There are currently three known methods of confining and heating plasma.

The first method, gravity, is the way stars throughout the galaxy keep the plasma confined long enough to produce significant energy outputs. The compression of the plasma by gravitational forces and the subsequent fusion energy produced keep the system heated and continue fusion reactions. The plasma confined by this system lasts upwards of 30 million years. However, scientists here on earth are not yet able to recreate the amazing confining forces characteristic of gravity-bound fusion systems. Shown below is the extremely famous photograph of M16, a newly forming star system.

The second method, inertia, utilizes laser beams to compress the plasma. Unfortunately, this method requires extreme precision (the entire system is less than 10 cm), and the plasma produced by these means typically lasts for less than 1 tenth of a nanosecond (10^-7 seconds), an extremely brief time. A piece of equipment at the forefront of inertia-driven fusion reactions is the Glass Nova Laser, currently housed at The Lawrence Livermore National Laboratory (LLNL).

A laser pointer. Laser beams compresses plasma.	The Nova Target Chamber at LLNL
Above images courtesy of The Lawrence Livermore National Laboratory

The third method utilizes magnetic fields to compress the plasma. An electromagnetic field encapsulates the plasma chamber with currents that flow in the shape of a helix. The "tokamak" is a type of magnetic field confinement chamber which today is seen as having one of the most promising prospects for harnessing fusion energy.

Click here to learn more about the "tokamak"