LINUS

The Linus program was an experimental fusion power project developed by the United States Naval Research Laboratory (NRL) starting in 1971. The goal of the project was to produce a controlled fusion reaction by compressing plasma inside a metal liner. The basic concept is today known as magnetized target fusion. The reactor design was based on the mechanical compression of a molten metal liner. A chamber would be filled with molten metal and rotated along one axis, creating a cylindrical cavity in the center. A suitable fusion fuel, heated to several thousand degrees to form it into a plasma, is injected into the center of the cavity. The metal is then rapidly collapsed, and due to the conservation of magnetic flux within the metal, the plasma is confined within the resulting collapsing shell and is itself collapsed. The adiabatic process would raise the temperature and density of the trapped plasma to fusion conditions. The use of a liquid metal liner has many advantages over previous Soviet experiments that imploded cylindrical solid metal liners to achieve high-energy-density fusion. The liquid metal liner provided the benefits of recovering the heat energy of the reaction, absorbing neutrons, transferring kinetic energy, and replacing the plasma-facing wall during each cycle. Added benefits of a liquid liner include greatly simplified servicing of the reactor, reducing radioactivity, protecting the permanent sections of the reactor from neutron damage, and reducing the danger from flying debris. The concept was revived in the 2000s as the basis for the General Fusion design, currently being built in Canada.