How does Fusion work?

In order for fusion reactions to occur, the particles must be hot enough (temperature), in sufficient number (density) and well contained (confinement time). These simultaneous conditions are represented by a fourth state of matter known as plasma. In a plasma, electrons are stripped from their nuclei. A plasma, therefore, consists of charged particles, ions and electrons. There are three principle mechanisms for confining these hot plasmas - magnetic, inertial and gravitational.

Magnetic confinement utilizes strong magnetic fields, typically 100,000 times the earth's magnetic field, arranged in a configuration to prevent the charged particles from leaking out (essentially a "magnetic bottle"). Inertial confinement uses powerful lasers or high energy particle beams to compress the fusion fuel. The enormous force of gravity confines the fuel in the sun and stars.