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Bubble fusion- SonofusionBubble fusion, also known as Sonofusion, is the non-technical name for a nuclear fusion reaction hypothesized to occur inside extraordinarily large collapsing gas bubbles created in a liquid during acoustic cavitation.
In other words Sonofusion involves tiny bubbles imploded by sound waves can make hydrogen nuclei fuse.INTRODUCTION
Apparition of BubbleSlow ExpansionQuick and sudden contractionPurported fusion eventAcoustic CavitationCavitation is the formation of vapour cavities in a liquid i.e. small liquid-free zones ("bubbles" or "voids") that are the consequence of forces acting upon the liquid. It usually occurs when a liquid is subjected to rapid changes of pressure that cause the formation of cavities where the pressure is relatively low. When subjected to higher pressure, the voids implode and can generate an intense shockwave.
SonoluminescenceWhen a gas bubble in 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 implodes, or cavitates.If we can get the bubbles generate enough heat, we might just be able to make atoms in the surrounding liquid fuse together.A simple way ,in theory at least, of producing nuclear fusion and the vast supply of energy promises.
Original experimentsThe earliest documented reference to a sonofusion-type reaction is patented by Hugh Flynn in 1978.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. Another approach was developed and done by Rusi P Taleyarkhan and colleagues of Purdue University claimed to have observed evidence of sonofusion in 2002.
Taleyarkhan Approach Sonofusion-Technically known as Acoustic Inertial Confinement Fusion. In this piezoelectric crystal attached to a liquid-filled flask send pressure waves through the fluid, exciting the motion of tiny gas bubbles.
High temperatures and pressure speculated at the bubble core .
This leading to conditions suitable for thermonuclear fusion.Taleyarkhan Approach In the paper, the authors described how bubbles were created via nucleation by fast neutrons with an initial radius of 10-100 nm. The bubbles grew in an acoustic field at 19.3 kHz to a maximum size of 1 mm, then collapsed. The implosion creates an instantaneous pressure of 10 trillion kPa and temperature of more than 100 million degree C, making the deuterium fuse.D-D fusion leads to either production of helium and 2.5 MeV neutrons or tritium and protons. Taleyarkhan claimed to have observed both excess 2.5 MeV neutrons and tritium.The claim was quickly surrounded by controversy, including allegations ranging from experimental error to academic fraud.
Vacuum pump Liquid scintillator Neutron source Acoustic wave generatorTest chamber with fluid Microphone Photomultiplier tubeTwo deuterium atoms collide8a. Possible fusion event creating Helium and a neutron 8b. Possible fusion event creating Tritium and a protonSonofusion device used by Rusi Taleyarkhan. FUSION REACTION
Deuterium-Deuterium fusion has two probable outputs, helium and a 2.45-MeV neutron or tritium and a proton.The energy of 2.45MeV neutron can be harnessed in a reactor to create water vapor & drive an electricity generator.
Sequence of eventsTaleyarkhan 2006 ReportTaleyarkhan published another report in 2006 indicative of nuclear fusion in cavitation bubbles in a mixture of acetone and benzene. This time the pulsed neutron generator was replaced with alpha-radioactive uranium salts dissolved in the mixture to address the criticism of the original ORNL effort, which was relying on an external pulsed neutron source to nucleate the cavitation bubbles.Energy Harnessing ChallengesEach individual fusion reaction is very brief--it lasts only about a picosecond--and it is confined to a very small region. As a result, the energy output is relatively small.To obtain something interesting in terms of energy, the next step is to scale up the apparatusHave to make the fusion reactions self-sustaining.Present Approaches Research groups throughout the world have concentrated on two approaches:
Extremely Energetic Laser Beams
Magnetic Confinement FusionExtremely Energetic Laser BeamsExtremely energetic laser beams converge on a tiny solid pellet of deuterium-tritium fuel. The result is a shock wave that propagates toward 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 the lasers require. Magnetic Confinement FusionMagnetic confinement fusion, has been under investigation since the 1950s. It uses powerful magnetic fields to create immense heat and pressure in a hydrogen plasma contained in a large, toroidal device known as a Tokamak. The fusion produces high-energy 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.
Recent Developments Building the ITER--International Thermonuclear Experimental Reactor : a US $5 billion, 500-megawatt reactor based on magnetic confinement. A consortium of institutions from China, Japan, South Korea, the European Union, Russia, and the United States.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 2050, give or take a few decades.ADVANTAGESFusion produces no greenhouse gasesSafe, environmentally friendly way to produce electrical energy.Unlike conventional nuclear fission reactors, it produces no noxious radioactive wastes that last for thousands of years.Low cost and Easily available raw materials. ApplicationsThe technology might one day, in theory, lead to a new source of energy. It may result in a new class of low cost energy.
Compact detectors for security applications.
To analyze molecular structure of materials.
Machines that cheaply manufacture new synthetic materials & efficiently produce tritium, which is used for medical imaging to watch dials.ConclusionWith 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 energy source. Even it is not yet successful, the evidences already show a big future of sonofusion which might be the new source of cheap clean energy in our life.Thank You