Image of the inside of a magnetic confinement experiment during plasma discharge.
Image of the inside of a magnetic confinement experiment during plasma discharge.

Plasma confinement refers to the containment of a plasma by various forces at the extreme conditions necessary for thermonuclear fusion reactions. These conditions exist naturally in stars, where they are sustained by the force of gravity. In the laboratory, researchers use strong magnetic fields to confine plasma. This magnetic confinement strategy may allow them to confine fusion grade plasmas over the long term. Another confinement strategy relies on the inertia of imploding matter. This inertial confinement strategy has been demonstrated on Earth in hydrogen bomb detonations and specialized facilities. Inertial confinement is an active research area. Laboratories use high power lasers or electrical discharges, to compress hydrogen fuel to very high densities for billionths of a second.

DOE Office of Science: Plasma Confinement Contributions

The Department of Energy Office of Science Fusion Energy Sciences program is the main source of support for magnetic plasma confinement research and development in the United States. Key among these efforts is DOE support for the ITER experiment. Once completed, ITER will be the first experiment to study confined nuclear fusion plasmas that can generate energy at the scale of a power plant. It will be the largest scientific experiment ever constructed by humankind. The primary source of support for inertial confinement fusion research is the National Nuclear Security Administration of DOE. Inertial confinement fusion has a potential role in energy production, but it is also essential for the core NNSA mission of ensuring a safe, secure, and effective nuclear stockpile for the United States. NNSA conducts research at two inertial confinement fusion facilities, the National Ignition Facility and the Z machine.

Plasma Confinement Facts

  • Magnetically confined plasmas have achieved temperatures 10 times hotter than the core of our sun.
  • ITER will be the first burning plasma in the world. It aims to generate 500 megawatts of fusion power–10 times more power than will be injected. NIF is the most energetic laser in the world with 2 megajoules of light energy (the energy consumed by 20,000 100-watt light bulbs in one second) delivered in 16 nanoseconds.

Resources and Related Terms


Josh King (U.S. DOE Office of Science), Charles Greenfield (Director of the U.S. Burning Plasma Organization)


Scientific terms can be confusing. DOE Explains offers straightforward explanations of key words and concepts in fundamental science. It also describes how these concepts apply to the work that the Department of Energy’s Office of Science conducts as it helps the United States excel in research across the scientific spectrum.