The Inertial Confinement Fusion Concept

Fusion is the nuclear reaction that powers the sun and stars. Atoms of light elements such as hydrogen are squeezed together under very high pressure and temperature, and fuse together to form heavier elements such as helium, liberating energy in the process. To learn more about fusion, visit the General Atomics Fusion Education Web site.

To make fusion occur, the atoms of hydrogen must be heated to temperatures of 100 million ° C and held at high pressure (or "confined") long enough for fusion to take place. The sun heats and confines hydrogen by gravity. Magnetic confinement fusion uses strong magnetic fields to confine the hydrogen, heated by microwaves or other means. Inertial Confinement Fusion (ICF) uses powerful energy beams, such as lasers, to compress and heat the hydrogen fuel to fusion temperatures, and uses the inertia of the fuel itself to confine it long enough for fusion to occur.

The Inertial Confinement Fusion Concept1

Laser energy
Blowoff
Inward transported thermal energy

1) Atmosphere formation: Laser beams rapidly heat the surface of the fusion target forming a surrounding plasma envelope.
2) Compression: Fuel is compressed by the rocket-like blowoff of the hot surface material.
3) Ignition: During the final part of the laser pulse, the fuel core reaches 20 times the density of lead and ignites at 100,000,000 degrees Celsius.
4) Burn: Thermonuclear burn spreads rapidly through the compressed fuel, yielding many times the input energy.

Inertial Confinement Fusion is supported by the US Department of Energy Office of Secondaries and Inertial Fusion as a part of the US DOE "science-basedstockpile stewardship" program. The temperatures and pressures that must be achieved for inertial fusion -- 100 million ° C and densities 1000 times normal solid densities -- are similar to those produced in a nuclear weapon. It is the primary mission of the ICF program to provide these conditions so that the research on nuclear weapons necessary for the maintenence of the US nuclear defense arsenal can be carried out without the need for actual nuclear testing. The long-term goal of the ICF program is fusion energy for electric power and other energy applications.

1Pictures courtesy of Lawrence Livermore National Laboratory.

This page http://web.gat.com/icf/concept/index.html was updated on Friday, 15 February 2002 at 05:04:03 PM.