s fuel supply would be virtually infinite. A cubic kilometer of sea water would contain enough heavy hydrogen to provide a thousand years’ worth of power for the united states.
Such a technology also could result in anew class of low-cost, compact detectors for the security application 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 nuclear application ranging from medical imagine to watch dials; and a new technique to study various phenomena in cosmology , including the workings of neutron stars and black holes.
Fig. 7.1 Sonocapsule
Impulse devices are trying to produce sonofusion using a stainless steal chamber in which pressure waves are created at 8 different points. Meanwhile, Impulse devices, in California, has chosen an approach similar to our sonofusion method .The main difference is that ,instead of a glass flask, the company is using a stainless steel spherical chamber, about 24 centimeters in diameter that can resist extremely high pressures .Piezoelectric crystals are mounted on cylindrical attachments distributed on the chambers surface. Using various test liquid and different methods to seed an initial cluster of bubbles , impulse devices has been successful in consistently imploding the bubbles and in observing the resulting light emissions. The company hasn’t detected any signs of fusion to date , but it is repeating the experiment with different adjustments.
Recently, a consortium of institutions from china Japan, South Korea, the European Union, Russia , and United States said it was ready to start building ITER (International Thermonuclear Experimental Reactor) a US $ 5 billion , 500 Megawatt reactor based on magnetic confinement. The consortium is now deciding between Cadarache, France , and Rokkasho, Japan ,as a home for the reactor. ITER is not expected to begin operating until 2015 and a commercially viable version will be even further away, some say 2009, give or take a few decades.
Fig 7.2 NOVA-50,000 joule laser
The target chamber, pictured above, is fabricated from aluminum support the ten large final-optics assemblies , which focus laser energy on to a variety of targets, including into hohlraums the size of grains of rice. Target enter on target-positioner arm from the top of the chamber , while a variety of instruments for observing target phenomena and capsule compression can be inserted through other small ports in the target chamber wall .
Even though sonofusion applications may be years or decades away, at least two companies are betting they are not only feasible but also commercially viable. General fusion Inc., in Vancouver, B.C., Canada, has come up with an approach that companies sonofusion and laser inertial confinement. The plan is to achieve high pressures inside a vessel 1 meter in diameter filled with liquid lithium, with in which a small hydrogen-based shell is positioned. A pressure of 1 million kPa is launched all around the shell . as this spherical pressure waves converges towards the center, according to the company, its peak intensity grows to 10 billions kPa as it reaches the shell. The subsequent collapse, much like a laser-induced collapse, will generate fusion energy in excess of the energy invested or so the designers hope.
1. one major application of sonofusion is the study of thermonuclear fusion itself; the method is considerably simpler and cheaper than other means of studying fusion in the laboratory.
2. Anther possible application is as a low cost pulsed neutron generator. While a commercial device can cost up to $250,000, this set up could be produced for $1000.
3. As a neutron-emitting device, the apparatus may be useful , for example, to probe the molecular structure of materials or to activate certain anti-cancer drugs, as in an experimental therapy called boron-neutron capture.
4. Sonofusion paves way for the development of a new, safe, environmentally friendly way to produce electric energy. Fusion produces no green house gases and unlike conventional nuclear fission reactors produces no noxious radio active waste that lasts for thousands of years.
5. Used as compact detectors for security applications , which use neutron to probe the contents of suitcases.
6. Sonofusion is a new technique to study various phenomena in cosmology including the workings of neutron stars and black holes.
Now at least five groups; three in the United states and two in Europe, are working on reproducing sonofusion result. Some have apparently already succeeded and are now preparing to publish their findings. As this group has learned , it is not an easy experiment to run, despite its apparent simplicity. Inside that glass flask there are many kinds of process going on. The dynamics of the fluid, shock wave propagation , plasma formation, chemical reactions nuclear process and you need to understand treat them carefully.
Despite the ongoing developments in wind, solar tidal and biofuels, it would be good to add fusion—especially in a form that does not require massive , multi-story reactors—to our toolkit of power sources. Every method its drawbacks , and the greater diversity of energy options we have , the better we will be able to handle unexpected demands and problems. Sonofusion’s biggest drawback, for now at least , is that it’s entirely unproven. If sonofusion works—and we’re probably still another couple of years from having solid confirmation—it will take a decade or to at least before we could see any real world applications from it. It’s not going to save us from having to do the hard work of moving away from the fossil fuels. But another decade or two would mean it would be starting to come online in early part of the 2020s,just when conversion gasoline and coal will start to really hit high gear—an ideal moment, then, for another clean source of power to step onto the stage.
With the steady growth of world population and with economic progress in developing countries , average electricity consumption per person will increase significantly. Therefore, seeking new sources of energy isn’t just important, it is necessary . much more research is required before it is clear whether sonofusion can become a new new energy source. Even through some sonofusion application may be years or decades away, they have been proved not only feasible but commercially viable too. Sonofusion could just be final resort to our power needs!!
By 2050, we could be living in a world powered by wind, the sun and stars in a jar
1. IEEE Spectrum magazine
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BUBBLE POWER.ppt (Size: 2.21 MB / Downloads: 46)
TINY BUBBLES IMPLODED BY SOUND WAVES CAN MAKE HYDROGEN NUCLEI FUSE AND ONE DAY MAY BECOME A REVOLUTIONARY NEW ENERGY SOURCE
WHEN GAS BUBBLES ARE EXPLODED BY SOUND WAVES THEY EMIT SHORT FLASHES OF LIGHT KNOWN AS SONOLUMINESCENE THAT LAST LESS THAN 50 PICO SECONDS
1.THE TEMPERATURES INSIDE ARE 10 MILLION DEGREES AND PRESSURE OF 1000 MILLION ATMOSPHERE.
2.DEUTERIUM FUSES RELEASING NEUTRONS AND ENERGY.
3.RELEASES TRITIUM AND IT IS USED AS A FUEL TO DRIVE ENERGY PRODUCING REACTIONS.
A single apparatus produces 400000 neutrons per second.
For operating a few mega watts of thermal power, output of 10^22 neutrons per second required.