Difficulties of Producing Fusion

1. Heating the Plasma

In order to operate, the plasma in the tokamak needs to be heated to about 100 million degrees Celsius. In order to produce usable fusion power, the reactor would need to produce at least enough power to maintain the temperature of the plasma and this has currently not been achieved.

http://www.ccfe.ac.uk/assets/Images/Research/START%20plasma%20web.jpg

2. Impurities

Another problem may be impurities in the plasma. In the tokamak, the plasma is contained within a vacuum inside the magnetic coils. New plasma is introduced by ionizing deuterium gas. This gas can easily become contaminated with other elements. This can cause the plasma to interact with the walls which will result in cooling. This makes it even more difficult to maintain the plasma temperature and stability.

3. Instabilities

The plasma is inherently unstable and always trying to escape the magnetic field. Any small displacement may cause the entire plasma to be lost. This instabilities make it very difficult to maintain operating conditions to produce fusion power, but they are safe and do not result in any damage.

Magnetic Confinement - How it Works

Below is a simple illustration of how these tokamaks work. They operate by something called magnetic confinement. The basics of a tokamak is that there are two magnetic fields. One, called the toroidal field, is made from copper coils in the shape of a torus. (A torus is the donut-like shape seen in the image below.) The second magnetic field, called the poloidal field, is made by an electric current that flows in the hot plasma. These magnetic fields basically squeeze the plasma, made from deuterium and tritium fuel, to create fusion. The hot plasma can then create steam that can turn a turbine to create electrical power.

http://kids.britannica.com/comptons/art-163523/Tokamak-magnetic-confinement

A Torus

http://upload.wikimedia.org/wikipedia/commons/thumb/c/c6/Simple_Torus.svg/310px-Simple_Torus.svg.png

What is fusion power?

Fusion power is produced when two atomic nuclei fuse to form a larger nucleus. The amount of power produced when this happens is immense. Fusion power is the same power that fuels the sun. It is still in research stages and scientists are still trying to produce fusion on a scale that can be used for commercial power. This would be a great thing for the world that relies so much on energy. Fusion power would produce more energy for the littlest amount of fuel and be safer and cleaner than any energy source that the world currently uses.

http://en.wikipedia.org/wiki/File:Sun_in_X-Ray.png

What is a Tokamak?

A Tokamak is a toroidal shaped magnetic confinement device that accelerates plasma through a magnetic fields in order to produce fusion power. There are different methods of producing fusion power, but tokamaks are, right now, the most promising for its future. The word "tokamak" is an acronym for "toroidal chamber with magnetic coils" in Russian.

http://alltheworldstokamaks.files.wordpress.com/2012/07/jg99-518-1bmed.jpg