Feasibility of Net Energy Gain in Kinematic Nuclear Fusion Devices

A design principle is suggested to overcome obstacles that prevent positive net energy output in nuclear fusion devices based on electrostatically accelerated ions. Since Coulomb scattering cross-section dwarfs that of nuclear fusion, the focus is on re-capturing energy of elastically scattered ions before the energy is lost to heat. Device configuration to achieve efficient energy re-capturing is proposed and a favorable estimate of net energy gain is obtained.