Nuclear Fusion is the reaction that makes the Universe shine and lights upall of the stars including the one we are most familiar with, the sun. Nuclear Fusion isthe process that mainly converts Hydrogen into Helium. This produces a tremendousamount of energy in the form of light and heat. The conversion of Hydrogen andHelium is the reaction that makes almost all life on Earth possible.
This is a diagram of This produces athe Proton-Proton Gamma Ray andchain reaction forms a light heliumwhich is the major atom, which isreactions that designated as 3He.make fusion Two 3He’s then joinpossible. As you together andcan see on the produce two 1Hright this reaction atoms and form arequires four regular heliumhydrogen atoms. atom which has twoAt the beginning neutrons and twotwo hydrogen protons. The endatoms or 1H product, the heliumcombine and atom, is actuallyproduce one less massive thanpositron and one the four hydrogenneutrino and then atom’s addedform a heavy masses. This loss inhydrogen atom or mass is converteda 2H atom which into the light andhas a neutron in it. heat that makeAfter this another stars shine through1H atom is joined the equationto the 2H atom. E=MC2.
The Proton-proton chain as explained on the otherpage is a wonderful way to make energy, but theconditions have to be just right to make this reactionhappen. For one, the temperatures have to beincredibly high, as high as 15.7 million Kelvin and thereaction requires high amounts of pressure. Thisreaction also requires huge amounts of hydrogenatoms. This makes it rather hard to initiate thisprocess on Earth , but the one place in the universethat fusion is achieved with ease is the center of a starlike our sun.
The Sun is a main sequence, G2 class star.This means that the sun is middle agedwhich means that it is about 5 billion yearsold and has an expected life spanned ofabout 10 billion years. Also contrary to thepictures of the sun, it is actually a yellowdwarf star. In the picture on the left , thecore is visible in the very center of the star,this is where 99% of the sun’s energy isgenerated. In one second the sun uses 620million metric tons hydrogen to fuel thefusion reaction.
In other Stars Hydrogen is the most abundant element in the space and makes up about 90% of the weight of universe. Most of this hydrogen is in expansive clouds that are remnants of stars that went supernova. A lot of hydrogen is also being burned inside of stars to create heat and light. Most stars use the proton-proton chain reaction to make their energy for most of their lives, but when they run out of hydrogen they start to fuse other elements, such as Helium, Carbon, Oxygen, Silicon and other elements until it reaches Iron which is designated as Fe on the diagram to the left.Once the star reaches Iron, it cannot fuse it with out a net loss of energy, but the startries to ignite the fusion by collapsing and it keeps getting smaller and smaller untilthe collapsing layers hit the core of the star and explosively rebound creating asupernova. This usually only happens with a star that has a much greater mass thanthe sun. The core of these stars then either turn into a Neutron star or a Black holedepending on how massive the star was.
Fusion in Our WorldThere are really two different uses of fusion in our worldtoday: as a power source and as a weapon.Scientists and engineers have been trying for years toachieve a Fusion reactor. The picture on the right shows oneof the largest prototype reactors in the world and is locatedin France. It is called JET which stands for Joint EuropeanTorus and it has now produced 16 megawatts of fusionpower. It is the largest magnetic confinement fusionresearch facility in the world and is built in the tokamakdesign. The tokamak design uses magnetic fields to containsuper hot plasma that contains the hydrogen. There are alsoseveral other designs like Inertial confinement fusion whichuses lasers to ignite a pellet of hydrogen and create fusion.Nuclear fusion is also used in making weapons of massdestruction such as the Hydrogen bomb, otherwise known asthe H-bomb. These H-bombs are over 450 times morepowerful than the bomb dropped on Nagasaki. Most modernH-bombs use lithium deuteride as their fusion fuel, but olderH-bombs actually used liquefied deuterium, otherwiseknown as heavy hydrogen for fuel.
Sources:http://en.wikipedia.org/wiki/Nuclear_fusion.Nuclear Fusion - Wikipedia. Access date11/10/12.http://www.ccfe.ac.uk/introduction.aspx.Fusion Energy - CCFE. Access date 11/11/12http://physics.info/fusion/: Fusion – ThePhysics Hypertextbook. Access date 11/12/12