In plasma physics, confinement means keeping hot, ionized gas within a controlled region for long enough to study or use it. Fusion experiments must limit plasma escape and energy loss so the material can reach and maintain conditions needed for nuclear fusion. In a toroidal device, magnetic fields can guide charged particles around a ring-shaped path.
Confinement is central to fusion research because plasma is extremely hot and difficult to contain with ordinary materials. Researchers assess how effectively a system holds the plasma and its energy; a visible glow or donut shape alone does not demonstrate successful confinement or fusion. Educational demonstrations may illustrate the concept, while experiments require measurements and diagnostics to establish what is happening.