Image Credit: Science Magazine/YouTube
The key to an effective nuclear reactor of any type is to produce, confine, and control a blob of super-heated matter, called a plasma. Plasma is a gas that has touched temperatures of more than 100 million degrees Celsius.
At these tremendous temperatures, the electrons are ripped from their atoms, creating what are called ions. Under these intense conditions, the repulsive forces, which usually make ions bounce off each other like bumper cars, are overcome.
Therefore when the ions collide, they fuse together, producing energy in the procedure, and you have what is called nuclear fusion. This is the procedure that has been fueling our sun for nearly 4.5 billion years and will last to do so for another projected 4 billion years.
Diagram of the normal tokamak. Notice how it has fewer coatings than the stellarator and the form of the magnetic coils is different. Image Credit: Uploaded by Matthias W Hirsch on Wikipedia
When engineers have heated the gas in the reactor to the precise temperature, they use super-chilled magnetic coils to produce powerful magnetic fields that comprise and control the plasma.
Tokamaks thus ingest more energy than they actually produce, which is simply not what you want from nuclear fusion reactors, which have been publicized as the “most significant energy source over the next millennium.”
As of the stellarators’ design, researchers think it could withstand a plasma for at least 30 minutes at a time, which is considerably longer than any tokamak. The French tokamak “Tore Supra” holds the highest time of withstanding plasma: 6 minutes and 30 seconds.