The torus-shaped magnetic chamber that leads the pursuit of fusion power, designed in 1951 by Soviet physicists Andrei Sakharov and Igor Tamm. Magnetic fields confine a plasma of deuterium and tritium at temperatures no material wall could touch; the challenge, unsolved after seven decades, is to hold the fuel hot and dense for long enough that fusion releases more energy than the heating consumes, which is what the international ITER machine is built to demonstrate.
Facts
Classification
MaturityTRL 9: Actual System Proven in Operational Environment 1 Technology TypeMagnetic confinement fusion device 2 Invented Year FAQs
How is the plasma in a tokamak shaped and heated?
A central solenoid induces a current in the plasma that helps shape the field and heats it to about 10 million degrees Celsius; extra heating systems supply the rest.
The toroidal magnetic field comes from a series of coils evenly spaced around the torus-shaped chamber, and the poloidal field comes from a system of horizontal coils outside that toroidal magnet structure. A strong electric current is induced in the plasma using a central solenoid, and that current contributes to the poloidal field. The same current also heats the plasma to about 10 million degrees Celsius. That is not hot enough for fusion, so additional heating systems are needed to reach the temperatures fusion requires.
Connections
Associated With
Inertial confinement and magnetic confinement (tokamak) are the two main experimental approaches to fusion energy.
Source World Nuclear Association Information Library
Stellarators and tokamaks are the two leading magnetic confinement fusion device designs.
Developed By
Source Tokamak - Wikipedia
Source Tokamak - Wikipedia
Uses Source
Source World Nuclear Association Information Library
Sources
1. Tokamak - Wikipedia
Technology maturity, Wikipedia introduction extract fetched 2026-09-25
In the late 1970s, the Kurchatov Institute tested the first superconducting magnets and divertors in tokamaks, ubiquitous in modern large designs.
Developed By: Andrei Sakharov, Lead
Tokamaks were first conceptualized by Soviet physicists Andrei Sakharov and Igor Tamm.
Developed By: Igor Tamm, Lead
Tokamaks were first conceptualized by Soviet physicists Andrei Sakharov and Igor Tamm.
View the Source2. World Nuclear Association Information Library
World Nuclear AssociationInformation Library, Nuclear Fusion Power, Fusion technology
Magnetic fields are ideal for confining a plasma because the electrical charges on the separated ions and electrons mean that they follow the magnetic field lines.
Associated With: ITER, Information Library, Nuclear Fusion Power, Fusion research
The goal of ITER is to operate with a plasma thermal output of 500 MW (for at least 400 seconds continuously) with less than 50 MW of plasma heating power input.
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