As the name suggests, plasma physics concerns the physical properties of plasmas.
With increasing temperature, all materials are transformed successively from the solid, to liquid and then gaseous state. If the temperature is increased even more, a plasma is formed. Plasma is thus also described as the “fourth aggregate state of matter”: the gas atoms split into their constituent components – electrons and nuclei. Everyday examples of plasmas include plasma columns in neon tubes, electric sparks and the plasma filament in a lightning flash.
The properties of plasma are very different to those of a normal gas. For example, a plasma is electrically conductive; its motion can be influenced by electric and magnetic fields.
The fusion devices of the Max Planck Institute for Plasma Physics (IPP) in Garching (ASDEX Upgrade) and Greifswald (Wendelstein 7-X) exploit this particular property of plasma: they confine the hot plasma in a “magnetic field cage”.
Fusion as an energy source
The Max Planck Institute for Plasma Physics (IPP) uses these devices to investigate the principles of a fusion power plant that would harness energy from the fusion of light atomic nuclei – just like the sun.
The aim here is to add to the range of efficient energy sources that could replace coal, oil and gas in the future: nuclear fusion is a third option along with nuclear fission in nuclear power plants and renewable energies, like wind and solar power.
The fusion of the hydrogen isotopes deuterium and tritium is the easiest form of fusion that can be achieved on Earth. The process generates a helium nucleus and a neutron is also released along with large volumes of usable energy. With fusion, one gram of combustible fuel could generate 90,000 kilowatt hours of energy in a power plant, which is equivalent to the combustion heat of eleven tonnes of coal.
Fusion fuels are inexpensive and evenly distributed throughout the world. Almost inexhaustible quantities of deuterium are available in seawater. Tritium – a radioactive gas with a short half-life of 12.3 years – only occurs in trace quantities in nature. However, it can be produced within the power plant from lithium, which is also available in abundance. Given that a fusion power plant could also offer favourable environmental and safety features, fusion could make a sustainable contribution to the world’s future energy supply.
You can find out about the current status of nuclear fusion and research findings on plasma physics here: