Enhanced Energy Recovery in a Secondary Electron Direct Energy Converter Through Reduction of the Magnetic Mirror Effect

With an aim to improve the total efficiency of a D-³He nuclear fusion direct energy conversion system, a secondary electron direct energy converter (SEDEC) is proposed. The incident high-energy protons in an SEDEC penetrate a large number of foil electrodes aligned in the direction of the proton beam, and emitted secondary electrons are recovered. The results of the initial experiments showed that most of the secondary electrons flowed into anteroposterior electrodes and did not arrive at the electron collector located alongside and perpendicular to the direction of the proton beam. A magnetic field was introduced to push the electrons toward the electron collector, but it was not effective for energy recovery. This technical note analyzes the trajectories of electrons in the presence of the magnetic field and proposes and examines a revised arrangement of permanent magnets. The arrangement of the magnets along one side of the proton beam greatly improved the energy recovery; however, the recovery level was lower than that without magnets.