Fusion: Source of Energy and Elements

A fusion reaction involves the fusing, or combining of two or more atoms to make one single atom. Fusion reactions are the ones which power our stars. In a simple fusion reaction shown below, two isotopes of hydrogen combine to form one atom of helium.

Here is a small animation of the same reaction

To the left are the four states of matter. In order for atoms to be able to fuse together, they must be in the plasma state.

This is a state of matter in which the atoms have been stripped of their electrons. Below is a crude picture of a plasma at the atomic level. Notice that the electrons are not tied to any specific atoms.

To create a plasma we have to have enormous amounts of energy to strip an atom of its electrons. To make the atoms in this plasma fuse, we also need to keep the plasma in one place and squeeze it together. The picture below shows different methods for confining the plasma to create a fusion reaction.

The sun uses gravity to crush the plasma together. Most current fusion reactor designs use magnetic confinement methods. To the left is a diagram which shows how a fusion reactor would keep the plasma contained for a fusion reaction.

The reason that we would like to build fusion reactors is that a fusion reaction is capable of delivering huge amounts of energy. Like fission, the products of a fusion reaction weigh less than the reactants (see the picture at left). This means that a small amount of matter is converted into a large amount of energy according to Einstein's equation E=mc2. The amount of energy that is released by fusion however is much greater than that released by fission because more mass is converted into energy.

So much energy can be gained from fusion that one cup of water can deliver the energy contained in two tons of coal. One thimblefull of heavy water can deliver the energy contained in two tons of coal. If fusion were attainable in controlled reactions we would be able to harness huge amounts of energy.

As our energy demands increase, it is important that we be able to increase our energy production to meet them. If this does not happen our economy as well as the quality of our lives will be threatened. Building a reactor which could work with fusion power would be one way to meet our suspected energy shortfall in the future

This picture shows a fusion reactor which was built in the United States. The problem with this fusion reactor and other prototypes we now have built is that they require more energy to create and confine the plasma than we are able to capture from the fusion reaction.

Scientists have been getting closer and closer to producing more energy with their fusion reactors than they need to run them. This is a graph which shows the progress scientists have made so far, and their projected progress.

This picture shows the first reactor which scientists believe will be a viable fusion reactor. This reactor is currently being built with money from many countries including the U.S., Russia, Japan, England, and France. Included in the picture is a human for scale.

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