Experimental study on electrostatic direct conversion of kinetic energy of charged energetic particles to electric energy

Direct conversion of fusion energy to electric energy constitutes a key task of ENN’s spherical torus proton–boron fusion energy development project. Prior to observation of fusion alpha particles in experiments, ENN conducted low-parameter experiments on direct conversion of kinetic energy of charged particles to electric energy to validate the principles of electrostatic direct energy conversion (DEC) based on a fundamental unit structure and address the current shortage of first-hand experimental data. This paper reports the recent experimental results on DEC at ENN, which demonstrate an energy conversion efficiency exceeding 80% and indicate that the space-charge density of extracted alpha particles may not be a major factor affecting the conversion efficiency in EHL-3B or future fusion reactors. It also discusses the problems encountered during the experiments and potential directions for future device optimization.